True... but anything that inspires you to get out on the bike more and for longer can only be a good thing. Unfortunately this step usually requires a chat with your finance manager but a lot of manufacturers have started selling direct to consumer which brings the price down a fair bit. You could save £200-400 if you know where to look and are at the right place at the right time and not be a snob about the branding on the wheels. Im waiting for my own set to arrive. It only cost me £530 though you can find others for around £300-400 built with reliable but _'brand-x'_ hubs and spokes.
Very interesting and well explained. I love my 50mm deep carbon wheels, lighter and faster than standard ones. Also keep the speed much easier. I am 86Kg, never had problems with sidewind so I would not consider shallower ones.
I went from 35mm alloys to 60mm carbons and if I interpret my stats correctly, I get just a bit higher avg speeds than before with the same effort. Besides that, they really look the part, which to me is an equally valid reason to buy them. 😎✨
I've had the same experience going from shallow alloys to deep carbon. I feel less energy needed to maintain the same speed. I'm not going any faster but I feel it not as difficult to hold speed.
@@user-bv3lr3en2q well 2 things determine sprint if it's just wheels we are talking about. 1) weight: if the carbon rims are heavier than the alloy you replaced then it's slower to start or a little harder to start a sprint vs a lighter wheel. This only applies based on weight of the wheels as you have to rotate the weight. Deep rims usually aren't quick on stop to sprint scenario. 2) wheel stiffness carbon vs alloy. Carbon if built properly is very stiff. The parts that make it has to be able to handle the power of the rider. Hubs, choice of spokes and to an extent depth of rims. Balance of all 3. Hubs with large flange spacing are generally stiffer than say smaller flanges that hold the spokes. Sprint based on wheels = light weight + built stiffness.
Didn't cover the reason I was persuaded to upgrade my wheel to be more aero - which isn't to do with going quicker - it was about going the same speed over the same distance with less effort. For multi-day bikepacking managing the effort is more important than shaving time off the ride...
Really interesting topic. I've just recently upgraded to some Zipp 303s and I believe they have made a difference in both speed and effort produced, but that could just be some sort of placebo effect.
They won't impact your power output (only training and position will do that). But, they may be more reactive than your existing ones. This will make the bike feel more responsive when you put the power down. Even upgrading from standard alloy, to alloy with a good hub, makes you feel better.
@@MacedonianGrace what are good wheels is a bit subjective. Sure you want good hearings but I can't notice much until I go over 35kmh on deep dish quality to cheaper training wheels
Great video, very well explained. Loved the "are they faster?" "yes" lol. LOVE my aero wheels (DT Swiss 62mm) and aero bike. I'm not climbing mountains so I ride that more than my lightweight bike.
I'd never go above 45mm front and 50 rear for general cycling or group rides as I see very little gain and mostly hassle from winds and the extra weight. I'm actually going the other way to very shallow carbon disc as I find the lower weight at the rim is better up hills.
Good video. One of the (subjective) aspects about wheel depth is that a stiff, light wheel is going to feel more responsive and add to the enjoyment particularly if you're into attacking the climbs or dropping your mates
nice video, a good explanation....have been riding deep rims for years and having recently had to wait for a replacement for a cracked rim, i used my standard shallow rims...really aware in all types of riding of the difference.
@@highfived the question was “are carbon wheels that much faster”. I replied “not if I’m riding on them”. Meaning they will be equally as s…l…o…w … understand ???
Would love to hear more on how deep wheels are affected on cross winds and what the difference in speed and watts saved compared to wind tunnel testing to real world riding - what is the difference between the 2
It's a great question & crosswind handling stability is a massive focus for us when we're working on a new wheel, especially a deeper-section model. As for the translation from wind tunnel to "real world", that's a whole video in itself! Any numbers we share from the wind tunnel use a weighted average yaw angle to give the closest approximation we can to real world riding. To determine what weightings to use, we've actually used an instrumented bike to measure real world wind conditions at both the front and rear wheels. We'll have to get Francis out for a ride on an instrumented bike sometime to give you a look at how it all works!
I would also love to hear about this. As a light person and average rider with below average bike handling I tent to get a bit freaked out in strong crosswinds. The concept of adding a deep section front wheel on I generally feel would be unsafe on the open road where I'm generally not given the space by other road users to control the bike in crosswinds scary.
@@andrewstokoe1850 it is scary... even for a heavy rider like me, especially when there is no bike lane. Hold on tight, and focus,focus, focus. This is on 58/62 wheels.
I ride 45mm mainly because I like the looks. And I use 28mm so my lightbulb setup destroys all of the aero benefits anyways.. However I ride carbon with alloy brake face which looks a bit ugly. But I'm on rimbraked and I'm scared to descend on carbon. Thanks for the video, expert opinions are always interesting!
Having gone from basic box section rim brake wheels (stock ones on my $500 road bike with ~10,000 miles on them) to a bottom-tier (for a well-known, expensive western brand) set of 42mm carbon rims, the difference was pronounced; for the same power, I was maybe moving 1-2 miles per hour faster, essentially from one day to another. That's an extreme example, but I found it huge how much of a difference in ride quality those wheels make.
You've hit the nail on the head. Let's suppose you average 1.5 mph extra that's 15 miles on a 10 hour ride, if racing worth it. Other than that a few minutes here and there might feel good but does it really matter? I'm off to buy some 50s.
@@vinniep01 it is upto you. I personally try to race myself with setting personal records. Also I try to cover more distance so for me it is a benefit with higher speed. However yes it is not a super high marginal gain. If you dont care about 1-1.5 mph average speed gain then yes I dont see a point in spending $$$ for new set of wheels.
Totally agree a nice set of carbon deep rims make a huge differnce to the ride. I upgraded to a set of VEL+ this year and they are like night and day compaired to my Mavic's i bought a few years ago
I used mavic cosmic's (alu) for a couple years and when I started using carbon wheels I couldn't feel much difference. They were abviously more aero, but everything else seemed the same. Actually the Mavic's were a bit better in the stiffness depo. Pretty sure it's because those wheels had some beasty proprietary spokes.
No mention of cross winds? Find my deeper wheels horrible at times when it's windy out, although I'm no racer. Have a lot more confidence in my shallower wheels when going quickly down hills.
Great point & certainly something we're hoping to cover in the future. Handling stability is a really important consideration because as soon as you're unable to control your bike, there's precisely zero benefit from any reduction in drag. You won't be riding very quickly if you're off the road! Just would have made for a much longer video if we tried to dive into that for this one!
@@Jakiou I am a heavy rider...in group rides when many are pedaling on a slight slop, I am in neutral, downhill- I either catch up to the group or leave them behind, until they catch up again going up hill🤣
Yes but in terms of overall aero savings - getting your body in an aero position is going to be the biggest change you can make in terms of going faster. When that is sorted and you have an aero helmet, socks, clothes, etc... then wheels will make you faster. Of course when it comes to looking good, then wheels are the obvious place to start
And here come the “what about?“ police despite no one calling them… Why not both? Why not all the things? For some people the expense of deep carbon wheels is less “expensive” than the time it would take to make up that speed differential through more training, stronger core to hold that aero position, etc. They can afford deep wheels but can’t afford another five hours/wk on the bike and in the gym and away from their family and jobs. These things don’t happen in a vacuum. Plus, one could easily make the case that it’s that much easier to hold a more aero position at your target race speed because you can do that speed at a lower wattage and thus lower effort level BECAUSE of the wheels. Literally you can make yourself more aero and thus faster because your wheels allow you to push on the pedals less for the same speed. Your chest doesn’t need as much room because you’re now doing 45 kph at Z3 instead of Z4. Faster wheels, chain, helmet, etc. all allow for a faster body position too as they all equal more speed for less effort. The body I will fully agree is the biggest drag, both literally and figuratively, but it also needn’t be the first thing you address, especially if your individual situation leaves you with more money than time. End of rant.
@@ryanspivey2453 if they can afford deep wheels then they can afford training more. Its that simple. Its because their riding is not structured. You can ride all you want with that z2 bs zone for 15 hours a week and someone who trains less doing threshold work, strength work in the gym will smoke any of the carbon blings in any grand fondo rides 😂😂😂 most mamils are just riding for the looks and to look the part. The serious ones know which ones will make them faster.
What I get from people who don't want to spend any money at all on their bikes, is that they will find "placebo" excuses for everything. All the know-it-all, big time cyclists use to say disc brakes are for looks, blah, blah, blah. Fast forward to now, there are completely used In the tour of France. Also those same people that complain about upgrades have spent a lot of money on their bikes because now they see those old 70' bikes that they are trying to ride to save money aren't cutting it on the group rides. If people don't want to spend money to upgrade, then don't, but you don't have to knock the people that do, whether it be for looks or whatever, so that you feel better about being cheap. Working out, or losing weight is all irrelevant to someone adding or changing items on their bike because it still does not change the fact that it is THEIR bike, and they can do what they want with it. Don't get mad at the carbon aero guys because you can't keep up with them downhill.
49 Seconds over a 40km ride. Okay, I dont need those wheels. Took me around 50 seconds to get my snickers out of the packaging. So I will switch to gels instead. Just saved 1000 bucks. Thanks guys.
It would be interesting to get an answer to the aerodynamic benefits of a stacked setup like 80 front, 100 rear or a "reverse stack" with 100 front, 80 rear
From a purely aero perspective, the front wheel has a greater impact than the rear. So in theory the setup with the deeper front wheel would be faster than the shallower setup. However, if you also add in handling stability to the equation, that's why you'll more often see a shallower front paired with a deeper rear.
Good video, but there was one thing that I'd like to hear much more about: I've heard and read that having a deep section on the front matters way more than rear. Particularly because starting a laminar flow on the front would continue throughout most of your bike, so the benefit is more. But I often see deeper section at the back, probably because it's harder to control a deep front wheel when there are strong cross winds. What are your thoughts on that?
Class video. I'm building a track/fixed bike and have just bought a 60mm carbon wheelset. Would love to see some more fixed gear videos like your NY episodes... X
I ride two single speed alloy aero frame track rigs with a 55mm carbon deep up front, and 30mm alloy in the rear and it's a crazy fast set up, love it, accelerates like a fighter plane. The heavier rear wheel helps you to retain speed via inertia, while the front of your bike is important for setting up uniform air flow and punching through the wind like a ship's rudder. Haven't tried deep dish front and rear fixed yet though, but I'm sure it's just as fast man. Hope this helps!
All these things make sense in a wind tunnel or on a velodrome but out on the road crosswinds change the story A LOT. Aero components at low speed will increase drag during crosswinds. The deeper wheels aren't always better, 50 mm has been showed to be a good middle ground where you get aero gains but not much penalty during crosswinds. Above 50 kph it's not so big a problem anymore since the general direction of airflow will be close to parallel to the direction of travel anyway
You're right that crosswinds will have an impact on the open road, but that's in relation to handling not aero performance. If you have a look at a wind tunnel drag chart, you'll almost always see that a deeper wheelset will have a bigger impact in crosswinds (higher yaw angle) versus a straight head or tailwind (lower yaw angle)
@@ParcoursDov True for wind tunnel drag charts but as @S. Planiden pointed out, the air speed is often kept constant during these tests, hiding a part of the additionnal drag created by deeper rims. Also the impact on handling is actually the result of this additionnal drag in crosswinds and thus is tightly correlated with aero performance in crosswinds
Saving 49-90 Seconds over 40km for non-racing is not worth it in my opinion, especially considering the added instability that deep section wheels cause in cross winds. I wonder if a non-UCI compliant bike will actually make some significant difference in speed.
The immediate front isn't where the main gains are from deep wheels it's from the top and bottom where a larger section of the wheel front to rear allows the air to pass unbroken along it's entire length
So having gone from a set of fairly mediocre DT Swiss alloys (older ones) to a set of Prime 50mm carbon rims (a cheaper option) and I have noticed a huge difference. It made my fairly old bike feel brand new again.
System weight is still something to consider depending on distance & elevation gained. Both being aero and having a lighter set up can save the rider valuable energy. Not denying that deep dish rims or solid disc rims are not fast but they do add considerable weight and this means the rider has to expend a little more energy on the climbs.
Only issue I have with the technical explanation is that aero drag increases with the SQUARE of the speed, not the CUBE. If you double your speed, your aero drag increases 4X, not 8X. The equation is (1/2)*(fluid density)*(velocity)^2*(drag coefficient)*(reference area)
Hi Gabe, you're absolutely right, however the power required to overcome aero drag is a cubic relationship (Power = Force x Speed). I'm referring to power here as we generally think in terms of watts, or watts saved
Judging by the low number of watts saved at such high speeds, I will always prioritize light wheels over deep aero ones. Obviously not speaking of TT races here, but the casual road bike rider who rides 2-5 times a week on local roads.
Great discussion except rolling resistance does not increase linearly with speed but is more or less a constant determined mainly by the coefficient of friction between tire and riding surface, with factors like cornering and heat generated between rubber and surface having an effect.
Yes, this is similar to the comments below about drag having a quadratic relationship with velocity. the rolling resistance *force* is constant per the equation Frr = Crr * N where N is the normal force (in this case rider/bike weight). However, the *power* required to overcome rolling resistance does increase linearly with speed as Power = Force * Velocity
Problem I have is when reviewed these excellent Parcours Example Grimpeur was 700-800 bones, but now are 850 bones - something inside just hates the price increases so backs off any purchase and sticks to alloys and 2nd hand carbons. Still lovely wheels and UK support is nice to have, just not got the minerals to purchase.
I love mine on both of my bikes. 77 and 88mm. Do they truly make me faster? Yes, but usually in the way that they help me sustain a higher speed, not just be faster on its own.
there is a difference on a individual effort of course. Riding in groups it does nothing really as the air is already being broken by the front rider and not very turbulent once it gets to you. A great bang for your buck wheelset is the American classic aero 420 three tubeless. Nice for climbing too!
Hey Guillermo, just to clarify, the aero drag *force* will be proportional to velocity^2, but as power = force * velocity, the *power* required to overcome said drag force will be proportional to velocity^3
@@ParcoursDov that is indeed true, but when one refers to the word "drag" alone is usually talking about a force if you refer to an energy balance is better to say e.g. drag dissipation
Thanks for this, I would be really interested to see the difference in drag/watts saved at 30km/h, which is a more likely speed a person with a 200w FTP would travel at on a flat road. Not one company ever quotes the watts saved at 30km/h..........its always at 45km/h plus.......is this because at 30km/h the watts saved might be 1 or 2w at best and therefore wouldn't entice people into spending thousands on aero bikes and wheels? Would be good to know !
Hambini actually has run tests of how much watts are needed to sustain 30kph on his website. The difference between a standard wheel and a good aero one is almost 15 watts. (180 vs 195)
The relationship between speed & drag (in watts) is cubic, so to adjust from one speed to the other you need to take the cube of the reduction. What does that mean in English? For your example of 30kph (versus the often quoted 30mph or 48kph), you're reducing speed by a factor of 30/48 or 0.625. 0.625 ^ 3 is 0.244 So if we quote a "watt saving" of e.g. 16W at 30mph/48kph, you would save approximately 25% of that at 30kph, so 4W.
@Steven Vanlancker our website usually quotes watts saved for a complete wheelset. But the example above (16W) is the tested savings for one of our deeper section TT wheels (single wheel only)
I got some firecrests on cycle2work a year ago and i've got from being one of the slower descenders to one of the faster ones. Just seem to roll forever
While the science is sound, sometimes a rider just needs to be happy with what they’re seeing as they mount their bike. If the bike looks rad, you feel like a legend, and you ride well.
I want to see more aero alloy wheels. the only people I know of who have done that are Hunt. Give more aero to us mere mortals, and also the people who don't want our money going into a material that's soooooo bad for the environment
Alloy (or realistically aluminium alloy) is a great option for a wheelset, but does make for a much heavier rim versus carbon - hence why the shallow alloy rim in the video is barely any lighter than the super deep carbon wheel. Given that aero performance is linked to rim depth, if you optimised an alloy rim you'd end up with a really heavy wheel. Another consideration is that a deep alloy rim would need additional strengthening against e.g. impact damage (or dents) which would likely add even more weight, versus carbon.
My bike went from looking meh to looking dope, when i put deep carbon wheels, which is arguably the most important element, because it makes me ride more, which is the most important factor to improve performance.
Preachin to the choir, carbon wheels bring the bike out big time. I ride a 2009 alloy Specialized Allez triple on 55mm deep dishes / rim brakes and better believe she's both a looker and a killer - mostly future proof, burning Madones, Tarmac SL7's and other pure aero formats on the regular, Deep dishes are a must in my book if you enjoy speed, literally feels like I'm riding on top of an arrow.
Here's a somewhat open ended question: what's his opinion on mixed depth wheels for dealing with the somewhat changeable weather conditions we face in the UK. Seems like a 40/50 or 50/60 mix would work well and the shallow front would keep you from getting blown about too much.
They're a great option, especially if you're considering running a deeper section wheelset & are concerned about handling on the front wheel. Our best-selling triathlon wheelset pairs a mid-depth front (Passista - 56mm) with a deeper-section rear (Chrono - 86mm) so it's clearly a popular choice! Then for roadies, all of our newer #thinkwider rim profiles pair a slightly shallower front wheel with a deeper rear, e.g. Ronde (35/39mm) & Strade (49/54mm). We've actually gone a bit further & can tweak the handling characteristics by using a different profile of rim on the front wheel versus rear wheel. Again, probably another video sometime to go into the full detail on this...!
Rolling resistance doesn't only happen in the tyre. The main contribution comes from the rider's body. So any test which doesn't involve a rider certainly doesn't test rolling resistance. See Bicycle Quarterly for more info.
Hi Max, I think you might have misunderstood here. Rolling resistance is caused by the frictional force between tyre and road surface. So it does technically only occur at the tyre. However, since RR is dependent on total weight through the tyre, the rider does indeed contribute. We don't actually test rolling resistance ourselves, instead referring to subject matter experts like Bicyclerollingresistance.com. You can see more on their test protocols on their website, however when testing I know that they load the tyre being tested to simulate a rider's body weight. Hope that makes sense!
@@ParcoursDov Thanks for your elaborate response. A supple tyre is not only more comfortable than a stiff tyre it also reduces the vibrations and energy transformation inside the body of the rider. This is hardly understood. Since it's definitely not aerodynamic drag those energy losses are part of the rolling resistance. The more coarse the road surface is the more prominent the friction losses of the rider's body become in comparison to the hysteresis loss of the tyre. Experiments of the US army have shown that the body can absorb up to 2000 Watts for a short time until the soldiers aborted the test. On a bicycle the vibrations are less intense than those from the vibrated tank seat in the experiment but this shows that the losses in the rider's body are key to understand the actual rolling resistance of tyres.
@@maxsievers8251 I think here you're conflating physiological impact (vibration in the body) with a mechanical action (rolling resistance). That's not to say that the physiological impact of a stiffer tyre or a higher tyre pressure doesn't have an impact, however. It's something we're planning on investigating in more detail soon though as it's only likely to further strengthen the argument for running a wider tyre at a lower pressure. We've already seen this with some of the professional triathletes we work with - since swapping to 28mm tyres and running lower pressures, they're finding that they get off the bike and start running in better physical condition. So we're not just saving them time on the bike leg, but also on the run!
@@ParcoursDov Wind resistance comes from the disturbance of the air. Every molecule that gets to move needs energy to do so. That's the reason why we aim for laminar flow. When the tissues in the rider's body rub against each other that energy has to come from somewhere. If you are not going downhill then this energy comes from the pedaling. The Watts you put on the road get eaten up by vibrations in your body.
Crosswinds around here are regular and can be crazy. I’ll stick with my super-shallow (19mm!) rims for now. Besides, riding in traffic? Acceleration/deceleration trumps aerodynamics all fucking day.
All you talked about was aero in a time trial setting but most road cycling is done in a club/ group ride setting. What does riding in a group make to the aero contribution of a wheelset?
Does anyone have any feedback on Parcours? They are considerably less expensive than DT Swiss or Zipp, but that makes me wonder if the R&D has been adequately implemented... any thoughts?
I've been eye balling my first set of carbon wheels for next month and this video has come at the perfect time. Trying to decide between 303 or 404. Leaning towards 404 because deeper looks cooler and looking cooler is automatically faster, right?
@@mr.galaxy3762 I actually went with the 404FC in the end. They've been amazing, especially since I've been doing most of my riding in Zwift recently. Oops.
The problem is, this is all assuming the air is coming from the front. What if there is a 5mph wind perpendicular to you? I live in an area where there's at least 5-10mph winds literally everyday. Some months get so bad they cut off our power because it's so windy and it will knock down power lines. I have both 50mm wheels and 30mm wheels. I pretty much only use the 30mm ones now because of how the bike feels with the 50mm - the wind literally pushes me around, especially on descents.
Interesting....in that case....i could take my deep wheels and cycle in french alps as they would be not much different to shallow ones....if they are the same weight of course
What do you have to say about cross wind on these deep dish wheels? I live in a windy area, ride Hunt 35 carbon wheels and feel deeper could start to create problems with the front end. Is there a happy medium?
So you're telling me the difference between basic alloy rims and the deepest carbon rims is 16 watts at 30 mph? Ouch that's only about 4 watts at 30 km/h 😂 (Disclaimer I don't know the real calculations, I just roughly reverse engineered it a bit with the gribble cycling power at speed calculator)
Hey Kyle, great question. Simple answer is yes, when we're testing in the wind tunnel the wheel is spun up (mechanically) to match the wind speed at which we're testing
Aero and non aero on a hand cycle let's say go a 80mm deep dish on front with a tubular so more weight and aero on our drive wheel but for the back 2 we are laying down in-between them what is better there ultra light weight 20" wheels or medium or deep dish 20" wheels
My Farsports 45mm deep wheels are lighter than my stick aluminium wheels, so fairly easy choice once I could justify the cost in the budget 😜 Brisbane just hasn't stopped raining / flooding since I got them though 😞
I've told this story about a hundred times but when I started cycling it took me 1 hour for a 20km ride, and I rode that route everyday for three weeks, lost a lot of weight and slowly got faster, in the second week it only took me 55 minutes and in the third I could do it in 45 minutes, so basically I was 25% faster after only three weeks of cycling which is more than any bike upgrade could ever give you.
Unless you live up "Noorf" and massive cross winds, clean you out on most summer days with deep rims.....change your inner tubes, and buy some proper shoes, as Francis and James have said in the past, stay upright.... an upright rider is a faster rider..... :)
deeper is better. that's what she said. upgraded from quite old alloy wheels to bontrager aelous comp 5 ... still allov but with carbon fairing. huge improvement for 700€ so yeah even some cheap deep wheels are very worth it l'd say.
Cubic relationship? I'm pretty sure it's square. Drag = Cd 1/2 ρ V² S Double the speed and you quadruple the aerodynamic drag. Please give your formula showing it's cubed.
Hey Dominic, if you're looking at drag force then yes, you're absolutely right. However, we're looking at this in terms of power output, so when you take Power = Force x Speed, you'd end up with a cubic relationship
Does rim width and tyre width have to be the same for more watt saving? Or how much can a tyre width be bigger than the rim width? I need answer for this.
I was about to ask this question as well! Glad to hear a video is coming. I have Zipp 303s on my gravel bike, and wonder if I am getting any aero benefits with tires above 30 mm.
I bought a used 2019 bike with 80 mm deep wheels. Hate them. They blow me off the road. I out an aluminum rim wheel on the front for now ( yes changed rim brake pads)
Would I make an upgrade by changing from a 24/27 alloy rim to 35/35 alloy rim? I'm riding 40, 90 & 180km for ironman events and would like to stick with alloy, for budget & rim-brake reasons
I would say they if can ride in in the wheels out of the wind on the flats but get dropped on the climbs. Then you need to be thinking about weight and what you need to do to not get dropped. Will the effort saved on flats with deeper wheels help you on the climbs enough to over come the weight. There must be reason climbers drag their skinny wheels around all day just got a few climbs.
100% - if you're racing then you need to consider the in-race dynamics as well. So if you know that the key point on a stage will be on a climb (e.g. final climb of the day), then you may be better off trading low weight for improved aerodynamics. Especially if you have a team of domestiques to do the work for you up until that point.
I know that my bike rolls faster down a hill with my 50mm deep carbon wheels on than the standard alloy wheels it came with. On a route I regularly ride a friend of mine-who is heavier than me-would always roll away from me. When I fitted my carbon wheels I could freewheel past him-same bikes/people/hill-the only difference was the wheels so I know they are faster which must be the aerodynamics. They also catch crosswinds a LOT more-which is something to bare in mind.
I have a canyon ultimate with 650B wheels, the only deep wheel on the market is the zipp 303 (£2200). Would I gain from upgrading my wheels or would I be best to remain with my lightweight climbing wheels? Could I have a set custom made?
Depends which wheels they're riding 😉 Joking aside, our test data is based on a rider speed of 30mph because this helps increase the resolution of the test data. It magnifies the differences between e.g. different tyre widths to exceed the margin of error of the wind tunnel, meaning we can provide useable data rather than it being lost in "noise" from the tunnel sensor readings. However, it's important not to confuse the test speed in the wind tunnel with time savings over a fixed distance (e.g. 40km). As I explained to Francis, the time savings over that fixed distance are (broadly speaking) the same, regardless of what speed you're riding at.
@@markb9571 it would be, but there comes a point where the airflow characteristics begin to differ from lower speeds, which could skew the results further from "real world" conditions. 30mph is a good mid-point where you can test at a decently high resolution, whilst also simulating airflow conditions that a majority of riders will experience
@@ParcoursDov It's also an unrealistic speed to quote for the purposes of advertising. Which was my point really. Shame, so far Francis' channel has been free of 'bike industry bs'
SO marginal gains for way TOO MUCH MONEY !! SO STAY AFFORDABLE FELLOW CYCLISTS SAVE YOUR $$ FOR MORE IMPORTANT PARTS !! OVER PRICED AERO IS FOR BIKE SNOBS AND PRO s who dont pay for their stuff like we do !!
What is the science behind rear wheels being set up with more deeper rim? For me it seems like it is the front wheel that works most in terms of aero because it is at the leading edge. What is the benefit then of the deeper rear wheel vs same depth rear wheel as front?
You're right that the front wheel will have a greater impact on aerodynamics, but you also have to consider the impact on handling stability. Generally speaking, a deeper front wheel will be less stable in windy conditions. However the rear wheel is not impacted in the same way as it's not free to turn like a front wheel. Hence a rider can choose a deeper rear wheel without impacting handling stability but still improve aero efficiency (albeit not by as much as running a deep front wheel)
@@ParcoursDov thanks for the reply. I often see this in time trial bikes where the rear wheel is way wider but I always wondered if there is any real benefit to that or not vs keeping the same depth size as front.
Because I'm always torn between growing up in the UK (mph) & training as an engineer (kph) who conducts wind tunnel testing in the USA (mph) but is also a cyclist (kph)!
Do I upgrade my bike flow chart -----> Does it look cool------>Yes------>Buy
I love the "swoooosj" sound my deep carbon wheels makes when I ride my bike.
That and the good looks makes it worth it in my opinion🤗
The best things I've done to get faster are simply to lose a couple of kilos from my body and to ride a bit harder a little more often.
agreed.
True, but you can lose body weight, ride harder and become more fit AND improve your equipment. These things are not mutually exclusive.
True... but anything that inspires you to get out on the bike more and for longer can only be a good thing. Unfortunately this step usually requires a chat with your finance manager but a lot of manufacturers have started selling direct to consumer which brings the price down a fair bit. You could save £200-400 if you know where to look and are at the right place at the right time and not be a snob about the branding on the wheels.
Im waiting for my own set to arrive. It only cost me £530 though you can find others for around £300-400 built with reliable but _'brand-x'_ hubs and spokes.
@@Rose.Of.Hizakihow do you save that much money on wheels?
Below 80kg is optimal, my preferred is 76, but I'm currently between 88-90kg.
Very interesting and well explained. I love my 50mm deep carbon wheels, lighter and faster than standard ones. Also keep the speed much easier. I am 86Kg, never had problems with sidewind so I would not consider shallower ones.
I went from 35mm alloys to 60mm carbons and if I interpret my stats correctly, I get just a bit higher avg speeds than before with the same effort. Besides that, they really look the part, which to me is an equally valid reason to buy them. 😎✨
I've had the same experience going from shallow alloys to deep carbon. I feel less energy needed to maintain the same speed. I'm not going any faster but I feel it not as difficult to hold speed.
And the whooshing sound
Yes to everybody right here. I have a similar experience.
How about your experiences in terms of sprinting after you bought deep carbon rims? How much faster did you get?
@@user-bv3lr3en2q well 2 things determine sprint if it's just wheels we are talking about.
1) weight: if the carbon rims are heavier than the alloy you replaced then it's slower to start or a little harder to start a sprint vs a lighter wheel. This only applies based on weight of the wheels as you have to rotate the weight. Deep rims usually aren't quick on stop to sprint scenario.
2) wheel stiffness carbon vs alloy. Carbon if built properly is very stiff. The parts that make it has to be able to handle the power of the rider.
Hubs, choice of spokes and to an extent depth of rims. Balance of all 3. Hubs with large flange spacing are generally stiffer than say smaller flanges that hold the spokes.
Sprint based on wheels = light weight + built stiffness.
It takes me 49 seconds to eat half of my caramel short bread at the coffee stop so that throws out that deep aero rim advantage 😄
Carbon wheels would give you the time to eat an extra half caramel short bread... ;o)
Didn't cover the reason I was persuaded to upgrade my wheel to be more aero - which isn't to do with going quicker - it was about going the same speed over the same distance with less effort. For multi-day bikepacking managing the effort is more important than shaving time off the ride...
100% - exactly what I meant by saying you could do the same ride but with a lower power!
Really interesting topic. I've just recently upgraded to some Zipp 303s and I believe they have made a difference in both speed and effort produced, but that could just be some sort of placebo effect.
They won't impact your power output (only training and position will do that).
But, they may be more reactive than your existing ones. This will make the bike feel more responsive when you put the power down.
Even upgrading from standard alloy, to alloy with a good hub, makes you feel better.
Well good wheels are definitely faster
@@MacedonianGrace what are good wheels is a bit subjective. Sure you want good hearings but I can't notice much until I go over 35kmh on deep dish quality to cheaper training wheels
@@glennoc8585 most good wheel sets only “feel” faster when lent against a tree outside the coffee shop. Same speed on the road …
Great video, very well explained. Loved the "are they faster?" "yes" lol. LOVE my aero wheels (DT Swiss 62mm) and aero bike. I'm not climbing mountains so I ride that more than my lightweight bike.
I'd never go above 45mm front and 50 rear for general cycling or group rides as I see very little gain and mostly hassle from winds and the extra weight. I'm actually going the other way to very shallow carbon disc as I find the lower weight at the rim is better up hills.
Really Good to hear Dov's expertise on "Facts & figures" Friday! 👌. Have a very canny weekend Francis 👊
Good video. One of the (subjective) aspects about wheel depth is that a stiff, light wheel is going to feel more responsive and add to the enjoyment particularly if you're into attacking the climbs or dropping your mates
nice video, a good explanation....have been riding deep rims for years and having recently had to wait for a replacement for a cracked rim, i used my standard shallow rims...really aware in all types of riding of the difference.
Not if I’m riding on them …
Explain
@@highfived the question was “are carbon wheels that much faster”. I replied “not if I’m riding on them”. Meaning they will be equally as s…l…o…w … understand ???
Lol 🤣
@@SimonAElson no bro you will
Be quick. Trust me king
That hit a little too close to home for me
Would love to hear more on how deep wheels are affected on cross winds and what the difference in speed and watts saved compared to wind tunnel testing to real world riding - what is the difference between the 2
It's a great question & crosswind handling stability is a massive focus for us when we're working on a new wheel, especially a deeper-section model.
As for the translation from wind tunnel to "real world", that's a whole video in itself! Any numbers we share from the wind tunnel use a weighted average yaw angle to give the closest approximation we can to real world riding. To determine what weightings to use, we've actually used an instrumented bike to measure real world wind conditions at both the front and rear wheels.
We'll have to get Francis out for a ride on an instrumented bike sometime to give you a look at how it all works!
I would also love to hear about this. As a light person and average rider with below average bike handling I tent to get a bit freaked out in strong crosswinds. The concept of adding a deep section front wheel on I generally feel would be unsafe on the open road where I'm generally not given the space by other road users to control the bike in crosswinds scary.
@@andrewstokoe1850 it is scary... even for a heavy rider like me, especially when there is no bike lane. Hold on tight, and focus,focus, focus. This is on 58/62 wheels.
They look cool = faster 😎
best explanation of deep section wheels that i've been looking for. Thank youu
Love this vid , great looking wheels . Will look at these for my next upgrade
I’ve just ordered mine after watching this interview last week. Really looking forward to receiving them.
Thanks Francis and Dov....Peace
I ride 45mm mainly because I like the looks. And I use 28mm so my lightbulb setup destroys all of the aero benefits anyways..
However I ride carbon with alloy brake face which looks a bit ugly. But I'm on rimbraked and I'm scared to descend on carbon.
Thanks for the video, expert opinions are always interesting!
Hello do you have a carbon alloy set of wheels to recommend ? It becomes rare on the market
@@romanlf5620 i ride Vision Trimax 45 carbon but changed the rear hub and spokes. But as you said, not really a lot of wheelsets are avilable.. Sadly
Having gone from basic box section rim brake wheels (stock ones on my $500 road bike with ~10,000 miles on them) to a bottom-tier (for a well-known, expensive western brand) set of 42mm carbon rims, the difference was pronounced; for the same power, I was maybe moving 1-2 miles per hour faster, essentially from one day to another. That's an extreme example, but I found it huge how much of a difference in ride quality those wheels make.
You've hit the nail on the head. Let's suppose you average 1.5 mph extra that's 15 miles on a 10 hour ride, if racing worth it. Other than that a few minutes here and there might feel good but does it really matter? I'm off to buy some 50s.
@@vinniep01 it is upto you. I personally try to race myself with setting personal records. Also I try to cover more distance so for me it is a benefit with higher speed. However yes it is not a super high marginal gain. If you dont care about 1-1.5 mph average speed gain then yes I dont see a point in spending $$$ for new set of wheels.
Totally agree a nice set of carbon deep rims make a huge differnce to the ride. I upgraded to a set of VEL+ this year and they are like night and day compaired to my Mavic's i bought a few years ago
I used mavic cosmic's (alu) for a couple years and when I started using carbon wheels I couldn't feel much difference. They were abviously more aero, but everything else seemed the same. Actually the Mavic's were a bit better in the stiffness depo. Pretty sure it's because those wheels had some beasty proprietary spokes.
No mention of cross winds? Find my deeper wheels horrible at times when it's windy out, although I'm no racer. Have a lot more confidence in my shallower wheels when going quickly down hills.
Great point & certainly something we're hoping to cover in the future. Handling stability is a really important consideration because as soon as you're unable to control your bike, there's precisely zero benefit from any reduction in drag. You won't be riding very quickly if you're off the road!
Just would have made for a much longer video if we tried to dive into that for this one!
Being a larger rider, the advantage for deep section wheels for me is that they are strong. The extra speed is a nice bonus :)
This is a great point & one that's often overlooked. With a deeper rim, spoke lengths are shorter, meaning a wheel will flex less under load.
How much more speed did you gain?😊
@@Jakiou I am a heavy rider...in group rides when many are pedaling on a slight slop, I am in neutral, downhill- I either catch up to the group or leave them behind, until they catch up again going up hill🤣
Yes but in terms of overall aero savings - getting your body in an aero position is going to be the biggest change you can make in terms of going faster. When that is sorted and you have an aero helmet, socks, clothes, etc... then wheels will make you faster. Of course when it comes to looking good, then wheels are the obvious place to start
That’s wasn’t the question.
This point was literally addressed from 8:09 onward
And here come the “what about?“ police despite no one calling them…
Why not both? Why not all the things? For some people the expense of deep carbon wheels is less “expensive” than the time it would take to make up that speed differential through more training, stronger core to hold that aero position, etc. They can afford deep wheels but can’t afford another five hours/wk on the bike and in the gym and away from their family and jobs. These things don’t happen in a vacuum.
Plus, one could easily make the case that it’s that much easier to hold a more aero position at your target race speed because you can do that speed at a lower wattage and thus lower effort level BECAUSE of the wheels. Literally you can make yourself more aero and thus faster because your wheels allow you to push on the pedals less for the same speed. Your chest doesn’t need as much room because you’re now doing 45 kph at Z3 instead of Z4. Faster wheels, chain, helmet, etc. all allow for a faster body position too as they all equal more speed for less effort. The body I will fully agree is the biggest drag, both literally and figuratively, but it also needn’t be the first thing you address, especially if your individual situation leaves you with more money than time. End of rant.
@@ryanspivey2453 if they can afford deep wheels then they can afford training more. Its that simple. Its because their riding is not structured. You can ride all you want with that z2 bs zone for 15 hours a week and someone who trains less doing threshold work, strength work in the gym will smoke any of the carbon blings in any grand fondo rides 😂😂😂 most mamils are just riding for the looks and to look the part. The serious ones know which ones will make them faster.
What I get from people who don't want to spend any money at all on their bikes, is that they will find "placebo" excuses for everything. All the know-it-all, big time cyclists use to say disc brakes are for looks, blah, blah, blah. Fast forward to now, there are completely used In the tour of France. Also those same people that complain about upgrades have spent a lot of money on their bikes because now they see those old 70' bikes that they are trying to ride to save money aren't cutting it on the group rides. If people don't want to spend money to upgrade, then don't, but you don't have to knock the people that do, whether it be for looks or whatever, so that you feel better about being cheap. Working out, or losing weight is all irrelevant to someone adding or changing items on their bike because it still does not change the fact that it is THEIR bike, and they can do what they want with it. Don't get mad at the carbon aero guys because you can't keep up with them downhill.
Great video. Very informative!
Losing weight could also benefit many and improve speed and efficiency but apparently that’s too difficult for many ppl
49 Seconds over a 40km ride. Okay, I dont need those wheels. Took me around 50 seconds to get my snickers out of the packaging. So I will switch to gels instead. Just saved 1000 bucks. Thanks guys.
It would be interesting to get an answer to the aerodynamic benefits of a stacked setup like 80 front, 100 rear or a "reverse stack" with 100 front, 80 rear
From a purely aero perspective, the front wheel has a greater impact than the rear. So in theory the setup with the deeper front wheel would be faster than the shallower setup. However, if you also add in handling stability to the equation, that's why you'll more often see a shallower front paired with a deeper rear.
Very nice informative quick and easy video
Good video, but there was one thing that I'd like to hear much more about: I've heard and read that having a deep section on the front matters way more than rear. Particularly because starting a laminar flow on the front would continue throughout most of your bike, so the benefit is more. But I often see deeper section at the back, probably because it's harder to control a deep front wheel when there are strong cross winds. What are your thoughts on that?
I’m no expert but saw a couple videos where they showed smaller front wheels to alleviate wobble from head winds with larger on back still
Great, informative video… the only downside to deep dish wheels - crosswinds… 😬
Class video. I'm building a track/fixed bike and have just bought a 60mm carbon wheelset. Would love to see some more fixed gear videos like your NY episodes... X
I ride two single speed alloy aero frame track rigs with a 55mm carbon deep up front, and 30mm alloy in the rear and it's a crazy fast set up, love it, accelerates like a fighter plane. The heavier rear wheel helps you to retain speed via inertia, while the front of your bike is important for setting up uniform air flow and punching through the wind like a ship's rudder. Haven't tried deep dish front and rear fixed yet though, but I'm sure it's just as fast man. Hope this helps!
All these things make sense in a wind tunnel or on a velodrome but out on the road crosswinds change the story A LOT.
Aero components at low speed will increase drag during crosswinds. The deeper wheels aren't always better, 50 mm has been showed to be a good middle ground where you get aero gains but not much penalty during crosswinds.
Above 50 kph it's not so big a problem anymore since the general direction of airflow will be close to parallel to the direction of travel anyway
You're right that crosswinds will have an impact on the open road, but that's in relation to handling not aero performance. If you have a look at a wind tunnel drag chart, you'll almost always see that a deeper wheelset will have a bigger impact in crosswinds (higher yaw angle) versus a straight head or tailwind (lower yaw angle)
@@ParcoursDov I've always wondered about those yaw tests. When they do them, do they also increase the airspeed in the tunnel?
@@ParcoursDov True for wind tunnel drag charts but as @S. Planiden pointed out, the air speed is often kept constant during these tests, hiding a part of the additionnal drag created by deeper rims.
Also the impact on handling is actually the result of this additionnal drag in crosswinds and thus is tightly correlated with aero performance in crosswinds
Saving 49-90 Seconds over 40km for non-racing is not worth it in my opinion, especially considering the added instability that deep section wheels cause in cross winds.
I wonder if a non-UCI compliant bike will actually make some significant difference in speed.
modern U shaped deep wheels are much more stable. If you have the older V shaped ones then yes those are scary.
The immediate front isn't where the main gains are from deep wheels it's from the top and bottom where a larger section of the wheel front to rear allows the air to pass unbroken along it's entire length
Great Q&A Francis
Big question how do i get the money for a carbon frame and deep wheels?
Preferably without working.
So having gone from a set of fairly mediocre DT Swiss alloys (older ones) to a set of Prime 50mm carbon rims (a cheaper option) and I have noticed a huge difference. It made my fairly old bike feel brand new again.
Interesting facts, but completely academic to ordinary mortals like me. I waste several minutes on a 40km ride stopping for a pee 🤣
Same brother
System weight is still something to consider depending on distance & elevation gained. Both being aero and having a lighter set up can save the rider valuable energy.
Not denying that deep dish rims or solid disc rims are not fast but they do add considerable weight and this means the rider has to expend a little more energy on the climbs.
Only issue I have with the technical explanation is that aero drag increases with the SQUARE of the speed, not the CUBE. If you double your speed, your aero drag increases 4X, not 8X. The equation is (1/2)*(fluid density)*(velocity)^2*(drag coefficient)*(reference area)
Hi Gabe, you're absolutely right, however the power required to overcome aero drag is a cubic relationship (Power = Force x Speed). I'm referring to power here as we generally think in terms of watts, or watts saved
enjoyed very much. thanks.
Judging by the low number of watts saved at such high speeds, I will always prioritize light wheels over deep aero ones. Obviously not speaking of TT races here, but the casual road bike rider who rides 2-5 times a week on local roads.
fact is that it is futile for 99 percent of the riders. there is a lot of expensive aero bullshit floating around.
Great discussion except rolling resistance does not increase linearly with speed but is more or less a constant determined mainly by the coefficient of friction between tire and riding surface, with factors like cornering and heat generated between rubber and surface having an effect.
Yes, this is similar to the comments below about drag having a quadratic relationship with velocity. the rolling resistance *force* is constant per the equation Frr = Crr * N where N is the normal force (in this case rider/bike weight). However, the *power* required to overcome rolling resistance does increase linearly with speed as Power = Force * Velocity
Problem I have is when reviewed these excellent Parcours Example Grimpeur was 700-800 bones, but now are 850 bones - something inside just hates the price increases so backs off any purchase and sticks to alloys and 2nd hand carbons. Still lovely wheels and UK support is nice to have, just not got the minerals to purchase.
I love mine on both of my bikes. 77 and 88mm. Do they truly make me faster? Yes, but usually in the way that they help me sustain a higher speed, not just be faster on its own.
Do they make you faster in terms of sprinting on the flat and achieving a new max speed?
@@user-bv3lr3en2q all of my speed personal bests in the last year have been in the last few months since I got aero wheels.
Some gravel racers are saying an aero bike and position is more important than wheels for gravel since it’s with wider tires
Cross winds with deep wheels is a big problem at speed.
there is a difference on a individual effort of course. Riding in groups it does nothing really as the air is already being broken by the front rider and not very turbulent once it gets to you. A great bang for your buck wheelset is the American classic aero 420 three tubeless. Nice for climbing too!
When you double the speed you actually get 4 times more aero drag instead of 8. Drag is proportional to V^2
Hey Guillermo, just to clarify, the aero drag *force* will be proportional to velocity^2, but as power = force * velocity, the *power* required to overcome said drag force will be proportional to velocity^3
@@ParcoursDov that is indeed true, but when one refers to the word "drag" alone is usually talking about a force if you refer to an energy balance is better to say e.g. drag dissipation
Something I've been looking to upgrade, as I need all the help I can get. :)
Thanks for this, I would be really interested to see the difference in drag/watts saved at 30km/h, which is a more likely speed a person with a 200w FTP would travel at on a flat road. Not one company ever quotes the watts saved at 30km/h..........its always at 45km/h plus.......is this because at 30km/h the watts saved might be 1 or 2w at best and therefore wouldn't entice people into spending thousands on aero bikes and wheels? Would be good to know !
Hambini actually has run tests of how much watts are needed to sustain 30kph on his website. The difference between a standard wheel and a good aero one is almost 15 watts. (180 vs 195)
The relationship between speed & drag (in watts) is cubic, so to adjust from one speed to the other you need to take the cube of the reduction. What does that mean in English?
For your example of 30kph (versus the often quoted 30mph or 48kph), you're reducing speed by a factor of 30/48 or 0.625.
0.625 ^ 3 is 0.244
So if we quote a "watt saving" of e.g. 16W at 30mph/48kph, you would save approximately 25% of that at 30kph, so 4W.
@@Silvermanav I know the Hambini tests and they are very good. My comment was a general one about the speeds quoted for aero tests.
@@ParcoursDov Thanks Dov, makes sense.
@Steven Vanlancker our website usually quotes watts saved for a complete wheelset. But the example above (16W) is the tested savings for one of our deeper section TT wheels (single wheel only)
But isn't the air resitance quadratic to the velocity. Still same arguments apply here but i wonder if there is a special equation for bikes?
Skin suit??? with my belly !!!! 🤣🤣
Great item to have and easy to maintain.
I have a set of Knight 60 mm clinchers, I can feel every gust of wind in the front. I may need to go back to 50's or 40's.
I got some firecrests on cycle2work a year ago and i've got from being one of the slower descenders to one of the faster ones. Just seem to roll forever
While the science is sound, sometimes a rider just needs to be happy with what they’re seeing as they mount their bike. If the bike looks rad, you feel like a legend, and you ride well.
I want to see more aero alloy wheels. the only people I know of who have done that are Hunt. Give more aero to us mere mortals, and also the people who don't want our money going into a material that's soooooo bad for the environment
Alloy (or realistically aluminium alloy) is a great option for a wheelset, but does make for a much heavier rim versus carbon - hence why the shallow alloy rim in the video is barely any lighter than the super deep carbon wheel. Given that aero performance is linked to rim depth, if you optimised an alloy rim you'd end up with a really heavy wheel.
Another consideration is that a deep alloy rim would need additional strengthening against e.g. impact damage (or dents) which would likely add even more weight, versus carbon.
My bike went from looking meh to looking dope, when i put deep carbon wheels, which is arguably the most important element, because it makes me ride more, which is the most important factor to improve performance.
Preachin to the choir, carbon wheels bring the bike out big time. I ride a 2009 alloy Specialized Allez triple on 55mm deep dishes / rim brakes and better believe she's both a looker and a killer - mostly future proof, burning Madones, Tarmac SL7's and other pure aero formats on the regular, Deep dishes are a must in my book if you enjoy speed, literally feels like I'm riding on top of an arrow.
Thanks great video..
Here's a somewhat open ended question: what's his opinion on mixed depth wheels for dealing with the somewhat changeable weather conditions we face in the UK. Seems like a 40/50 or 50/60 mix would work well and the shallow front would keep you from getting blown about too much.
They're a great option, especially if you're considering running a deeper section wheelset & are concerned about handling on the front wheel. Our best-selling triathlon wheelset pairs a mid-depth front (Passista - 56mm) with a deeper-section rear (Chrono - 86mm) so it's clearly a popular choice!
Then for roadies, all of our newer #thinkwider rim profiles pair a slightly shallower front wheel with a deeper rear, e.g. Ronde (35/39mm) & Strade (49/54mm). We've actually gone a bit further & can tweak the handling characteristics by using a different profile of rim on the front wheel versus rear wheel.
Again, probably another video sometime to go into the full detail on this...!
@@ParcoursDov a proper video would be very cool. Love the hardcore techy sides!
I wonder how many channels can cover this topic?
Rolling resistance doesn't only happen in the tyre. The main contribution comes from the rider's body. So any test which doesn't involve a rider certainly doesn't test rolling resistance. See Bicycle Quarterly for more info.
Hi Max, I think you might have misunderstood here. Rolling resistance is caused by the frictional force between tyre and road surface. So it does technically only occur at the tyre. However, since RR is dependent on total weight through the tyre, the rider does indeed contribute.
We don't actually test rolling resistance ourselves, instead referring to subject matter experts like Bicyclerollingresistance.com. You can see more on their test protocols on their website, however when testing I know that they load the tyre being tested to simulate a rider's body weight.
Hope that makes sense!
@@ParcoursDov Thanks for your elaborate response. A supple tyre is not only more comfortable than a stiff tyre it also reduces the vibrations and energy transformation inside the body of the rider. This is hardly understood.
Since it's definitely not aerodynamic drag those energy losses are part of the rolling resistance. The more coarse the road surface is the more prominent the friction losses of the rider's body become in comparison to the hysteresis loss of the tyre.
Experiments of the US army have shown that the body can absorb up to 2000 Watts for a short time until the soldiers aborted the test. On a bicycle the vibrations are less intense than those from the vibrated tank seat in the experiment but this shows that the losses in the rider's body are key to understand the actual rolling resistance of tyres.
@@maxsievers8251 I think here you're conflating physiological impact (vibration in the body) with a mechanical action (rolling resistance). That's not to say that the physiological impact of a stiffer tyre or a higher tyre pressure doesn't have an impact, however.
It's something we're planning on investigating in more detail soon though as it's only likely to further strengthen the argument for running a wider tyre at a lower pressure. We've already seen this with some of the professional triathletes we work with - since swapping to 28mm tyres and running lower pressures, they're finding that they get off the bike and start running in better physical condition. So we're not just saving them time on the bike leg, but also on the run!
@@ParcoursDov Wind resistance comes from the disturbance of the air. Every molecule that gets to move needs energy to do so. That's the reason why we aim for laminar flow.
When the tissues in the rider's body rub against each other that energy has to come from somewhere. If you are not going downhill then this energy comes from the pedaling. The Watts you put on the road get eaten up by vibrations in your body.
Crosswinds around here are regular and can be crazy. I’ll stick with my super-shallow (19mm!) rims for now. Besides, riding in traffic? Acceleration/deceleration trumps aerodynamics all fucking day.
All you talked about was aero in a time trial setting but most road cycling is done in a club/ group ride setting. What does riding in a group make to the aero contribution of a wheelset?
Does anyone have any feedback on Parcours? They are considerably less expensive than DT Swiss or Zipp, but that makes me wonder if the R&D has been adequately implemented... any thoughts?
Why does no one admit that deep carbon rims are useless in British weather.
With those sails attached my bike will be ready for the regatta.....
Right now (Springtime) where I live regular 55mph crosswinds make deep dish wheels suicidal.
I've been eye balling my first set of carbon wheels for next month and this video has come at the perfect time. Trying to decide between 303 or 404. Leaning towards 404 because deeper looks cooler and looking cooler is automatically faster, right?
Its all about being a poser rather than performer. All the gear no idea 😂😂😂
Whatever makes you happy, and makes you wanna ride your bike more matey that's the important part 😉
@@PhiyackYuh that's my motto in life! Fake it til I make it! (I never make it)
@@mr.galaxy3762 I actually went with the 404FC in the end. They've been amazing, especially since I've been doing most of my riding in Zwift recently. Oops.
Wrong
The problem is, this is all assuming the air is coming from the front. What if there is a 5mph wind perpendicular to you? I live in an area where there's at least 5-10mph winds literally everyday. Some months get so bad they cut off our power because it's so windy and it will knock down power lines. I have both 50mm wheels and 30mm wheels. I pretty much only use the 30mm ones now because of how the bike feels with the 50mm - the wind literally pushes me around, especially on descents.
Interesting....in that case....i could take my deep wheels and cycle in french alps as they would be not much different to shallow ones....if they are the same weight of course
I just think their neat. Also the sound.
What do you have to say about cross wind on these deep dish wheels? I live in a windy area, ride Hunt 35 carbon wheels and feel deeper could start to create problems with the front end. Is there a happy medium?
So you're telling me the difference between basic alloy rims and the deepest carbon rims is 16 watts at 30 mph? Ouch that's only about 4 watts at 30 km/h 😂
(Disclaimer I don't know the real calculations, I just roughly reverse engineered it a bit with the gribble cycling power at speed calculator)
I'm assuming the wheels are tested while spinning and not while standing still
Hey Kyle, great question. Simple answer is yes, when we're testing in the wind tunnel the wheel is spun up (mechanically) to match the wind speed at which we're testing
@@ParcoursDov sick, thanks!
Aero and non aero on a hand cycle let's say go a 80mm deep dish on front with a tubular so more weight and aero on our drive wheel but for the back 2 we are laying down in-between them what is better there ultra light weight 20" wheels or medium or deep dish 20" wheels
My Farsports 45mm deep wheels are lighter than my stick aluminium wheels, so fairly easy choice once I could justify the cost in the budget 😜
Brisbane just hasn't stopped raining / flooding since I got them though 😞
The best and cheapest way to get faster is to work on the man not on the bike!🥵🤣😂
I've told this story about a hundred times but when I started cycling it took me 1 hour for a 20km ride, and I rode that route everyday for three weeks, lost a lot of weight and slowly got faster, in the second week it only took me 55 minutes and in the third I could do it in 45 minutes, so basically I was 25% faster after only three weeks of cycling which is more than any bike upgrade could ever give you.
Unless you live up "Noorf" and massive cross winds, clean you out on most summer days with deep rims.....change your inner tubes, and buy some proper shoes, as Francis and James have said in the past, stay upright.... an upright rider is a faster rider..... :)
deeper is better. that's what she said. upgraded from quite old alloy wheels to bontrager aelous comp 5 ... still allov but with carbon fairing. huge improvement for 700€ so yeah even some cheap deep wheels are very worth it l'd say.
Cubic relationship? I'm pretty sure it's square. Drag = Cd 1/2 ρ V² S
Double the speed and you quadruple the aerodynamic drag.
Please give your formula showing it's cubed.
Hey Dominic, if you're looking at drag force then yes, you're absolutely right. However, we're looking at this in terms of power output, so when you take Power = Force x Speed, you'd end up with a cubic relationship
Does rim width and tyre width have to be the same for more watt saving? Or how much can a tyre width be bigger than the rim width?
I need answer for this.
Yes it makes a difference, we have a video on this filmed already just need to edit 👍
@@Cade_Media thanks for the reply. I will be waiting for the video.
I was about to ask this question as well! Glad to hear a video is coming. I have Zipp 303s on my gravel bike, and wonder if I am getting any aero benefits with tires above 30 mm.
Zip 808s for me front and rear
I bought a used 2019 bike with 80 mm deep wheels. Hate them. They blow me off the road. I out an aluminum rim wheel on the front for now ( yes changed rim brake pads)
Would I make an upgrade by changing from a 24/27 alloy rim to 35/35 alloy rim? I'm riding 40, 90 & 180km for ironman events and would like to stick with alloy, for budget & rim-brake reasons
I would say they if can ride in in the wheels out of the wind on the flats but get dropped on the climbs. Then you need to be thinking about weight and what you need to do to not get dropped. Will the effort saved on flats with deeper wheels help you on the climbs enough to over come the weight. There must be reason climbers drag their skinny wheels around all day just got a few climbs.
100% - if you're racing then you need to consider the in-race dynamics as well. So if you know that the key point on a stage will be on a climb (e.g. final climb of the day), then you may be better off trading low weight for improved aerodynamics. Especially if you have a team of domestiques to do the work for you up until that point.
Well i don't know are they faster or not but I'm sure that they look so good
And sound good too.
I know that my bike rolls faster down a hill with my 50mm deep carbon wheels on than the standard alloy wheels it came with. On a route I regularly ride a friend of mine-who is heavier than me-would always roll away from me. When I fitted my carbon wheels I could freewheel past him-same bikes/people/hill-the only difference was the wheels so I know they are faster which must be the aerodynamics. They also catch crosswinds a LOT more-which is something to bare in mind.
May it also have something to do with the hubs of the carbon wheels?
I have a canyon ultimate with 650B wheels, the only deep wheel on the market is the zipp 303 (£2200). Would I gain from upgrading my wheels or would I be best to remain with my lightweight climbing wheels? Could I have a set custom made?
How many people can ride at 30mph for 40km? 😂😂
Depends which wheels they're riding 😉
Joking aside, our test data is based on a rider speed of 30mph because this helps increase the resolution of the test data. It magnifies the differences between e.g. different tyre widths to exceed the margin of error of the wind tunnel, meaning we can provide useable data rather than it being lost in "noise" from the tunnel sensor readings.
However, it's important not to confuse the test speed in the wind tunnel with time savings over a fixed distance (e.g. 40km). As I explained to Francis, the time savings over that fixed distance are (broadly speaking) the same, regardless of what speed you're riding at.
@@ParcoursDov Why not use 40mph for your test data, your resolution will be even higher!
@@markb9571 it would be, but there comes a point where the airflow characteristics begin to differ from lower speeds, which could skew the results further from "real world" conditions. 30mph is a good mid-point where you can test at a decently high resolution, whilst also simulating airflow conditions that a majority of riders will experience
@@ParcoursDov It's also an unrealistic speed to quote for the purposes of advertising. Which was my point really. Shame, so far Francis' channel has been free of 'bike industry bs'
SO marginal gains for way TOO MUCH MONEY !! SO STAY AFFORDABLE FELLOW CYCLISTS SAVE YOUR $$ FOR MORE IMPORTANT PARTS !! OVER PRICED AERO IS FOR BIKE SNOBS AND PRO s who dont pay for their stuff like we do !!
What is the science behind rear wheels being set up with more deeper rim? For me it seems like it is the front wheel that works most in terms of aero because it is at the leading edge. What is the benefit then of the deeper rear wheel vs same depth rear wheel as front?
You're right that the front wheel will have a greater impact on aerodynamics, but you also have to consider the impact on handling stability. Generally speaking, a deeper front wheel will be less stable in windy conditions. However the rear wheel is not impacted in the same way as it's not free to turn like a front wheel. Hence a rider can choose a deeper rear wheel without impacting handling stability but still improve aero efficiency (albeit not by as much as running a deep front wheel)
@@ParcoursDov thanks for the reply. I often see this in time trial bikes where the rear wheel is way wider but I always wondered if there is any real benefit to that or not vs keeping the same depth size as front.
Does the bike come fully assembled?
Just curious, why did the engineer friend refer distance as KM but speed as miles per hour?
Because I'm always torn between growing up in the UK (mph) & training as an engineer (kph) who conducts wind tunnel testing in the USA (mph) but is also a cyclist (kph)!
How many watts am I going to save at an average 12mph?