David goes out test riding in the pouring rain in winter so that we don't have to.... another way to look at it is, ride big tyres in winter so you put out more power and don't have to be out so long in the muck to achieve the same effect... then jump on your summer bike when it perks up and boom, you fly. My own testing has somewhat confusingly shown that go even bigger and there is negligible difference in speed between a fast 40c gravel tyre (Conti TS) and a 2.1 Thunderburt (48C), some tyres seem to defy the laws of physics if supple enough...
I've been riding the Pirelli 40s for a couple months and they're wonderful. No, not the fastest, but they make up for it in a number of other ways - grip, ride quality, puncture resistance.
I have also ridden the 40mm, and I don't like them. They have high rolling resistance and are not very agile in corners. The robust Conti 5000 AS in 35 mm is near the same volume but rolls much better.
@@blackjackpinoko Depends what you're coming from and what you're looking for. For me, they're durable and reasonably fast and feel nice. With the right tire pressure they're also remarkably grippy on the backroads we ride.
Thanks for the great work as always, David! I believe you missed out on the true grail width: 35mm! The P Zeros come in 700x35 and don’t suffer from the same weight penalties as the 40s, and just feel faster overall than the 28s I was riding previously. I’d be interested to get your perspective on the 35s as compared to the 30s and 40s.
I’m actually riding the Goodyear VectorR Z35s designed for Zipp wheels. I couldn’t wait for my desired PZero 35s to be launched, so I took a flyer on the Goodyear’s and am surprisingly happy with them! I think your comment and my experience point even further to 35s being the true sweet spot with a growing number of options.
@@davidcook8065 I've got those in 1.5-inch (38mm), tubeless ready, and they feel pretty fast. I rode them with butyl and TPU tubes for 2-3 months, and kept getting little pinhole flats. I patched them from the inside, switched over to tubeless using Vittoria sealant, and haven't had a single problem since.
As someone who has decided to go the gravel bike serving as both my road and gravel solution, Im pumped to see the wider road tires so my bike handling wont change too much when swapping on road wheels
do you notice your gravel bike becomes 'twitchier' with a road tire vs. gravel tire? I ask 'cause I'm trying to pin down the best tire size for an all-road/light gravel bike to be used purely as a dedicated road bike. though I figure 32mm is probably the Goldilocks size for that.
I have started riding vittoria corsa n.ext 700x34s (the clincher version) with TPU tubes. They are only 315g which is pretty good for a tyre that big. Ride really nicely and don't feel too slugish.
I have 34 mm Vittoria Corsa N.ext set up tubeless. Great tyre, tons of grip in the wet. Possibly not the fastest rolling tyre but not too bad. Very easy to set up tubeless. They held air even before I put sealant in.
I have a pair of these exact tire coming in today for road use on my Revolt. Mounting on 303s wheels, coming off 28's it should be interesting. Thanks for you review, can't wait to see how they feel myself!
wide tyres like this is extremly picky on tire pressure + - 3 PSI you will feel something is off. Either too mushy no corner grip or too highpressure slow and vibrations. Keep in mind some 35mm road tires measure 37mm or so, for me 35-37mm is sweet spot and for some 32mm that actual is 34mm. I guess you run tubeless. I find Sram calculator to be spot on maybe add 2-3more psi in front tire then calculator tells
@@allemyr yeah, I figure on the 23mm inside diameter, they should be right around 40mm. I haven't checked rims pressure chart yet, but on my 28th I've been running about 50 to 55 PSI with good luck.
@@allemyrSo I Finally got these installed and got in a quick 9 miles today. Inflated according to SRAM. On the 303S wheels (23mm IW) they measure out at just shy of 38mm at ~40psi. I suspect they may stretch out to 39 or 40 over the next few rides. 28, 30 ,and 32 all measured 2mm larger after a couple of rides. They def ride smooth and seem pretty durable, I immediately rode into a couple hundred yards of smashed up chunky asphalt off the side of the road and survived. So far, I like them, and will experiment with pressures for a sweet spot. I know they are slower and heavier, but they don’t feel bad at all.
Seems incredible to think that back in the mid-70s Pros were riding 23mm tubulars in Paris-Roubaix. Steel frames and skinny aluminium rims would have taken a little of the sting out of it, but not much.
But, with steel frames and rim brakes the tires don't need as much compliance. I'm riding a modern steel rim brake frame with 30mm tire clearance, but will just try out 28mm out of curiosity once my current 25mm are worn out
I rode Roubaix on skinny aluminium rims and 30c's and wished I'd ridden 45c tubeless. If I ever do it again I'll use a drop bar 29er Hardtail and I bet I'll be quicker.
That's a good test. Could be most of your viewers are not racers, so perhaps you could expand on that wider tire testing. Thanks for the good content this year and Merry Christmas!
Merry Christmas! Be interesting to see how the 35mm go. Clearly 40 is too wide for most of us, but maybe 30 is not the sweet spot? But I hate heavy wheels, so I’ll stick to 25 or 28mm for most of my road riding, especially if it’s hilly. Maybe 30 in the winter…
love my G-ONE RS, plenty fast in 40, was riding a few days recently, nothing competitive but kept up with others that strictly ran high 20's to mid 30's. My 40 was the widest tire out of a group of maybe 100 riders. However that being said, the outer treads aren't that useul.
I think a read of Jan Heine has some great tire information and writeups on the Ren'e Herse website regarding tire sizes and uses. Frankly, I like a more comfortable ride quality and that means running a little fatter tire, higher TPI on a nice wide rim at lower riding pressure. They simply work! A low TPI tire will drag like a Titanic anchor while a high TPI tire will roll very efficiently.
.and, there’s also 32, 35, and 38 increments to choose from (depending on the manufacturer) if you include slick gravel tires and road tires. Plenty of room to choose depending on height, weight, and road surface quality!
soon riders will no longer need to develop any skills, they will ask their Formula One derived AI assistant to route a course, choose a set from their 2000 $ tires stockpile and program the bluetooth compressor with the proper pressure for the gravels coarsness, temperature, humidity and distance. -_-
These tires are so much on my radar, but as road tires for my Checkmate or maybe the very fast gravel tires for dry conditions. But thanks for pointing my attention at the René H tires. I have to check them out (and run 32mm tires on my winter bike. Love them).
I think rider weight is going to have an impact on this as well. At 250lbs I like 32mm and I want to try something in the 35mm range next as that the max size i can stuff into the frame. Another thing is the effort to get the bike up to speed from a stop and lighter tires help with that.
Happy Holidays! As a lightweight rider with 65kg my sweetspot between speed and agility are 28mm in the summer and 32 in the winter. The pressure is 4.5 bar in the front and in the back riding tubeless. Mostly tarmac in good conditions and dry weather on a Giant Defy. Weather bad or offroad -> mtb.
I'm riding the Continental GP 5000 AS with 35mm width on my Factor Ostro Gravel. That's for me the perfect choice for mixed terrain (roads, wood, park). Very fast, feels more like a road bike, agile handling and comfortable too. It's significantly faster than my older setup with 40mm tires on all surfaces. Which you all a merry Christmas.
@@cricanwa dumb would be running 26mm tires and having 1mm of tire extend beyond the rim width. Think of the aero man. This is serious, I have places to be, I can't jeopardize my times for that extra tire width.
@@davidarthurlove to see you compare the G- One RS in 35mm with these. From what the Schwalbe rep told me they are as fast as the Schwalbe Pro One tyres but the side lugs may affect speed/grip in the wet on the road. Be interesting to see. Always fancied a set on an Allroad style bike!
I’d totally put the 40s on my gravel bike for mixed use, where paved surfaces are more than half of the ride. If you’re not a racer, you’re probably better off with wider yet slower tires
I switched to gravel bike on-the-road just so I could slap on some fat slicks and no longer have to keep one eye on the road looking out for cracks and holes while looking where I was going with the other. 38 mm seems perfect but those Pirelli's might get a try next time - even better if they offer 'em with (proper) brown sidewalls. Not that I much care, but I don't feel like the tires are slowing me down - an experience trying to keep pace (on a bike with 50 mm slicks) with a guy on a newest-latest, skinny-tired roadrace bike showed me there's not much difference.
100%. My local roads here in the California desert are straight up garbage. I’ve been riding a track bike with 28 touring tires and slime tubes for years, but much prefer my “road rides” on my cx bike with 45c gravel tires. My next road bike build will be with 35s to split the difference. Tried 30 and 32 tires and they were fast, but they get eaten up by the road conditions here.
Thanks for the review David! Do you think these would fit on a Giant Defy? I also really enjoy your channel. Thanks again! Merry Christmas and Happy Holidays!
I just got mine a week ago and they are noticeably slower compared to the 30 mm but are also very comfortable on rough roads. I did 2 twenty mile rides on different days and averaged 175 watts each time at 19.5 mph. They are on hunt 35 mm carbon wheels and mounted on my diverge. Right now I'm not going for speed. I'm mainly going for distance and if it takes me longer that just means more time training on my bike. I also find myself pushing harder because I'm trying to maintain my normal speed. So it's a win win situation and to top it off they make the bike very comfortable/smooth. Overall, they are more sensitive in crosswinds, slower but their comfort more than makes up for it.
Can you test new Hutchinson Caracal Race TLR 40 against these? They're 4w faster according to bicyclerollingresistance while being semislick gravel tire.
I have the Pirrellis , Caracals Race, and Terra Speeds in 45…the Caracals and Terra Speeds feel the most supple and speedy. If you want a fast big road tire get the Rene Herse 44c slick, or the Conti GP5K ASTR in 35.
I have been riding Rene Herse tires for several years now, gradually going up to the Barlow Pass Extralight tires for my Salsa Warbird gravel bike. Lovely, ride, almost as plush as the ride of my Alex Moulton bikes. David is correct regarding mounting the tires. I've never had a pleasant experience getting them on. However once on, they had been fairly resistant to punctures, at least in my riding. I suspect, I have been fortunate, and might have just cursed myself...
At 50kmph I can see how aero factors more into the 40mm but speed is a function of how hard the rider can pedal as well. On a 5 hour ride the absorbing of shocks, much of that energy going into the riders muscles and fatiguing them, might result in higher power output capability vs the thinner ones.
It's worth noting that Bicycle Rolling Resistance found that the 40c Pirelli P Zero Race TLER SpeedCore tires had a different construction than the 28c version of the same tire, with 20% more total thickness measured at the center of the tread. So it's not quite an apples to apples comparison. While the extra weight and aerodynamic drag of the wider tire undoubtedly influenced the outcome, some of the speed differential found here can likely be attributed to this thicker construction. A beneficial side effect of this thicker construction is that the 40c tire has outstanding puncture resistance in the tread area.
Really interested in the comparison to the Schwalbe G-one. I would recon that the Pirelli's are a bit faster, and thus a good option for converting a Gravel bike to road use.
Thanks for the review. I didn’t know such a tire exists, so when I found out that the BMC Roadmachine Four I ordered yesterday from my local bike shop will accommodate up to 40mm tires, I ordered a pair of these chubby meats. Very much looking forward to the maiden voyage.
My experience is that super wide tyres feel a lot slower than they are. I swapped some 32mm Sworks Mondo tyres for 42mm Sworks Pathfinders, and the bike felt sort of sluggish / slower to accelerate etc on good roads , but the data over a whole range of my normal rides was very similar only slightly slower in average. Some rides were actually faster over the same course at the same average power.. But whilst the wide tyres are amazing on bad roads / gravel etc, I definitely prefer the feel of the 32mm tyres - just feels more lively and fun, so they’ll go back on when the weather is better.
I agree. I've ridden the same tires on 42c and currently 32c. The 32c is faster. I think 32c is the best all rounder for tarmac riding. If you're gonna ride through dirt then 35c at the minimum would be better.
My Mondos did measure very fast, but were also appalling to get on and off the rim. As someone who has suffered many and bad punctures on long rides they just were not worth the risk.
@ I find the Mondos go on Ok; quite tight, but manageable on my Roval Terra wheels. But I do seem to get more punctures with them - great to ride summer and winter on road - but definitely not bulletproof. They do seem to patch well though. When they are done, I’m going to try some P Zeros.
I would think that 30 to 32 mm on road bikes hits the sweet spot on road bikes. I pretty much ride the widest tires I can fit: 28 mm on my road bike; limited by the brake calipers. I'm tempted to try 30 mm on my next tire. 45 mm on my gravel bike; limited by the fork legs. My Gravelking X1-R inflate to almost 48 mm. 2.4" on my XC bike; limited by the fork legs and rear stays.
On 28c I wish I could lower the psi more for maximum comfort but scared of getting pinch flat. I hope 30c could fix issue. The downside would be the weight?
@@thelmaviaduct It's hard to tell as wheels and frames flex when you ride, especially when riding out of the saddle. My gravel bike seemed to clear the gravelking tires while in the bike stand. But I recently noticed that the front tire rubbed into the right fork leg; so I will sand down the side knobs.
Interesting assessment. I love 28’s and recently fitted 30’s and while I don’t think there’s a world of difference with speed and power between them, I would say 30’s feel way more “sure-footed”; a much safer feeling of contact with the road. I was wondering in your assessment whether the variance in PSI between the 30’s and 40’s would play any part in the 10 watt power differential. It seems from posts on the grand tours that riders’ PSI is a closely guarded secret, so I’m guessing it’s an important factor.
I measured the Panaracer Tour 38c and Vittoria Randonneur 38c both at 36mm. I think it's a good compromise between 28mm and 40mm. And yes, I would go for the extra 1mm compared to 35mm tires.
I agree with you, I prefer 32mm max tyre size on my gravel, 28 on my racing and 25mm on my daily commute bike. Why 25mm on my daily commute!? Because it’s an old Cannondale Synaps and can only take 25mm 😂! But my favourite sweet spot for tyres is between 28-32 mm. really nice video by the way - thank you ☺️
On your test lap you rode at 30kph, at that speed would the aero delta really be significant? I would assume the 25% higher mass is probably a bigger factor
Merry Xmas David. I look forward to your reports on hill climbing with the 40s. I suspect your 11k route was mostly flat. There's a lot of chat about 35mm in the comments too...
Nice to hear some thoughts on this extra size. The cost of a 42mm (?) OD wide rims to allow for rule of 105, makes actual apple to apple testing costly. That you could ride at the same speed with only 12W penalty, with aero optimised wheels there may be nothing lost for the extra comfort. CdA vs Rr. Extra mass will always feel heavier when starting off; some say 'never again', others say 'no sweat'.
I've ridden for 5 decades now and favour a wide tyre up front , narrower rear set-up , 40/30 is a bit extreme , would consider 40 front and 35 rear though .
9:20 and thereabouts, you're testing these tires in terrible weather, what a champ! what do you wear to stay (reasonably) dry and warm in this weather?
A couple of comments: what tire width you select has to be dependent on your road or trail conditions. A wider tire has to have very rough roads to justify its width. I would say it’s similar to how you would approach the amount of suspension you need in your mtb. Rough trails need more, smooth trails need less. Re your reference to the Plus tire movement with MTB’s: lots of journalist tested the plus tires and repeatedly proved that they were better especially in rougher conditions yet they didn’t sell well. I think the failure of the Plus tires was down to consumer rejection rather than a lack of merit. Most consumers felt that they ‘looked’ heavy and slow and that was enough to kill that movement. The industry was quick to bail on it also because they didn’t want to stock yet another tire size. It’s easier for them if everyone was on the same tire and wheel size. PS: hat off for riding in such shit conditions!
Did you worry those tires aren’t approved on your Zipp wheels according to their approved tires page? I’ve thought a lot about doing your set up but don’t quite dare because of their untested newness on hookless Zipps. Thoughts?
yes they are quite different. I have the P Zero RS 32mm and they are a rather thin tire. but!! how he calculated 33 psi? thats way too low. 43-50 psi I would go for. idk if I can watch further then that.
why 35 psi? I run 59 and 57 psi back and front on GP5000 AS TR 35mm that measure 37mm on a 21mm Shimano carbon hooked rim. If I run them at 52 psi they are super muchy and 5 psi above, too stiff. rest of video gonna be nightmare I feel
maybe more about the aerodinamics than anithing else. It may be harder to accelerate but it should be easear to maintain the speed and these should compensate one another and rolling resistance should be better with the wider one actualy.
I believe in areas where the road is poor like where I live, that the wider tires, up to a point, are faster. I have given up riding my road bikes due to the poor road conditions! Even where there are no pot holes, the road is rough and gives me a terrible brain scrambling riding with anything under 32 mm.
For the last 16 years the old faithful Scott addict R2 has run 19mm, fast light and GP 5000 are a good combo of hardness and speed and lightweight. At 58 I can still chase Hill climbs KOMs
Basically wider tires are faster on ruff and wet roads. Narrow tires are more efficient on smooth roads. I have a rim brake bike running good quality 28m tires on it. Fast and efficient. But when I ride a lot back roads and gravel rail trails, that can be soft. I'll take my heavier gravel bike bike with 38m tires. They are more efficient and don't sink in as much in the soft mud or loose soil.
good comparison!! I wonder why you put the picture of the Propain in, when discussing switching between narrower and wider tires for road vs gravel; from your review of the Propain i concluded this was a semi-MTB. Not really an ideal bike to use narrower tires on then for road riding right? or did I not draw the right conclusion from your Propain video?
I personally use a 40 x 1 5/8" on the front wheel with an inner tube and a 80mm Hookless carbon rim and on the back a 700x19c Panaracer clincher with a Mavic GP4 rim, but I can't quite understand why the clincher tire won't stay on the TUB rim? maybe I've got the wrong tub glue / cement?
I'm riding the Pirelli 40mm in my commuter gravel bike comming from Schwalbe G-one bite 45mm. No gravel on my daily commute and therefore ideal for the purpose. Fast in comparison with the gravel tyres. For speed I have my aero bike in the weekends.
I also ride the 38c Barlow pass in extralight compound. So, based on your experience of trying all, unless you were racing, would you ever run 30c instead of the RH?
For me, average weight, 32 seems to be the sweet spot for road. Ride around 55 psi or less. Feels great, not super heavy, good compromise for comfort, rolling resistance, aero.
id like to see a 40mm on the back and a 30 or 32 on the front for the aero gains. since there isnt really any aero benefit in the back end- that's a good reason to just put in a big tyre and be comfortable.
How about comparing a 30 with a 35mm tire? Still a difference in size, but what about tryout power usage there. Narrowing it down, 35 or 32, or 30? We want to know. I am riding 30mm now.
I've watched a ton of these width comparison videos now and what seems to be the consensus is that most riders want 28-32mm, with 35mm being the upper limit of what's practical even for heavier riders unless you really want comfort over speed. Which if that's the case, why ride a road bike at all? I'm 190cm tall, 100kg and my "best setup" is a 30mm on a 32mm wide wheel. That way you get both aero and width, and if I wanted to up the width to a 32mm, I keep decent aero.
Interesting comparison. It seems that weight and aerodynamics have more of an effect beyond a certain width than lower rolling resistance. Pirelli has a 35 mm in that tire. It would be interesting to see how they perform. Could be the sweet spot. I have a titanium gravel bike with two sets of wheels. One set has 32mm Conti GP 5000 clinchers with TPU tubes and the other set has 35mm Pirelli Cinturado gravel H tires. These are my daily ride choice. The first set are my fast ride choice. They feel quite fast and are comfortable. I recently did my fastest 100k ride in several years on them. It seems they are fast. The question is, where is the sweet spot? At what size does aerodynamics and weight have more of an effect than rolling resistance? Rolling resistance is generally less with wider tires.
Not a surprise to see these results really - those roads don't look too bad and 40mm is definitely too wide for optimal speed, even if they might have other advantages. It would be really interesting to see exactly the same test with the Pirelli 30mm vs 26mm. I bet the 26mm would be faster still.
No one mentions the change in trail and handling characteristics going to 40mm tires? Steering response will be slower. Bottom line is the geo of these roadbikes weren't designed for these wide tires.
@davidarthur too bad! If one plays around with online trail calculators, can see how tire change alone can lengthen trail by several mm, which is not insignificant. Recently, I had to update my fork for different rake on my 25yo titanium road bike when putting on 28c tires to reconcile the intended trail.
I know it's tires comparition, but I would like to see you David reviewing quite interesting gravel racing bike. Bianchi Impulso RC with Shimano GRX 825 Di2 groupset. Unfortunately no reviews about this bike.
hmm, seems like front and back have different (but less than a gravel or mtn bike) demands ...with the rider on the bike weigh each wheel and then size, tread and pressure accordingly, worth considering ?
You might as well add a 35mm tire in the mix, and then depending on the results something around 37.5 or 32.5mm... and find the perfect one for real world conditions. I'm leaning towards 32mm.
I'm riding 35 mm G-One RS for all road stuff as well as group rides with pur road bikes. I've seen my share of flat tires but never had one. I hit potholes that took out the rider in front of me with no problem. What's 0.2 more kph, when you lose 10 minutes changing tubes?
I've got one on the back, but with the 40mm tyres there's annoyingly not enough space between the tyre and down tube :( So dry bum wet feet it is sadly
Something everyone missed: these Pirelli 40's are actuality 38's. Dave measured the width as 39.7mm, on Zipp 353 the internal width is 25mm which adds about 2mm to every tire after being mounted. I'm sure Pirelli do this to keep the weight down and to capitalize on the "wider is better" trend lately. So to me, these tires are seriously overweight for their size. I run both GP5000STR in a 30 and 32 {2 bikes} and the Panaracer GK+ Slicks 35mm. All appear to be a better choice than these Pirelli 40's.
Formula One cars run different width front & back. Why not bikes, since about 60-70% of the weight is on the rear? I've been using a non-matching set of tyres on the road (endurance) for about a year now - 28mm (measures 30) on the front & 30mm (measures 31) on the back - & it seems to work very well. This combo provides the benefit of maximum aero at the front (tyre is 105% of rim width on a 28mm external wide, 52mm deep rim), with more comfort & better grip at the rear. I'm 82kg, so I'm running 70psi front & rear for good road surfaces. At next tyre upgrade, I'll try 30/35.
David goes out test riding in the pouring rain in winter so that we don't have to.... another way to look at it is, ride big tyres in winter so you put out more power and don't have to be out so long in the muck to achieve the same effect... then jump on your summer bike when it perks up and boom, you fly. My own testing has somewhat confusingly shown that go even bigger and there is negligible difference in speed between a fast 40c gravel tyre (Conti TS) and a 2.1 Thunderburt (48C), some tyres seem to defy the laws of physics if supple enough...
I've been riding the Pirelli 40s for a couple months and they're wonderful. No, not the fastest, but they make up for it in a number of other ways - grip, ride quality, puncture resistance.
I have also ridden the 40mm, and I don't like them. They have high rolling resistance and are not very agile in corners. The robust Conti 5000 AS in 35 mm is near the same volume but rolls much better.
@@_msc-ds9sj Baesd on that comment ,I'm going to treat myself to a pair next week for Christmas.
lol 19 mm 21 23 25. 28 30 et now 40 mm 😂
Additional weight is quite significant, no?
@@blackjackpinoko Depends what you're coming from and what you're looking for. For me, they're durable and reasonably fast and feel nice. With the right tire pressure they're also remarkably grippy on the backroads we ride.
Thanks for the great work as always, David! I believe you missed out on the true grail width: 35mm! The P Zeros come in 700x35 and don’t suffer from the same weight penalties as the 40s, and just feel faster overall than the 28s I was riding previously. I’d be interested to get your perspective on the 35s as compared to the 30s and 40s.
Or a 35mm P Zero vs a 35mm Schwalbe G-One RS 🎉
I’m actually riding the Goodyear VectorR Z35s designed for Zipp wheels. I couldn’t wait for my desired PZero 35s to be launched, so I took a flyer on the Goodyear’s and am surprisingly happy with them! I think your comment and my experience point even further to 35s being the true sweet spot with a growing number of options.
@@Sb23global Def. a sweet spot with a mix of fast gravel tyres and pure slicks. Quite a lot of manufacturers as well.
@ArnageLM is there a 35mm Schwable? I have the 34mm One pro haven't seen a 35mm size. Maybe Europe only?
35mm RH slicks tires would be perfect. Or 38mm(really 40mm) if the frame can fit it in the supple casing.
Split the difference! I’ve been riding 35mm Panaracers and loving it.
I have as well!
Me too. Tserv ProTite in 35mm are great.
Same here. 35mm Gravelking slicks. Getting time to buy new tires, and I can't think how I can improve on the current setup.
Just bought another set of panaracer pasela 35s. It's just a really good tire. A great balance between performance and price.
@@davidcook8065 I've got those in 1.5-inch (38mm), tubeless ready, and they feel pretty fast.
I rode them with butyl and TPU tubes for 2-3 months, and kept getting little pinhole flats. I patched them from the inside, switched over to tubeless using Vittoria sealant, and haven't had a single problem since.
As someone who has decided to go the gravel bike serving as both my road and gravel solution, Im pumped to see the wider road tires so my bike handling wont change too much when swapping on road wheels
do you notice your gravel bike becomes 'twitchier' with a road tire vs. gravel tire?
I ask 'cause I'm trying to pin down the best tire size for an all-road/light gravel bike to be used purely as a dedicated road bike.
though I figure 32mm is probably the Goldilocks size for that.
Is changing wheels out easy or do you have to adjust gears or brakes
@@graemeross1998 I’ve never had too much issue. Gears I’ve never had an issue but have had to adjust my brake calipers slightly a couple times
I have started riding vittoria corsa n.ext 700x34s (the clincher version) with TPU tubes. They are only 315g which is pretty good for a tyre that big. Ride really nicely and don't feel too slugish.
@@The_Trojan i will test tubeless 34mm at 350g. Will see..
I have 34 mm Vittoria Corsa N.ext set up tubeless. Great tyre, tons of grip in the wet. Possibly not the fastest rolling tyre but not too bad. Very easy to set up tubeless. They held air even before I put sealant in.
I have a pair of these exact tire coming in today for road use on my Revolt. Mounting on 303s wheels, coming off 28's it should be interesting. Thanks for you review, can't wait to see how they feel myself!
wide tyres like this is extremly picky on tire pressure + - 3 PSI you will feel something is off. Either too mushy no corner grip or too highpressure slow and vibrations. Keep in mind some 35mm road tires measure 37mm or so, for me 35-37mm is sweet spot and for some 32mm that actual is 34mm. I guess you run tubeless. I find Sram calculator to be spot on maybe add 2-3more psi in front tire then calculator tells
@@allemyr yeah, I figure on the 23mm inside diameter, they should be right around 40mm. I haven't checked rims pressure chart yet, but on my 28th I've been running about 50 to 55 PSI with good luck.
@@allemyrSo I Finally got these installed and got in a quick 9 miles today. Inflated according to SRAM. On the 303S wheels (23mm IW) they measure out at just shy of 38mm at ~40psi. I suspect they may stretch out to 39 or 40 over the next few rides. 28, 30 ,and 32 all measured 2mm larger after a couple of rides. They def ride smooth and seem pretty durable, I immediately rode into a couple hundred yards of smashed up chunky asphalt off the side of the road and survived. So far, I like them, and will experiment with pressures for a sweet spot. I know they are slower and heavier, but they don’t feel bad at all.
Seems incredible to think that back in the mid-70s Pros were riding 23mm tubulars in Paris-Roubaix.
Steel frames and skinny aluminium rims would have taken a little of the sting out of it, but not much.
But, with steel frames and rim brakes the tires don't need as much compliance. I'm riding a modern steel rim brake frame with 30mm tire clearance, but will just try out 28mm out of curiosity once my current 25mm are worn out
@@Paganizondaf650 Yes, that's exactly my point.
I rode Roubaix on skinny aluminium rims and 30c's and wished I'd ridden 45c tubeless. If I ever do it again I'll use a drop bar 29er Hardtail and I bet I'll be quicker.
In the 1970ies, we used 18-21mm tubulars
That's a good test. Could be most of your viewers are not racers, so perhaps you could expand on that wider tire testing. Thanks for the good content this year and Merry Christmas!
Thanks and I think you're right, will do some more in the new year. Merry Christmas!
Merry Christmas! Be interesting to see how the 35mm go. Clearly 40 is too wide for most of us, but maybe 30 is not the sweet spot? But I hate heavy wheels, so I’ll stick to 25 or 28mm for most of my road riding, especially if it’s hilly. Maybe 30 in the winter…
Would be great to see the 40mm slick vs g-one rs!
Both in 35mm would be interesting!
love my G-ONE RS, plenty fast in 40, was riding a few days recently, nothing competitive but kept up with others that strictly ran high 20's to mid 30's. My 40 was the widest tire out of a group of maybe 100 riders. However that being said, the outer treads aren't that useul.
I think a read of Jan Heine has some great tire information and writeups on the Ren'e Herse website regarding tire sizes and uses.
Frankly, I like a more comfortable ride quality and that means running a little fatter tire, higher TPI on a nice wide rim at lower riding pressure. They simply work! A low TPI tire will drag like a Titanic anchor while a high TPI tire will roll very efficiently.
.and, there’s also 32, 35, and 38 increments to choose from (depending on the manufacturer) if you include slick gravel tires and road tires. Plenty of room to choose depending on height, weight, and road surface quality!
soon riders will no longer need to develop any skills, they will ask their Formula One derived AI assistant to route a course, choose a set from their 2000 $ tires stockpile and program the bluetooth compressor with the proper pressure for the gravels coarsness, temperature, humidity and distance.
-_-
Merry Christmas, David!! I really appreciate your efforts in creating great content that’s very enjoyable to watch!! Looking forward to 2025 content!!
Thanks! :)
These tires are so much on my radar, but as road tires for my Checkmate or maybe the very fast gravel tires for dry conditions. But thanks for pointing my attention at the René H tires. I have to check them out (and run 32mm tires on my winter bike. Love them).
I think rider weight is going to have an impact on this as well. At 250lbs I like 32mm and I want to try something in the 35mm range next as that the max size i can stuff into the frame. Another thing is the effort to get the bike up to speed from a stop and lighter tires help with that.
Happy Holidays! As a lightweight rider with 65kg my sweetspot between speed and agility are 28mm in the summer and 32 in the winter. The pressure is 4.5 bar in the front and in the back riding tubeless.
Mostly tarmac in good conditions and dry weather on a Giant Defy. Weather bad or offroad -> mtb.
I'm riding the Continental GP 5000 AS with 35mm width on my Factor Ostro Gravel. That's for me the perfect choice for mixed terrain (roads, wood, park). Very fast, feels more like a road bike, agile handling and comfortable too. It's significantly faster than my older setup with 40mm tires on all surfaces. Which you all a merry Christmas.
Happily riding 25mm to maintain aero performance with my wheels. I'm not giving up 2 watts. Nowai.
dumb
@@cricanwa dumb would be running 26mm tires and having 1mm of tire extend beyond the rim width. Think of the aero man. This is serious, I have places to be, I can't jeopardize my times for that extra tire width.
@@Thezuule1This could be slove with a wider rim
Although it is costly, the difference of ride quality between 25mm and 32mm is insane
meanwhile losing more watts on rolling resistance...
@@Thezuule1 you are joking
Would love to see the comparison between this tire and the g-one!
Cool, I'll get on that in the new year - I'm really intrigued to see what the difference is as well
@@davidarthurlove to see you compare the G- One RS in 35mm with these.
From what the Schwalbe rep told me they are as fast as the Schwalbe Pro One tyres but the side lugs may affect speed/grip in the wet on the road.
Be interesting to see.
Always fancied a set on an Allroad style bike!
I’d totally put the 40s on my gravel bike for mixed use, where paved surfaces are more than half of the ride. If you’re not a racer, you’re probably better off with wider yet slower tires
I switched to gravel bike on-the-road just so I could slap on some fat slicks and no longer have to keep one eye on the road looking out for cracks and holes while looking where I was going with the other. 38 mm seems perfect but those Pirelli's might get a try next time - even better if they offer 'em with (proper) brown sidewalls.
Not that I much care, but I don't feel like the tires are slowing me down - an experience trying to keep pace (on a bike with 50 mm slicks) with a guy on a newest-latest, skinny-tired roadrace bike showed me there's not much difference.
100%. My local roads here in the California desert are straight up garbage. I’ve been riding a track bike with 28 touring tires and slime tubes for years, but much prefer my “road rides” on my cx bike with 45c gravel tires. My next road bike build will be with 35s to split the difference. Tried 30 and 32 tires and they were fast, but they get eaten up by the road conditions here.
Thanks for the review David! Do you think these would fit on a Giant Defy? I also really enjoy your channel. Thanks again! Merry Christmas and Happy Holidays!
I just got mine a week ago and they are noticeably slower compared to the 30 mm but are also very comfortable on rough roads. I did 2 twenty mile rides on different days and averaged 175 watts each time at 19.5 mph. They are on hunt 35 mm carbon wheels and mounted on my diverge. Right now I'm not going for speed. I'm mainly going for distance and if it takes me longer that just means more time training on my bike. I also find myself pushing harder because I'm trying to maintain my normal speed. So it's a win win situation and to top it off they make the bike very comfortable/smooth. Overall, they are more sensitive in crosswinds, slower but their comfort more than makes up for it.
Those narrow, slick roads - no question what tire width I'd use. Not to mention the comfort factor.
Can you test new Hutchinson Caracal Race TLR 40 against these? They're 4w faster according to bicyclerollingresistance while being semislick gravel tire.
Seconded!!
I tried them last summer on my gravel paths, and got new PRs. Yeah, I was using Hutchinson Overide 38mm before, so, the gain was obvious.
I have the Pirrellis , Caracals Race, and Terra Speeds in 45…the Caracals and Terra Speeds feel the most supple and speedy. If you want a fast big road tire get the Rene Herse 44c slick, or the Conti GP5K ASTR in 35.
I have been riding Rene Herse tires for several years now, gradually going up to the Barlow Pass Extralight tires for my Salsa Warbird gravel bike. Lovely, ride, almost as plush as the ride of my Alex Moulton bikes.
David is correct regarding mounting the tires. I've never had a pleasant experience getting them on. However once on, they had been fairly resistant to punctures, at least in my riding. I suspect, I have been fortunate, and might have just cursed myself...
At 50kmph I can see how aero factors more into the 40mm but speed is a function of how hard the rider can pedal as well. On a 5 hour ride the absorbing of shocks, much of that energy going into the riders muscles and fatiguing them, might result in higher power output capability vs the thinner ones.
It's worth noting that Bicycle Rolling Resistance found that the 40c Pirelli P Zero Race TLER SpeedCore tires had a different construction than the 28c version of the same tire, with 20% more total thickness measured at the center of the tread. So it's not quite an apples to apples comparison. While the extra weight and aerodynamic drag of the wider tire undoubtedly influenced the outcome, some of the speed differential found here can likely be attributed to this thicker construction. A beneficial side effect of this thicker construction is that the 40c tire has outstanding puncture resistance in the tread area.
Really interested in the comparison to the Schwalbe G-one. I would recon that the Pirelli's are a bit faster, and thus a good option for converting a Gravel bike to road use.
I ride 32's as a set of road tires on my Gravel bike but this might make me go for something wider to see how it feels.
Thanks for the review. I didn’t know such a tire exists, so when I found out that the BMC Roadmachine Four I ordered yesterday from my local bike shop will accommodate up to 40mm tires, I ordered a pair of these chubby meats. Very much looking forward to the maiden voyage.
"chubby meats" lol
My experience is that super wide tyres feel a lot slower than they are.
I swapped some 32mm Sworks Mondo tyres for 42mm Sworks Pathfinders, and the bike felt sort of sluggish / slower to accelerate etc on good roads , but the data over a whole range of my normal rides was very similar only slightly slower in average.
Some rides were actually faster over the same course at the same average power..
But whilst the wide tyres are amazing on bad roads / gravel etc, I definitely prefer the feel of the 32mm tyres - just feels more lively and fun, so they’ll go back on when the weather is better.
I agree. I've ridden the same tires on 42c and currently 32c. The 32c is faster. I think 32c is the best all rounder for tarmac riding. If you're gonna ride through dirt then 35c at the minimum would be better.
My Mondos did measure very fast, but were also appalling to get on and off the rim. As someone who has suffered many and bad punctures on long rides they just were not worth the risk.
@ I find the Mondos go on Ok; quite tight, but manageable on my Roval Terra wheels. But I do seem to get more punctures with them - great to ride summer and winter on road - but definitely not bulletproof. They do seem to patch well though. When they are done, I’m going to try some P Zeros.
You need to try the Hutchinson Caracal race tyres, stupidly quick for a 40mm semi slick gravel tyre, very supple as well
Seriously low RR 🎉🎉
Have you considered trying this again with wider rims and seeing the difference it makes to the aerodynamics?
I would think that 30 to 32 mm on road bikes hits the sweet spot on road bikes.
I pretty much ride the widest tires I can fit:
28 mm on my road bike; limited by the brake calipers. I'm tempted to try 30 mm on my next tire.
45 mm on my gravel bike; limited by the fork legs. My Gravelking X1-R inflate to almost 48 mm.
2.4" on my XC bike; limited by the fork legs and rear stays.
On 28c I wish I could lower the psi more for maximum comfort but scared of getting pinch flat. I hope 30c could fix issue. The downside would be the weight?
@@diegoeleazar9154 I doubt you'll be able to notice the weight difference between 28 and 30 mm tires.
Would 30mm definitely not fit? I'm wondering what to buy 28 or 30 on R8000 cantis.
@@thelmaviaduct It's hard to tell as wheels and frames flex when you ride, especially when riding out of the saddle. My gravel bike seemed to clear the gravelking tires while in the bike stand. But I recently noticed that the front tire rubbed into the right fork leg; so I will sand down the side knobs.
@hansschotterradler3772 Cheers 👍🏿
Interesting assessment. I love 28’s and recently fitted 30’s and while I don’t think there’s a world of difference with speed and power between them, I would say 30’s feel way more “sure-footed”; a much safer feeling of contact with the road.
I was wondering in your assessment whether the variance in PSI between the 30’s and 40’s would play any part in the 10 watt power differential. It seems from posts on the grand tours that riders’ PSI is a closely guarded secret, so I’m guessing it’s an important factor.
I measured the Panaracer Tour 38c and Vittoria Randonneur 38c both at 36mm. I think it's a good compromise between 28mm and 40mm. And yes, I would go for the extra 1mm compared to 35mm tires.
I agree with you, I prefer 32mm max tyre size on my gravel, 28 on my racing and 25mm on my daily commute bike. Why 25mm on my daily commute!? Because it’s an old Cannondale Synaps and can only take 25mm 😂! But my favourite sweet spot for tyres is between 28-32 mm. really nice video by the way - thank you ☺️
On your test lap you rode at 30kph, at that speed would the aero delta really be significant? I would assume the 25% higher mass is probably a bigger factor
Bang on. At 31kph he's not getting any aero differential
Merry Xmas David.
I look forward to your reports on hill climbing with the 40s. I suspect your 11k route was mostly flat. There's a lot of chat about 35mm in the comments too...
Nice to hear some thoughts on this extra size. The cost of a 42mm (?) OD wide rims to allow for rule of 105, makes actual apple to apple testing costly. That you could ride at the same speed with only 12W penalty, with aero optimised wheels there may be nothing lost for the extra comfort. CdA vs Rr.
Extra mass will always feel heavier when starting off; some say 'never again', others say 'no sweat'.
I’ve been using Barlow pass for 10 years😊
32mm Conti 5000 TR is perfect for my riding.
I just started riding those a couple of weeks ago. They are amazing.
I've ridden for 5 decades now and favour a wide tyre up front , narrower rear set-up , 40/30 is a bit extreme , would consider 40 front and 35 rear though .
would love to see you try a 34 vs a 30 see if it gets faster or not
Agree would be interesting to see if that’s the Goldilocks
9:20 and thereabouts, you're testing these tires in terrible weather, what a champ! what do you wear to stay (reasonably) dry and warm in this weather?
28C tires work great for me,Happy Festive season and don't eat to much Turkey.💯🎅🎄🎄
I love my Continental GP5000 AS 700X35
A couple of comments: what tire width you select has to be dependent on your road or trail conditions. A wider tire has to have very rough roads to justify its width. I would say it’s similar to how you would approach the amount of suspension you need in your mtb. Rough trails need more, smooth trails need less. Re your reference to the Plus tire movement with MTB’s: lots of journalist tested the plus tires and repeatedly proved that they were better especially in rougher conditions yet they didn’t sell well. I think the failure of the Plus tires was down to consumer rejection rather than a lack of merit. Most consumers felt that they ‘looked’ heavy and slow and that was enough to kill that movement. The industry was quick to bail on it also because they didn’t want to stock yet another tire size. It’s easier for them if everyone was on the same tire and wheel size.
PS: hat off for riding in such shit conditions!
Did you worry those tires aren’t approved on your Zipp wheels according to their approved tires page? I’ve thought a lot about doing your set up but don’t quite dare because of their untested newness on hookless Zipps. Thoughts?
Did he compare the normal Race TLR with the RS version? The 40mm has a much higher casing thickness and puncture protection.
yes they are quite different. I have the P Zero RS 32mm and they are a rather thin tire. but!! how he calculated 33 psi? thats way too low. 43-50 psi I would go for. idk if I can watch further then that.
why 35 psi? I run 59 and 57 psi back and front on GP5000 AS TR 35mm that measure 37mm on a 21mm Shimano carbon hooked rim. If I run them at 52 psi they are super muchy and 5 psi above, too stiff. rest of video gonna be nightmare I feel
How is cornering with wider tires compared to skinnier ones?
How about a wider tire on the rear wheel and a smaller on the front?
Is the power difference due to rolling resistance or the extra energy required to accelerate the extra weight?
maybe more about the aerodinamics than anithing else. It may be harder to accelerate but it should be easear to maintain the speed and these should compensate one another and rolling resistance should be better with the wider one actualy.
Just looking at the video, are there two bikes used here? One with mudguards and the other without?
Would the aero disadvantage be minimized riding in a group?
I believe in areas where the road is poor like where I live, that the wider tires, up to a point, are faster.
I have given up riding my road bikes due to the poor road conditions! Even where there are no pot holes, the road is rough and gives me a terrible brain scrambling riding with anything under 32 mm.
The point in winter is - How long will it take you to fix a puncture in poor conditions against I'm slightly slower but wont have to fix a puncture
For the last 16 years the old faithful Scott addict R2 has run 19mm, fast light and GP 5000 are a good combo of hardness and speed and lightweight. At 58 I can still chase Hill climbs KOMs
Basically wider tires are faster on ruff and wet roads. Narrow tires are more efficient on smooth roads.
I have a rim brake bike running good quality 28m tires on it. Fast and efficient. But when I ride a lot back roads and gravel rail trails, that can be soft. I'll take my heavier gravel bike bike with 38m tires. They are more efficient and don't sink in as much in the soft mud or loose soil.
One needs to ask whats the use case for this tire. Is it perhaps for classics riders, the hell of the north perhaps?
Schwalbe already offers their Pro One road performance tire in 700x38c. 425 g per tire is also a big number in race bike language.
35mm is sweet spot for all road - x road / light- aero gravel
No.
Yes.
Agree. Riding the Conti GP Urban in 35 mil with TPU tubes. Just the right balance between rolling well and comfy. Not the heaviest either.
@davidarthur have you tried 40mm front to get steering grip and 30mm rear for speed?
good comparison!! I wonder why you put the picture of the Propain in, when discussing switching between narrower and wider tires for road vs gravel; from your review of the Propain i concluded this was a semi-MTB. Not really an ideal bike to use narrower tires on then for road riding right? or did I not draw the right conclusion from your Propain video?
I personally use a 40 x 1 5/8" on the front wheel with an inner tube and a 80mm Hookless carbon rim and on the back a 700x19c Panaracer clincher with a Mavic GP4 rim, but I can't quite understand why the clincher tire won't stay on the TUB rim? maybe I've got the wrong tub glue / cement?
I'm riding the Pirelli 40mm in my commuter gravel bike comming from Schwalbe G-one bite 45mm. No gravel on my daily commute and therefore ideal for the purpose. Fast in comparison with the gravel tyres. For speed I have my aero bike in the weekends.
I love 40c. Riding a mtb hybrid
I also ride the 38c Barlow pass in extralight compound.
So, based on your experience of trying all, unless you were racing, would you ever run 30c instead of the RH?
I’ve the Schwalbe Pro One’s; 30mm in the front and 34mm in the rear.
Maybe you could test this combo?
For me, average weight, 32 seems to be the sweet spot for road. Ride around 55 psi or less. Feels great, not super heavy, good compromise for comfort, rolling resistance, aero.
id like to see a 40mm on the back and a 30 or 32 on the front for the aero gains. since there isnt really any aero benefit in the back end- that's a good reason to just put in a big tyre and be comfortable.
@davidarthur My hands would freeze riding in that cold and rain. Don't know how you ride gloveless in those conditions...
How about comparing a 30 with a 35mm tire? Still a difference in size, but what about tryout power usage there. Narrowing it down, 35 or 32, or 30? We want to know. I am riding 30mm now.
I've watched a ton of these width comparison videos now and what seems to be the consensus is that most riders want 28-32mm, with 35mm being the upper limit of what's practical even for heavier riders unless you really want comfort over speed. Which if that's the case, why ride a road bike at all? I'm 190cm tall, 100kg and my "best setup" is a 30mm on a 32mm wide wheel. That way you get both aero and width, and if I wanted to up the width to a 32mm, I keep decent aero.
Interesting comparison. It seems that weight and aerodynamics have more of an effect beyond a certain width than lower rolling resistance. Pirelli has a 35 mm in that tire. It would be interesting to see how they perform. Could be the sweet spot. I have a titanium gravel bike with two sets of wheels. One set has 32mm Conti GP 5000 clinchers with TPU tubes and the other set has 35mm Pirelli Cinturado gravel H tires. These are my daily ride choice. The first set are my fast ride choice. They feel quite fast and are comfortable. I recently did my fastest 100k ride in several years on them. It seems they are fast. The question is, where is the sweet spot? At what size does aerodynamics and weight have more of an effect than rolling resistance? Rolling resistance is generally less with wider tires.
Not a surprise to see these results really - those roads don't look too bad and 40mm is definitely too wide for optimal speed, even if they might have other advantages. It would be really interesting to see exactly the same test with the Pirelli 30mm vs 26mm. I bet the 26mm would be faster still.
who are these tires for? maybe a 'solution' for gravel bikes that want road tires? because when you install a 28mm on them, it looks a bit silly.
No one mentions the change in trail and handling characteristics going to 40mm tires? Steering response will be slower. Bottom line is the geo of these roadbikes weren't designed for these wide tires.
This one was. And I ran out of time to talk about that in this video though did film a whole section , it’s an interesting topic though for sure
@davidarthur too bad! If one plays around with online trail calculators, can see how tire change alone can lengthen trail by several mm, which is not insignificant. Recently, I had to update my fork for different rake on my 25yo titanium road bike when putting on 28c tires to reconcile the intended trail.
I know it's tires comparition, but I would like to see you David reviewing quite interesting gravel racing bike. Bianchi Impulso RC with Shimano GRX 825 Di2 groupset. Unfortunately no reviews about this bike.
My best all-around for speed and comfort is 38mm
I had a good experience with challenge strada bianche 36mm. Didn't feel slow at all.
hmm, seems like front and back have different (but less than a gravel or mtn bike) demands ...with the rider on the bike weigh each wheel and then size, tread and pressure accordingly, worth considering ?
Need to get to the Zipp 303 xplr and wider rim width than 25mm internal. Rims are coming out to optimize a 40mm tire.
Hi David can you please tell me the tilt of your argo adaptive? Same saddle for me, find comfort only with “extreme” tilting…
You might as well add a 35mm tire in the mix, and then depending on the results something around 37.5 or 32.5mm... and find the perfect one for real world conditions. I'm leaning towards 32mm.
How about 30 on the front and a 40 on the rear to see if that finds a balance between aero and comfort?
I'm riding 35 mm G-One RS for all road stuff as well as group rides with pur road bikes.
I've seen my share of flat tires but never had one. I hit potholes that took out the rider in front of me with no problem. What's 0.2 more kph, when you lose 10 minutes changing tubes?
Think you need to invest in a set of mudguards for the Sika. See what Father Christmas brings you 🧑🏻🎄
I've got one on the back, but with the 40mm tyres there's annoyingly not enough space between the tyre and down tube :( So dry bum wet feet it is sadly
What psi do you run on tubless?
형님 수고가 많습니다. 최근에 추세를 보면, 타이어의 발전이 튜블리스 휠셋의 발전과 함께 진행 되는 것 같습니다. 이번에 테스트한 40mm 타이어도 나중에 더 완성된 기술로 만들어지게 되고 와트 차이와 무게 차이는 더 줄어들겠죠
I'm looking for slicks in 45mm....any suggestions? Turning my gravelbike into beachracer the cheap way
Rene Herse, but no cheap.
Something everyone missed: these Pirelli 40's are actuality 38's. Dave measured the width as 39.7mm, on Zipp 353 the internal width is 25mm which adds about 2mm to every tire after being mounted.
I'm sure Pirelli do this to keep the weight down and to capitalize on the "wider is better" trend lately.
So to me, these tires are seriously overweight for their size.
I run both GP5000STR in a 30 and 32 {2 bikes} and the Panaracer GK+ Slicks 35mm. All appear to be a better choice than these Pirelli 40's.
375gr for the 30mm? Is that for a TLR option? I have 30mm PZeros at 245 grams ❤
Once you are up to speed and you have correct shaped rims, yes. So, perfect for triathlon or TT.
25mm Ritchey WCS Racing Slick Tyres, are Genuinely the Best Tyres I've Used.
Formula One cars run different width front & back. Why not bikes, since about 60-70% of the weight is on the rear? I've been using a non-matching set of tyres on the road (endurance) for about a year now - 28mm (measures 30) on the front & 30mm (measures 31) on the back - & it seems to work very well. This combo provides the benefit of maximum aero at the front (tyre is 105% of rim width on a 28mm external wide, 52mm deep rim), with more comfort & better grip at the rear. I'm 82kg, so I'm running 70psi front & rear for good road surfaces. At next tyre upgrade, I'll try 30/35.
Def curious this tire vs the G-One RS (pro version)
Maybe a mix, 30 in the front, 40 in the back?