TL;DR - run the biggest rotors you can, and just pay attention to what you and the bike are doing. I'm a bike mechanic. Most of the bikes I work on have the rear brakes more worn down than the front, regardless of rotor size. On my (previous) personal bike, I put 203 rotors front and rear. I shift my weight around when I ride, I don't drag my brakes unless I'm on really slippery, steep stuff (and even then I use both brakes), I don't brake in corners, and after 200,000' of descending, my pads and rotors were ready to be replaced. The rear were worn a hair more than the front. I never had any issues feeling like the rear was easier to lock up than the front. On my current bike, same brakes, same size rotors, but it's a mullet bike. So far, I'm not noticing any issues with differences in braking power, but then I can get my weight further back on this bike. We'll see how I feel when Hayes comes out with 223mm D-series rotors.
On trails back brakes are used to slide the tail. To stop safer and faster best to use both brakes. As the body weight shifts forward and inertia, more force is on the front wheel to the ground, it needs a bigger rotor to stop.
big front disc and small rear disc is purely for theoretical front/back brake force distribution ratio in specific braking scenario under linear forward riding condition. It does not apply to specific intent of braking, where a rider specifically wanted his rear wheel to lock up irrespective of the front.
I use TRP 220mm with 2.3mm thickness on both front and back, the power is unreal, I would never go below 220mm, especially with 29" wheels, they look just like 203 on a 26" wheel.
If you can lock your brake up without much effort, you don't need a larger brake setup. Raced motocross for years and left the rear stock but went to a 280 front rotor for single finger stopping ability. Weight transfers to the front under hard stopping. These questions have already been answered by motorcycles and physics.
it's not just braking power, it's heat management. The larger rotors are going to run cooler given the same stopping usage. I also use way more rear brake than front most of the time. A rear wheel skid is no big deal, a front wheel skid is often carnage.
On a motorcycle the front is used much more because of weight transfer, under hard straight line breaking all the weight transfers to the front and the back will lock up very easy, with minimal breaking force. So no need for very powerful back breaks. But in mountain biking I agree, why have a small back break? It get used more in that style of riding.
This is an engineering question that relates to physics and leverage. When any vehicle slows, the load moves to the front. Since the rear is unloaded during braking, less braking force will result in the tire locking (reducing braking performance significantly). A larger rotor has more leverage (more braking torque given then same force at the caliper). A larger rotor will make it very easy to lock your rear wheel when braking. Also more weight, also rotational mass. The small rotor has plenty of cooling capacity for the braking energy it is dealing with.
yeah, the other side of this argument is that if you surveyed bike mechanics, my guess is that you'd find that rear rotors and brake pads are replaced more often or are more worn on most bikes than front rotors.
I agree with you, but for the sake of discussion: does the rear unload though, since good mtb technique includes constantly shifting rider weight to optimise grip. Any experienced rider will lean backwards when braking hard
You are correct apart from the your last sentence. Non-pro riders often drag the rear brake. On a longer DH run, this can cause smaller rotors to over heat. Larger rear rotor will be able to cope with this constant heat better than a smaller one. Pro riders won't drag the rear brake, but during braking, they do have the ability to stamp down on the pedals to momentary drive the rear wheel in to the ground, and be able to utilize the increased braking force a larger rotor provides without loosing traction.
To those saying is for weight saving, a fart weights more than 15 203mm rotors, the difference between 140/160mm and 203mm is in grams, not even ounces,
Even though you use the rear brakes more. The rear brakes are not holding back the entire weight if the rider and the bike like the front brake. The rear tire will skid way before the front brake with the same brake effort.
on my enduro stock was 203f 203r but the rear just locks up too easily, since I got a 180r it feels much better balance. Look at not just size of rotor but also thickness and if that rotor is meant for intened use. For example my 130mm trail bike is 203f 180 rear but is only 1.8mm thick with organic pads and is meant for trail riding. While my 161mm enduro is 203f now 180r but is 2mm thickness with metallic pads and the rotors are meant for more gravity focus.
Rear time spent under pressure = 3 times more than Front, even subconsciously one is always feathering the rear. When you do want to initiate hard straight line breaking, you want the front big. 180 back and front makes sense to me or bigger. For that matter if your a single tracker / general rider / I would argue 160 back and front (not cheap stuff) is fine too. Good points, the unequal to me is silly.
Because when you are heading downhill you use the brakes the most and the centre of gravity is nearer the front wheel contact patch than the rear. It's far easier to lock up the rear than the front in any braking situation, even on the flat your centre of gravity moves forward under braking. Having said all that I personally run 230mm FR and 203mm RE as I ride a mix of steep technical and long fast downhill. I find the larger rotor deals with drag brake heat more and gives better modulation, I do not skid, ever. Skidding means you are out of control. I also use my front brake mid corner to move my ride line wider if i need to or scrub speed with it at the same time as using the rear. To do this you need proper cornering and braking technique, with that you won't wash the front wheel out.
The rear tire is always (for me) with lower rolling resistance. I like 180/160 because I feel more the rear before locking. If I have let's say xt on the front and deore on the back maybe 180/180 will be fine
People think the front gets more use and gives more power, which on a road bike is true. But do that off road you’ll be on your face quicker than a fart especially down hill. Sandy condition in the wet in an event in Surrey hills the back brake used all 50% of the remaining rear pads by half way round. The front was untouched. Note to self always start an event with new pads. Upgraded rear to 4 pot caliper and 203 discs. I think 220 will warp and rub more though? Please advise
Maybe its because the stays in the back are not that sophisticated (mount) like the casting of a beefy fork?!there is a lot leverage going on over 180mm rotors… Its just a guess.
Interesting. Yet when I gravity brake I'm punching my weight down while shifting back. Super modulation. Galfer wave 223x2.0 front, magura storm hc 203x2.0 rear. Zero fade. MTX RED 4 piece MT5 pads and MT5 calipers.
180mm front 160mm rear for me works just fine. Just trail riding though. The rear wheel breaks loose easier with a bigger rotor which is not desirable unless you really want to break the rear tire loose like this guy is talking about.
anyone who rides steep slippy terrain will know. brake bias if your back brake is more powerful than the front it will loose traction first making the back of the bike faster than the front.
Engineering and physics is one thing and it's true that your front rotor is more efficient to slow you down but in practice, your rear brake is more often applied in descents to slow you down in a controlled manner. My XC hardtail has 160mm rotors front and back and the rear pads are 50% more worn than the front ones and my rear rotor has more heating mark than the front one.
Sure, on dirt and gravel a bigger rear brake rotor could make sense, but on the road (tarmac) it's pointless to have 180+mm rear rotor as the moment you start braking, all the weight goes above the front wheel and the rear wheel gets light and locks up. That's why cars and motorcycles have ''bigger'' brakes on the front wheel/s.
He made a great point about the engine brake on a motorbike. I am using both of my brakes all the time, but there are situations where I only use rear break (corners, steeps, slippery) but rarely use front brake only (unless doing stoppie)
I raced MX for years and in race situations, we don't care about engine braking to stop. You'll stall the engine with hard braking while the clutch is engaged and that is no bueno.
@@marthamryglod291 Don't know much about braking while MX racing, but when I trail ride on my dirt bike I use the engine brake pretty often. That being said I am not trying to compare it to race situation, which I understand is completely different for leisure trail raiding. But I know that the guys racing road bikes MotoGP, TT road racing etc. also rely on the engine brake quite a bit.
@@KapitanPisoar1 yes you're correct with your examples. I raced in the two stroke era but still ride casually a two and four stroke. I still will disagree with the man being interviewed on his reasoning, though not his preferences.
A lot of misapplication of principles of motorcycles. On a motorcycle the weight and momentum is vastly higher than that of even old school downhill bikes. This results in an inability for body position to have significant affects on the weight distribution, as moving 200 lbs backwards on a 400lb sportbike won't have the same affect as shifting 200lbs backwards on a 35lb bike. Beyond that, you're also discussing motorcycles on a flat surface, traveling in a straight line. We're talking bicycles going downhill, often turning or leaned over. In these situations the front traction limits are significantly lower, and the consequences for loss of traction drastically higher as it guarantees a washout. The rear, while also having reduced traction limits, has far less consequence for sliding, with high side crashes being very uncommon in mountain biking.
Weight transfer to the front wheel. This equates to more traction. Bigger rotor, more power. Less modulation. Smaller back brake equals better modulation. Smaller rotor equals smaller lever arm. This provides the better modulation.
The rear rotor is NOT SMALLER than the front....rather, the front is bigger than the rear. Because its all about the cheapest amount of material to maximize profits and balance form vs function. The minimum rotor size needed in front will always be bigger than what's needed in the rear.... because physics; e.g., weight and motion.
I just put a 180 on my front today!!...I've now ordered another 180 disc rotor for the back, up from from 160s....this guy makes sense about the back brake and has me convinced bigger at the back is better.
Modern motorcycles especially pro bikes don't engine brake much because they have slipper clutch. I prefer a bigger front rotor on my mtb but a mtb does get closer to a 50/50 bias compared to moto.
His theory is wrong about why motorcycles have small rear brakes and big front brakes, assuming he's talking about road bikes, specifically sports bikes, the reason why is because at least 90% of your stopping power comes from the front, and when you're hard on the brakes the rear gets very light, sometimes it can skip off the ground.
A smaller disc is more modular, so It doesn't lock up so easy, on the other hand the front one is bigger couse it's more aggressive but since when you brake your weight goes foreword it's very unlikely for your front wheel to lock up and slide... Therefore you can brake more aggressively without having to worry about skidding
I think is cuz: 1. U want the same brake power feel in the front and in the rear and more % of your body weight is on the rear wheel 2. U want to have some modulation and didn't like 0-1 block feeling on your rear wheel 3. U use rear brake more than a front brake so 180mm is less expose to bent than 203mm 4. Smaller rotors are cheaper so companies dont care, throw some "better" brake and save on rotors and pads 5. Most of people use cheaper rotors, they bent quite easily so smaller is better choice
Tried it out. 200mm front and 220mm on the back. Works way better than the other way around. The front brake gets more adjustable and the backwheel comes loose easelier.
Because front brakes are harder to lock up, due to that being where most of the weight is. The rear brake rotor would be smaller to keep the rear brake feeling as equal as possible to the front brake in terms of how much pressure they take to lock up. Depends how much you like pulling skiddies...
@@willbennett7107 Good point, but @Matt Clarke also has a good point (Below comment) When you brake in any vehicle, the weight will always be thrown to the front, unloading weight from the rear regardless of where the weight is when the brakes are off. a larger rotor would help to counter this because of the added weight, but not much. personally I have equal sizings of rotors/calipers on my mtb and it's always been far easier to lock the back, I'm guessing this is why.
John Bennett jumping back in a few months later, but bikes have a property called antirise which dictates the weight shift when using the rear brake. A bike like the Commencal supreme has extremely high antirise, which will mean your weight shifts backwards under breaking, going against the hypothesis of weight shifting forward. A bike like a Kona operator will not have any weight shift under braking, where a specialized demo or other 4 bar bike will have some forward weight shift
Absolutelly right. Back brake shouldn’t be smaller than front. Both equal, the best. If I need to choose which one needs to be bigger I would choose bigger rotor on the back
It’s all about physics really. The front brake is always bigger because once its engaged all of the energy from mass and momentum of the rider, their bike & the speed they’re carrying is transferred to the front wheel/brake. The front tire therefore gains more traction, and can take more braking force.
thats true for road racing, where youre doing hard braking and then completely let go off the brakes all the way to the next braking point where you brake hard again. its different for offroad use even if you compare a wtcc and a wrc car. on two wheels you do need the rear brake to controll the bike and it is indeed use more than the front brake (but not as strong as the front brake) wich makes it hotter than the front brake, wich has more time to cool down.
I use the front brake to stop or to slow down, and the back brake is usually used to skid because it's harder to make a bike slowing down with that brake without locking the wheel (so you use it to repositioning the bike on the trail). So in my opinion, a bigger rotor is required at the front because that's where you convert the most of your kinetic energy into heat, in the back your tyre will do the job, cause the rotor will be locked in place by the brake (not much heat to be dissipated). Probably the brands are building their bikes like that for weight reduction purposes idk. If anyone has telemetry data that shows equal heat dissipation between the two rotors please comment below, I would love to know if I'm right or wrong!
WOW! What an interesting topic. I've never heard anyone talk about this. I know I should use the front stopping power more than I do. But, I think for most amateur riders we should have a larger rotor in the back. Because everyone I know and ride with using the back break more than the front.
yeah thats right but that isnt the same thing as wanting a smaller in the back. I can understand if you go from 180/180 to 203/108 (front/back), ´cause you want a bit more power. But why would you go from 203/203 to 203/180?
@The Syndicate please measure the disc- and caliper temperatures front and rear right when the rider comes through the finish (on a training run of course) i think this would give really interesting data comparing different tracks and riders.
smaller rear rotor for more clearance to obstacles like rocks etc, less flex/bending issues, less weight, less costs and less need to modulate as at the front. I certainly use the front brake more than the back brake. Maybe 70% at the front to 30% at the rear. Thanks for sharing your thoughts, guyz! ^^
I like my brakes to feel consistent between the front and back and want the brakes to be as effective as possible. The more power available the better!
I didn't finish the video... The reason why there is a smaller disc on the back is because a bigger disc will make it very easy to stop the wheel completely and u will skid the wheel after, which means less stopping power so smaller disc will have better stoping power in this case because it doesn't skid as much. However it's a different case on the front wheel because front wheels rarely skid because there is alot of weight on that wheel during breaking. It's really not that hard to understand, I thought it's obvious 😅
@The Syndicate I personally think it depends on preference and rider parameters. It's a fact that when you slow down a bicycle (or any vehicle for that matter), the rider maintains its inertia, loading the front wheel more than the back, so it would make sense to have a bigger braking power at the front and/or less at the back to tune the needed braking power just enough to decelerate but not lock up or skid. However, it''s also true is that it only happens momentarily, and once full system deceleration (bike and rider) is achieved, the load difference between wheels returns to normal, so you never really need the difference in braking power unless if your only purpose of braking is braking to a stop. There are also other factors (besides rotor size) like: -system weight -piston number per caliper -pad material and pad backing heat management -mechanical vs hydraulic -rider skill level (weight balance management, cornering technique, braking technique, etc.) -rider preference (locking up, dragging, feathering, not braking, etc.) -optimization (braking performance, weight saving, etc.) -intent/needs (racing, casual riding) -discipline (road, touring, CX, XC, enduro, downhill) Therefore, there is no universally 'best' setup. The best setup is one where, taking all those factors into account, you should have sufficient braking power for intended purpose without compromising component function and performance. If you feel like needing more braking power, or your rotors are having discoloration, or you notice fading, upgrade braking power and heat management (4 piston, mechanical to hydraulic, bigger rotor, heatsink/finned rotors, grippier pad material, finned pads, etc.). If you feel like there's too much braking power (which sounds absurd but is possible), then simply downgrade. This applies independently to each wheel.
Rear wheel braking does very little to resist acceleration when compared to the front. Real stopping power comes from the front, it’s physics. Locking up your rear wheel may help in direction control, but relatively little in resisting acceleration. That being said WC riders may be happy with their speed/acceleration and increased wear on their rear rotor is representative of how much they use it for direction control, but minimal speed control (when it’s locked up, ie: coefficient of friction, static vs dynamic). Smaller rotors in the back would reduce biting power of the callipers, but in effect adding modulation (reducing how easily the rear wheel locks up). If a rider uses rear wheel braking for direction control (ie: locking it up), increased modulation could be undesirable.
Bigger rotor, more leverage, less rider input needed. Bigger rotors ramp up quicker than smaller ones, meaning less finger travel. You can setup the levers closer to the bar. So, if you like long brake levers and fatigued fingers, go for small rotors. If you like short comfy brake levers go for big rotors. Edit: It's more about feel and confidence than theoretical performance. That being said. if you blue your rotors, they're obviously too small.
Small brake on the rear, like mark Clark said, on any bike/vehicle when breaking the weight moves to the front un-loading the back wheels so it's easy to lock up, my back brakes locked up for 5 minutes straight don't even get warm because there is little movement, my front brake gets glowing how down steep stuff
Rear brake controls acceleration (descending) and the front does the real braking. Having a big rotor in the back sends obvious to me for heat dissipation.
On front wheel the braking force needs to be much bigger than on the rear. Efficient braking ratio might be something around 70% on the front against 30% on the rear. Try to stop a bike using only rear brake - you will easily lock the wheel and the breaking distance will be relatively long. On the other side when you stop using front brake only, you will hardly lock the front whell (in case you're not cornering of course - not recommended) and you will stop almost immediately. I like to use 203mm rotor on the front and 180mm on the rear because of the mentioned reason. You want stopping force on the rear to be lower. When pressing both brake levers identically (same force), you really want to have bigger stopping power on the front, not the rear. While using rear brake when cornering, the force is really minor and the rear wheel locks quite easily so it's still not a big problem to use controlled skids during cornering.
Bigger is better, more power = less effort which= less arm pump. anyone who says it's easier to modulate a smaller disc just needs a better set of breaks.
Been riding downhill for 13years and initially I was riding 203 front and rear. As time went on I made a decision to swap 203 rear with 180. Why? Becausd it offers more ground clearance, bends not so often, sufficient for making rear wheel lock on when braking...Marshys dilema of different usage of front amd rear brake is weird to me. When I use my brakes I use them simultaneously. Thats the only was of slowing down in a controlled manmer -rear not locking, front not skidding.
Understand your point there, but I have two things. First, you said a smaller rotor offers more ground clearence and doesnt bend so often. Do you actually have a proplem with bendig or hitting your rotor while riding? Maybe when you lay your bike on the floor too aggressively, but that happens to me maybe once a year and to fix it i just bend my rotor a little back... . And I´m sorry but I cant imagine a situation on the trail where you hit your rotor, just because it is 23mm bigger. Otherwise, if you, for example, crash those two centimeters also dont make a difference, really. The other thing is, that I also dont all the time use both of my brakes. If i just want to stop or really slow down, then yes of course. But when youre riding fast and you for example recognize that youre a bit fast for a section or jump, you know the speed of, you just want to pull that rear brake a tiny bit to get the speed that you want. I personally do that on my Hometrail every time before one exact jump, I know I´m just a bit too fast for. So please tell me if I´m wrong here
It's good to know I'm not the only one that wonders the same thing. I have a160mm on the front and a 203mm on the back and let me tell you, even with that tiny 160, I get more braking power from it than I do from the back. I also ride a bike with rim brakes and I seldom touch the front brakes. Unless you want to become a human trebuchet, an over powered front brake doesn't make sense. The front brake is stronger by nature and it's the back that needs more force to compensate for the fact that the weight is being shifted onto the front
Because when you Break all of your energy shifts forward. With a bigger Rotor upfront you can compensate for the braking power you need Btw sorry for the bad English
It’s simple- it’s less sensitive to lock up! If you have a bad ass four piston caliper front and rear, you’re gonna need to concentrate harder to actually use the back brake to slow the bike without locking. I made the mistake of a four piston caliper on the back of my all Mtn bike, now I have to run different pads to use it. I am an moto guy, so I get my braking done late and hard before the turn with the front. I pride myself on outbraking everyone while staying off the rear brake, but if I could do it over, I’d put a Code up front and some single piston out back. Within 3 grams of my Guides, and then I could justify the big rear rotor I run.. Just like my last MX bike!
The whole braking is different. The rear wheel brakes quite harsh and is blocked often in order to skid, slide etc. that doesn’t produce much heat, since the wheel experiences all the friction. The front has the most weight and grip in steep sections and you use it for decelerating, what means friction over a time period and produces heat at the brake.
As long as the brakes used are not "light switch" modulation, 203mm front and rear. My 130lb wife with 180mm rotors goes through rear brakes faster than I do, at 200lbs with 203mm. Large rotors front for the straight line leverage for stopping power, and big rotors in the rear for fade resistance and to try to make the pads wear longer!
I've been asking this question myself. But since I have very little knowledge in braking technique for different riding condition (not to mention I only ride once a week on mostly tarmac), I keep my brakes on manufacturer standard (160/160).
It's not just about rotor diameter. Rotor thickness (2 mm Magura vs 1.8 mm SRAM-Shimano) and rotor-vs-pad chemistry matters. Bedding-in matters. How many people actually do it right? I wonder about using sintered steel pads up front and organic pads out back, or vice-versa, or just stay with the same front & rear pads? There's one way to find out... I'm going to experiment with sintered steel pads / 203mm rotor in front and organic pads / 180mm rotor on my SRAM G2. Actually there are an infinite number of variables (tire characteristics, wheel diameter, trail surface adhesion, etc.) Even within one brand and model of rotor people seem to have dramatically different experiences. Some people scorch their rotors after a couple hours riding while other riders never scorch rotors. Maybe there's variability between rotor production runs? Maybe people bed-in rotors differently between front and rear? All of this makes generalizing about rotor diameter near impossible. So far I've only been riding stock organic pads / 180mm SRAM rotors on my Tallboy 29'er - so I don't have much personal experience to add. I tried to bed them in correctly, but who even knows if I did it right? Great video and discussion.
if you slam the front brakes your weight gets shifted forward making the front tire get more grip, so it needs more stopping power. if you slam the back brakes your weight gets shifted forward and it loses grip (skids easier than the front), so you don't need as much stopping power. A simple google search would have given you your answer...
I have 203 / 180 mm Shimano brakes and it's super easy to lock the rear end. Definitely don't see the need for more rear brake performance. So I'd say having a smaller rotor there makes sense - less rotating mass and better bend-resistance. Good debate though :-)
Yeah, to lock the rear is pretty easy, even with smaller brakes or 2 calipers. But I had heat distribution problems with smaller rotors. So if you have long descents, where you cannot open the rear brake to give the possibility of a cool down, your rotor will heat up and give you fading.
You have the complete mass of the rider and the bike behind the front brake. You need more power to handle the inertial forces as well as the friction between the ground and tire. If you run a FBD you'll be able to see that the normal force for the front wheel is greater than that in the rear. It's why motos have the bigger brake up front - it has to stop the motor and the rider as opposed to the fraction of that distributed over the rear. Additionally, a larger disc would offer more modulation, because the distance between the center of the rotor and the bite point of the calipers is greater than that of a smaller rotor, which gives a longer moment arm. The longer moment arm means you can apply less force to achieve the same amount torque as a shorter moment arm using greater force (ie the smaller rear disc). The rear brake doesn't need as much modulation and is still able to be effectively locked up with a smaller rotor where the front needs better modulation, considering the additional forces from the mass of the rider and the bike itself as mentioned above. Smaller disc up front, less modulation = more likely to lock the wheel = involuntary dirt sample collections. All that said, proper technique is the most important factor to consider.
I feel that I would not need a bigger back brake because there is a limit to my tires grip and It is already achieved by a 180 rotor. But the front tire has a way higher level of grip which a bigger rotor fits with. Plus a bigger rotor has less modulation
your tire grips depends on how much load(weight) your tire have, that's why F1 has a lot of traction because of downforce. when you brake, your body or weight turn to the front which makes front tire have more traction and rear tire less which make it lock up. its impossible the front tire to lock up unless the terrain is slippery or loose or you go over the bar, so overall front tire can handle big rotors before it lose traction and the rear tire has smaller rotor so it wont lock up. im 18 and I know this stuff for a professional mechanic this should be basic.
also in street bike, you can see 1000cc engine and up, they have 2 big rotors in front and 1 small in the rear, because of the terrain its smooth and grippy. unlike off-road, you won't see high cc engine because you don't need that much power on loose terrain, and the rotor is not that big because you don't need a lot of braking force unless you want your tire to lose traction
I think they have a bigger rotor on the front because you put more force through the front brake and that dragging with the rear brake doesn't produce so much heat as the front. I'd still have a bigger rotor on the rear though, just because you use it more so the larger one is more durable.
203 front and rear for me. The reason for a smaller rear rotor is due to weight transfer under braking. You use your rear brake more which means you need better heat management in the rear. I believe these balance out pretty close.
Rotor size doesn't control modulation master cylinder/lever ratio, caliper type, piston size/quantity and pad size/material are just some of the things that can influence modulation. If your brakes have poor modulation changing to a larger or smaller rotor will not help, it will still modulate poorly, just with more or less force.
take a look at sport bikes. thet have dual front brakes and a smaller rear rotor. 70% of your stopping power comes from the front. it's so your brake levers can have the same pressure on them and have the proper brake balance.
I go through front brake pads more frequently than rear brake pads on the same make, model and size rotors.
TL;DR - run the biggest rotors you can, and just pay attention to what you and the bike are doing.
I'm a bike mechanic. Most of the bikes I work on have the rear brakes more worn down than the front, regardless of rotor size. On my (previous) personal bike, I put 203 rotors front and rear. I shift my weight around when I ride, I don't drag my brakes unless I'm on really slippery, steep stuff (and even then I use both brakes), I don't brake in corners, and after 200,000' of descending, my pads and rotors were ready to be replaced. The rear were worn a hair more than the front. I never had any issues feeling like the rear was easier to lock up than the front. On my current bike, same brakes, same size rotors, but it's a mullet bike. So far, I'm not noticing any issues with differences in braking power, but then I can get my weight further back on this bike. We'll see how I feel when Hayes comes out with 223mm D-series rotors.
On trails back brakes are used to slide the tail. To stop safer and faster best to use both brakes. As the body weight shifts forward and inertia, more force is on the front wheel to the ground, it needs a bigger rotor to stop.
big front disc and small rear disc is purely for theoretical front/back brake force distribution ratio in specific braking scenario under linear forward riding condition.
It does not apply to specific intent of braking, where a rider specifically wanted his rear wheel to lock up irrespective of the front.
I use TRP 220mm with 2.3mm thickness on both front and back, the power is unreal, I would never go below 220mm, especially with 29" wheels, they look just like 203 on a 26" wheel.
If you can lock your brake up without much effort, you don't need a larger brake setup. Raced motocross for years and left the rear stock but went to a 280 front rotor for single finger stopping ability. Weight transfers to the front under hard stopping. These questions have already been answered by motorcycles and physics.
it's not just braking power, it's heat management. The larger rotors are going to run cooler given the same stopping usage. I also use way more rear brake than front most of the time. A rear wheel skid is no big deal, a front wheel skid is often carnage.
Yeah larger rotor! Skid like a squid!🤣
On a motorcycle the front is used much more because of weight transfer, under hard straight line breaking all the weight transfers to the front and the back will lock up very easy, with minimal breaking force. So no need for very powerful back breaks. But in mountain biking I agree, why have a small back break? It get used more in that style of riding.
Now running 220mm rear rotor 😎
203/220mm front/rear.
On most bikes, 203/203mm.
This is an engineering question that relates to physics and leverage. When any vehicle slows, the load moves to the front. Since the rear is unloaded during braking, less braking force will result in the tire locking (reducing braking performance significantly). A larger rotor has more leverage (more braking torque given then same force at the caliper). A larger rotor will make it very easy to lock your rear wheel when braking. Also more weight, also rotational mass. The small rotor has plenty of cooling capacity for the braking energy it is dealing with.
yeah, the other side of this argument is that if you surveyed bike mechanics, my guess is that you'd find that rear rotors and brake pads are replaced more often or are more worn on most bikes than front rotors.
Thats pretty obvious. Still not a reason to make your brakes worse.
I agree with you, but for the sake of discussion: does the rear unload though, since good mtb technique includes constantly shifting rider weight to optimise grip. Any experienced rider will lean backwards when braking hard
You are correct apart from the your last sentence. Non-pro riders often drag the rear brake. On a longer DH run, this can cause smaller rotors to over heat. Larger rear rotor will be able to cope with this constant heat better than a smaller one. Pro riders won't drag the rear brake, but during braking, they do have the ability to stamp down on the pedals to momentary drive the rear wheel in to the ground, and be able to utilize the increased braking force a larger rotor provides without loosing traction.
@@jamie101010 You dont need to be a pro rider to not drag your brakes.
To those saying is for weight saving, a fart weights more than 15 203mm rotors, the difference between 140/160mm and 203mm is in grams, not even ounces,
Even though you use the rear brakes more. The rear brakes are not holding back the entire weight if the rider and the bike like the front brake. The rear tire will skid way before the front brake with the same brake effort.
on my enduro stock was 203f 203r but the rear just locks up too easily, since I got a 180r it feels much better balance. Look at not just size of rotor but also thickness and if that rotor is meant for intened use. For example my 130mm trail bike is 203f 180 rear but is only 1.8mm thick with organic pads and is meant for trail riding. While my 161mm enduro is 203f now 180r but is 2mm thickness with metallic pads and the rotors are meant for more gravity focus.
Rear time spent under pressure = 3 times more than Front, even subconsciously one is always feathering the rear. When you do want to initiate hard straight line breaking, you want the front big. 180 back and front makes sense to me or bigger. For that matter if your a single tracker / general rider / I would argue 160 back and front (not cheap stuff) is fine too. Good points, the unequal to me is silly.
Swapped a rear 180 for 203 and am never going back!
Because when you are heading downhill you use the brakes the most and the centre of gravity is nearer the front wheel contact patch than the rear.
It's far easier to lock up the rear than the front in any braking situation, even on the flat your centre of gravity moves forward under braking.
Having said all that I personally run 230mm FR and 203mm RE as I ride a mix of steep technical and long fast downhill.
I find the larger rotor deals with drag brake heat more and gives better modulation, I do not skid, ever.
Skidding means you are out of control.
I also use my front brake mid corner to move my ride line wider if i need to or scrub speed with it at the same time as using the rear.
To do this you need proper cornering and braking technique, with that you won't wash the front wheel out.
The rear tire is always (for me) with lower rolling resistance. I like 180/160 because I feel more the rear before locking. If I have let's say xt on the front and deore on the back maybe 180/180 will be fine
People think the front gets more use and gives more power, which on a road bike is true. But do that off road you’ll be on your face quicker than a fart especially down hill.
Sandy condition in the wet in an event in Surrey hills the back brake used all 50% of the remaining rear pads by half way round. The front was untouched. Note to self always start an event with new pads. Upgraded rear to 4 pot caliper and 203 discs. I think 220 will warp and rub more though? Please advise
Because it's much easier to lock up your rear brakes. I want more power up front.
☠BLACK BARON☠ Good Title ... good question 👍
My current Build 180mm Rear and 160mm Front
Maybe its because the stays in the back are not that sophisticated (mount) like the casting of a beefy fork?!there is a lot leverage going on over 180mm rotors…
Its just a guess.
Interesting. Yet when I gravity brake I'm punching my weight down while shifting back. Super modulation.
Galfer wave 223x2.0 front, magura storm hc 203x2.0 rear. Zero fade.
MTX RED 4 piece MT5 pads and MT5 calipers.
180mm front 160mm rear for me works just fine. Just trail riding though. The rear wheel breaks loose easier with a bigger rotor which is not desirable unless you really want to break the rear tire loose like this guy is talking about.
anyone who rides steep slippy terrain will know. brake bias if your back brake is more powerful than the front it will loose traction first making the back of the bike faster than the front.
203 front and rear for my bike. Love it.
Engineering and physics is one thing and it's true that your front rotor is more efficient to slow you down but in practice, your rear brake is more often applied in descents to slow you down in a controlled manner. My XC hardtail has 160mm rotors front and back and the rear pads are 50% more worn than the front ones and my rear rotor has more heating mark than the front one.
Sure, on dirt and gravel a bigger rear brake rotor could make sense, but on the road (tarmac) it's pointless to have 180+mm rear rotor as the moment you start braking, all the weight goes above the front wheel and the rear wheel gets light and locks up. That's why cars and motorcycles have ''bigger'' brakes on the front wheel/s.
But you have to take into account inertia and weight transfer elements of riding
He made a great point about the engine brake on a motorbike. I am using both of my brakes all the time, but there are situations where I only use rear break (corners, steeps, slippery) but rarely use front brake only (unless doing stoppie)
I raced MX for years and in race situations, we don't care about engine braking to stop. You'll stall the engine with hard braking while the clutch is engaged and that is no bueno.
@@marthamryglod291 Don't know much about braking while MX racing, but when I trail ride on my dirt bike I use the engine brake pretty often. That being said I am not trying to compare it to race situation, which I understand is completely different for leisure trail raiding. But I know that the guys racing road bikes MotoGP, TT road racing etc. also rely on the engine brake quite a bit.
@@KapitanPisoar1 yes you're correct with your examples. I raced in the two stroke era but still ride casually a two and four stroke. I still will disagree with the man being interviewed on his reasoning, though not his preferences.
A lot of misapplication of principles of motorcycles.
On a motorcycle the weight and momentum is vastly higher than that of even old school downhill bikes. This results in an inability for body position to have significant affects on the weight distribution, as moving 200 lbs backwards on a 400lb sportbike won't have the same affect as shifting 200lbs backwards on a 35lb bike.
Beyond that, you're also discussing motorcycles on a flat surface, traveling in a straight line. We're talking bicycles going downhill, often turning or leaned over. In these situations the front traction limits are significantly lower, and the consequences for loss of traction drastically higher as it guarantees a washout. The rear, while also having reduced traction limits, has far less consequence for sliding, with high side crashes being very uncommon in mountain biking.
I think either bigger rear rotor or 203mm front and back
Weight transfer to the front wheel. This equates to more traction. Bigger rotor, more power. Less modulation. Smaller back brake equals better modulation. Smaller rotor equals smaller lever arm. This provides the better modulation.
203r/180f all the time
The rear rotor is NOT SMALLER than the front....rather, the front is bigger than the rear. Because its all about the cheapest amount of material to maximize profits and balance form vs function. The minimum rotor size needed in front will always be bigger than what's needed in the rear.... because physics; e.g., weight and motion.
I just put a 180 on my front today!!...I've now ordered another 180 disc rotor for the back, up from from 160s....this guy makes sense about the back brake and has me convinced bigger at the back is better.
Modern motorcycles especially pro bikes don't engine brake much because they have slipper clutch. I prefer a bigger front rotor on my mtb but a mtb does get closer to a 50/50 bias compared to moto.
His theory is wrong about why motorcycles have small rear brakes and big front brakes, assuming he's talking about road bikes, specifically sports bikes, the reason why is because at least 90% of your stopping power comes from the front, and when you're hard on the brakes the rear gets very light, sometimes it can skip off the ground.
I use a smaller rotor in the back because I can’t fit more than 140mm or it will start hitting
And those saying cus it locks up know nothing about break adjustment nor lever force, sounds like yall just squeeze and prey 😂
I totally agree with you. I run a 203 on the back and a 180 on the front.
Braking on bikes is 60 front 40 back..
Because it's a way for the company that made the bike to save money?
A smaller disc is more modular, so It doesn't lock up so easy, on the other hand the front one is bigger couse it's more aggressive but since when you brake your weight goes foreword it's very unlikely for your front wheel to lock up and slide... Therefore you can brake more aggressively without having to worry about skidding
I am so with you in Tunis issue .No one uses Front Break more offroad on a mtb
I think is cuz:
1. U want the same brake power feel in the front and in the rear and more % of your body weight is on the rear wheel
2. U want to have some modulation and didn't like 0-1 block feeling on your rear wheel
3. U use rear brake more than a front brake so 180mm is less expose to bent than 203mm
4. Smaller rotors are cheaper so companies dont care, throw some "better" brake and save on rotors and pads
5. Most of people use cheaper rotors, they bent quite easily so smaller is better choice
ABSOLUTELY!! How about all the lower end bikes spec'd with 160mm rears!! ....USELESS!!!
For looks 220mm front, 203mm rear 😆
what a great topic!!! need more views for knowledge purposes! thanks team syndicate.
Tried it out. 200mm front and 220mm on the back. Works way better than the other way around. The front brake gets more adjustable and the backwheel comes loose easelier.
I agreee!!!! Wondered the same damn thing before
This video has inspired me to ride with a 160mm front and 220mm rear
Because front brakes are harder to lock up, due to that being where most of the weight is.
The rear brake rotor would be smaller to keep the rear brake feeling as equal as possible to the front brake in terms of how much pressure they take to lock up.
Depends how much you like pulling skiddies...
Front brake isn’t harder to lock up the back is exactly the same if you are over the back of the bike
@@willbennett7107 Good point, but @Matt Clarke also has a good point (Below comment) When you brake in any vehicle, the weight will always be thrown to the front, unloading weight from the rear regardless of where the weight is when the brakes are off. a larger rotor would help to counter this because of the added weight, but not much. personally I have equal sizings of rotors/calipers on my mtb and it's always been far easier to lock the back, I'm guessing this is why.
Your right there mate never thought like that
John Bennett jumping back in a few months later, but bikes have a property called antirise which dictates the weight shift when using the rear brake. A bike like the Commencal supreme has extremely high antirise, which will mean your weight shifts backwards under breaking, going against the hypothesis of weight shifting forward. A bike like a Kona operator will not have any weight shift under braking, where a specialized demo or other 4 bar bike will have some forward weight shift
Absolutelly right. Back brake shouldn’t be smaller than front. Both equal, the best. If I need to choose which one needs to be bigger I would choose bigger rotor on the back
I do like this format a lot.
It’s all about physics really. The front brake is always bigger because once its engaged all of the energy from mass and momentum of the rider, their bike & the speed they’re carrying is transferred to the front wheel/brake. The front tire therefore gains more traction, and can take more braking force.
thats true for road racing, where youre doing hard braking and then completely let go off the brakes all the way to the next braking point where you brake hard again.
its different for offroad use even if you compare a wtcc and a wrc car.
on two wheels you do need the rear brake to controll the bike and it is indeed use more than the front brake (but not as strong as the front brake) wich makes it hotter than the front brake, wich has more time to cool down.
I'm on 180 front and back on my trail bike. Also, I could listen to this all day. :)
I use the front brake to stop or to slow down, and the back brake is usually used to skid because it's harder to make a bike slowing down with that brake without locking the wheel (so you use it to repositioning the bike on the trail). So in my opinion, a bigger rotor is required at the front because that's where you convert the most of your kinetic energy into heat, in the back your tyre will do the job, cause the rotor will be locked in place by the brake (not much heat to be dissipated). Probably the brands are building their bikes like that for weight reduction purposes idk.
If anyone has telemetry data that shows equal heat dissipation between the two rotors please comment below, I would love to know if I'm right or wrong!
WOW! What an interesting topic. I've never heard anyone talk about this. I know I should use the front stopping power more than I do. But, I think for most amateur riders we should have a larger rotor in the back. Because everyone I know and ride with using the back break more than the front.
When you brake your weight naturally moves fowards so need more force on the front brake to slow down the wheel.
yeah thats right but that isnt the same thing as wanting a smaller in the back. I can understand if you go from 180/180 to 203/108 (front/back), ´cause you want a bit more power. But why would you go from 203/203 to 203/180?
@The Syndicate
please measure the disc- and caliper temperatures front and rear right when the rider comes through the finish (on a training run of course)
i think this would give really interesting data comparing different tracks and riders.
smaller rear rotor for more clearance to obstacles like rocks etc, less flex/bending issues, less weight, less costs and less need to modulate as at the front. I certainly use the front brake more than the back brake. Maybe 70% at the front to 30% at the rear. Thanks for sharing your thoughts, guyz! ^^
What type of riding do you do? Are you mostly on trails? Are you doing a lot of downhills?
I like my brakes to feel consistent between the front and back and want the brakes to be as effective as possible. The more power available the better!
Larger rotors are for downhill riders.
I agree, I use the back brake way more than the front.
I just got a new bike an it its got 160 on the back and 203 on the front, looks daft
203 front and rear always 👍🏼
I didn't finish the video...
The reason why there is a smaller disc on the back is because a bigger disc will make it very easy to stop the wheel completely and u will skid the wheel after, which means less stopping power so smaller disc will have better stoping power in this case because it doesn't skid as much. However it's a different case on the front wheel because front wheels rarely skid because there is alot of weight on that wheel during breaking.
It's really not that hard to understand, I thought it's obvious 😅
@The Syndicate
I personally think it depends on preference and rider parameters.
It's a fact that when you slow down a bicycle (or any vehicle for that matter), the rider maintains its inertia, loading the front wheel more than the back, so it would make sense to have a bigger braking power at the front and/or less at the back to tune the needed braking power just enough to decelerate but not lock up or skid.
However, it''s also true is that it only happens momentarily, and once full system deceleration (bike and rider) is achieved, the load difference between wheels returns to normal, so you never really need the difference in braking power unless if your only purpose of braking is braking to a stop.
There are also other factors (besides rotor size) like:
-system weight
-piston number per caliper
-pad material and pad backing heat management
-mechanical vs hydraulic
-rider skill level (weight balance management, cornering technique, braking technique, etc.)
-rider preference (locking up, dragging, feathering, not braking, etc.)
-optimization (braking performance, weight saving, etc.)
-intent/needs (racing, casual riding)
-discipline (road, touring, CX, XC, enduro, downhill)
Therefore, there is no universally 'best' setup. The best setup is one where, taking all those factors into account, you should have sufficient braking power for intended purpose without compromising component function and performance. If you feel like needing more braking power, or your rotors are having discoloration, or you notice fading, upgrade braking power and heat management (4 piston, mechanical to hydraulic, bigger rotor, heatsink/finned rotors, grippier pad material, finned pads, etc.). If you feel like there's too much braking power (which sounds absurd but is possible), then simply downgrade. This applies independently to each wheel.
Rear wheel braking does very little to resist acceleration when compared to the front. Real stopping power comes from the front, it’s physics. Locking up your rear wheel may help in direction control, but relatively little in resisting acceleration. That being said WC riders may be happy with their speed/acceleration and increased wear on their rear rotor is representative of how much they use it for direction control, but minimal speed control (when it’s locked up, ie: coefficient of friction, static vs dynamic). Smaller rotors in the back would reduce biting power of the callipers, but in effect adding modulation (reducing how easily the rear wheel locks up). If a rider uses rear wheel braking for direction control (ie: locking it up), increased modulation could be undesirable.
Bigger rotor, more leverage, less rider input needed. Bigger rotors ramp up quicker than smaller ones, meaning less finger travel. You can setup the levers closer to the bar.
So, if you like long brake levers and fatigued fingers, go for small rotors. If you like short comfy brake levers go for big rotors.
Edit: It's more about feel and confidence than theoretical performance. That being said. if you blue your rotors, they're obviously too small.
Thank you sir I’ve been wondering that same thing.👍🏼
Small brake on the rear, like mark Clark said, on any bike/vehicle when breaking the weight moves to the front un-loading the back wheels so it's easy to lock up, my back brakes locked up for 5 minutes straight don't even get warm because there is little movement, my front brake gets glowing how down steep stuff
Rear brake controls acceleration (descending) and the front does the real braking. Having a big rotor in the back sends obvious to me for heat dissipation.
You make no sense
@@stuvademakaroner9607 just because you don't understand, doesn't mean what I said makes no sense.
Depends on riding style and terrain. I use my front brakes more than my rear, but I don't ride long steep sections.
On front wheel the braking force needs to be much bigger than on the rear. Efficient braking ratio might be something around 70% on the front against 30% on the rear. Try to stop a bike using only rear brake - you will easily lock the wheel and the breaking distance will be relatively long. On the other side when you stop using front brake only, you will hardly lock the front whell (in case you're not cornering of course - not recommended) and you will stop almost immediately. I like to use 203mm rotor on the front and 180mm on the rear because of the mentioned reason. You want stopping force on the rear to be lower. When pressing both brake levers identically (same force), you really want to have bigger stopping power on the front, not the rear.
While using rear brake when cornering, the force is really minor and the rear wheel locks quite easily so it's still not a big problem to use controlled skids during cornering.
Bigger is better, more power = less effort which= less arm pump. anyone who says it's easier to modulate a smaller disc just needs a better set of breaks.
Been riding downhill for 13years and initially I was riding 203 front and rear. As time went on I made a decision to swap 203 rear with 180. Why? Becausd it offers more ground clearance, bends not so often, sufficient for making rear wheel lock on when braking...Marshys dilema of different usage of front amd rear brake is weird to me. When I use my brakes I use them simultaneously. Thats the only was of slowing down in a controlled manmer -rear not locking, front not skidding.
Best reply..
Understand your point there, but I have two things. First, you said a smaller rotor offers more ground clearence and doesnt bend so often. Do you actually have a proplem with bendig or hitting your rotor while riding? Maybe when you lay your bike on the floor too aggressively, but that happens to me maybe once a year and to fix it i just bend my rotor a little back... . And I´m sorry but I cant imagine a situation on the trail where you hit your rotor, just because it is 23mm bigger. Otherwise, if you, for example, crash those two centimeters also dont make a difference, really.
The other thing is, that I also dont all the time use both of my brakes. If i just want to stop or really slow down, then yes of course. But when youre riding fast and you for example recognize that youre a bit fast for a section or jump, you know the speed of, you just want to pull that rear brake a tiny bit to get the speed that you want. I personally do that on my Hometrail every time before one exact jump, I know I´m just a bit too fast for.
So please tell me if I´m wrong here
Ive got 160 front 180 rear 😂😂
It's good to know I'm not the only one that wonders the same thing. I have a160mm on the front and a 203mm on the back and let me tell you, even with that tiny 160, I get more braking power from it than I do from the back. I also ride a bike with rim brakes and I seldom touch the front brakes. Unless you want to become a human trebuchet, an over powered front brake doesn't make sense. The front brake is stronger by nature and it's the back that needs more force to compensate for the fact that the weight is being shifted onto the front
Because when you Break all of your energy shifts forward.
With a bigger Rotor upfront you can compensate for the braking power you need
Btw sorry for the bad English
It’s simple- it’s less sensitive to lock up! If you have a bad ass four piston caliper front and rear, you’re gonna need to concentrate harder to actually use the back brake to slow the bike without locking.
I made the mistake of a four piston caliper on the back of my all Mtn bike, now I have to run different pads to use it.
I am an moto guy, so I get my braking done late and hard before the turn with the front. I pride myself on outbraking everyone while staying off the rear brake, but if I could do it over, I’d put a Code up front and some single piston out back. Within 3 grams of my Guides, and then I could justify the big rear rotor I run.. Just like my last MX bike!
The whole braking is different. The rear wheel brakes quite harsh and is blocked often in order to skid, slide etc. that doesn’t produce much heat, since the wheel experiences all the friction.
The front has the most weight and grip in steep sections and you use it for decelerating, what means friction over a time period and produces heat at the brake.
As long as the brakes used are not "light switch" modulation, 203mm front and rear. My 130lb wife with 180mm rotors goes through rear brakes faster than I do, at 200lbs with 203mm. Large rotors front for the straight line leverage for stopping power, and big rotors in the rear for fade resistance and to try to make the pads wear longer!
I've been asking this question myself. But since I have very little knowledge in braking technique for different riding condition (not to mention I only ride once a week on mostly tarmac), I keep my brakes on manufacturer standard (160/160).
It's not just about rotor diameter. Rotor thickness (2 mm Magura vs 1.8 mm SRAM-Shimano) and rotor-vs-pad chemistry matters. Bedding-in matters. How many people actually do it right?
I wonder about using sintered steel pads up front and organic pads out back, or vice-versa, or just stay with the same front & rear pads? There's one way to find out... I'm going to experiment with sintered steel pads / 203mm rotor in front and organic pads / 180mm rotor on my SRAM G2.
Actually there are an infinite number of variables (tire characteristics, wheel diameter, trail surface adhesion, etc.) Even within one brand and model of rotor people seem to have dramatically different experiences. Some people scorch their rotors after a couple hours riding while other riders never scorch rotors. Maybe there's variability between rotor production runs? Maybe people bed-in rotors differently between front and rear? All of this makes generalizing about rotor diameter near impossible.
So far I've only been riding stock organic pads / 180mm SRAM rotors on my Tallboy 29'er - so I don't have much personal experience to add. I tried to bed them in correctly, but who even knows if I did it right?
Great video and discussion.
if you slam the front brakes your weight gets shifted forward making the front tire get more grip, so it needs more stopping power. if you slam the back brakes your weight gets shifted forward and it loses grip (skids easier than the front), so you don't need as much stopping power. A simple google search would have given you your answer...
Maybe helps with brake jack? Cus it’s got less leverage
No... Stopingpower is essentially leverage anyways..
Depends on you're weight, I'm 240lbs and ran 203 front and rear and brakes are amazing. If you are heavy you definitely want more stopping power.
I have 203 / 180 mm Shimano brakes and it's super easy to lock the rear end. Definitely don't see the need for more rear brake performance. So I'd say having a smaller rotor there makes sense - less rotating mass and better bend-resistance. Good debate though :-)
Yeah, to lock the rear is pretty easy, even with smaller brakes or 2 calipers. But I had heat distribution problems with smaller rotors. So if you have long descents, where you cannot open the rear brake to give the possibility of a cool down, your rotor will heat up and give you fading.
You have the complete mass of the rider and the bike behind the front brake. You need more power to handle the inertial forces as well as the friction between the ground and tire. If you run a FBD you'll be able to see that the normal force for the front wheel is greater than that in the rear. It's why motos have the bigger brake up front - it has to stop the motor and the rider as opposed to the fraction of that distributed over the rear.
Additionally, a larger disc would offer more modulation, because the distance between the center of the rotor and the bite point of the calipers is greater than that of a smaller rotor, which gives a longer moment arm. The longer moment arm means you can apply less force to achieve the same amount torque as a shorter moment arm using greater force (ie the smaller rear disc).
The rear brake doesn't need as much modulation and is still able to be effectively locked up with a smaller rotor where the front needs better modulation, considering the additional forces from the mass of the rider and the bike itself as mentioned above. Smaller disc up front, less modulation = more likely to lock the wheel = involuntary dirt sample collections.
All that said, proper technique is the most important factor to consider.
Its because 70% of your braking is in the front.😜
I feel that I would not need a bigger back brake because there is a limit to my tires grip and It is already achieved by a 180 rotor. But the front tire has a way higher level of grip which a bigger rotor fits with. Plus a bigger rotor has less modulation
your tire grips depends on how much load(weight) your tire have, that's why F1 has a lot of traction because of downforce. when you brake, your body or weight turn to the front which makes front tire have more traction and rear tire less which make it lock up. its impossible the front tire to lock up unless the terrain is slippery or loose or you go over the bar, so overall front tire can handle big rotors before it lose traction and the rear tire has smaller rotor so it wont lock up. im 18 and I know this stuff for a professional mechanic this should be basic.
also in street bike, you can see 1000cc engine and up, they have 2 big rotors in front and 1 small in the rear, because of the terrain its smooth and grippy. unlike off-road, you won't see high cc engine because you don't need that much power on loose terrain, and the rotor is not that big because you don't need a lot of braking force unless you want your tire to lose traction
I find smaller rotors to warp less on longer rides.
I think they have a bigger rotor on the front because you put more force through the front brake and that dragging with the rear brake doesn't produce so much heat as the front. I'd still have a bigger rotor on the rear though, just because you use it more so the larger one is more durable.
203 front and rear for me. The reason for a smaller rear rotor is due to weight transfer under braking. You use your rear brake more which means you need better heat management in the rear. I believe these balance out pretty close.
It's so you have more modulation at the rear so you aren't constantly locking up
Rotor size doesn't control modulation master cylinder/lever ratio, caliper type, piston size/quantity and pad size/material are just some of the things that can influence modulation. If your brakes have poor modulation changing to a larger or smaller rotor will not help, it will still modulate poorly, just with more or less force.
Is it just me, or are the Fox Crew tryin to look Amish this week?? I'm waiting to see a horse and carraige with some kind suspension on the back...
Nick Carolan amazing.
Any time. I'll be watchin out for you guys this season..
@@TheSyndicate
@@TheSyndicate yeah where are the leaf springs :D
Im at 160 both wheels now. Think I'll just bump to 180 both and call it good :)
take a look at sport bikes. thet have dual front brakes and a smaller rear rotor. 70% of your stopping power comes from the front. it's so your brake levers can have the same pressure on them and have the proper brake balance.