# Why is it front brake is stronger than rear brake?



## nolight (Oct 12, 2012)

Is it because front brake is pushing power and rear brake is pulling power, and pushing is stronger than pulling?


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## wim (Feb 28, 2005)

When the bicycle starts to decelerate, weight transfers forward onto the front wheel. This weight shift gives the front wheel much more traction than the rear wheel, making you think the front brake is "stronger" even though it is not. It's all about weight transfer, not stronger or weaker brakes.

You can prove this to yourself by walking your bike forward and pulling the front brake. If you pull hard enough, the rear wheel will come off the ground. Then walk the bike backwards and pull the rear brake. You will find that the rear brake now feels like the "stronger" brake, able to easily lift the front wheel off the ground.


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## gte105u (Aug 12, 2012)

As was said, it is inertia and traction. In motorcycle safety courses they say for rapid deceleration it is around 70% front vs 30% rear. Imits why for emergency stops the front brake is crucial. It is also why if you slam the front brake too hard you can flip over the bars if you are going fast enough.


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## cxwrench (Nov 9, 2004)

^ exactly what was posted above^
on bicycles the brakes have the same 'power', weight transfer is responsible for the feeling you have. on cars and motorcycles, the front brakes ARE actually stronger, because of larger rotors (more leverage) and larger calipers/pads. the master cylinder volume is matched to the piston area to give the proper feel and power at the lever or pedal.
and if you want to slow a motorcycle down as quickly as possible, you might as well leave the rear brake in the garage.


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## Pirx (Aug 9, 2009)

cxwrench said:


> on cars and motorcycles, the front brakes ARE actually stronger,


Same on some Campy-equipped bikes, too...


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## naawillis (Oct 6, 2004)

doesnt really have anything to do with weight shift 

if you use only your rear brake you still have the entire rotating mass of the front wheel dragging you along your inertial vector. when you use the front brake you slow down everything behind it (you and the rear wheel)

if you were riding backwards the rear brake would be more powerful


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## wim (Feb 28, 2005)

naawillis said:


> if you use only your rear brake you still have the entire rotating mass of the front wheel dragging you along your inertial vector.


Ah yes, why didn't I think of that? Sounds so...scientific.


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## RJP Diver (Jul 2, 2010)

naawillis said:


> doesnt really have anything to do with weight shift
> 
> if you use only your rear brake you still have the entire rotating mass of the front wheel dragging you along your inertial vector. when you use the front brake you slow down everything behind it (you and the rear wheel)



Wait... what?


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## cxwrench (Nov 9, 2004)

naawillis said:


> doesnt really have anything to do with weight shift
> 
> if you use only your rear brake you still have the entire rotating mass of the front wheel dragging you along your inertial vector. *when you use the front brake you slow down everything behind it (you and the rear wheel)
> *
> if you were riding backwards the rear brake would be more powerful


and why do you think that is the case? 

wait for it...



weight shift. if the majority of the weight is transferred to the front, that brake will do the most work, and that tire will have more traction. the rear wheel, w/ much less weight on it is pretty much not doing any work. 
if you only use the rear brake you still get weight shift, obviously. 
and as pirx posted, Campy actually does make 'Differential Brakes', the front is a more powerful dual pivot, the rear a less powerful single pivot. if weight shift didn't matter, why would they do this? why would sport bikes have 2 huge rotors w/ multi-piston calipers on the front and a tiny rotor w/ a 1 or 2 piston caliper on the rear(that no one ever uses)? why would race cars have a brake bias adjustment so they can adjust the bias as the fuel in the car burns off (weight distribution changes) and/or tires lose traction as they get old?


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## looigi (Nov 24, 2010)

Face-palm. Holy cow... No wonder this country is going downhill...or maybe it's because downhill is more powerful than uphill rotating mass?


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## turbodogs02 (Oct 24, 2011)

you can also see the effect of weight transfer in motorcycle racing when braking hard into a corner and the rear wheel is actually coming off the ground....not gonna much matter how "strong" the rear brake is when the wheel isn't even touching the ground. 


So you've got weight being thrown to the front and now the rear feels "lighter".... consider how much easier it is to skid out the rear wheel when too much rear brake is applied. Another good reason for more front, less rear....someone mentioned 70/30, it can also be higher...in my motorcycle riding/racing, I'm virtually 100% front brakes. On the bicycle probably 60/40 or 70/30 typically.


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## OldZaskar (Jul 1, 2009)

"doesnt really have anything to do with weight shift 

if you use only your rear brake you still have the entire rotating mass of the front wheel dragging you along your inertial vector. when you use the front brake you slow down everything behind it (you and the rear wheel)

if you were riding backwards the rear brake would be more powerful"

Nope. Try again.


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## lbkwak (Feb 22, 2012)

naawillis said:


> doesnt really have anything to do with weight shift
> 
> if you use only your rear brake you still have the entire rotating mass of the front wheel dragging you along your inertial vector. when you use the front brake you slow down everything behind it (you and the rear wheel)
> 
> if you were riding backwards the rear brake would be more powerful


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## MikeWMass (Oct 15, 2011)

naawillis said:


> if you were riding backwards the rear brake would be more powerful


At least this part is correct!


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## naawillis (Oct 6, 2004)

wim said:


> Then walk the bike backwards and pull the rear brake. You will find that the rear brake now feels like the "stronger" brake, able to easily lift the front wheel off the ground.


this is really all i was trying to say. i can see how my other post was not that clear. however, to clarify - i was taking the differential load on the wheels (weight shift) as a given, based on the nature of the bicycle. 

it is true that front and rear calipers may have the same power in terms of their ability to squeeze the rim. however, the singletracking nature of a bike means that the front brake system will more rapidly decelerate a bike in motion when the same load is applied vs the rear. this happens because of where the weight IS, not _because_ it is shifting or moving (although it is a dynamic system and it does). 

this is kind of a semantic question. im saying 'by definition the weight is behind the front brake because its the front', and it will always be behind the front brake, even though the exact loading of the front and rear ends does change with braking. 

flaming accepted, i swear im not THAT dumb


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## Kerry Irons (Feb 25, 2002)

naawillis said:


> this is really all i was trying to say. i can see how my other post was not that clear. however, to clarify - i was taking the differential load on the wheels (weight shift) as a given, based on the nature of the bicycle.
> 
> it is true that front and rear calipers may have the power in terms of their ability to squeeze the rim. however, the singletracking nature of a bike means that the front brake system will more rapidly decelerate a bike in motion when the same load is applied vs the rear. this happens because of where the weight IS, not _because_ it is shifting or moving (although it is a dynamic system and it does).
> 
> ...


So this is how you make a really simple explanation so complicated that hardly anybody can understand it? Success!


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## kmunny19 (Aug 13, 2008)

turbodogs02 said:


> you can also see the effect of weight transfer in motorcycle racing when braking hard into a corner and the rear wheel is actually coming off the ground....not gonna much matter how "strong" the rear brake is when the wheel isn't even touching the ground.
> 
> 
> So you've got weight being thrown to the front and now the rear feels "lighter".... consider how much easier it is to skid out the rear wheel when too much rear brake is applied. Another good reason for more front, less rear....someone mentioned 70/30, it can also be higher...in my motorcycle riding/racing, I'm virtually 100% front brakes. On the bicycle probably 60/40 or 70/30 typically.




I've seen sources that adressed the idea of "why a rear brake at all" with saying that the rear brake helps stabilize the 2 wheeled vehicle, while the front brake slows it. I've clearly seen what you have on racing motorcycles. I've felt the difference in stabilization on a motorcycle under very hard braking notably more than I ever have on a bicycle, but it still exists. Also, rear braking gains value in conditions of poor grip. When in wet/slippery conditions, getting really lousy, the 2 wheeled vehicle is more stable when braked near equally front to rear.


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## Dave Cutter (Sep 26, 2012)

I am not sure if this even fits in here... 

But it might help a newbie to mention that the weight distribution isn't completely static. When descending... if I find a need to brake... I slide my butt off the back of the saddle. Moving some of my body weight rearward helps me keep the rear wheel on the road.


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## wim (Feb 28, 2005)

Dave Cutter said:


> Moving some of my body weight rearward helps me keep the rear wheel on the road.


It's a very good point. In fact, people who have seriously looked at "going over the handlebars" accidents will tell you that on dry, level ground, it's almost impossible to "go over the handlebars" through the action of the front brake _unless your butt leaves the saddle and your upper body lurches forward into or onto the handlebars._

In another RBR thread, there's a fear-mongering video selling some braking gizmo which illustrates this pretty well. Just before his endo, you see the rider without the gizmo get off the saddle and put all his weight into / onto the bars. Otherwise, the endo wouldn't happen.


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## Wallstreet (Aug 24, 2011)

On a decline, it's often impossible not to prevent an endo, to the point that even the police at the scene agreed with me when I went over a car. I hit the brakes all hard, the front gripped faster! My ass went back too but not enough possible as the decline was already going to jean speed vs slope = endo!

I had numerous fractures and scrapes thanks to the lady in the black Audi estate. 

I know for certain the front due to weight & slope grips quicker. The rest is body inertia and its impossible to prevent. Being strapped in helps prevent legs flailing and breaking so only my arms were hurt.

If I had to do it again there is nothing else I would change but now I ride with wrist supports as a protection for future falls.


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## MrMook (Nov 18, 2007)

Wallstreet said:


> I know for certain the front due to weight & slope grips quicker. The rest is body inertia and its impossible to prevent.


It doesn't grip "quicker". There's simply more traction available to the front tire under load, so it can slow the bike better than the rear, which, unlike the loading on the front, actually "lifts", though not always off the ground.

And as far as endo's being unpreventable...Thats more a question of skill. Maybe it's because I started mountain biking first, and learned the ways of the endo early, but I'd have a pretty hard time doing an endo on a road bike just by gripping the front brake and sitting on the saddle. Sounds to me like you hit that Audi, which would explain your brief flight over the bars.


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## Wallstreet (Aug 24, 2011)

Mr Mook: Normally I am quite good at preventing Endo's (I also MTB)  it happened far too fast - the car came from nowhere out of a blind spot - I normally do 70kph but thankfully this day I did much less. Witnesses saw my rear lift before the hit. I lay next to the car still strapped on. 

Since changed my pedal clips from Exustar (super light) to XTRs. My front brake lever broke hitting the ground and that side got most of the fractures.

It al happened in slow motion, it's engrained in my head. 

I would recommend practising at low speeds.


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## Dave IV (Jan 20, 2009)

naawillis said:


> doesnt really have anything to do with weight shift
> 
> if you use only your rear brake you still have the entire rotating mass of the front wheel dragging you along your inertial vector. when you use the front brake you slow down everything behind it (you and the rear wheel)


Wrong! 

A wheel can exhibit two independent types of momentum, angular (L=mvr) and translational (p=mv). A stationary rotating wheel exhibits angular momentum. A non-rotating wheel moving through space (think of someone throwing the wheel across a room) exhibits translational momentum. A rotating wheel of a moving bicycle exhibits both angular and translational momentum. 

The angular momentum (mass*angular velocity*radius)has no effect on the translational momentum (inertial vector?) of the bicycle . This is clearly demonstrated when someone riding rollers falls (rides off the side) off the rollers. The bicycle does not move forward. If the angular momentum contributed to the translational movement of the bicycle the bicycle would travel forward when ridden off the rollers.

It is about weight transfer.


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## cxwrench (Nov 9, 2004)

Wallstreet said:


> Mr Mook: Normally I am quite good at preventing Endo's (I also MTB)  it happened far too fast - the car came from nowhere out of a blind spot - I normally do 70kph but thankfully this day I did much less. Witnesses saw my rear lift before the hit. I lay next to the car still strapped on.
> 
> Since changed my pedal clips from Exustar (super light) to XTRs. My front brake lever broke hitting the ground and that side got most of the fractures.
> 
> ...


Mook is correct...the front brake doesn't 'grip' or actuate quicker because it's the front brake. the speed at which the brake is applied is only controlled by your hand. if you end up going over the bars, it's because you applied too much brake. a brake can be too powerful for the weight and traction of the vehicle it's supposed to stop, but the speed at which it works is controlled (properly or not) by the operator.


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## Wallstreet (Aug 24, 2011)

Cxwrench: sometimes these things happen far too fast  the police traced my contact points to see if I was speeding, lucky not . The bike was 56 slightly bigger for me. I have another road bike that's size 54 & more like a glove, I think on that I would not have had the Endo as its more controllable to my body. Why as its easier to control as it fits best to me. I didn't have time to think, the car came from a blind spot. It could be that the front was powered first quicker than the rear although I moved both hands down. I was on the hoods and moved down & shifted my rear off the seat back. The rear started to immediately lift. Once it started there was nothing left. I remember feeling it lift, my eyes were always on the car and I thought this is the end my friend! As in it will hurt & yes it did. The car had momentum. The cop said it was good I didn't ease off the brake as a higher speed would have been more deadly.

Since this I stopped riding the bike I crashed, although fixed it's now an indoor training bike or for guests. I use my size 54 glove like bike more. I even just got a mirror to give me security (bike pedlar) as our Swiss mountains are very curvy and I like to see how close they get.


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## danl1 (Jul 23, 2005)

cxwrench said:


> Mook is correct...the front brake doesn't 'grip' or actuate quicker because it's the front brake. the speed at which the brake is applied is only controlled by your hand. if you end up going over the bars, it's because you applied too much brake. a brake can be too powerful for the weight and traction of the vehicle it's supposed to stop, but the speed at which it works is controlled (properly or not) by the operator.


And in an interesting (OK, maybe not) extension, grip (friction) goes until the wheel locks, then drops off quickly - a skidding wheel has less friction than the same wheel with the same load that is not skidding. 

The upshot: Endo'ing is hard unless the butt comes up or off the saddle. But that's easy to happen in high-speed, panic stop situations - you don't have time to work out the bracing, and the sudden deceleration carries a lot of force at speed, so a handful of brake will shift the weight and it's endo time. But if someone knows it's coming, and can brace themselves in position, they will probably be able to keep it together. And if they can lock up the front wheel without shifting (it's actually not hard with over-inflated 23's) , they'll skid the front and make the endo impossible. Of course, they'll also not have good control and actually take longer to stop than a well-modulated braking effort. But in that situation, it could be said that the solution to braking too hard is to activate the brake harder - if the brakes are strong enough to lock the wheel, the net braking force will be self-limiting. (though it's a silly argument and not a recommended practice.)

https://pavemaintenance.wikispaces....8/Figure_2_pavement_friction_vs_tire_slip.jpg


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## cxwrench (Nov 9, 2004)

Wallstreet said:


> Cxwrench: sometimes these things happen far too fast  the police traced my contact points to see if I was speeding, lucky not . The bike was 56 slightly bigger for me. I have another road bike that's size 54 & more like a glove, I think on that I would not have had the Endo as its more controllable to my body. Why as its easier to control as it fits best to me. I didn't have time to think, the car came from a blind spot. It could be that the front was powered first quicker than the rear although I moved both hands down. I was on the hoods and moved down & shifted my rear off the seat back. The rear started to immediately lift. Once it started there was nothing left. I remember feeling it lift, my eyes were always on the car and I thought this is the end my friend! As in it will hurt & yes it did. The car had momentum. The cop said it was good I didn't ease off the brake as a higher speed would have been more deadly.
> 
> Since this I stopped riding the bike I crashed, although fixed it's now an indoor training bike or for guests. I use my size 54 glove like bike more. I even just got a mirror to give me security (bike pedlar) as our Swiss mountains are very curvy and I like to see how close they get.


i don't disagree w/ anything you've said. It may very well be true that you were better to go over the bars than to hit the car while still on the bike. all i'm saying it that the front brake doesn't do anything mechanically quicker than the rear. a brake is just like a derailleur, really. it can only do what the thing on the other end of the cable tells it to do. hope you heal up fast!


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## danl1 (Jul 23, 2005)

And we may as well include the classic discussion on the topic:

Braking and Turning Your Bicycle


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## Dave IV (Jan 20, 2009)

cxwrench said:


> i don't disagree w/ anything you've said.


You have much better comprehension than I do, because I have no idea what he was trying to say.


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## vette (Feb 1, 2009)

gte105u said:


> It is also why if you slam the front brake too hard you can flip over the bars if you are going fast enough.


Have proven that with shimano 7800 brakes & almost on my motorcycle.


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## Wallstreet (Aug 24, 2011)

cxwrench said:


> i don't disagree w/ anything you've said. It may very well be true that you were better to go over the bars than to hit the car while still on the bike. all i'm saying it that the front brake doesn't do anything mechanically quicker than the rear. a brake is just like a derailleur, really. it can only do what the thing on the other end of the cable tells it to do. hope you heal up fast!


Cheers mate. 2 operations & 6months recovery long gone. I look forward to this years season 

Interesting conversations on here & I totally agree with your points.


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## WaynefromOrlando (Mar 3, 2010)

wim said:


> It's a very good point. In fact, people who have seriously looked at "going over the handlebars" accidents will tell you that on dry, level ground, it's almost impossible to "go over the handlebars" through the action of the front brake _unless your butt leaves the saddle and your upper body lurches forward into or onto the handlebars._
> 
> In another RBR thread, there's a fear-mongering video selling some braking gizmo which illustrates this pretty well. Just before his endo, you see the rider without the gizmo get off the saddle and put all his weight into / onto the bars. Otherwise, the endo wouldn't happen.


It is not almost impossible to go over the handlebars on a bicycle or motorcycle based on my own experiences and the lesson taught in the AMA Motorcycle Safety Course. I have gone over the handlebars twice while sitting on my saddle with my hands on the brakes when I over braked. I have had my rear wheel lift off the ground on my motorcycle when I was leaning back in the saddle, again overbraking the front end. My commuter bicycle still has the scars from my last trip over the front wheel a couple of years ago. Someone decided that putting a yellow construction tape up over a cycle path was a good idea. One early morning commute in the dark and I panic braked hard enough to lock up my front wheel and voila, I ended up on the asphalt with my bike on top of me.

Lots of videos of that were shown in the AMA training too, particularly the short wheelbase sport bikes with dual discs on the front wheel.


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## cxwrench (Nov 9, 2004)

WaynefromOrlando said:


> It is not almost impossible to go over the handlebars on a bicycle or motorcycle based on my own experiences and the lesson taught in the AMA Motorcycle Safety Course. I have gone over the handlebars twice while sitting on my saddle with my hands on the brakes when I over braked. I have had my rear wheel lift off the ground on my motorcycle when I was leaning back in the saddle, again overbraking the front end. My commuter bicycle still has the scars from my last trip over the front wheel a couple of years ago. Someone decided that putting a yellow construction tape up over a cycle path was a good idea. One early morning commute in the dark and I panic braked hard enough to lock up my front wheel and voila, I ended up on the asphalt with my bike on top of me.
> 
> Lots of videos of that were shown in the AMA training too, particularly the short wheelbase sport bikes with dual discs on the front wheel.


wim was saying it's nearly impossible to send yourself over the bars on a ROAD BIKE, and he's right...remember, this is RBR. if you go over the bars on a road bike it's because you don't know how to ride. we all know how strong motorcycle brakes are, and they have only been used as reference here. if you've launched yourself over the bars more than once, you need some practice w/ those brakes.


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## bashple (Jan 4, 2013)

I have never heard it.
is it really?


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## Dave Cutter (Sep 26, 2012)

Wallstreet said:


> ...... If I had to do it again there is nothing else I would change but now I ride with wrist supports as a protection for future falls.


Wrist supports. An interesting idea. 

My wife and I took the some of the grandkids roller skating last weekend. I hadn't been on roller skates for 30 years... so I was a tad rusty. I fell once... and while I did make a effort to NOT catch myself using my hands (to prevent hand/wrist/arm injuries) and instead.. roll. I did slightly stub one wrist. But I was basically uninjured. 

Although when bicycling, I do use a helmet and other safety equipment... there are limits as to how much stuff I want to wear. Of course the helmet, and yes I do wear gloves, OK wrist braces..._ maybe I could consider those_. But then what about knee protection? A mouth-guard? Elbow pads?

I believe.... when bicycling... one of the restrictions to overcome and be a fast rider is the self-confidence of being properly balanced and "feeling" in control. I have done a little balance training using my wii fitness games as well as some basic balance exercises. 

Decades ago they used to "teach tumbling in gym classes" (for kids). I think... _have become convinced_... that learning how to "take a fall" is an important "cycling skill". Just as is becoming better balance-trained. I have advocated tumbling classes for seniors at the local recreation center. 

But there doesn't seem to be an interest in what some may consider (I guess) a stunt-man skill.


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## Wallstreet (Aug 24, 2011)

Dave Cutter said:


> Wrist supports. An interesting idea.
> 
> My wife and I took the some of the grandkids roller skating last weekend. I hadn't been on roller skates for 30 years... so I was a tad rusty. I fell once... and while I did make a effort to NOT catch myself using my hands (to prevent hand/wrist/arm injuries) and instead.. roll. I did slightly stub one wrist. But I was basically uninjured.
> 
> ...


Hi Dave

It's only on the left hand and cycle specific. My left wrist is slightly weaker. I agree with you that it's all about confidence the older we get. I still love being quick. I will never go beyond gloves & helmet. 

I saw a documentary on old age, a guy in Greece 98 looks younger, his secret lots of Veg and he still climbs vines and works each day. In Okinawa Japan lots of veg keeps the older younger and lowest rates of cancer etc. maybe if you get them to eat more veg they will tumble better  inspiration all the same.

Good food exercise will make us better and being flexible and tumble a tad bit better.


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## YamaDan (Aug 28, 2012)

cxwrench said:


> wim was saying it's nearly impossible to send yourself over the bars on a ROAD BIKE, and he's right...remember, this is RBR. if you go over the bars on a road bike it's because you don't know how to ride. we all know how strong motorcycle brakes are, and they have only been used as reference here. if you've launched yourself over the bars more than once, you need some practice w/ those brakes.


This is why we need warning lables..lol.

For the tech guys... Bicycle Brake Modulation

For the OP, the first two comments are probably the best. No offense to any other posts in this thread, but, a simple concept can get very complex with the ammount of expert advice on these forums.


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## fatoni (Jan 8, 2013)

weight transfer. like on cars or almost anything with brakes really


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## AndreyT (Dec 1, 2011)

Deleted


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## scottzj (Oct 4, 2010)

My answer..........I am left handed, so my left hand is stronger than my right. Therefore, my front brake is stronger than the right hand (rear brake) haha.


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## kathy20052012 (Jan 9, 2013)

You'll find this on most cars. It's due to physics - when decelerating the weight and energy transfers to the front of the vehicle, as a result front brakes are larger since they have more energy to cope with, and that extra weight also gives the front wheels extra grip and thus more braking ability.



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## CHARLES M (Oct 17, 2012)

Your front brake is mechanically stronger than your rear.

Motor bikes... cars all have larger rotors and Calipers on the front making them mechanically stronger. 

On your bicycle, the manufacturer will up the leverage for the front brake so that the same hand squeez force creates higher clamping power (rim braking)


weight shift increasing is why they are able to make the front brakes stronger on virtually all vehicles.

Weight shift puts more weight on the front tire and dramatically increases traction. 

With that extra traction, a mechanically stronger front brake can work harder to slow you down before breaking traction and skiddind.


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## cxwrench (Nov 9, 2004)

CHARLES M said:


> Your front brake is mechanically stronger than your rear.
> 
> Motor bikes... cars all have larger rotors and Calipers on the front making them mechanically stronger.
> 
> ...


while you're right about cars and motorcycles, you're somewhat confused about bicycle brakes. campy is the only maker that offers a less powerful rear brake and very few people actually use it.


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