powbob

I know this is a stupid question, but I currently only have a track bike to which I have added a front brake. This stops me very well from speeds up to about the low 30's MPH. So why do I need a rear brake on the geared bike I'm building? I'm sure there are real world reasons. Just curious.

datlas 

Even better stopping and better modulation.

The front break is clearly better than the rear, but the combo is better.

It's like asking why have a front derailleur, just a 1x10 is adequate.

powbob

Makes sense. Thank you.

MrTuner1970

What datlas said. And I don't know about you, but if my front brake cable broke during a ride, having the rear brake would kinda be nice.

Homebrew01

How about the mid 50s, when a car pulls out in front of you ?

AdelaaR

If you are ever going down a steep, winding, wet road ... and you pull your front brake, inevitably falling down and breaking about every bone in and around your neck ... THEN will you know why bikes have rear brakes ... if you're not dead, at least.

ahsposo 

Bingo.

And of course with a fixed gear you can stop the bike by stopping the pedals from turning.

ahsposo 

Your world is a very dangerous place...

thump55

You also can use your rear brakes only when slowing to a stop or in most "non-critical" braking situations. This'll help spread out your brake wear on rims/pads so you are not destroying only the front rim/pads.

thinktubes 

You need a rear brake so you can lay down some "awesome patches".

andrewclaus

Braking with the rear brake is more stable, I think. I was taught to start braking with the rear, then add the front for a quicker "panic" stop if needed. The front wheel has less weight on it on a typical road bike, and is therefore easier to brake which is not always a good thing. In an extreme front-only stop, you could pitch over the front wheel. I picture it as throwing an anchor behind you rather than a block in front of you.

Altbark

There is absolutely nothing correct in this reply. Nothing!!! Andrewclaus does not know how weight transfers when braking and clearly does not know how to apply the brakes on a two wheeled vehicle when doing an emergency stop. How sad.

Ooompa Loompa

I suggest reading Sheldon Brown's page on braking. https://sheldonbrown.com/brakturn.html When I first started coming to bikeforums I was one of those who used thier rear brake 90% of the time. I've since trained myself to instead use the front brake 90% of the time and I can feel a massive difference. It's so much safer, and it works better.

rm -rf

From Sheldon Brown:

Before I knew better, I locked up the rear in an emergency stop and started the fishtailing. Letting off the back brake stopped it. But I was lucky I didn't crash.

~~~~~~~~~~~~~~~~

Back brakes are good for alternating wheels on long downhills, so the rims don't get too hot, and are fine for normal easy braking. And I use the back brake in slippery conditions.

pallen

and if you think you can yank the front brake and hold it at exactly that point, on the edge of tipping over the front wheel, for the duration of a stop, I would like to see that. A little light use of the rear brake helps fill in with extra stopping power where you don't quite have the guts to push that envelope on the front. Yes, you have to use it carefully to avoid locking up the rear. The rear is also good for other reasons mentioned here - backup, alternating for heat management, slower stops, and most importantly for laying down "awesome patches"

AdelaaR

I don't know how you ride, but I tend to "hang" while going fast in turns.
If I were to come across anything unexpected while "hanging" on wet or muddy roads ... and if I would apply my front brake ... I would surely go down.
Rear brakes can be very handy in these situations. A bit of skidding may occur but at least I could brake without my front wheel drifting.
I have never crashed and I have never had any accident with my bike yet, so I might know what I'm talking about or I might just get lucky.

andrewclaus

Thank you for the link and constructive reply. I've just learned something which is why I'm on this forum!

After reading the above Sheldon Brown link, I would delete the second sentence but otherwise I stand by my reply. I do agree, now, that learning to brake correctly with the front brake is an excellent skill to have. I accept your criticism about not knowing how to apply the brakes. Yes, it's sad, but it's why we continue to learn things from good teachers.

But there's apparently nothing wrong with my basic understanding of the physics. The Sheldon Brown article states that when braking with the front, the rear wheel can leave the ground, not exactly a stable position to be in, and exactly what I said.

pallen

In my experience, that fear is generally unfounded. Yes, you can can brake with the front hard enough to go over the bars, but that is a LOT harder to do than most people who avoid the front brake think.

Mike F

I find the back brake for me is better at feathering my speed on a decent.

EdIsMe

A hammer is not the best tool for all jobs and a front brake is not the best tool for all braking. Having both is just better.

DropDeadFred

like a motorcycle, if you're in dirt or gravel (which I cross on certain rides) you don't want to use your front brake, you want to use your rear, if you don't chances are you're going down.

Juan Foote

I am not even sure I agree with the article written by Mr Brown. I do not doubt his experience or knowledge, but would never tell ANYONE to brake only with the front wheel in any situation.
I fall back to what I learned from motorcycle instruction, as it applies to bicycles just as well.

Front brake is 80% of your braking power, back is 20%. In most situations the front brake will do most of the stopping, and the back brake is much like an indicator. If it skids during stopping you should modulate slightly on both in order to eliminate the skid from the back end. In any situation where you are making a low speed turn, or in wet conditions, the back brake should be applied a bit more than the front. Your stopping power will be lessened, but so will the possibility of loosing traction on the front wheel and going down.
Really has a lot to do with feel and experience. Over application of the front brakes pushes your center of gravity too far forward and makes you unstable on the bike. Aside from that, the mention above about a back up brake in case of failure is golden.

DropDeadFred

seems like shifting your weight back will help avoid the "lifting" of the rear wheel.

Ricanfred

Back brakes only in slippery conditions and both brakes with a lot more lever pressure on the front brake for me works the best.

RollCNY

There are many youtube videos of folks going over the front of their bars when braking hard. And if you pay attention, you can see that every one of them had their arms loose and elbows bent. If one uses their arms and skeletal system, there is very little chance of doing an "endo" when using your front brake.

This is not an original concept, and has been the basis of some previous fairly educational threads. And the video evidence is always entertaining.