LarrySellerz

Hey guys, in an emergency do you use both brakes or just the front? I was told by someone I ride with that you get about 30% of your braking power from the rear which I thought was nonsense, but I didn't have a back brake and didn't want to get into an argument at the time. I feel like people are overly reliant on the back .

Seattle Forrest

Brakes are for fakes.

ClydeClydeson

At max braking under ideal conditions there is approximately zero input from the rear brake. There is an argument to be made that, at least when beginning to brake from speed you should use both brakes, and the rear brake is certainly useful on loose surfaces esp. when cornering, but if you need to immediately 'drop the anchor' on a hard surface then the front does all or almost all of the braking.

Bob Ross

I think it can be misguided to take factual information about how much braking comes from front versus rear and conclude that therefore one shouldn't use the rear brake for emergency stops. That info should inform how you use the two brakes, not whether you use them both.

But it's definitely valuable to experiment with how you use them, so that split-second decisions can be informed rather than knee-jerk.

Bob Ross

But I'll add this tidbit: When looking for a pithy aphorism to educate newbs, I like to tell them "rear brake is for slowing, front brake is for stopping." It makes it easier for them to understand how to use the brakes in combination...though it does run the danger of potentially making them think they should always use them in isolation.

datlas 

Shift your weight WAAAY back. Use BOTH brakes but it's true the front has more stopping power. But if you don't shift your weight way back and brake too hard, you could do a face plant. But use both front and rear if emergency stop.

There are lots of youtube videos on this, so check that out.

Zaskar

You said "in an emergency" so I'll mention body position. Where you should be on the bike during braking isn't a black or white thing. It's more of a spectrum, e.g., you don't just change body position from "normal" to "emergency" mode. The harder you brake - or more accurately - the faster you need to stop, the further forward you should be pushing the bike. In a full-on emergency stop, you should look like a sprinter lunging for the line. If you have the bike way out front - butt low, arms straight, heels down - you can use a lot, or at least a lot more rear brake.

greatbasin

It's false to think the front provides the most possible braking. This misconception is based on the idea that 100% of the weight will transfer off the rear wheel, leaving it with no traction. This is a consequence of weight distribution and moment of force and maximum braking is not achieved in an "endo" or "stoppie."

The front tire's traction does have a limit and it will lock at the limit of its traction. As mentioned above, an endo is not necessarily the result of a locked front brake. The front can be made to slide. No doubt as disc brakes on bicycles continue to improve, ABS is next. Until then, maximum braking is achieved by modulating the front manually such that it is close to locking. Under these conditions, the rear tire can still have traction and the rear brake does contribute to braking.

There are some children's bicycles that use linked brake systems to maximize braking. They use a lever in lieu of counter-intuitive coaster brakes, and the single lever actuates both the front and rear brake proportionally so as to prevent endos and provide the shortest stopping distance with kid-operated "mash the brake" technique.


Motorcycles have similar dynamics to bicycles. I think it was in the late 90's that Honda introduced a linked brake system because the knew some consumers were using only the front brake, resulting in excessive stopping distances. There are also a few knuckleheads that only use the rear brake. Honda's linked brake system reduced stopping distances prior to the widespread adoption of ABS on motorcycles. BMW and Honda were the major market participants that were early-adopters of ABS and linked brake systems. Since 2016, the EU requires linked brakes or ABS on motorcycles, scooters, etc. Linked brakes or Combined Brake Systems (CBS) have been adopted on motorcycles because they shorten stopping distances by applying both brakes. https://en.wikipedia.org/wiki/Combin...0rear%20brakes.

terrymorse 

On dry pavement, it is essentially impossible to lock up the front brake to cause the wheel to skid.

Zaskar

That assumes zero sand/pebbles, etc. and that the rider is dead nuts squared up and going straight. Otherwise, yeah, the front tire will absolutely push.

WhyFi

Is this going to be the latest Larry thread wherein he displays ignorance only to eschew any knowledge offered and then tell us how he knows better? Cool.

genejockey 

I tend to ride with two fingers on the front lever and one on the rear, so that it's easier to automatically use more force on the front. Mind you, since I'm right handed, the fingers on my right hand are stronger, so it's possible I am really only bringing them to parity. I also pay attention to how the bike feels, because it's pretty easy to tell when the rear wheel is locked up and skidding, and you can relax your grip a little.

Lately I've been practicing late braking, on a couple segments where there's a fast downhill with a stop at the bottom (Larry - Alpine, rolling down to the intersection with Portola), where I'm going >35 mph. I slide back a bit and see how quickly I can take off speed, whether I lock the rear wheel, etc. I think it's good practice for emergency stopping.

Lastly, one of my bikes has a built-in mechanism for making braking force on the rear less than the front - the 2006 Chorus brakeset is dual pivot in front, but SINGLE pivot in back.

genejockey 

Nobody at the LBS ever told him to use his rear brake.

datlas 

He says he didn't HAVE a rear brake. Unclear if that's still the case.

Hmm....

Zaskar

I have GOT to pay more attention to the original posters of these threads. Mr. Chairman, may I recall my time?

genejockey 

Depends on the bike, I guess, because there was another bike that had a rear wheel so wobbly he had to open the brake up, making it effectively absent.

datlas 

Yeah, I kinda lost track of my Larry stories.

Waiting for the movie.

big john

Wasn't the train wreck in the other thread enough of a **** show?

genejockey 

You gotta be more specific than that! That doesn't narrow it down hardly at all!

big john

It was a thread which got derailed into the abyss where front brake only threads always go.

Crashing techniques and styles - Page 8 - Bike Forums

big john

I heard it's going to be a mini-series.

MoAlpha

Locking up the rear wheel feels stoppy.

datlas 

Comedy?? Drama? Tragedy???

Inquiring minds want to know!

big john

All of that and more!

greatbasin

If locking and pushing/washing out the front weren't a thing, then neither would ABS be a thing. Shimano evidently thinks otherwise and filed a patent in 2019. https://www.freepatentsonline.com/y2019/0233049.html

Even before Shimano, Bosch and Blubrake had ABS systems on the market for e-bikes. Shimano no doubt intends their system for the e-bike market, but the language in their patent intentionally includes other types of bikes including, "a road bike, a mountain bike, or a cross bike”. E-bikes are the natural initial target for ABS systems since they will require a source of electrical power to drive the controller and the pump/valves, but as Di2 systems become more prevalent on non-e pedal bikes, a substantial auxiliary power source for more than just lights will pervade there also.

The bottom line is ABS and electronic traction control are coming to bicycles of all types, and similar systems on motorcycles have already proven that maximum braking and shortest stopping distances are achieved with the combined/integrated use of both front and rear wheel brakes.