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I've recently started riding a fixed-gear bicycle and I love it. It's simple, light and fast. However, being new to "fixies" I have two brakes with a drop-down bar, like a road-bike. It just feels safer. Many fixies I've seen have one front brake, usually from a simple brake lever in the middle of the bar.

What if you suddenly brake hard, wouldn't the momentum flip you over the front? Is the front brake a "minimalist" look just to look different, with no regard to its possible safety downside?

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    (UK) law requires 2 independent brakes on a bike : on a fixie, the pedals legally count as one. Aug 3 at 18:16
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    Seems odd to me that folks would prefer this setup over a coaster brake. What's the advantage?
    – keshlam
    Aug 4 at 0:53
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    @keshlam You can't have a coaster brake on a fixie; there's no freewheel mechanism on the rear wheel -- the pedals have a fixed (hence the name) attachment to the wheel. Pedal backwards (the way a coaster brake activates) and the wheel turns backwards.
    – mpez0
    Aug 4 at 12:14
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    @keshlam If you're asking why someone would want a fixie over a bike with a freewheel and a coaster brake, it's because there are a few advantages in the tradeoff. It's lighter and easier to maintain. Riding a fixie also forces you to actively work on the upstroke, which teaches you to pedal more efficiently on non-fixed gear bikes. They're also pretty fun to ride, while at the same time presenting some unique challenges that you don't get on any other bike. Some people also think fixies are just cool, so there's a social status factor.
    – jimchristie
    Aug 4 at 15:04
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    @Fandango68 Definitely not. I would never ride a fixie without a front brake (outside of a track). I just thought there were two different interpretations to keshlam's comment. mpez0 had done a good job of answering one interpretation. I was attempting to answer the other.
    – jimchristie
    Aug 5 at 13:30

6 Answers 6

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From the phyics of things, braking on the rear wheel using the pedals or using a conventional brake will not make any difference. The limiting factor for braking is the traction you get between the tire and road, and the unloading of the rear wheel due to the torque of the forward momentum being reduced. Whether the braking of the wheel is done via the pedals or via an actual brake doesn't change the limiting factor.

The center of gravity of rider and bike is well above the road; during deceleration this creates a torque that has to be balanced by vertical forces on the wheels. The front wheel will be loaded (increasing its braking capacity) and the rear wheal will be unloaded. This torque is the reason that braking too hard on the front brake will flip you over the handlebars, but it is also the reason that the front brake can contribute more to the stopping force than the rear one. It doesn't have to contribute more force, you can come to a stop braking only with the rear wheel, but the front brake is more effective.

As to the reason that fixies don't use rear brakes: it's the weight! A fixie is an absolute minimum, trimmed down bicycle that eliminates everything you don't absolutely need. [Edit to address @DuncanRMI]: They were developed for track racing, and for them, low weight is high tech. (Think carbon frames, etc.) That is its appeal and that is also what makes it cool.

As to being unsafe--the chance of your brake cable snapping is probably a lot higher than the chance of the chain breaking, so braking by the pedals comes out on top on this measure.

The front brake is kept to fulfill traffic regulations which in most countries require two separate means of stopping the bicycle. But of course, as @MattMenzeski has already mentioned in his answer, you might want one yourself for safety reasons even when it's not legally required.

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    "that is also what makes it cool." I can't leave that unchallenged. over a century of engineering evolution went into the modern bicycle, & you're chucking all of it away to look cool?
    – duncan rmi
    Aug 4 at 15:51
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    Someone else said that too - that the rear brake cable has far more chance of snapping than the front one. why is that? In all my years of riding a bike, I've never ever snapped a brake cable. The FD gear cable - yes that has snapped on me and it's obvious why
    – Fandango68
    Aug 5 at 7:04
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    I don't know that the rear brake cable has a higher chance of snapping than the front one. I have definitely snapped brake cables, though. That's why my tandem has three brakes-- if one snaps while steeply going downhill, the chances are that the other one would too if I only had two and had to up the pressure on it--so I then would use my third emergency brake. It has fortunately never been needed! My point is that a cable snapping has a higher chance than the chain breaking. Aug 5 at 14:11
  • I gave you the tick because I saw a video on the weekend (lost link) of pro cyclists avoiding falling off as they descended at speed and turning corners hard. I noticed they used their front brake literally immediately and as hard as they could, whilst applying some brake force on the rear wheel, but in all cases their rear wheel skidded or lifted off the road. Your comment about not making a diff w the rear wheel proved it to me the front brake is king. Thank you
    – Fandango68
    Aug 7 at 23:27
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It feels safer because it is safer.

With a fixie you can brake the rear wheel from the pedals. In theory, you only need a front brake. The theory is great for experienced fixie riders. For novice fixie riders a second brake on the rear wheel is wise. You have to learn to control speed with pressure the wrong way on the pedals and if you feet ever leave the pedals you can be in deep trouble with just a front brake.

In theory, even the most experienced could find themselves in a situation where a rear brake would be helpful.

You may ask why not put the one brake on the rear - this is ineffective for hard braking, as vast majority of your braking comes from the front wheel.

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    @ojs - the 99.9% of braking where it isn't an emergency situation? Aug 3 at 6:52
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    @ojs crank or pedal falls off (never happened to me, but seen both happen irl) or broken chain. Rider can no longer brake by resisting the pedals and might not be able to get weight distribution right to get maximum force from front brake any more.
    – Andy P
    Aug 3 at 7:01
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    @AndyP the same could be argued for rear brake failing on freewheel bikes, but still we don't have redundant double brakes. Anyway, if you need maximum braking force, you shouldn't be using the rear brake in any case (except maybe on tandem or cargo bike, but those probably wouldn't be fixies)
    – ojs
    Aug 3 at 9:01
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    "You may ask why not put the one brake on the rear" It is also to have two independent braking mechanisms - if the single brake is on the rear, all braking happens through the rear tyre. With the single brake on the front, you can brake through both wheels. This is also (two independent mechanisms for braking) why such bikes are legal (in the UK, where I am, at least - I don't know about other jurisdictions). Aug 3 at 10:22
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    @ojs yes and no. As many (even most non-track) fixies can be turned into single speed freewheel bikes at the roadside, and may be if the freewheel gearing is different, it could be worth having a brake fitted even if you only intend to ride fixed. If your fixie isn't set up that way, fine, I'd still want a rear brake but I could see why you might not
    – Chris H
    Aug 3 at 21:14
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Longtime fixed-gear rider here (~14 years, thousands of miles), and I run a front brake only.

I won't go fully brakeless because I consider it too risky. I am a year-round commuter and I have actually had a chain *snap* twice coming down a hill in the winter (in New York state - I blame road salt for corroding the chain). If I did not have the separate front brake in those moments I would have careened down the hill unable to stop. Not good.

I don't run a rear brake for a few reasons:

  1. It's a pain to adjust. My bike has horizontal dropouts, and on a fixed gear it's important to get the chain tension just right to avoid "pedal slop" (when slack in the chain lets the cranks rotate without moving the wheel). Whether a rim brake or a disc brake, moving the wheel in the dropouts means adjusting the brake to match, and that's annoying.
  2. While in theory it's possible to grab the front brake forcefully and flip over the bars, I don't believe there's any real risk of it on a fixed-gear bike. In order to flip, I feel like you need to unweight the rear of the bike and with the constant rotation of the pedals I just don't consider it very possible to do that.
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    If the front brake is a V-brake or hydraulic disk, then it is definitely possible to flip over the bars purely by strong front braking. (On dry tarmac. On worse surfaces it would more likely lock the front wheel and cause a crash by loss of sideways balance.) But controlling that is just a skill any rider should learn, by occasionally taking the brake to the limit and practicing to notice when it gets dangerous. On a fixie this may be easier because the leg-braking gives a very direct feedback how close the rear wheel is to lifting up. Aug 4 at 9:51
  • @leftaroundabout that's a fair clarification - I have a cable disc on mine so can't speak to v-brake or hydraulic discs (although I do run hydraulic discs on other bikes). Aug 4 at 15:57
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    I'd expect that (not) lifting the rear wheel / going over the handlebars on a fixie isn't very different from avoiding the same thing on a normal bike when braking hard with good brakes. With weak brakes it may be impossible, but my mountain bikes with V brakes have all been capable of lifting the rear wheel when stopping hard on flat roads, hence you learn to drop your weight behind the saddle for maximum stopping power. Possibly a fixie has a lighter tail, without the weight of a derailleur + cassette + brake back there, but that's probably pretty minor. Aug 4 at 21:06
  • Great answer but this "when slack in the chain lets the cranks rotate without moving the wheel". Whhaaaa?! How is that even physically possible - assuming as you said riding fixed gear (not coasting)? The chain moves, the wheel moves I would have thought.
    – Fandango68
    Aug 5 at 7:08
  • @Fandango68 I'm referring to a chain that has too much slack in it - if it is not tensioned "tightly" enough, it can make it more difficult to apply backwards pedal pressure to brake, or to trackstand, because you'll need to move the pedals through a bit of "free space" before the chain tensions in the right direction and moves the wheel. Aug 5 at 13:45
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Because a rear brake on a fixie is not very useful. First, a fixie (unlike a single speed bike with freewheel) allows some braking by resisting the pedals. Second, braking removes weight from the rear wheel, so rear brake does not do much to slow down the bike in any case. Since most of the braking is done with the front brake anyway, you could as well leave out the rear brake and use your legs for what the rear brake can do.

If you don't know what you are doing, you can certainly flip over the bike with front brake. With rear brake you're guaranteed to not slow down quickly, no matter if you can brake or not, and you can still slide and fall.

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  • So you're saying I have to "know what I am doing" in order to use a front-brake only? Any links on describing on what I "should" be doing?
    – Fandango68
    Aug 3 at 5:56
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    @Fandango68 I think a safe rule of thumb is that if you have to ask about using the front brake, you're not ready to ride a fixie. The quotes around "should" sound a lot like you're looking for a debate, though. Perhaps a search for "front brake tutorial" finds you something relevant.
    – ojs
    Aug 3 at 6:07
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    @Fandango68 sheldonbrown.com/brakturn.html
    – Noise
    Aug 3 at 8:23
  • @ojs - no not wanting a debate, but some of the answers and comments in here suggest not everyone agrees with you
    – Fandango68
    Aug 5 at 7:10
  • @Fandango68 some people are also completely wrong. Welcome to the internet. As far as I can tell, those who disagree generally have never ridden a fixie but have an opinion anyway.
    – ojs
    Aug 6 at 7:11
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Bicycles have one effective brake (in the front) and a backup "slow-down device" in the rear.

What if you suddenly brake hard, wouldn't the momentum flip you over the front?

Yes, of course.

If you never use the front brake out of fear to flip over the bars, then you won't be trained to use it properly. Then when a driver piles on the brakes right in front of you because something happened further ahead, and their car screeches to a halt... your hand will squeeze the rear brake because that's what you trained your reflexes to do by always using the rear brake.

About a second later, you realize you're not slowing down nearly enough... and your rear wheel is also skidding. So you try the front brake. But you've already wasted precious braking distance, and you never use the front brake, so you can't automatically apply the proper pressure by instinct. So you either don't squeeze enough and crash into the stopped car, or panic and really squeeze it, then flip over the bars and crash face first into the rear window of a stopped car.

However, if you use the front brake most of the time, especially in situations when there is no emergency and the rear brake would be fine, then you can really train your reflexes to use it properly. Then, when you actually need to brake hard to avoid crashing, you will be able to apply the maximum braking power that still keeps the rear wheel on the ground almost immediately.

It's one of these paradoxes: if you're too afraid to flip over the bars and don't learn to use the front brake, you'll eventually flip over the bars anyway.

Do not practice on a slippery surface, though.

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A rear brake is not effective on any bike. A rear brake makes you skid, because when braking, weight shifts from the rear of the bike to the front, sometimes lifting the rear wheel. A front brake makes use of the larger weight on the front wheel to brake more effectively.

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    That's only true in hard braking. Most braking isn't hard braking. You or I may choose to only or mainly use a front brake, but it's perfectly possible to ride never using the front brake (fixed or otherwise) and plenty of people do because they're afraid of going over the bars. Rear brakes are also very useful if there's a chance of the front skidding, because a rear skid is far more recoverable and to make best use of the limited grip. Of course then you won't be stopping quickly
    – Chris H
    Aug 3 at 21:19
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    I would say a rear brake is less-effective than a front brake.
    – Criggie
    Aug 4 at 0:45
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    @Christine have you tried mountain biking? the rear brake is used there all the time. when the surface is slippery or loose you don't have enough traction available to unweight the rear wheel that much
    – Andy P
    Aug 4 at 13:52
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    @AndyP I think we're going in circles, but have you seen many people mountain biking on fixies, with or without rear brakes?
    – ojs
    Aug 4 at 14:50
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    @ojs the answer says "any" bike, not specifically a fixie
    – Andy P
    Aug 4 at 19:58

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