# Fixed gear disc brake at crank?



## Fixed (May 12, 2005)

Would it make sense to put a disc brake on the left side of the crank, in between the bottom bracket and the left crank arm (like the right side chain ring)? Could mount the caliper on the left chain stay. Seems like a very elegant fixed gear only solution. Thoughts?


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## Fixed (May 12, 2005)

*oh*

Googleizing it shows it's been done. Oh well.


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## Love Commander (Aug 20, 2009)

Still the same beef have with "brakeless" setups. There's a single point of failure between stopping and not stopping - assuming no front brake, of course. I'm too much of a safety nerd to ever feel comfortable with that.

Still, a cool idea and (in this case) well executed. Looks like White Industries. Is this just a one-off they did for a show or something?


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## cda 455 (Aug 9, 2010)

I see lots of tattoo's (leg burns) with that set up  .


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## Love Commander (Aug 20, 2009)

I'd be curious if the brake caliper is still within design spec, since the braking forces acting on a crank-mounted brake would be the brake force for 700c wheel x gear ratio.


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## Fixed (May 12, 2005)

Love Commander said:


> I'd be curious if the brake caliper is still within design spec, since the braking forces acting on a crank-mounted brake would be the brake force for 700c wheel x gear ratio.


Hmm. Good point. Still, on the rear, I'd guess the tire would skid before exceeding design specs and breaking something. Dunno.


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## Fixed (May 12, 2005)

cda 455 said:


> I see lots of tattoo's (leg burns) with that set up  .


Cool! Just like pipe burns from my motorcycle days!


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## JCavilia (Sep 12, 2005)

Hard to see how it's worth the mechanical complexity. Compared to brakeless setup, the advantage is you don't have to use backpressure (maybe easier on the legs) and you can get maximum braking (lockup) maybe quicker and more reliably than a typical brakeless rider, though maybe not better than the really skilled guys.

On the other hand, it has all the other disadvantages: rear only (therefore, poor) braking, and as LC noted, loss of brakes if chain breaks or derails.

Seems like the mechanically simpler front rim brake gets you much more utility.

But it looks sort of cool, I guess.


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## Fixed (May 12, 2005)

I would still use a front rim brake. This would be useful for those long descents that can overheat a rim brake, though. I have blown out clinchers and melted rim glue using just a front brake. (but I do some extreme rides on a fixed gear around here)



JCavilia said:


> Hard to see how it's worth the mechanical complexity. Compared to brakeless setup, the advantage is you don't have to use backpressure (maybe easier on the legs) and you can get maximum braking (lockup) maybe quicker and more reliably than a typical brakeless rider, though maybe not better than the really skilled guys.
> 
> On the other hand, it has all the other disadvantages: rear only (therefore, poor) braking, and as LC noted, loss of brakes if chain breaks or derails.
> 
> ...


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## JCavilia (Sep 12, 2005)

Fixed said:


> I would still use a front rim brake. This would be useful for those long descents that can overheat a rim brake, though. I have blown out clinchers and melted rim glue using just a front brake. (but I do some extreme rides on a fixed gear around here)


You make a good point. Dragging the brake on long descents is the one place this would be an advantage.

"Extreme" hardly does justice to your rides.


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## Love Commander (Aug 20, 2009)

A minor advantage would be that you wouldn't have to worry about brake pad alignment if you decide to flip your wheel mid-ride, assuming you're using a rear rim brake.


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## cda 455 (Aug 9, 2010)

Fixed said:


> I would still use a front rim brake. This would be useful for those long descents that can overheat a rim brake, though. I have blown out clinchers and melted rim glue using just a front brake. (but I do some extreme rides on a fixed gear around here)


This is why I like disc brakes.


All you have to worry about is warping the disc if you have to use it as you described.

On my daily commuter I put a 203mm disc up front for that very purpose.


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## UrbanPrimitive (Jun 14, 2009)

If it's an issue of needing a drag brake, I'd say use a bar end shifter attached to a drum brake on the front hub. Between that and a rim brake or two there's no real need for reinventing the wheel. On the other hand, if this is about a cool concept and having an engineering problem to sort out, the crank mounted disc brake covers those bases well.


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## axlenut (Sep 28, 2010)

Hi all, some cars use inboard mounted disk brakes on the rear (google jaguar rear brakes). I believe the main reason is it takes some of the weight away from the wheel and gives a better ride but this is only because of the suspension.

Don't really see any advantage doing this on the fixie. Seems to me setting up one disk brake on the front would be the way to go. If it was me I would put a rim brake on the rear too. I ride 5 different bikes and want them all to have both a front and rear brake. If I have to make a panic stop I want all the bikes to have the same setup so when I on reflexes I'm not reaching for air.


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## L_Byrne (Aug 1, 2021)

I'm riding a dragonfly handcycle. One of the problems with the handcycle is with the brakes and the gears on the crank handles. I was going to convert to a mid drive unit to assist me. I'm going to add a frame mounted shifter for the gearing and was checking into bottom bracket controlled brakes


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## No Time Toulouse (Sep 7, 2016)

Dumb idea 9 years ago, and still dumb today. You slip your chain, and you become a projectile....


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## L_Byrne (Aug 1, 2021)

No Time Toulouse said:


> Dumb idea 9 years ago, and still dumb today. You slip your chain, and you become a projectile....


Thinking about this in conjunction with a handcycle. The wires for the brake and gear shifter get caught up in the crank arms. An emergency brake can be put elsewhere on the handcycle frame if the main brake goes.


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## Coolhand (Jul 28, 2002)

Yeah, those bikes are a whole different deal. The response below yours was to the original post. Have you reached out to Dragonfly- they may have seen how other customers and shops have done this.


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