At the Handbuilt Bike Show: Another Brake on a Fixie

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by Mark V on Feb 10, 2008 at 8:29 PM

sycip%20disc%20crank.jpg Here’s a brake configuration that I had never even thought of. Sycip Designs put a disc brake caliper on the down tube which grabs a rotor mounted to the left side of a special White Industries crank. Since the rear wheel is directly linked with no freewheel to the crank, stopping the crank stops the rear wheel. Kinda odd, but you would never have to worry about disc/caliper alignment while adjusting the chain tension and you would use a normal track hub. But I think you’d definitely want a real track hub with a reverse-thread lockring.

Update

We heard from Jay at Sycip and he said

This was just a one off attempt to see whether it would work or not. Its an idea we have had for a few years now and kept on shelving it due to the weak link a normal track hub and reverse thread cog w/ or w/o lock. The White Industries track hub with a spline cog is whats making it possible. We would never in a millions years try it with a threaded cog for obvious reasons.

The crank will never turn fast enough under braking to heat the rotor unlike a wheel and most important its serving as a assisted brake working in conjunction with the riders legs. Lets not forget the inertia or the wheels and riders legs which will continue to turn even under immediate braking.

Isn’t it a fun idea?

I will have to say it works well. Front brakes are the simple way to go and is for sure more effective since it does most of the braking.

I will have to say it works well. Front brakes are the simple way to go and is for sure more effective since it does most of the braking.

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Comments: 10

I know Sycip is a preferred builder on this blog, but this contrivance seems like a really bad idea.

In a high speed emergency, I can only see the low-side slide as your way out.  Playing it straight, a rear disc brake with the drivetrain as the transfer medium, will only send you flying over the handlebars or helplessly coasting into disaster when the chain snaps.

At first glance that looks like a good idea.  Then I thought, what happens if the rotor got a bit hot and you hit it with your leg, you could end up burning your leg.  Maybe it wouldn’t be an issue in practive.  I also somehow see myself scrapping all the skin off my left ankle on the rotor.  I am a bit of a cluts.  Once again, this is just theory.

Very innovative, and a cool idea. But, I’d much rather have a brake on a wheel than a brake on a crank, given that chains may break too. I know the argument doesn’t hold for no-brake track guys, but then again you won’t find them signing up for this anyway. Front disc brake works great for me on my rain bike.

“But I think you’d definitely want a real track hub with a reverse-thread lockring.”

and one HELL of a strong chain, lol:)

When I saw it, I thought, “it’s a show after all,” I mean look [at the Naked bike](http://flickr.com/photos/45335443@N00/2256098499/sizes/o/in/set-72157603743781844/)—[video here](http://bikehugger.com/2008/02/hugger_nuggets_at_the_north_am.htm)—and how many of those would expect to see out on the streets? Back from the show, I thought we need more innovations and ideas.

I’ve been thinking about the chain breaking thing for a couple days, and I can’t see that it would be that big of a deal.  I mean, unless you had loaded bags on the bike to increase the normal force on the rear wheel, you can only put so much load on the chain before the rear tire slides.  People slide brakeless fixies all the time, so I don’t think that the crank disc brake would be exploding chains left and right.

I guess there would be initially more force, though, because the disc could lock it up faster than human legs could. But then the tire grip would give and legs and discs would be the same.

And if you did snap your chain, well then the bike is in the same boat as a regular fixie with a snapped chain.

On the other hand, I don’t understand why there’s no front disc to accompany the crank brake on this bike.  I’ve never run a rear brake on a fixie, always fronts alone.

well, of course rear brakes are very poor stopping devices anyways (over the handlebars?  what?  the wheel will slip before your body would be hurled forwards by braking force).  pretty slick, though.  i can see wealthy portland yuppies springing for this sort of thing.

“wealthy portland yuppies?” not at this show . . .

“wealthy portland yuppies”

lmao

those stuck up portland kids who still own cars

Right . . . this is a show where dudes complain about 18 dollars to get in, to look at 8K bike. Commenting on the show, a friend said, “Portland is provincial and in love with itself.”

On other hand, Seattle can’t seem to build a good infrastructure for bikes . . . .

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