Rr.

Hi folks! Bike noob here.

I just stumbled into possession of a set of vintage NOS Araya Super Aero rims (Araya SA-230S). I'm still new to riding fixed gear and not comfortable riding without front brakes.

These rims don't have a machined brake surface and I can't find much information about them online, I have an image of the rim profile but unfortunately I don't have permission to share it on here as I'm new to the forum. Would it be crazy for me to use cantilever rim brakes on the front rim? Your thoughts would be appreciated!

Thanks

TejanoTrackie 

Those rims are an aero shape without a flat braking surface, so you should not use them with rim brakes.

Rr.

This is the answer I expected... Unfortunate! They are so swaggy.

Thanks anyways!

JohnDThompson 

That's true, but many cantilever brake shoes come with spherical washers that allow you to set toe-in AND contact angle.

TejanoTrackie 

The problem isn't the contact angle, but the fact that the contact surface isn't flat. Instead, it is continuously curved, such that there will be only a small amount of contact between the brake block and the rim.

JohnDThompson 

That's only for a short time, until the pad surface wears to match the rim profile. I've been running rim brakes on Matrix ISO tubular rims with similar curved cross-section for years without problems. FWIW, the Araya rim appears to have more material for a brake track than the Matrix ISO:

Rr.

Really appreciate this second opinion. Obviously it's a bit janky and probably not the intended use (and also sacrilege to do this to such a beautiful set of rims), but if it's not a huge safety issue and it means I can run them then I might go for it...

79pmooney

Jeese, just about any brake pad and rim can work together. Set it up to the best you can do at the outset and watch it carefully as the pad wears in, adjusting as needed. Done right, pads can wear into very secure fits to well rounded rims. The two big cautions - make sure the pad cannot slip off the rim as you brake hard. Off the top may well blow the tire, off the bottom may put the pad into the spokes. And make sure there is enough rim material. Thin and light velodrome rims, for example, may have short usable lives as road rims with rim brakes. Clincher rims will explode, often throwing sharp shards outward that can cut carbon fiber and calves. Tubular rims are considerably safer here; even rideable after wearing clear through the sidewall.

That said, I have to ask - where are you riding? What works just fine on flat ground may not at all going down San Francisco's streets. Or in wet weather. In the wet, pads slipping off the rim is far more likely, both because of the lubrication and the added caliper force. In San Francisco, your life may be riding on that one brake. (And it could be wet.)

I am not a fan of one brake only on any street ridden bike. OK, I guess for heavy and slow American coaster brake cruisers but not on faster bikes. I was told to keep both brakes by my race club vets when I started out on fix gear almost a half century ago, always have done just that and have racked up a few thank Gods that I did. I know, not hip, not s**y. But I am still here and still riding fix gear.

Rr.

I'm in Vancouver; quite similar to san francisco with very wet weather and a few decent hills around. My bike is an old steel road bike that I've converted. When I first started riding fixed gear I thought that 2 forms of braking would be safe enough for me (front brake and fixed gear crank). You're right, though, I definitely am stressing a little bit while going down the hills. I suppose on a hill the cranks can hardly be considered a brake anyway, so god forbid I lose the front brake.

I have a set of rear cantilevers waiting for me at the bike shop now. I will also likely be switching to single speed, as I have learned that going down hills at reduced speed to maintain control of the cranks is a but of a buzz kill.

Thanks for the advice!

JohnDThompson 

If you're running fixed, you always have your feet to apply braking action, too.