Airfoil braking surface?

The 36er airfoils are light and strong, but the powder coating, which covers the entire exposed part of the rim, seems to make for a less than ideal braking surface.

I’m wondering if anyone has tried either machining the sidewalls of the rim, sanded it, or maybe applied paint stripper to the sidewalls in order to expose the bare aluminum, like the '07 KH muni rims. Seems to me that it would greatly improve braking efficiency, but I could be wrong.:stuck_out_tongue:

Livewire unicycles has been doing that for awhile.

http://www.livewireunicycles.com/CokerWheels.htm

I’ve heard of others taking the time to expose the sidewalls for better braking, but my rim seems to work alright with the magura brake. I guess, if it’s not broken, don’t fix it…

My Magura brakes were making some awfully loud noises when engaged on the powder coated airfoil rim. I figured they would probably wear in and quiet down after enough riding, so I ignored it for a while.

After weeks of riding lots of hills, and hearing no signs of my brakes becoming any quieter, I hit the search function hard to see if anyone on here had dealt with similar issues in the past. I found a couple threads regarding the issue and read through them all. Some people recommended trying different brake pads, others advised letting the brakes wear in some more, and a few people talked of removing the powder coating. The Livewire removal service was mentioned, but I did not want to go without my unicycle for longer than necessary, and someone mentioned that they had removed the powder coating from a sun rim’s braking surface using an orbital sander.

This is what I did. I used 150 grit paper until I could see a bit of the aluminum shining through the powder coating, and then switched over to 220 grit to finish the job. The whole process took about an hour. I like my rim’s new look, and my braking is now a silent process.

–Danny

Post pics please!:smiley:

This might be dumb, but on my 29er, I’ve made the braking surface all lovely and shiny metal, by riding through gritty mud lots and using the brake.

I know you’ll find it hard to find much mud, but maybe you could replicate this by sticking some sandpaper on the pads, and riding along with the brake loosely on.

Joe

i want to do the sandpaper trick, but i want to know what it will look like when i’m done? will it be shitty bare aluminium with black dodgily around it or a nice stripe or what?

if anybody has pics this would be really helpful

I had the same loud squealing issue. I just turned the leading edge of the pad in towards the rim and that cured it.

(I removed my tire and clamped the frame in a table clamp for this, and it was not a 36" rim but a 24")

I trued my rim laterally to within 5 thousandths nearly perfect so that it would sand evenly. Put a fine sanding pad on an angle grinder. Held the angle grinder steady and positioned it so that it would spin the wheel at a moderate speed while sanding very lightly and evenly from ID to OD. I continued until all the powercoat was gone and then until the seam in the rim was no longer an issue.

Stop posting and go take a dremel to it… :smiley:

Haha that’s EXACTLY what I was thinking! Just use that litte barrel sanding attachment, which is just about the right size for the side of the rim!

But that might cause too much “scoring”, so maybe something else. I still think if you could apply paint stripper to the sides, without it slopping all over the rest of the rime, that would be the cleanest result.

Woo how much braking do you need on a coker? I’ve always found the stock airfoil braking surface sufficient. If you want more power perhaps stickier pads would be a much quicker and easier way of achieving this.

I have this same problem. Being lazy, I took the pads off and hot-glue gunned sandpaper strips directly to the pads. So far, it hasn’t done that much (and I can still brake), and I think I need to put new sandpaper on them. I really should take the tire off the rim and sand it down…

-corbin

Unless you use gravel as your abrasive, or you do your sanding in the back of a rally car during a race, it’d be hard to score the rim beyond the point of no repair.

Even then, scoring improves the function of the brake. What do you have to lose?

Oh, they do indeed have enough braking power. It’s just that everyone within three city blocks will hear you comming. …and sanded mine down, and it helped, but they’re still quite loud.

Have you tried toeing out your blocks? I’ve not had any noise problems with mine on my N36 or muni but know maguras are reknowned for it, setting the blocks so that the front edge is further away form the rim than the rear edge can help. Having said all that an airofil with a bare alloy brake surface must look pretty cool.

I haven’t, mostly out of laziness. I’ll give it a shot.

i tried this and it didn’t help mine.