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A how-to on rim braking surface finish (sorry!)(10 posts)

A how-to on rim braking surface finish (sorry!)Breakfast
Nov 17, 2003 5:31 PM
Sorry?

Well, my wife always tells me that I like to go on raving about my way of doing things just because I think it's the best or only way. Surely my way isn't the only way, I've read about many other ways concerning all kinds of bike maintainance, but still I'm going to tell you all anyways.

So, if you've done the old sandpaper or steel wool method of cleaning and putting a new braking surface on your aluminum bicycle rims I've got something neat to try.

Get out your trusty Dremel tool and get the tiny disc sanding attachment part that takes adhesive sandpaper discs and put the sanding disc accessory on the Dremel. Now, with your bike in a repair stand with the wheels free to spin, turn on the Dremel and apply the spinning sanding disc (not a drum sander piece, please!) against the rim braking surface and watch as the bicycle wheel starts turning, slowly at first and then at a remarkable speed all the while you're moving the sanding disc evenly on the rim and putting on a neat surface at the same time sanding off the old braking surface. Repeat on the other side and on the other wheel. This method sure beats hand work with sandpaper or steel wool, let me tell you!

I learned this trick watching my auto mechanic doing my brakes one day as he took a big grinder machine tool to my newly turned front disc brakes. He spun the disc up to speed and then started grinding on it leaving a cool looking swirly brake surface.

Try it.
I wouldn't, the rim is much thinner than an auto disk brakerussw19
Nov 17, 2003 7:06 PM
And with a rim you are going to destroy it that much faster. The guy was taking off any oxidation on your brake's surface, and he can get away with it because car brake discs are over an inch thick. Your rim on the other hand is a few millimeters thick at the rim wall and I sure as heck wouldn't take a dremel to mine and then go ride it. And I wouldn't recommend anyone else do it either unless you are just dying to test out your new health care plan.

I also wouldn't clean the rim surface with anything that abrasive. I would use the green scrubbies you clean pots and pans with or super fine sandpaper, because all you are trying to do is take the rubber glaze your brake pads left on the rim off. Taking rubber glaze residue off, good, sanding down the walls of your rims to nothingness, bad.

Maybe I am overreacting to this, and I know a Dremel is not the same thing as a belt sander, but I sometimes think my hand isn't capable of sanding a surface that fast for a reason. By hand may be slow and tedious, but I would think it's a whole lot harder to get in over your head than with the Dremel.

Russ
green scrubbieslikeguymontag
Nov 17, 2003 7:46 PM
Hey, those green scrubbie pads are definitely abrasive. I've scratched glass with a fresh one.
Maybe you should experiment first, RussBreakfast
Nov 17, 2003 9:18 PM
Think about it, the sanding disc is less than an inch in diameter, comes in different grades of coarseness, and is pretty delicate to apply to the aluminum rim. A light touch is all thats needed and the spinning bike wheel keeps the process consistent.

It truly does work. Try it on a older wheel if you're scared.
Maybe so, but my rims are not a science project for merussw19
Nov 18, 2003 12:49 PM
The potential failure of that little experiment is too great to test just for the sake of testing it. Personally I use a very small amount of acetone and a clean dry rag to clean my rims. Nothing abrasive. The brake bads are the most abrasive thing to touch my rims. When sand and grit get in there and start to build up gunk on the rims, it's time to clean them. Simple as that.

I do see your point, and sanding by hand is not what I took issue with. But a Dremel motor turns at over 20,000 rpm. That's a whole heck of a lot harder to control than sanding by hand with a light abrasive like a green scrubby or some super fine sand paper. For me, that's just one step away from taking your rims to a belt sander. This is the same thing I said in my first post about this. I think if you must sand, sand by hand.

Russ
Then, buy new rims before they fail. I do nothing.Spunout
Nov 18, 2003 7:12 AM
The brake pads clean the rims everytime I slow down! Really!
OverkillMel Erickson
Nov 18, 2003 8:47 AM
and too much work. Take a green scrubby pad, open up the quick release on your brakes, put a piece of the scrubby under each brake pad (making sure not to contact the tire), clamp down on your brake with the lever to hold the pad against the rim and ride down the driveway. Voila, clean rims and you don't even have to take the wheel off the bike.
Ummm, I'll stick to my salmon Koolstops.jw25
Nov 18, 2003 10:39 AM
I've used the Scotchbrite pad trick, and didn't notice too much benefit. Unless you've been riding in lots of rain, and have deep scores in the rim, most of what's left is brake pad residue.
I prefer using pads that don't leave nasty stuff behind, like the salmon Koolstops. They're a little harder than the black version, and don't pick up and hold grit. They also seem to scrub off residue left by other pads. They also work very consistently in wet or dry weather.
The Aztec F1 pads seem to be the same compound, as well.
not a chanceCrankist
Nov 18, 2003 10:52 AM
I think this is simply a bad idea.
Typical rim wall thickness in this critical area is relatively thin. Metal removal with a power tool of any sort with any abrasive is not for me, cool looking swirly brake surface or not.
Just what are you doing?Kerry Irons
Nov 18, 2003 6:11 PM
I've never felt the need to "refinish" the braking surfaces of my rims. Anything that gets on there comes off with a rag, a damp rag, or at worst a little bit of solvent on a rag. What is it you're trying to accomplish? Seems a bit obsessive (to no purpose) to me. But that's just me.