Bicycle Mechanics - Rims finally dead??

Hey - Just out of curiousity, is there a way to tell when rims have finally worn out(braking surface gone.)? I have been struggling with my MTB rims for a while, in regards to braking. I have XTR V-Brakes, and have tried 3 different pad brands and cleaned my rims several times with Simple Green, allwowing them to be used for several hard rides in between to ensure that cleaning wasn't causing the problem. The problem is that my front brake does not seem to grab the front rim at all. It squeaks when pulled very hard, but I, and the shop, have toed them in and adjusted them many times to maken sure they are aligned correctly. When the brake is applied, the brake pads skip on the rim, seeming to only cling for a second or two at a time. It is enough so that I can feel it grabbing and letting go quickly while riding. This problem did not appear until after I had had the XTR V-brakes for several months, so I have eliminated them as the problem. Is this what happens when rims are worn down enough to not have the proper braking surface?? Is there a way other than the symptoms that I am having now to tell if my rims have finally died. I have owned the rims for about a year and and a 1/2. I ride almost every day, but I expected that the rims would last longer than this. They are Tioga Factory XC rims which came stock on my Schwinn Moab 3, before the company was bought out. Any help would be greatly appreciated!!!

So the bikeshop you took your bike too isnt very good since they didnt solve the problem....right?


Originally posted by moabrider47
When the brake is applied, the brake pads skip on the rim, seeming to only cling for a second or two at a time. It is enough so that I can feel it grabbing and letting go quickly while riding.

It sounds like your rim is out of true, but since you took it to your bike shop, they would have fixed that.....maybe. And I assume that you have the right pads since you took your bike to a shop. Try taking some steel wool and rubbing all the sh¡t out of your rims (not if their ceramic). The sidewalls arent wore down or anything are they?

The wheels are true, the pads are the right kind. I was just wondering if there is a way to tell if the rims(sidewalls) are worn out. Would they look concave, or is there another way to tell other than poor braking?

Normally you can see wear from the brake pads. It looks like a groove.

As a test, take a countersink awl like you use to countersink nails.

Push it into the sidewall area that comes in contact with the brake.

Give it a good push. If the sidewalls are thin, they will easily dent or you might punch a hole right through the rim (yes, you can cry, but thank God you didn't find out the hard way).

Thanks for the suggestions!

You could proof test your rims by over-inflating your tyres. Take the pressure quite a bit over the limit, and if the rim explodes, its too thin. You are best wearing safety goggles and gloves for this test.
For an 80psi tyre, I would go to 120psi.

You can feel a worn rim w/ your fingers. It will be worn in at wear the brake pads contact (hopefully the center of the rim). As for power, i have XTR vbrakes as well, but i have ceramic rims and pads so the power is always there when i need it. Do you have XTR levers as well? if you do, then disconnect your brake cable and pull the lever in and start spinning that little knob on the inside to make your leverage greater. That'll bring the power up a bit. And i agree w/ cleaning your rims w/ a pad, the rims might be glazed w/ crud. And what kind of fork are you running? The brakes might be flexing the posts of the fork therefore making them mushy and weak. You might need a brake booster..
Anyways, good luck.