I've got some brake grab on my front rim, right around where the joint is. Searching through other threads, I found some ideas on how to correct it. Here are some things I've tried (not necessarily in this order):
- Cleaning the rim with rubbing alcohol.
- Cleaning the brake pads with rubbing alcohol.
- Adjusting the toe of the brakes.
- Sanding the rim smooth.
- Roughing up the rim with sandpaper.
- Tightening the headset.
- Replacing brake pads.
- Truing the wheel.
The toe does not appear to be the problem. In fact, the grab sill occurs when I hold the brake and pull the bike in reverse. Tightening the headset helped some of the vibration, but I can still see the bottom of the fork vibrate and feel a sudden additional braking force in a small area when I pull on the front brake. Sanding didn't help either--the joint is extremely smooth.
This was a minor problem when I originally bought the bike used, and it has grown worse over time. It's becoming a major nuisance when I need to stop suddenly, and has even started to lift the back tire up suddenly and unexpectedly when it hits this small portion of the rim. It's almost as if the aluminum surface is different there--possibly due to heating when they join the rim?
Anyway, are there any more ideas about what to try, or should I just give up and get a new rim/wheel already?