Arai drum brake question

[bumknees]

I recently built up a set of wheels for my tandem -- 48 spoke 4x, Phil Wood hubs, Velocity Dyad rims. The rear hub is threaded for a drum brake, so I decided to install one. I'll go through my procedure, so if I did anything wrong, please let me know.

I removed the axle end and the brass spacer. After putting a bit of antiseize on the threads, I threaded on the "body" portion. After cleaning up an residual antiseize compound, I slid on the "guts" and reattached the axle end.

I notice that there is a bit of rub with the drum brake when I spin the wheel. Is this normal, or did I do something wrong in the installation process? Thanks!

[tim]

Maybe it willl wear it's way in with no interference as time goes by..............I had the same problem years ago. Or, maybe the hub is bent? Good luck, Tim

[R900]

If it's very slight I think your ok, if it has a drag, something might be wrong.

[bumknees]

Thanks for the replys. The rubbing is only slight, so hopefully it will go away over time. Also, as far as I can tell, the axle isn't bent.

[TandemGeek]

I notice that there is a bit of rub with the drum brake when I spin the wheel. Is this normal, or did I do something wrong in the installation process?

It shouldn't rub. Make sure you followed Tip #6 from Precision Tandem's Arai Drum Brake Installation page:
http://www.precisiontandems.com/arai.htm

[oldacura]

I had a similar problem when I first installed the Arai. I think the rubbing can be either:

1) A radial rub. The drum is not concentric to the shoes. When you install the plate that holds the shoes to the axle, don't tighten the nut fully. Then, pull the lever that actuates the shoes such that they expand against the drum. Then tighten the nut. This should ensure that the shoes are concentric.

2) An axial rub. If the plate that holds the shoes has a slight warp in it, it will likely rub against the face of the drum at least once per revolution. If this is the case, you should either try to flatten the plate or space it away from the drum slightly with some spacers.

I'm doing this from memory. I don't have the bike with me now. Good luck.

By the way, I removed the Arai from our bike some time ago. I found that we rarely need it. The only time it seems to be of help is if we are descending a big hill with many tight switchbacks.

[bumknees]

Actually, the plate with the pads does look a slight bit warped. I'll try to flatten it, but to do so, what kind of procedure would you recommend? Thanks!

[oldacura]

Off the top of my head, I'd suggest a pair of adjustable ("Crescent") wrenches. Tighten them down on the plate & use the handles to try to flatten it. If it is too strong, you might have to use a bench vise.