headset cup shims

[Bicycle808]

OK, here's the deal: I am trying to switch headsets in my worksman. I have a new "BMX"-sized headset, which has the bigger 32.5mm cups, but this is just a tiny bit loose in the headtube. (A standard road-size 1" headset is waaaaaaaay lose in there.) Before someone else says it, yes, I know about the Wald headset with the nubs, but i wanna use what i got on hand first, and i got some HVAC metal tape to try to shim the headset to fit.

Before I start to work on this, i figured I'd ask the forum for advice on doing the job. Not so much advice on other approaches, but specifically using metal tape or even beer cans to shim a headset into a frame... Anyone got any for me?

Thanks!
-rob

 

[ozzmonaut]

I had an old wood-rim bike with shims in the bottom brackets for the cups. I lost a shim and just cut the adjuster off of a hose clamp and used the strip of metal that was left. Any thin metal can be a shim. I guess my advice would be "get creative". It will be that much funnier when another person owns the bike and they take it apart and find beer logos or whatever. I had a 79 Yamaha motorcycle that I had to rewire a few things on while on the road. I bought a lamp from a little junk shop and used the cord. I rode it that way for some time, forgot about it and when I sold the motorcycle, the guy called me a few months later asking who put lamp cord in there.

 

[LowpowerD]

I've used beer can shims a few times. Worked good for me.

 

[gcrank1]

Aluminum tape (HVAC) is pretty delicate for this application and tears easily when trying to force in, though it can get you by for a while. Alum. can shims are a little tougher, but steel shim stock is available (try a local machine shop) or get creative. The best is annealed feeler gauges; way tough.

 

[Bicycle808]

Thanks for the info; I'm going to probably tackle this project this weekend...

Gcrank, I understand what you mean about the HVAC tape tearing easy; i'm going to try and use it anyway, but I'll be careful not to tear it. My question is: you say it'll get me by *for a while*... are you suggesting i may be able to get it in, shimmed tight, but that it's gonna break down over time??

thanks again, everyone!
-rob

 

[gcrank1]

You wont know if it tears upon installation until you take it back apart, so if it goes together tight, and works for you, great. My experience is that it need to be a bit on the slip fit side, and lubed, to go together without tearing and for this application that may not be tight enough for you. The proof is in the doing, though, just check for some slop-knock once you have the fork on, and recheck periodically. There is a fair bit of stress on those fork parts.
Thing is, that since it takes as much work to do this with thin, soft material as with stronger stuff, why not just do it with the better?

 

[deorman]

I've used HVAC tape for both inner and outer steering races, holds up fine once you get it fit right. Put enough so that you have to work it in to avoid play, trial and error. Never tried lube, seems to me it would degrade the adhesive and actually increase the likelihood of tearing.

 

[Bicycle808]

Well, i just crammed the thing in there...seems tight-and-straight on the stand. gonna take it for a local ride to see how it shakes out, and I reckon it'll probably need further tuning, but i feel confident so far. Thanks, everyone, for the advice! For the record, I used a few layers of HVAC tape, just a tiny bit of lube in the frame's headtube, and i wrapped it thick enough on the headset cup that i really had to torque on the press to get it in. We shall see how that turns out, i guess. (Still have plenty of tape, and access to AL cans, so I don't mind doing a few attempts on this schtuff....)

Thanks again!
-rob

 

[gcrank1]

Alum. is kinda 'sticky' on its suface and any tiny bit of lube on that outside will help keep it from grabbing so bad on the steel of the headtube. It wont seep through the alum into to adhesive underneath, which is some pretty good stuff.

 

[Bicycle808]

I had to tighten things up a bit after the first testride, but subsequent jaunts indicate that I've got her dialed in...Thanks again, everyone!

-rob