jdgreen

I am installing new tubulars on some Zipp 303 rims. There is a thin coat of glue left on the rim from the previous mount that appears will be very difficult to remove. I am reinstalling using tufo tape. How big a deal is it if I mount without removing the old film of glue?

Road Fan

My opinion is that the mechanical issues with old glue on the rim are:

1. there could be so much build up that lumps on the rim will lead to initially uneven tire lie - such lumps would probably even out over time under tire inflation pressure.
2. there could be so much glue that softens that it oozes on the brake surface after everything sets - I haven't seen this, but I think it could happen
3. the origina glue was not well-adhered to the rim, so even though the new glue adheres to the old glue, there isn't a good connection to the rim!

You said your residual layer is thin, so I don't think you have problems 1 or 2. If it's uniform, I suspect you don't have problem 3. If you're a neat freak, clean it.

I don't know if these Zipps are aluminum or carbon. I'm not sure I'd use much in the way of solvents or scraping on a carbon rim!

Road Fan

jdgreen

They are carbon rims, and I am concerned about appling alot of harsh cleaners to try and remove this glue. I am hoping to find out this is a common situation and that many tubulars have been installed in this manner without having a problem.

Road Fan

I have installed several dozen tubulars on new and old rims, and not seen any problems beyond lumps. Tho other issues I raise are possible, but not what I have seen. I think you are safer not disturbing the carbon seating surfaces you have, than attacking them with tools and solvents to make it clean, especially if they're carbon.

I don't know where you're going to find a recognized expert on this, if Sheldon Brown declines to comment. Maybe phone Peter Chisolm at Vecchio's in Boulder? or Cycle Smithy in Chicago? Both have a lot of heritage with high-performance bike stuff. Sheldon as well, but does not advocate use of tubulars. Or ask your question over in Road Cycling or Road Racing.

I think you are wise in not wanting to use solvents on the CF without knowing more. The carbon fibers are held together by organic materials, that may be affected by the wrong choice of organic solvent.

Maybe you should email to Zipp!

Road Fan

kytyree

Use "Goof Off" to remove the old glue from the rim, you can go to the Zipp website and download their owner's manual where they suggest using that particular latex paint remover (Home Depot). I don't think they are necessarily big fans of the Tufo tape though and I believe in that same owners manual you will read where they comment that people have torn up Zipps when removing the tape.

The Goof off shouldn't harm any part of the carbon fiber but I would try and keep it away from the stickers unless you are removing them.

auk

Agree. Use Goo off or Opps to soften and then remove the old glue. You really only need to do this if the old glue is dry and dusty. Otherwise add a new layer of glue to the rims.

Tufo tape is nasty stuff. I've seen firsthand the removal of carbon along with the removal of the Tufo tape. Thankfully, it was not my rim.