Do I really need to clean old glue off a wheel?

[jspaceman]

I have an aluminium HED Belgium tubular wheel with a worn tire glued onto it. The tire is just about done and I want to take it off and glue a new tire onto the wheel. Is it necessary to clean the old glue off, apply a fresh layer of glue, and then mount the new tire?

From reading around on this and other forums it seems that some recommend keeping the old glue on. I was thinking of applying glue to the base tape of the new tire and letting it dry for a day, peeling the old tire off the wheel, applying a fresh coat of glue onto the old glue on the wheel, and then mounting the tire onto the wheel. This would save me a bit of time, and it would be less messy. Is it safe to do?

It seems to me that the old glue will still have some tackiness to it and still be useful; unlike, say, a wheel that has been lying around for years with no tire on it and the glue becoming hard.

[ghostinthemachine]

As long as the glue hasn't been there years, and still looks in fairly decent condition (no big patches of dirt, lumpy bits, gaps through to the rim etc) personally, I'd have no concerns about tidying it up and riding it.

[boysa]

+1

Yes, as long as it's clean (what ghostinthemachine said... no dirt, debris, etc.) a new layer of glue will "activate" the old one. Should be good with one coat on the rim, one on the tire, slap them together. Give it 24 hours and you'll be good as new.

To each his own, but in my experience I go through quite a few tires before I even consider stripping the rim down to bare metal or carbon.

[kgt]

+1

[bm0p700f]

+1

[Frankie - B]

As long as you use the same brand of glue.

[Calnago]

I suppose I'll be the lone dissenter here. But not because I feel it would be unsafe to go the above route. As long as it's clean and not ages old you should be good. Still, I just like to start fresh every time, with a squeaky clean rim and fresh glue. It's a pay me now, or pay me later kinda thing and i don't like more than two thin even layers of glue buildup on the rim. The only time I wouldn't clean it completely is if I flatted a relatively newly mounted tire and know everything is very fresh and still clean around the edges.

[Geoff]

As others have said, it really depends upon the quality of your initial glue job.

If you have pulled-off the tire and the glue stayed on the rim bed and not on the base tape, that is a pretty good sign that the rim and glue was properly prepared in the first place. If the glue comes-off the rim bed in clumps or strips (especially along the edges), that may indicate that the previous rim preparation was not perfect. In the case of the former, i would be more inclined to leave the glue and just add a new layer before installing a new tire. If the latter, i would probably suggest starting over.

As well as the quality of the original glue job, the condition is important, too. While rare, it is possible to 'contaminate' the glue with grime or road salt. I have seen this on 'cross wheels, but rarely on road tires. If there is any 'grtty' residue under the basetape when you pull the tire off, that would be a rim you would want to re-do.

Whatever you decide to do, don't forget to prepare the tire-side of the equation, too.

[RyanH]

For those that remove the glue from time to time, how? I spent over an hour removing Continental glue from a secondhand rim, since I use Mastik. I couldn't get it squeaky clean.

I personally apply a very light coat over existing, and touch up with thicker where necessary. I struggle to get my tires off when it comes time.

[Geoff]

Unfortunately, there is no easy way.

Personally, I prefer to use a 'mechanical' method (an old screwdriver and kitchen knife that I have used for the purpose for over 20 years). To get it really clean, though, you will need to resort to a terry cloth rag (changed very frequently) and dampened with a good solvent. I have had good luck with a substance called 'Goof-Off', but it is quite aggressive, so use outdoors with nitrile gloves. If that is too much for you, then household paint thinner will also work pretty well (it is cheaper and less toxic, as well).

If you do resort to a chemical remover, remember to really clean the rim well afterward, as it will leave a residue that is not conducive to a good glue-job.

[Calnago]

I finally got hold of some Schwalbe Tubular Glue remover and it's like "Look Ma, no hands, just goop on, wait 20-30 minutes and spray off with waternozzle and some good pressure. Pretty amazed at how it works so far. You do need to do this outside however. But it actually works as claimed. Of course like anything, a bit of real life experimentation is always a good thing to get a feel for it. Prior to that I was using a combo of Adhesive Remover (which included Mastics in the list of adhesives it works on) from the hardware store and Goof-Off, with an acetone wipedown afterwards just to clean the residue. Acetone's not good for much else in the actual removal process.
But without some sort of chemical removal, I think I'd still be on clinchers, or at least abandoning my "new rim fresh" ideal for every glue job.

[djconnel]

Al Morrison has tested this and rolling resistance is fine keeping the glue on. More glue is generally better, actually. So I'd just leave it on. Spraying nasty solvents off is just dumping toxic crap into the drainage.


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[Calnago]

I'm pretty sure I couldn't distinguish a difference in rolling resistance either way. But I do like a fresh even glue job each time. I spray it off on my lawn. It's still green.

[mattyNorm]

I heat up the old glue with a hairdryer and then scrape it off, usually gets 95% of it in one long strip. The last little bit I do with a rag and some white gas.