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Lurker Extrordinair
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Discussion Starter · #1 ·
Well it sure seemed easier to glue tubulars 20 years ago...

Of course all I've ever glued were road tubulars, never cross tubulars, maybe thats the problem.

Anyways, I glued up a set of Griffo's today. I did the 3 stage gluing process; put a coat of glue on the base tape and the rim, another coat on the rim 24 hours later, and another coat before installattion. I think I used too much glue (~ 1.5 tubes per rim), but I got the tires mounted. However, here is the problem; the tires have some fairly large hops to them (up/ down). I painstakenly trued the wheels which is now wasted on these tires with excessive amounts of run-out. I got frustrated with trying to true the tires on the rim by hand and gave up... once they tire hit the rim it was stuck and stuck good; any attempt by my weak girl hands to muscle them around were pretty much a wasted effort.

So what is the solution? Will they settle onto the rim in a day or two ( I doubt it ) or will I have to remove the tire and start over again?
 

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Do not touch the trim.
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desertdude70 said:
Well it sure seemed easier to glue tubulars 20 years ago...

Of course all I've ever glued were road tubulars, never cross tubulars, maybe thats the problem.

Anyways, I glued up a set of Griffo's today. I did the 3 stage gluing process; put a coat of glue on the base tape and the rim, another coat on the rim 24 hours later, and another coat before installattion. I think I used too much glue (~ 1.5 tubes per rim), but I got the tires mounted. However, here is the problem; the tires have some fairly large hops to them (up/ down). I painstakenly trued the wheels which is now wasted on these tires with excessive amounts of run-out. I got frustrated with trying to true the tires on the rim by hand and gave up... once they tire hit the rim it was stuck and stuck good; any attempt by my weak girl hands to muscle them around were pretty much a wasted effort.

So what is the solution? Will they settle onto the rim in a day or two ( I doubt it ) or will I have to remove the tire and start over again?

Early Grifos were notorious for being wobbly, even when the base tape was lined up perfectly with the rim...maybe they still are.
 

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veldrijder
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Riding 32mm tires at ~30 psi on bumpy ground and you think a few hops in the tire are going to be noticeable? Cross tubs do not have to be dead straight like road tubs. Get them as straight as you can, and roll with it. Horses for courses, or something like that?
 

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Discussion Starter · #4 ·
jmoote said:
Riding 32mm tires at ~30 psi on bumpy ground and you think a few hops in the tire are going to be noticeable? Cross tubs do not have to be dead straight like road tubs. Get them as straight as you can, and roll with it. Horses for courses, or something like that?
I know, I know, its just this nagging compulsion I have to do things right. Type "A" personality and all, you know how it is. Otherwise, I'd still be a singlespeed mtn biker :D
 

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mattpnewell
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it happens with a lot of handmade tubulars, especially challenge. I don't even look at the base tape much anymore, just look at keeping the tread straight, and if the basetape is within reason i let it go and ride them.
 

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Game on, b*tches!
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Man. I'm glad to hear this. The OCD person in me tries to get those matherfackers on perfectly and I wind saying "whatever" and letting it go......
 

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veldrijder
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It's not that I don't try as hard as possible, swearing often in the process, to get it as straight as I can before things get too sticky, but it's only going to be so straight with uneven handmade tires.
 

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I heard a mechanic share his thoughts on having one of the tires that he mounted roll off by a pro rider. He thought that part of the reason was because he spent too much time getting it perfectly straight, thereby moving too much glue around, making it too thin in some spots. He doesn't spend a lot of time trying to get them just right anymore, and feels this results in a stronger glue job.
 

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Discussion Starter · #10 ·
Its not so much that the tire wobbles side to side, its more of a "hop" up and down kind of thing. If it were a road tire I never would ride such a mishaped tire; it would be suicidal at speed. However, ten miles an hour on grass at 30 psi is probably not going to matter much, but it still bothers me quite a bit.

I probably won't buy another set of Challenge tires after these.
 

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'brifter' is f'ing stupid
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you only put one coat on the tires? challenge base tape soaks up glue big time, you need MIN 2 coats. ALWAYS make the last coat before sticking the tire the last coat you put on the rim. put a couple (or 3) coats on the tire and let them dry. put a coat on the rims and let it dry. then one last coat on the rims, let them sit for 5-10mins depending on temp and stick the tires. the glue will be wet enough you can get the tires straight. the ups and downs you have might be partially from uneven stretching when you're mounting the tires.
 

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I agree with CX wrench, had the same thought. With a new tubie, I generally put a coat of glue on the tape before I start counting coats, as the first one should soak right in (assuming it's not too think).

You can have hops due to a small valve-stem hole, in which the stem isn't snug against the rim (some have to be drilled out, just the mounting surface). Could also be that you didn't get the tension of the tubie even all the way around the rim. if it's loose at the stem and you really, really had to stretch it on the other side, that could cause the issue as well.

I've gone to the CX World Belgian tape method, a much easier process and sticks like nothing else. Good and bad, depending on if you swap your tubies frequently. I find it to be a very solid bond that will generally hold for a couple seasons.

I have noted that my FMBs are also quite wobbly when the tape is mounted straight. With low pressure, I don't really worry about it, but don't recall any major hops.

Best of luck.
 

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I had the same problem with the vertical hop of the tire after gluing tires last season. After a bit of research on various tubular gluing strategies earlier this year, I found a few mentions of a technique to get rid of the vertical hop. Once you get the tire centered on the rim, deflate it and roll it along a broomstick (with adequate force). By doing so, you ensure that the base tape is in full contact with the rim, and that no high spots develop from poor contact. I tried this method when I reglued for this season, and my tires have minimal vertical deviation. Seemed to work well for me, but it may have just been a result of a little more attention to detail/experience with gluing this time around. I think one_speed's point on equal tension may be a big culprit in the process too.
 

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desertdude70 said:
IHowever, ten miles an hour on grass at 30 psi is probably not going to matter much, but it still bothers me quite a bit.
You bought tubulars yet only expect to be racing 10 mph? :wink5:
 

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Discussion Starter · #15 ·
Well heres an update; The rear tire's hop smoothed out enough to be acceptable to me. I think this was due to it being really hot here and the glue remaining somewhat tacky whilst I rode it up many a hill and the tire's stretch evened itself out some on the rim. The front tire had a bad hop, so as I could feel it while riding on pavement. I removed the tire, put down another coat of glue and got a tighter stretch around the valve (where the high spot was) and got the tire re-centered fairly well. They both still have some hop to them but now I feel it is an acceptable amount that should be fine a cyclocross speeds. And yeah, the CrossVegas course does'nt allow speeds a whole lot faster than 10-15 mph with as long as the grass has been lately, at least for me and the guys I ride it with...
 
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