rolled off a mtb tubular yesterday, need guidance remounting

Discuss light weight issues concerning mountain bikes & parts.

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0sparky0
Posts: 8
Joined: Wed Dec 12, 2012 9:35 pm

by 0sparky0

I finally rolled a tubular off. It was a slow,but sandy turn. I had one prior ride with this tire mounted,with no issues. I suspect I was a bit shy with the glue. Nonetheless,it came off and now has some sand and debris on it. Racing Saturday and would appreciate some expert guidance on how to best clean it and re-mount it for Saturday pre-ride and Sunday race.

I'm mostly curious how I should best clean the rim and tire. I plan to start with soapy water.

Schwalbe racing Ralph,enve carbon rim.

Thank you!

Geoff
Posts: 5120
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

As you have seen, the gluing of tubular tires is not particularly difficult, but it does require some care and attention to be spent. There are no short-cuts.

First, having a clean, uncontaminated substrate is a must. As much as possible, the rim must be clean and free of grease, oil or grime as is possible. That means the first glue that goes down on the rim should be laid on a surface that has been stripped clean and wiped-down with alcohol. That is not to say that when you re-glue a wheel that you always have to strip-off the old glue. If the old glue was done correctly, you should still have a good base layer down on which to lay new final layers. If, however, there is grit and grime inn the glue, it is unlikely that you will be able to get that off. If you leave it like that, it will form 'weak spots' in the glue job, which could compromise your wheel.

In the 'Road' section, we have a thread on gluing tires. That would be a good place to start. I would personally recommend gluing the MTB tubulars in a fashion similar to the gluing of 'cross tires as opposed to road tires, but the basic principals (the application of many, thin layers on a clean rim; the application of glue to the base tape; and, the curing between layers) still apply.

tetonrider
Posts: 92
Joined: Wed Oct 06, 2010 3:38 am

by tetonrider

Geoff wrote:As you have seen, the gluing of tubular tires is not particularly difficult, but it does require some care and attention to be spent. There are no short-cuts.

First, having a clean, uncontaminated substrate is a must. As much as possible, the rim must be clean and free of grease, oil or grime as is possible. That means the first glue that goes down on the rim should be laid on a surface that has been stripped clean and wiped-down with alcohol. That is not to say that when you re-glue a wheel that you always have to strip-off the old glue. If the old glue was done correctly, you should still have a good base layer down on which to lay new final layers. If, however, there is grit and grime inn the glue, it is unlikely that you will be able to get that off. If you leave it like that, it will form 'weak spots' in the glue job, which could compromise your wheel.

In the 'Road' section, we have a thread on gluing tires. That would be a good place to start. I would personally recommend gluing the MTB tubulars in a fashion similar to the gluing of 'cross tires as opposed to road tires, but the basic principals (the application of many, thin layers on a clean rim; the application of glue to the base tape; and, the curing between layers) still apply.


geoff:

by the 'cross method, do you mean glue + tape? i've not yet had to remove a CX tire with that method -- does the belgian tape typically come off when the tire is pulled?

i'm about to make the foray into MTB tubular.

when geoff speaks (or writes!), i listen!!

Geoff
Posts: 5120
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

Yes, that is what I mean. The Belgian tape seems to stabilize the glue on the larger surface area of a 'cross or MTB rim.

Generally speaking, when you dismount a 'cross tire, the results of a properly glued wheel are similar to a road wheel: there should be a serviceable base layer upon which to glue a new tire. If the glue is contaminated (such as may occur in the instance of a rolled tire in mud or sand), you may be required to strip the rim.

tetonrider
Posts: 92
Joined: Wed Oct 06, 2010 3:38 am

by tetonrider

Geoff wrote:Yes, that is what I mean. The Belgian tape seems to stabilize the glue on the larger surface area of a 'cross or MTB rim.

Generally speaking, when you dismount a 'cross tire, the results of a properly glued wheel are similar to a road wheel: there should be a serviceable base layer upon which to glue a new tire. If the glue is contaminated (such as may occur in the instance of a rolled tire in mud or sand), you may be required to strip the rim.

thanks, geoff. it sounds as though -- in the case of a properly glued tire with the addition of belgian tape* -- you typically see the tape come off with the tire and not remain attached to the rim.

* - meaning several thin layers of glue on both rim and tire, then the tape applied to the rim with at least one layer of glue atop it before mounting the tire.

Geoff
Posts: 5120
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

No, I have never had the Belgian tape come-off on a tire before. In my experience, it stays really stuck to the rim. That can be a bit of an issue, as it requires removal before yo can get all the glue off the rim, if contaminated.

tetonrider
Posts: 92
Joined: Wed Oct 06, 2010 3:38 am

by tetonrider

Geoff wrote:No, I have never had the Belgian tape come-off on a tire before. In my experience, it stays really stuck to the rim. That can be a bit of an issue, as it requires removal before yo can get all the glue off the rim, if contaminated.


thanks for clarifying. assuming, then, that the glue is not contaminated (the tire didn't roll), the real purpose of the belgian tape is to build up the center channel of the rim so as to improve the shape to match that of the wider tire?

what i'm getting at is if a rim is specifically designed for a wider tire (whether that is a 700x33 or a 29x50), is the tape advisable if it doesn't alter (improve) the shape of the tire-rim interface?

some of these rims, like the enve XC, are said to be designed for these wider tires.

thanks for the additional information.

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