Stretching tubulars

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Stretching tubulars

Postby SenorP » Wed Feb 06, 2013 12:38 pm

I'm going out to play on tubulars. Before I fit them they should be pre-stretched. Can I do this on a spare CLINCHER rim? I could use the new tubular wheels, but that will delay the somewhat tedious rim glueing, which is done over 2 days. It's all new and probably sticky!
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by BNA » Wed Feb 06, 2013 7:59 pm

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Re: Stretching tubulars

Postby brit_in_oz » Wed Feb 06, 2013 7:59 pm

You dont *need* to stretch a tub, it just makes mounting easier on some of the less flexible tyres. i find Vittoria corsa evo flexible enough not to need stretching. That being said if you do you can use any wheel long as its not going to damage the tub with a rough edge etc
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Re: Stretching tubulars

Postby open roader » Wed Feb 06, 2013 9:04 pm

You don't need to stretch tubulars but I always do as they are usually well distorted with folds and twists from packaging/shipping. A well fitted pre-stretch irons out these ireegularities and makes for easier fitment when it comes time to glue them on.

I'd never stretch tubulars on anything other than a tubular rim , however, it indeed may well be possible to snap them over a clincher rim - too easy to inexpensively purchase an old pair oftrack tubular wheels for the purpose from fleaBay or other online auction sites.
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Re: Stretching tubulars

Postby jacks1071 » Wed Feb 06, 2013 9:28 pm

Unless you've got forearms like popeye, you're going to do a much better glue job by pre-stretching them.
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Re: Stretching tubulars

Postby scotto » Thu Feb 07, 2013 6:53 am

jacks1071 wrote:Unless you've got forearms like popeye, you're going to do a much better glue job by pre-stretching them.

this freak needs to pre stretch his tyres a lot. Would probably would have trouble opening the packet !!

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these guys just have to look at the tubular and it just surrenders
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Re: Stretching tubulars

Postby petal665 » Thu Feb 07, 2013 12:31 pm

jacks1071 wrote:Unless you've got forearms like popeye, you're going to do a much better glue job by pre-stretching them.
Contis maybe, Vittorias, I don't think so.
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Re: Stretching tubulars - thanks

Postby SenorP » Thu Feb 07, 2013 1:46 pm

Thank you gentlemen. Me no have forearms like PopEye! I've just pre-glued the rims with one coat. That Mastik is the stickiest stuff I've seen EVER. The instructions (Wot? You read the instructions?) say one thin coat rim and tyre. Wait 24. One thin coat rim and wait 5 then join in Holy Stickumoney. Oh the terror... Is it right that the only reason tubs are supposed to be faster is the adrenaline from hoping they're stuck on?
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Re: Stretching tubulars

Postby petal665 » Thu Feb 07, 2013 1:54 pm

'General' consensus for a new rim and tire is 2 thin layers of glue on the rim 24 hours apart + 1 thin layer on the tire. Then the next day, thin layer on the tire and rim and let it sit for 10-15 mins, then put it on. Obviously everyone has their own methods.
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Not so easy!

Postby SenorP » Sat Feb 09, 2013 5:07 pm

Well - I have the tyres glued on but what a carry on the first time.

First, there are conflicting instructions on how to glue the tyres on.

Vittoria mastik tin just say slam some glue on rim and tyre, wait a bit, put some more on mount the tyres and leave them 24 hours.

Vittoria tyre instructions say 2 to 3 layers of glue, 24 hours between, then a thin layer on rim, mount and wait 24 hours.

I erred on the side of caution which means I'll probably never get them off!

The instructions and videos fail to mention that it's nearly impossible to get the last bit of tyre over the rim without touching the rim...which has uncured glue on it....
It's also a lot harder to get the tyre aligned than all the clever experienced guys on You Tube. It seems you need a fair bit of pressure to make the tub behave. Too little and it winks at you sideways and ends up off centre. Too much and you can't shift it.

Under the heading of "Things I wish I'd known before!"

Dealing with punctures. "Carry a small bottle of sealant," they say. Then when you have a puncture, unscrew the valve and squirt some sealant in, spin the wheel, hit it with the greenhouse gas and ride on.

Er.... The new red valve Vittoria tubs do not have a removable core - the whole valve stem unscrews from a little stub on the tub. A little stub which is now hidden deep behind the rim where I can't get at it to add sealant. I should have added sealant BEFORE I mounted the tyre.

So when the pppssspuncture happens I'll have to resort to replacing the tub with a spare. If I can get the frickkatting tyre off. Or I suppose use 'Pitstop' which is reputed to be only 50% effective.

I did leave 4 cms of unglued tyre opposite the rim, so I'll be able to get a star post in there are lever it off. I hope.

I'll either get used to all this, or in a short time there will be a nice pair of Zeros on EBay! No one said I'd need to tow a trailer with spare tub, tool kit pro mechanic and laundry facilities.

They'd better ride well - tomorrow's the day when the glue has cured and we'll see.
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Re: Stretching tubulars

Postby foo on patrol » Sat Feb 09, 2013 6:41 pm

Never ever stretched them and quite often raced on them the same day I glued them on, without any problems. :?

Things must have changed big time between then and now. :shock:

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Re: Stretching tubulars

Postby open roader » Sat Feb 09, 2013 8:15 pm

I erred on the side of caution which means I'll probably never get them off!


You won't have difficulty getting the tyre off the rim if it's only 3-4 years old. I recently removed a pair of 8 year old glued perished tyres from a pair of wheels I'd purchased - the old glue was very hard and tight and ripped the cloth backer off the tyres when pulled with force. Peeling off a 4 year old tyre with a much heavier glue volume was a snap in comparison......

Getting glue on the rim/brake track irks me a tad too but after gluing up my 3rd pair I resort to adding a few strips of masking tape opposite the valve to cover this inevitablity.

This is your first attempt, just keep the tips and tricks in the forefront of your mind when you glue up your next set, it does become easier with pratice. I enjoy gluing tubulars, it's one thing I can be slow at and yet do a top shelf job of it at the same time.
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Re: Stretching tubulars

Postby ironhanglider » Sat Feb 09, 2013 8:41 pm

foo on patrol wrote:Never ever stretched them and quite often raced on them the same day I glued them on, without any problems. :?

Things must have changed big time between then and now. :shock:

Foo


Ahh the days of Clement Red glue, more pressure is better, and not wasting too much glue, or glueing between every other set of spokes when mounting so that you can get the tyre off more easily. :wink:

In these modern scientific times good enough is no longer good enough. In the pursuit of better mechanical performance (and an irrational fear of rolling a tyre) we want maximum adhesion rather than what will probably do. Glueing for novices is portrayed as some black art and best done by a 'professional' who charges for the privilege. It is in their interest to make the job sound complex so they can charge more for it. My experience of the modern theory is that it can be mighty hard to remove a well glued tyre without levers, bleeding thumbs and all. It certainly removes any doubt in the corners.

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Re: Stretching tubulars

Postby foo on patrol » Sun Feb 10, 2013 5:06 am

I only use the Clement Red a couple of of times Ironhanglider. Experimented with white and black Bostic glue but my glue of choice was Selleys' Bear Contact Cement. :mrgreen:

Put the wind up my sails a bit before I did my first glue on but after the first time, I thought, well that wasn't so hard. :shock: I also repaired and restitched them
myself, couldn't see the point in paying someone else to do it. :wink:

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