Front tyre won't seat on rim

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jmclean
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Front tyre won't seat on rim

Postby jmclean » Sat Dec 13, 2003 3:47 pm

I bought a new front tyre (2.75 x 21 Michelin) for my 2003 Beta and it refuses to seat evenly on the rim. I've blown 2 tubes trying to get it there. I took it to a motorcycle shop and they managed to get it seated after much cursing and with 60psi pressure. However after releasing it down to 20psi the next day, the bead slipped straight back into the rim.

Do I have a dud tyre, or is there a specific fitting technique ?



David Lahey
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front tyre problems

Postby David Lahey » Sat Dec 13, 2003 10:26 pm

I'll bet London to a brick you have been supplied with a tubeless type tyre. Have a look at the fine print on the wall of the tyre. Some tube type rims work OK with tubeless tyres and some don't. The problem is the profile of your rim where the bead sits (or doesn't sit in your case). The flat bit on the rim where the bead sits probably isn't wide enough to hold the wedge shaped edge of this tyre.
David Lahey



jmclean
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Postby jmclean » Sat Dec 13, 2003 10:51 pm

Thanks David, I had a look and you're absolutely right.
However I've now tried to refit the old tyre (tube type Michelin), and it's refusing to seat as well, though not as badly as the tubeless tyre. Yet it was fine before it was removed. I suspect it was the original tyre from the factory (I recently bought the bike secondhand).
I've spun the rim and checked it's reasonably true and isn't buckled or twisted etc. Looking at the inner rim profile, there isn't much for a tyre to seat on these things.
Is my problem characteristic of Michelin tyres?. Would I have better luck with a Dunlop ?



David Lahey
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front tyre problems

Postby David Lahey » Sat Dec 13, 2003 11:14 pm

Dear Jim
I haven't heard of problems fitting tube type Michelin tyres to tube type rims before but sometimes it takes a few inflations and deflations to get a tyre to sit evenly on a rim, especially if it is being fitted without a lubricant.
If this is your situation, let the pressure out and apply a dilute dishwashing liquid solution with a paintbrush or hand pump sprayer to the bits that have to slide across each other during inflation. This usually allows the tyre to sit evenly on the rim as it inflates. An alternate lubricant is WD40 but you have to be pretty quick inflating the tyre before it evaporates.
Also make sure the tube isn't trapped under the bead anywhere because that can cause problems too.
To answer your question fully; yes, you may find that Dunlops or Pirellis do fit your rim diferently to the Michelin. My riding buddies use both Michelin and Dunlops successfully on the fronts of their REV 3s.
David




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