20" tyre won`t fit?

1660bob

Well Known and Active Forum User
VOC Member
Hi All, been struggling for two days now to get the tyre on my shiny new WM1/20"stainless rim to go on straight. Tyre is a new Avon ribbed Speedmaster,( 20") and no amount of tyre soap/pulling/shouting will get it to come fully up out of the rim well and sit on the rim properly.Both sides have a "sunken" bit 6-8" long and I have pumped it up to over 55psi to no avail several times now.I am beginning to think the rim is oversize??? or the tyre is undersize??????-(less likely i would have thought, Avon have been a long time in the tyre business) I have had "reluctant" tyres before, but always managed to seat them eventually, not this one. Any Ideas ?, cheers, Bob.
 

davidd

Well Known and Active Forum User
VOC Member
I agree with John that 55lbs is not enough. I have found before that if there is a section that will not come up that I generally haver to start all over with the idea that it needs to all come up at once because the resistance on the last 6-8 inches is too high to allow it to pop up. At the risk of telling you something you may already know, the lube paste should be applied to the inside of the drop section and to the shoulder, not the area of the rim where the tire seats. This is difficult with a tube in the way.

David
 

Albervin

Well Known and Active Forum User
VOC Member
Assuming the rim is round then check the seating of the rim lock. Are any spoke nipples sitting proud. How old is the tyre??? It may be new to you but it may have been sitting on a shelf for a few years. If you are going to pump it past 80 psi make sure you are wearing safety glasses. I saw a large rear tyre "let go" while a friend was trying to seat it. Messy!
 

redbloke1956

Well Known and Active Forum User
Non-VOC Member
Assuming the rim is round then check the seating of the rim lock. Are any spoke nipples sitting proud. How old is the tyre??? It may be new to you but it may have been sitting on a shelf for a few years. If you are going to pump it past 80 psi make sure you are wearing safety glasses. I saw a large rear tyre "let go" while a friend was trying to seat it. Messy!

A guy I knew was pumping up an aircraft tyre (on a split rim) when the regulator failed and tried to put 3000 PSI nitrogen into the tyres, the very sad ending was a split rim letting go and removing both legs below the knee. Hi pressures scare me!!

Having said that, don't tyre shops pump tubeless tyres to quite high pressures to get them to seat?
 

1660bob

Well Known and Active Forum User
VOC Member
Update: surprising how a break and a fresh start can help, oh, and lashings of tyre soap.... went out for another try today, cleaned everything up, started from scratch and made sure plenty of tyre soap inside the rim as well as on the tyre beads.On went the tyre, straight up to 55psi and Eureka!-sat as straight as you like.Had to juggle around with the tyre security bolt a bit as that itself was holding the tyre down in the centre of the well, so i had to faff around and position the tyre correctly under it on the rim and nip the nut up BEFORE finally fitting the tyre over the rest of the rim.Worked a treat ... Thanks for the advice, cheers, Bob.
 

Albervin

Well Known and Active Forum User
VOC Member
Taking a break should be in the manual!

David

David, I agree. It is when you are tired, frustrated and running out of ideas that accidents (to you and the bike) happen. I remember well the day I was out of pocket a considerable amount of money because I thought I would "have one more go"!
 

vibrac

Well Known and Active Forum User
VOC Member
A 20" tyre is well worth the effort if you have a 19" and can borrow a 20" wheel just try it and feel the difference
pity is not that easy to swap Girdralics for Bramptons then others would appreciate what a good twin can handle like in the twisties
 
Top