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[Reds]

Guys,

I have suffered from 2 punctures in the last month on my model G , both have been through inner tube being pinched and no penetration by any object . Is this a common problem with Model G due to the rigid rear frame , is it better to have the tyre harder or softer to over come. This .

Reds?

[Mark M]

When replacing a tyre I always pump it up beyond the running pressure, up to 60 psi or more, this seats the tyre on the rim but also ensures the tube isn't kinked. Obviously before doing this you make sure the tube isn't trapped anywhere! Once I'm happy the tyre is properly seated into the rim I drop it back to it's proper pressure. Modern tyres need to run at modern pressures, (even if they have period tread) not the very soft numbers you see listed in period handbooks! So, I'd be inflating the rear tyre on a G to about 30 lbs, maybe slightly more as I know you are quite a big lad! I'd say even more if it was a swinging arm bike but as it's rigid I'd knock a few pounds off for comfort!

REgards, Mark

[Reds]

Thanks mark for the prompt reply.

Reds

[PeteF]

When replacing a tyre, make sure the tube is inflated so traps are unlikely. Obviously not so much that it protrudes from the tyre. Also, do not use levers for fitting tyres. It may seem impossible to do this but it is the proper way and do-able if your technique is right. Slight nips when fitting tyres can subsequently cause a puncture. Another tip is to use talcum powder on the tube (just a dusting) to help prevent creases. Mark's tip of over inflation is a good idea as well. If the tyre and tube are fitted correctly there should be no risk of the tube nipping unless the tyre is very under inflated.

[jefrs]

Consider push bikes where punctures are more prevalent. A proper off-road mountain bike running say 16-20psi for grip on grass and mud is prone to pinch punctures but a road bike running 100-120psi on race tyre is not, and more prone to flints piercing the tyre. Pinching the inner tube between the rim and the tread often results in two symmetrical or "snake bite" punctures. Old school cross-ply tyres were run at lower pressures because the side wall had more strength. Modern equivalent tyres are quite different, so ignore the handbook and use the tyre manufacturer's recommended pressures which will be a lot higher, typically 27/29psi.