Tyre expansion/dilation or whatever

[BlackPig]

How much clearance do you really need to leave between the rear tyre and a fixed muddy?
I know that tyres dilate/expand when you're riding but by how much?
Is there a formula to calculate this?
Thank'ee muchly :)

[xjtriker666]

my trikes muddy,s av about 20-mm all round clearence no probs as yet.....front has about 25-30mm...only coz it,s havin 200mm tyre in front.........

[dracken1]

it really does depend on the brand of tyre, the compound, if you are running a soft tyre which is a lot wider than the rim then it will grow more than a low profile correct width one.
i've run hardtails with 13mm clearance no probs :)

[BlackPig]

Thanks for that gentlemen. :)
The guard is fitted to the swingin' arm and,now I've fitted a new chain an' sprockets,I've only got about 6mm clearance,BUGGER !! :(

[Blackjack]

Source of many an argument is this, but having been in a few of them I can give you the distilled version.....

1" or 25mm is about the production industry standard for radial clearance. Or this seems to be what manufacturers consider to be the minimum allowing for idjiits fitting the wrong tyre, running it it at 2 psi, and small furry mammals getting jammed in the space.

1/2" or 13mm is considered sensible for a road going custom bike by most people.

1/4" or 6mm is often used by Yank builders, but this is really show bike territory.

If you keep the speed down and stay off motorways for a week, you should be OK with it, and by then the chain should need adjusting so your problem should solve itself.......

Failing that, fit a rear sprocket with a couple less teeth!!

[BlackPig]

Cheers Blackjack,I have heard the same arguments in the past :rolleyes:

Yeah I think I'll leave it at that and let the chain stretch a bit.I can get a couple of mm extra(tis all adjustable see),changing cogs means spendin',and we don't want t' be doin' that now do we ;)


Latest;I'm now up to 8mm at the closest point,and 10 elsewhere !!
Just gonna have t' give it a try !!! :eek: