Oversize (?) tyres

[Eamonn]

I've been in email conversation with a member in Switzerland and he's sent the following message through:

I have fitted the Avon 3.25 (front)and 4.0 x 19 for the rear and went off to have the bike newly registered in Switzerland.
This is taken minutely seriously here and the examiner pointed out that the rear tyre (he measured rim and tyre with with a verneer caliper) is not correct as this should be 3.5 according to his specifications and that having an improper tyre could be dangerous…

Is there a case for size 4.0 being correct equivalent to the old 3.5 and also being correct for this rim (original Dunlop, MB43 stamped on rim, whatever that may signify). Any idea who may be able to confirm this officially (someone at Avon UK?)


Any comments or suggestions (especially from other Swiss members!)

[clive]

The original spec was 19 by 3.50. I cannot see how 19 by 4.00 could be a correct equivalent. They are different sizes. Having said that I have a 19 by 4.00 on the rear of one of my singles and it handles and fits fine although i think technically it should not be fitted to a wm3 rim.

[g5wqian]

i have a 4.00x19 mitas on rear of my ajs model 30 twin but it is only really the same width as a dunlop or avon 3.50 width .
some of the modern imperial sized tyres seem to be slightly smaller width than the old original tyres were .
ian

[56G80S]

I have "oversize" tyres front and back and have had for many years (memory fails for the exact dims). I have to spin the sliders and let some air out to remove the front wheel.

Avon Roadriders, all good.

Can't recall if it's been mentioned but don't forget that the modern tyres need higher pressures than the manual says otherwise handling suffers.

Johnny B

[SPRIDDLER]

Well, whether or not it's dangerous the examiner has the standard specification so I guess the answer is to fit the specified tyre for the examination and then ............

[laxy]

Cheapest option would be to borrow a rear wheel with correct tyre for the day.from a friend I also have used 4.00 x19 on the rear for many years without a problem.

[SPRIDDLER]

Cheapest option would be to borrow a rear wheel with correct tyre for the day from a friend..........

Probably not too easy in Switzerland

(Although we don't know which bike he has).

[laxy]

I wonder if a bribe of a bar of toblerone would do the trick

[Greybeard]

Im with Spridds - the examiner had clearly done his homework and the owner was, or should have been aware of how strict the requirements were.

Steve