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Tyre rating

Posted: Sat Mar 21, 2015 11:00 pm
by bmcecosse
This question is about modern car tyres. I know the tyres on an 'axle' must be same size - but what about speed rating?? If one is 205x55x16 91H and the other is 205X55X16 91V - is that ok ?? The normal rating for the car is 91H - the 91V is therefore a 'better' tyre - is that allowed?

Re: Tyre rating

Posted: Sat Mar 21, 2015 11:18 pm
by andy.pointeer
Hi bmc the v/h is the speed rating, had the same issue with my modern

see http://www.ctyres.co.uk/tyre_info/Speed_ratings.html

H is 130mph and V is 149mph, but as it indicates on the ctyres site you should have what car maker states as may affect insurance

Hope the site helps

Re: Tyre rating

Posted: Sun Mar 22, 2015 5:55 pm
by bmcecosse
Indeed, and thanks - but to have one tyre with a BETTER speed rating shouldn't do any harm. Is that checked at MOT - or just the size to be the same ?

Re: Tyre rating

Posted: Sun Mar 22, 2015 6:51 pm
by M25VAN
I would think that the 91v is a safer tyre at 130mph than the 91H, being more within it's capabilites at that speed.
What about tyres on the same axle with one at maximum tread and one at minimum tread? Or one tyre with a wet grip rating of A and another with G? :-?

Re: Tyre rating

Posted: Sun Mar 22, 2015 10:41 pm
by bmcecosse
Since the speed limit is 70 - I can't see it being an issue!! The new modern came without a spare wheel - so I bought a wheel and tyre on ebay - which came with great tread and correct 16" size - but the 91V rating, where the wheels on the car are 91 H. Actually - I did buy a spare wheel with the car (£95) - on the strict promise that it would be a full size wheel and tyre. In the event - it was a 15" wheel with a 185/60 tyre - so I refused to accept it - still waiting for my £95 to be returned of course.... :roll:

Re: Tyre rating

Posted: Sun Mar 22, 2015 10:50 pm
by beero
Not always possible I know but I like to change tyres in matching axle pairs so at least the grip is the same on that axle.
I recently changed to Continentals from Bridgestones on the front of my daily driver and it now oversteers in the wet where it used to understeer so the difference in grip between two makes should not be underestimated.

Reading through the MOT manual I understand the MOT station should check load ratings and speed ratings on Class 5 and 7 only, ie motor caravans, ambulances and goods vehicles.

Re: Tyre rating

Posted: Sun Mar 22, 2015 10:54 pm
by bmcecosse
Oversteer is good ! You'll be able to drive like....Clarkson !! :lol: Try adjusting the tyre pressures to get a better balance.

Re: Tyre rating

Posted: Sun Mar 22, 2015 11:10 pm
by beero
Yes, oversteer on a fwd, I couldn't believe the difference in wet grip!
I prefer it like that, probably because I was brought up on rear wheel drive cars that rarely understeer.

Clarkson only drives like that because he wants to appeal to youngsters who appear to be obsessed with drifting ..... and he's not paying for the rubber. He needs to act his age.

Re: Tyre rating

Posted: Sun Mar 22, 2015 11:18 pm
by bmcecosse
It's only possible if you have a really tight Limited Slip diff in the axle... and unlimited budget for tyres!

Re: Tyre rating

Posted: Tue Mar 24, 2015 11:10 pm
by TFM150K
bmcecosse wrote:This question is about modern car tyres. I know the tyres on an 'axle' must be same size - but what about speed rating?? If one is 205x55x16 91H and the other is 205X55X16 91V - is that ok ?? The normal rating for the car is 91H - the 91V is therefore a 'better' tyre - is that allowed?
Forget about "allowed", Roy, and keep two identical tyres on the same axle if you possibly can. If you have an odd one, as long as it is the same size (per the numbers on the sidewall - not by measuring to compensate for wear) use it as the spare. Don't mix "winter" and "summer" tyres at all (if you use them).
:)

Re: Tyre rating

Posted: Wed Mar 25, 2015 12:12 am
by irmscher
Roy oversteer Clarkson most on here drive like captain slow :lol: :lol: