Another tyre question for Uk drivers?

[pereirac]

Hi,
In the Uk at least, does anybody know whether fitting tyres with a lower speed rating will invalidate ones insurance, leave one open to prosecution by the police or even be a MOT fail? I know HR rated are almost impossible to find and are very expensive but they do exist. Even if we don?t all drive our cars over 120mph, I thought the rule here was that the tyres has to be able to cope with the maximum speed of the car?

Carl

[JonB]

I hadn't heard that.

My view (opinion only, but hopefully someone with more direct experience will chip in here) is that if you have lower speed rated tyres and are involved in an accident, it has to be proven that you were exceeding the tyres' speed rating for that to be considered a factor in the accident.

[Orsom Weels]

This is a question that crops up every so often in the car world in general. As I understand it, as the maximum speed we are allowed to do on UK roads is 70mph, any tyre capable of that is technically legal. However, it is recommended that you contact your insurance co to see if they consider it a modification. Most don't it seems, but they do consider a size change a mod, so fitting 155's to a series 3 Elan would need to be notified, as would fitting 175/70's to a +2.
If you think about it, if it were an offence to drive on a tyre with a lower speed rating that the manufacturers spec, it would be an offence to drive on a space saver spare tyre, most of which have very low maximum speeds emblazoned all over them by the said manufacturer.
Speed rating does come into the MOT, but only in so far as to assess the tyre is capable of the maximum 70mph, here's what the MOT testers manual says on the subject,

"A Restricted Speed Vehicle is a vehicle displaying at its rear a 50 plate as shown below at l east 150mm wide and 120mm high.
A vehicle displaying this plate is required to have tyres suitable for speeds up to 50mph, i.e. F speed rating or greater.

Other Suitable Speed Ratings Class 5 only

Unless the vehicle is a Restricted Speed Vehicle the tyres are required to be suitable for use up to the maximum prescribed speed limit of 70mph, ie L speed rating.
Tyres of the lower speed ratings of J or K however are acceptable for use at 70mph although the increase from the nominated speed rating imposes a reduction in the tyres carrying capacity."

So no worries there, & therefore no worries of plod trying to prosecute you.
General consensus is that it's ok to use lower speed rated tyres, but check with your insurance co.

Regards, Tim