Tyres

Bob63

philhuff wrote:

It will not only invalidate your insurance, but it's should also lead to an MOT failure.

Wrong. Tyre speed ratings are not considered in an ordinary car MOT. This is only done on PSV and HGV. The MOT only considers tyre condition.

I have knobbly off-road style tyres fitted to my BMW motorcycle. These are rated at 98mph yet the bike is capable of 130mph. Not only are the tyres fully legal but they are a recommended fitment in the bike's manual and the bike can be supplied by BMW with the tyres fitted.

b.t.w. The speed rating means that the tyre is rated on a vehicle/bike travelling for extended periods of time at that speed at the maximum permitted gross vehicle weight. I can't think of a time when I have come even close to those criteria on my bike. I may have done the speed but only while solo and without luggage

Mike

mikey-mike_2

Not sure about this but I thought the rating also covers the forces generated by acceleration, braking & cornering

So, if I replace the Z’s on my 155mph car with H type because I never drive over 80 the new tyres could well be over stressed because the car will still do a sub six second 0-60 sprint

Big_O

Mikey-Mike is correct, the speed rating is much more than about just speed. It includes the forces that the tyre will withstand as pointed out.

It should be read as 'maximum sustained speed' - i.e. the speed that the tyre will do continuously. Accelerating and braking induce higher stresses in the tyre, thus despite accelating to 30 mph, you could be putting forces equivalent to 80 mph on the tyre, or even higher when braking, dependant on rate of acceleration, wheel size and weight of vehicle.

Personally, I would not fit tyres rated lower than the manufacturer specifies. Money saving is all very well, but never at the expense of safety.

Cumbrian_Male

Those 4 little rubber footprints are all that holds your car on the road.

Think about those words.

Is it worth your family being without you for the sake of £20 or so quid difference between the speed ratings?:o

mikey-mike_2

yep, there is a world of difference between buying things cheaply and buying cheap things

bagnall_2

I checked out blackcircles.com & they were competitive, but a local garage beat their prices. 2 Good Year NCTs, fitted, move rear axle wheels to front & front to back & balance all four wheels £119.14. Oh & they are V rated after all that. One garage said they would not fit less than V rated, not due to top speed but due to the torque that the tyres can take safely. Again, maybe clarification from our hero (:money:) would help. Thanks though for all the advice.

iluvmylexus

putting lower rated tyres on your car will invalidate your insurance, a reputable tyre shop would not sell you tyres with the wrong speed rating for your car