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tyre speed ratings
mad-butcher - 23/10/08 at 08:26 AM

morning all
my tyres are V rated 150mph. can I put 130mph as maximum road speed or do I have to put the speed that the tyres are rated for
many thanks
tony

adithorp - 23/10/08 at 08:31 AM

Max speed is that of the car. The tyre rating has to exceed the car max.

So yes 130 is fine.

adrian

m8kwr - 23/10/08 at 08:39 AM

Sorry to jump onto this post.

If you used a bike engine, with a top speed of over 150, but due to the ratio you are using it does not exceed 130.

Do you have to prove this when getting the car through the SVA/IVA

Many thanks

tomblyth - 23/10/08 at 08:40 AM

check to see the test is not harder with a high speed ! not sure but I remember reading there is a reason for having a lower max speed, cant remember why though!

minitici - 23/10/08 at 09:09 AM

Some useful information on previous topics

Topic

Rosco - 23/10/08 at 10:34 AM

My understanding is that top speed is about drag coefficients not weight, so although 7s accelerate very well their top speed will be lower than a similiary powerfull tin-top. And while gearing plays a part in terms of matching the drag curve to the power curve there will always be an aerodynamic limit where these curves cross.

As a guide, I've just had a look at the Top Gear Website and the figures they quote for a latest Cosworth-powered Caterham are; 200bhp gives 140mph and 260bhp gives 155mph.

So unless you've got serious bhp you can forget 150mph. I guess 130mph is more realistic for most of us.

speedyxjs - 23/10/08 at 01:58 PM

quote:
Originally posted by Rosco
So unless you've got serious bhp you can forget 150mph. I guess 130mph is more realistic for most of us.


Well someone had better design a more aerodynamic locost then

mad-butcher - 23/10/08 at 04:56 PM

Tomblyth
I'm glad you mentioned that as there is something in the back of my mind telling me exactly the same. think it's time to give up working nights