Tyre Size and Speed Rating

[campbellr2007]

Hi , I am looking for some input on tyre sizes and speed rating.

Currently building a MkIII sumo. Have recently bought a set of Halibrand replica wheels. They are 15" - 8J on the rear and 7J on the front. The tyres I have lined up are Cobra Coopers . Rear 235/60/15 and front 215/60/15. These sizes seem to be the most popular and will fill out the arches nicely. The speed rating is 'H' and as I understand good for 118 mph. The car is Vitesse RV8 with the fuel injection fitted. I have a concern that SVA and/or any likely Insurance company may not consider this high enough.

Does anyone have any thoughts or experience on these points ?

Many thanks

[TonyD]

Originally Posted by campbellr2007

Hi , I am looking for some input on tyre sizes and speed rating.

Currently building a MkIII sumo. Have recently bought a set of Halibrand replica wheels. They are 15" - 8J on the rear and 7J on the front. The tyres I have lined up are Cobra Coopers . Rear 235/60/15 and front 215/60/15. These sizes seem to be the most popular and will fill out the arches nicely. The speed rating is 'H' and as I understand good for 118 mph. The car is Vitesse RV8 with the fuel injection fitted. I have a concern that SVA and/or any likely insurance company may not consider this high enough.

Does anyone have any thoughts or experience on these points ?

Many thanks

The SVA will check first of all that the tyre has an "E". If the tyres are coming in from the USA check that it has the required E rating moulded into the sidewall or if it doesnt have the E mark, at the very least make sure it has a VR or ZR rating moulded into the sidewall..

H Rating is good ( acceptable) for up to 130mph, but you may have to prove to the examiner that the car is incapable of exceeding that speed, ie the car has a very low diff ratio and max permissable revs are well short of the 130mph level. He will of course be able to tell on the rolling road if the diff ratio is low or not.

Given that there is a good chance of the car being able to attain 130mph I would go for a a V rating at the very least.

Cheers,

Tony

PS re tyres another vote for Cheap Tyres Discount Tyres & Japanese Import Car Parts Spares Tuning Performance :: as I've just bought four 17inch Toyo T1R's Y rating for £397.60.......

As the wheels are winging it in from the USA as I type this I only have to get a local knowledgable and skilled tyre fitter to fit the beggars when they arrive.

[chr15w]

Along the same lines I saw on ebay a set of 18" wheels with tyres fitted 245/40/18 for around £659 for 4. Theyre not exactly Halibrands but with 225/40/18 on the front would they look good? would they need spacers at the rear? take a look
18" ALLOY WHEELS FIT JAGUAR XJ TYPE + 245/40/18 TYRES on eBay, also, Wheel Rims, Car Wheels, Tyres Trims, Cars, Parts Vehicles (end time 18-May-08 14:40:36 BST)

[TonyD]

Originally Posted by chr15w

Along the same lines I saw on ebay a set of 18" wheels with tyres fitted 245/40/18 for around £659 for 4. Theyre not exactly Halibrands but with 225/40/18 on the front would they look good? would they need spacers at the rear? take a look
18" ALLOY WHEELS FIT JAGUAR XJ TYPE + 245/40/18 TYRES on eBay, also, Wheel Rims, Car Wheels, Tyres Trims, Cars, Parts Vehicles (end time 18-May-08 14:40:36 BST)

All depends on the make of kit you have. Be aware that the front or rear rim must protrude beyond the wheel arch, otherwise an SVA failure will be on the cards.

Its nice to see some other Cobra builders looking "outside the box" for different wheels rather than stick to the well trodden Halibrand replica route.

Cheers,

Tony

[wilf]

Please insert "not" between "must" and "protrude".........

[Purple AK]

Originally Posted by campbellr2007

Hi , I am looking for some input on tyre sizes and speed rating.

Currently building a MkIII sumo. Have recently bought a set of Halibrand replica wheels. They are 15" - 8J on the rear and 7J on the front. The tyres I have lined up are Cobra Coopers . Rear 235/60/15 and front 215/60/15. These sizes seem to be the most popular and will fill out the arches nicely. The speed rating is 'H' and as I understand good for 118 mph. The car is Vitesse RV8 with the fuel injection fitted. I have a concern that SVA and/or any likely Insurance company may not consider this high enough.

Does anyone have any thoughts or experience on these points ?

Many thanks

Firstly Cooper Cobra tyres are "T" Rated (118mph) That in itself isn't a problem provided you state the maximum speed at below that for SVA. And your Insurance can't prove that in any accident claim you were exceeding 118mph! That said (apparently) they are Cr*p in the wet!! Sorry to be so blunt! But we all spend between £15 - £25K on a car then skimp on the ONE thing that holds it on the road and keeps us safe!!

[jeff]

I had no problem with Coopers at SVA last march, had stated max speed at 110.

They look really good but that’s as far as it goes, in the dry they are poor, too hard to generate much grip, and in the wet (or even mildly moist) they are down right fecking scary.

This Cooper owners advises dont touch with a barge pole

[Naumoff]

Originally Posted by Purple AK

Firstly Cooper Cobra tyres are "T" Rated (118mph) That in itself isn't a problem provided you state the maximum speed at below that for SVA. And your insurance can't prove that in any accident claim you were exceeding 118mph! That said (apparently) they are Cr*p in the wet!! Sorry to be so blunt! But we all spend between £15 - £25K on a car then skimp on the ONE thing that holds it on the road and keeps us safe!!

This is so true! The same way in the States.

[lutman]

Originally Posted by Purple AK

Firstly Cooper Cobra tyres are "T" Rated (118mph) That in itself isn't a problem provided you state the maximum speed at below that for SVA. And your insurance can't prove that in any accident claim you were exceeding 118mph! That said (apparently) they are Cr*p in the wet!! Sorry to be so blunt! But we all spend between £15 - £25K on a car then skimp on the ONE thing that holds it on the road and keeps us safe!!

Also agree 100% - lots of dosh spent during build and then go cheap for tyres and brakes. Little credence given for suspension set up either. All of which can cause major grief.
I knew of someone who built a kit (not Cobra) who ran with nitrous but had VW beetle drum brakes on the rear and skinny discs/small pads on the front and was quite upset I did not want to drive with him !
I have heard the Cooper tyres are not so good especially in the wet - better to run with branded tyres such as Toyo or Yokohama road legal semi slicks - at least then good in dry !
Also to add my comment - SVA -nothing wheel wise is supposed to extend out wider than the wheel arch - that includes any wheel spinners which includes any spinner threaded "axle" , a small amount of tyre wall is permitted to allow for the tyre wall bulging.

Bottom line is buy tyres with a rating that far exceeds the cars limitations. Fit brakes that are more than adequate and whenever possible set up the suspension to suit the gross weight of the car.

[KevinW]

I've seen 15" fat wall tyres with Goodyear (I think) written on the side. These not made any more, anyone know?