Swopping from H to T rated tyres?

[DuraAce]

One of my cars has H (130mph) rated tyres fitted to it currently. Can I swop onto T (118mph) rated tyres with no implications to insurance/MOT?

Manufacturers quoted top speed of the car is 98mph, which is of course under the T rating.

[BGarside]

DuraAce said:

One of my cars has H (130mph) rated tyres fitted to it currently. Can I swop onto T (118mph) rated tyres with no implications to insurance/MOT?

Manufacturers quoted top speed of the car is 98mph, which is of course under the T rating.

I'd guess the insurers would want to see that it is fitted with whatever the originally recommended / fitted speed rating was, or higher.

[anonymous-user]

Depends what speed rating the manufacturer originally specified for the car. Should be either in the handbook or on a sticker/plate somewhere on the car.

[saaby93]

That's anyone changing their tyre sizes done for.
Or anyone fitting anything to their car not OEM

Similar thread here
http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[BGarside]

saaby93 said:

That's anyone changing their tyre sizes done for.
Or anyone fitting anything to their car not OEM

Similar thread here
http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Not necessarily, but the speed rating (and load index) are presumably important to safety and must be sufficient for the car. I'm guessing the insurers would use 'lower-than-OE' values as a way to avoid paying out in the event of an accident, even if the speed and load ratings were actually OK for the weight and performance of the car.

[giger]

Speed ratings - you can go up but not down, you should notify the insurer. They may or may not charge, underwriters will treat this differently. This is different to changing tyre size. The difference in price of tyres with different speed ratings is generally quite small unless you go from one end of the scale to other - is it worth the hassle? Is it a supply issue?

[saaby93]

giger said:

Speed ratings - you can go up but not down, you should notify the insurer. They may or may not charge, underwriters will treat this differently. This is different to changing tyre size. The difference in price of tyres with different speed ratings is generally quite small unless you go from one end of the scale to other - is it worth the hassle? Is it a supply issue?

You generally get a load factor change too, which may be beneficial but still within the max speed of the car

[saaby93]

BGarside said:

saaby93 said:

That's anyone changing their tyre sizes done for.
Or anyone fitting anything to their car not OEM

Similar thread here
http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Not necessarily, but the speed rating (and load index) are presumably important to safety and must be sufficient for the car. I'm guessing the insurers would use 'lower-than-OE' values as a way to avoid paying out in the event of an accident, even if the speed and load ratings were actually OK for the weight and performance of the car.

That's what I'm saying
In safety terms the lower rating may well be sufficient for the car, but would it be used as a way of avoiding cover?

[SuperPav]

I'm not saying insurance wouldn't try to wriggle out of a claim, but I don't see how they can legally defend a position that says when you had a 20mph shunt, the fact that your tyres are rated to 160mph instead of 178mph makes any difference.

Any lawyers?

If you had a tyre failure/blow out, then perhaps, but unless it fails, the speed factor makes SFA difference.

[DuraAce]

It's not a supply issue per se, T rated gives more choice and are £10-£15 cheaper. It's just the legal side I am concerned about. I'm happy the tyres themselves will be totally fine. Car can't do 100, even downhill! T tyres are 118 so no worries there.

Just thinking if I can save £60 on aset of tyres then why not. I'll try calling insurance company later when I can get to a phone.

[ianrb]

Winter tyres often have lower speed ratings and insurance companies are all pretty relaxed about them.

I think some people need to put their foil hats away.

[Bluebarge]

When car manufacturers specify a tyre they specify a load and speed rating. The two go together and impact on the handling in extremis. For winter tyres the manufacturer will usually specify a narrower tyre and, yes, they will usually stipulate that one speed rating lower is fine for the winter tyre (but not the summer); however, winter tyres are now available in pretty well all speed ratings so this is less of an issue than it used to be. So, you shouldn't really go below the manufacturer's minimum spec.

However, I very much doubt whether your insurer will spot that you have a lower rated tyre than specified unless you are involved in an extremely bad pile-up leaving multiple folk requiring expensive medical treatment.

[TA14]

Bluebarge said:

So, you shouldn't really go below the manufacturer's minimum spec.

Good point but I've never seen a minimum spec, have you?

OP, by and large you'll be OK. If you have any doubts then write to your insurers to confirm the change.

[saaby93]

Bluebarge said:

When car manufacturers specify a tyre they specify a load and speed rating. The two go together and impact on the handling in extremis. For winter tyres the manufacturer will usually specify a narrower tyre and, yes, they will usually stipulate that one speed rating lower is fine for the winter tyre

thanks - where do they do that?

[andy-xr]

This really isnt the sort of thing that needs a H+S assessment approach

[TA14]

saaby93 said:

Bluebarge said:

When car manufacturers specify a tyre they specify a load and speed rating. The two go together and impact on the handling in extremis. For winter tyres the manufacturer will usually specify a narrower tyre and, yes, they will usually stipulate that one speed rating lower is fine for the winter tyre

thanks - where do they do that?

The owner's manual, eg p263 https://www.fiat-lancia.org.rs/Manuals/AlfaRomeo/1...

[carl_w]

Should be fine -- I did this on a 1.4 Saxo which came fitted with H rated tyres (Michelins) and I put T-rated Toyos on, whose speed rating still exceeded the max speed of the car. I think the only reason it came on H-rated tyres was that Michelin were Citroen's preferred supplier and they didn't do that size in anything other than H-rating.

[jon-]

Speed rating is fine, do as you please.

Never go lower than the OE specified load rating though, as this has safety, and therefore insurance implications. Going higher is fine.

[Rich1973]

As above. Load rating is the one you must not change for lower.

[saaby93]

Rich1973 said:

As above. Load rating is the one you must not change for lower.

Depends on the car. suppose you have a lightweaight car where the car manufacturer has specified a load rating of 81 because that's what's on the standard tyre available in that size.
Another manufacturer brings out a tyre with a load rating of 79 which may be much more suitable
Conversely a higher than specified load factor could make things worse
Anyway is a change from 81 to 79 going to be quibbled about