How about a Kumho 225/60x15 LS Ecsta? It has a "v" rating. I ran 225/60x15s on my XJS. No problems.

Or how about 215/65x15? There are some "H" rated (130 mph) choices out there.

Cheers
DD

 

What side effects, if any, are there from going with a tire other than one with OEM specs?

 

I picked up mine in a trade. I traded my lattice rims and tires in return for the starfish rims, multiple beautifully rust free body panels, chrome and other odds and ends to kind of rebuild my XJS.

 

When I ran my lattice wheels I used 225/60/15 Kumho's. The only side effect is that the tires may not fill the wheel well the same, i.e. it looks extra roomy or extra full. My dad had similar sized rims on both a '69 Stingray and a XJ6. I believe, if I remember him telling me correctly that he ran either 245/60/15 or 245/55/15 on both of them. He said both ran great with the off-the-book tire size choice.

 

If you're referring to just *size* then the effects are minimal if you don't stray too far from original dimensions. Slight changes in speedometer readings are one result.

Cheers
DD

 

Thanks for the info. That at least opens up a few more options.

 

Kirby Palm, in his book, recommends 225/60 15 tires. Type that size into a google search and there are quite a few tire choices in both H (130mph) and V (149mph) speed ratings. I am not sure what brand to go with on my existing Starfish rims or if I will replace with 17" Revolvers from a late 90's XK8.

 

Don't know but these look pretty good to me, and you have your V rating. They should fit straight on the starfish rim.
225 60R15 96 V Brand NEW Evergreen Tyre EH23 Overstock Clearance | eBay

 

Not sure about where you are but over here the tyre speed rating has to match the theoretical max speed of the car otherwise the insurance company will not like it.
I seem to remember in France that you can't get a CT (MOT) with incorrectly rated tyres (had to buy a full set for the 911S which was annoying and expensive).

 

Over here in Aus. As long as it is the correct size tyre with legal amount of tread and correct load rating you don't have a problem. The thing is the max speed anywhere here is 110kh(68mph) if you get caught doing over 140kh(87mph) its a huge fine and instant loss of licence.
Unless you want to put your car on the track, no real point in paying the big bucks for the speed rated stuff, you just can't use them.

 

We are a bit closer to the German Autobahns than a lot of you guys and gals so how do you think that the insurance company would view it if you were caning it on an unrestricted bit and had a prang.
Doing 150mph on tyres only rated for 130mph doesn't seem like a good idea to me or the insurers; mind you if you do happen to prang it at 150mph then it is unlikely that you are going to care about what the insurers think after the event!
I realise that not everyone is going to head for the autobahns for a major burn out but a lot of people do.
The Isle of Man is a bit closer to us on the mainland and generally has no speed limits outside of built up areas ('sight lines are such that there are parts of the network where someone in an appropriate vehicle could approach 200mph' - Wiki) so that is another place outside of a circuit that you can max the car.
Personnaly I don't think that you should fit lower rated tyres than the original spec.

 

I recently put a set of starfish wheels on my SIII XJ6. I put Uniroyal Tiger Paw tires on them, 225/60R15. H Rated (130mph) and 96 load rating. I've been very happy with them

I was looking at Kuhmo ecsta and the guy at the tire shop who I trust steered me towards the Uniroyal. They were cheaper than the Kuhmo tires also. I think I paid maybe $80/tire.

 

Not an issue in the 'States. Our insurance companies don't seem to 'go there'...possibly because only .5% of crashes here are tire related according to the NHTSB. And, of those, the majority are attributed to tire condition and under-inflation, not tire type/specification.

And, of course, we don't have Autobahns. Well, not official ones, at least

Cheers
DD

 

Wish we did have official ones...

But yes, not an issue here even in the stricter states. I'm pretty sure the "inspector" at our DMV doesn't know that tires have speed ratings. They just make sure your brake lights work...

 

I just pulled this from Discount Tires website and just like the true but counterintuitive "new tires on the back" rule, they advocate if you have to mix speed rating tires on a vehicle, put the higher ones on the back. As I remember in the UK, the tire shops will not fit under-rated tires to your car, probably because of liability concerns.
Speed Rating

A tire receives its speed rating by the U.S. Government through meeting minimum standards for reaching and sustaining a specified speed. What does that mean to you? Well, in general, a higher speed rating will result in better car handling.
Two Important Notes When Considering Speed Rating:

• We do not recommend downgrading the speed rating of your tires. This may result in poor handling and unpredictable steering. However, if you want better cornering response, there is no problem installing a higher speed rated tire on your vehicle.
• Tire manufacturers recommend not mixing and matching tires with different speed ratings on your vehicle. It is recommended that speed-rated tires be replaced in sets of 4. If replaced in pairs, the new tires should be of the same or higher speed rating. If tires with different speed ratings are installed on a vehicle, it is recommended that they be installed with like pairs on the same axle. It is highly recommended the lower speed-rated tires be place on the front axle, regardless of which axle is the drive axle, to help prevent oversteer. (Oversteer occurs when the vehicle loses traction at the rear tires first, causing the vehicle to spin and the driver to lose control.) The speed rating for all tires will become that of the lowest speed-rated tire on the vehicle.

 

(Oversteer occurs when the vehicle loses traction at the rear tires first, causing the vehicle to spin and the driver to lose control.)
That's interesting, understeer not considered a problem then!

 

The speed rating is for a sustained speed of whichever you choose, the real difference between the V and the others is the sidewall construction of the tires. I put Michillins that are T rated on my 85 XJS and have no fear of doing 70 to 90 MPH on the highway.

 

At the risk of over-egging the proverbial, I also found an article in Popular Mechanics "6 Common Tire Myths Debunked", easily googled, which leads to some good video showing the comparison when wet cornering.
I think I also read somewhere that the engine weight on the front helps prevent understeer if the tires are more worn - which may be why no-one ever, ever puts an engine behind the rear wheels - oh, yeah, except Porsche!

 

The majority of manufacturers have long considered understeer to be more safe than oversteer, as, generally the driver needn't do anything but slow down to regain control....and for most drivers, slowing down is the natural reaction to begin with.

Cheers
DD

 

Triumph Heralds used to suffer from roll over steer, literally.
Brother in law spent 3 months in hospital after his convertible landed on him.
Mind you the biggest injury was side impact to the head caused by the ghetto blaster in the passenger seat going all ballistic.