Indeed, commend the Mad Max series to all for some retro post apocalyptic escapism
Here in the USA the speed rating vs insurance company thing simply isn’t an issue…thankfully.
One possible explanation is that tire failures account for only a very small percentage of accidents. I once read the NHTSA (National Highway Traffic Safety Administration) information on tire failures and (something like) 2% of accidents are tire related and, of those, 80% were due to under-inflation or poor condition…not the type/design/specification of the tire. I might be slightly mis-remembering the numbers but, even so, the gist remains.
As I think someone suggested, if there must be a requirement, load rating would seem more to be a more real-world thing. But, even then, tire condition and inflation play a huge roll in safety.
It really comes down to the owner/driver more than anything else. A smart owner has properly inflated tires in good condition. A dumb owner doesn’t. We have have insurance policies that protect us, financially, from the dumb things we do…right?
It always seems silly to me that an insurance company would pay out if a fellow was dumb enough to drive when fatigued and thus fall asleep at the wheel…but then disallow a claim because his tires carried were the incorrect speed rating !
Cheers
DD
I tried one of the 16" wheels with a 225/60 tyre fitted and unfortunately it doesn’t work.
The front seemed to be ok but the rears were catching on the wheel arch on full droop.
I didn’t try the front on full droop or lock as it was pointless for me once I found out about the rears.
What a bummer. Thought I was being clever but apparently not 
I’ve put this here so anyone else can avoid the same mistake.
I would say that it was very close thing and maybe they could be made to work by modifying the rear arches but that’s not something I want to even consider.
The offset on these wheels is 33 mm and it would seem to me that they idea would work with larger offset wheels but a larger offset would not work on the front.
Not sure what to do now but I’m thinking o 215/65 r15 might work which are available in a V rating.
Really, I suppose I should bend over and just buy the correct tyres 
Dave
Frank is right. Read the fine print. I do know that insurance policies in the USA have no such limiting exclusion. At least in Ca, and most likely in most if not all of the other 49, the liability portion of the policy must meet certain standards so as to comply
with what is now a condition for registration of cars.
Never, a very long time, in my 50 years of Claim work did I consider speeds rating of the tires as a possible policy defense.
Tire failure as a cause of an accident. Yes, but, on rare occasions. And usually 'under inflation as a cause.
Would I ever call my insurance agent for advice as to tires?
A very smart lady. But only in policy language not in engineering, by a long shot.
Go back to 1951. The Pan American Roads race. all kinds of cars in Mexico. V rated tires unheard of. The USA Lincolns raced on street tires. Strope prepared, Speeds well over 100 mph. Any tire failures. Roads hazard, yes. design, I don’t recall any.
For me, the “T” rated B.F Goodrich 215 70 15’s on XJS lattice wheels look good, handle well and are safe at any speed I’m likely to drive at.
Carl
That’s what I’m running in my Ser III with no issues
Cheers
DD
My last set were that size–unidirectionals, Yoko IIRC. They were excellent…a noticeable increase in “crispness” of handling even at low speed as I exited the tyre place (they replaced 205/70 Pirellis). The modern tread pattern didn’t suit the car, I thought, and they were a bit short. So I decided to fill the fender wells when I replaced them with 215/70 Hankooks. Again, I noticed the change as soon as I drove away, but this time it was a sick “I goofed” feeling. Rims are 7 inch BTW.
Next set will return to 215/65 unless I go to 16 inch wheels.
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The 215/65s are a tad bit short, yes, particularly noticeable in the front. In my case, tho, I have the front ride height a bit lower than spec so the overall look is OK; no empty wheel well showing.
FWIW I decided on Falken tires although, at the moment, I cannot remember the exact model. I’ll look that up. So far I’m pleased in all respects except they’re a bit noisier than I’d prefer. Not horribly so. But you can hear 'em
Cheers
DD
I haven’t read everything written here but i have glanced at some of the comments here where people are suggesting fitting 60% or 65% profile tyres. that is wrong don’t compromise your car for the same of just buying cheap tyres.
We know that an XJ6 is an incredible bargain. it is an incredible bargain because it is a great car built out of great components, don’t then ruin it by fitting something inappropriate.
An XJ6 is only cheap because they made so many because they sold so well because they were such great cars.
In fact you bought it because it is such a great car.
Unusual obsolete tyres sizes that are made in small batches do cost a few quid. they just always will, so actually £ 200 per corner is not expensive. very fast heavy luxury car tyres just cost that. i am about to pay more than that for tyres for my 90’s Lexus.
here are your options http://www.longstonetyres.co.uk/page/jaguar-xj6
Everything is a compromise. Everything.
And I’m not sure what you mean by “cheap”. Low quality? If so, I agree. Nobody would advocate low quality tires. But we have many choices in good quality tires.
Inappropriate by whose standards? Yours?
We have choices now were not available to Jaguar (or us) in the 60s, 70s, and 80s. They’re worthy of consideration.
Those are options you offer and, frankly, it seems blatantly self-serving. But the choices you offer might be just right for some people. Others, maybe not. There are other options. Let’s not pretend otherwise.
What is or isn’t expensive isn’t defined by you. It’s defined by the customer’s own pocketbook and willingness (and ability!) to pay…and comparison to other choices. For many, cost-vs-benefit comes into the equation.
Cheers
DD
Thanks Doug, for speaking up.
Jochen
75 XJ6L 4.2 auto (UK spec)
I acknowledge that the tyre designed for the car should be optimal in most conditions,
however, I am genuinely curious what adverse effect fitting a 205/65/15 could have?
I am NOT a tyre expert, but 205/65 are designed for large sedans similar to XJ,
nearly all our Jag Club members fit them
dont push my vehicles hard in the rain or on race tracks
while I dont recommend my method to anyone else, owning several vehicles for 10yrs+, but not doing many miles, I would have spent thousands on tyres, as if one is to be strict, they would SURELY need to be changed out upon reaching specified age limit
personally, I cannot see how 205/65 profile tyres could make any difference in performance, or be noticed by driver (other than 3% rolling diameter)
Broadly speaking a 60 or 65 series tire will give a firmer ride and crisper steering response than a 70 series tire. Some people prefer that; others don’t. Some don’t even notice.
But there are so many variables beyond just the size. Tread design, sidewall construction/stiffness, rim width, inflation pressure.
To beat a dead horse I’m not quite convinced that sticking with a 25-30-40 year old tire design is optimal. The Pirelli Cinturato, Dunlop SP, etc date back to the 60s. If you want to re-create the original driving/handling/ride characteristics of your car then, yes, go with one of those vintage-design tires. Whether or not that’s ‘optimal’ is up to the individual to decide 
Cheers
DD
Generally the larger tyres are going to have a lower profile so the RPM/mile should not change to drastically, I have actually gone up on width on two of my cars as the speedo reads 8% down versus GPS Mazda 6/Attenza 100Klm indicated 92 GPS it now reads <>100/98 so much happier
There may be two different issues relating to “modern tires” and/or “modern sizes”.
Back in the times all tires were 80 % height/width ratio. Jaguar made a big thing of introducing /70 Dunlop tires on the E and later the XJ. Then they were considered low-ratio and contributed to the superior handling and roadholding (compared to /80 radials, let alone then common diagonal tires).
By today’s standards a 70 % ratio makes a balloon tire and is used only on minivans etc. A 65 or 60 % tire will give crisper response without sacrificing much of the benefits in comfort. I did the change on another car, simultaneously increasing width by 10 mm, thus filling the wheel well and keeping the speedo accurate. I’m very satisfied with the result. The looks are hardly changed, the feeling is good, the prices of the tire better, the choice bigger and there have been no adverse effects on other components over the last ten years.
Anything beyond this - such as a 50 or 40 % ratio - will not necessarily improve overall driveability any further, unless you’re looking for a slalom champ on smooth surfaces. It may look out of place - like the Queen on high heels -, get noisy at low speeds and make the car rattle. What is more, the stiffer structure of the tire will take much of its dampening qualities, dramatically increasing load on all suspension components. So I’m fairly sure that you will open up new construction sites on the longer run.
So, yes, modern tire sizes may be helpful to provide supply and even add to the driving pleasure, if applied with consideration.
On the other hand, tire technology has progressed dramatically since the 1970s or 80s. So if you’re not intending to keep those original looks with a period thread structure, just go for the most current rubber you can get for winter or summer. Braking, control, noise, fuel consumption will all profit …
At the bottom line I doubt though whether a 200 EUR Vredestein Sprint Classic at 205/70 is worth the extra money compared to a modern Michelin Energy Saver+ at 205/65 and 90 EUR.
Good luck
Jochen
75 XJ6L 4.2 auto (UK spec)
Hi Team
No Surprises to hear i don’t agree with some of what is written here. I should point out that the differences we are discussing are subtle. for instance if you drive on a 65% profile instead of a 70% profile tyre you are not suddenly find the car horrible to drive. the differences are subtle.
Yes tyres are very different to how they were in the '60s, but these developments have been done in conjunction with the developing car designs. so as the car design develops the tyre develops to suit these developments, and vice versa as there have been step changes in tyre design car designs have developed to take advantage of these enhancements.
Where we can all agree is that the build quality and materials used in tyre production have improved. But what should be pointed out is that the classic tyres that i sell today are classic tyres built with a carcass designed to suit the differences in classic car design compared to modern cars. However the ones i generally encourage Jag Lovers to fit are made by Pirelli and Michelin. they are built in their own modern factories with the best quality control, and with modern up to date compounds. so performance wise they are excellent. If you think you have taken off a Cinturato or an XWX and fitted a modern tyre that you feel handles better, please ask yourself how old they were when you consider them as a comparison to what you now have fitted.
On the price subject; the reason i came onto the Jag Lovers forum today was to tell you guys about a special offer we have on the 215/70VR15 XWX tyres on our French web site https://www.longstonetires.fr/pneu-voiture-collection/jaguar/xj6.html apologies for being so commercial
All of the above posts have their points but my feeling is my tires gripping the road could literally by the difference between life and death (mine or some innocent person). So I will go with modern radials every time. I almost never wear my tires out but from what I have read when a tire is over 7 years old it is time to get new (and better ones). As to speed rating, like Doug said, in America, we choose based on how fast we are going to be driving, not how fast the car is theoretically capable of.
Longhorn,
technical point taken, but commercials are to be placed in the ads section.
Good luck
Jochen
75 XJ6L 4.2 auto (UK spec)
[quote=“Longstone, post:35, topic:356432”]
Where we can all agree is that the build quality and materials used in tyre production have improved.
Different build quality, different materials. So they’re not really the same as the originals, correct? How can we expect them to feel the same?
But what should be pointed out is that the classic tyres that i sell today are classic tyres built with a carcass designed to suit the differences in classic car design compared to modern cars.
Which differences are you referring to, and what is unique about the carcass design that makes them especially suitable.
I’m running Falken ZE950s. What is unique about their carcass design that makes them less suitable for my older Jag.
and with modern up to date compounds.
Compound is a significant factor in tire behavior.
If the Jaguar suspension and tires were as precisely matched as you’ve previously asserted then a different compound would require a re-tuning of the suspension, wouldn’t it?
Sorry, but you can’t have it both ways!
If you think you have taken off a Cinturato or an XWX and fitted a modern tyre that you feel handles better, please ask yourself how old they were when you consider them as a comparison to what you now have fitted.
Please define “handles better”. What subjective standard or objective measurement is being used?
If you insist on selling us $250-$300/apiece tires then you’ll at least have to be specific . Tell us why we’d be so thrilled with our purchase that the sting of the much higher price will be very quickly forgotten.
C’mon ! We can read advertising copy anywhere on the internet. Do your job as a salesman !
Cheers
DD