Original XJ12 tyres

I have always just thought that the series 1 & 2 XJ cars fitted Dunlop as OE. I always thought up until '81/'82 when they introduced the HE version of the XJ12 they fitted Dunlop ER/70VR15 SP Sport.

However i have been looking at a selection of fitment guides from period and they all list the XJ6 as fitting ER/70VR15. but the 12 cylinder cars it lists as 205/70VR15.

Now a ER/70VR15, is actually a 205/70VR15. I think Dunlop just wanted to add some mystic by using the ER instead of 205. Pirelli were making low profile tyres as well in 1968, they were making a CN36 which Porsche used. then in '71 they made the CN12,

I am wondering if the V12 cars might not have fitted Pirelli instead of Dunlop?

Pirelli introduced the P5 in the later '70s. I know this was an OE tyre on the XJ saloons, and Pirelli have also already made the 225/65R15 P5 for the XJ40. I am just wondering if you chaps might be able to clear up some of this detail?

According to sales brochures, which are generally reliable but not 100%, the early V12s used Dunlop SP Sport just like the the 6-cylinder cars did.

However (and this is from memory so don’t take it to the bank) the V12 cars used a steel-belted version rather than fabric belted. For reasons not known, Dunlop didn’t use the alpha size designation on the steel belted versions? I dunno.

AFAIK, the Dunlops used on the early XJ6 cars were the only “Euro” tire to use the alpha size designation. I suspect it has something to do with the USA market, which was quite large for Jaguar. The alpha designations starting taking hold in the USA in the late 60s and soldiered on until the early 80s when a transition back to numeric designations began.

As long as I’m blathering…

Somewhere along the line Jaguar began specifying 215/70x15 for the V12 cars, I think when the Series III was introduced or, as you say, when the HE version was introduced. Later in Series III production the 215/70 was specified for the 6-cylinder cars as well, at least for the USA market.

Cheers
DD

1 Like

I worked at Pirelli Tires in the 1970s and I had a 1972 Series I XJ6.
The first batch of 205/70 VR 15 tires arrived in a Sea-Land container and when we unloaded it, we found the (10) ten 205/70 VR 15 tires as replacement Jaguar tires for the initial US shipments.

I went into the office and told the managers that I wanted 5 of the tires. They said NO, they are for the Jaguars.

I reminded them that I had a Jaguar. They reluctantly agreed to let me have 5 tires. (we were allowed 6 new tires every 2 years as part of a compensation package)

I think I was one of the first (if not the first) people in the US to have the Pirelli tires (205/70 VR 15) on an older XJ6. The new Jaguars already had them from the factory.

I did install the 185/70 VR 15 CN36 (Roadstars) that were meant for the Porsche 911 on my 1966 ‘E’ Type Coupe and they were AMAZING!!

They were 2 sizes too low but I did not care too much about ground clearance or speedo accuracy.

They were fabric belted and they only lasted about 15 or 20 thousand miles but the soft tires REALLY gripped.

Thanks for the memories.

bob

The Jaguar Clubs of North America (JCNA) has a comprehensive list of tires fitted by year and model in their Concours d’Elegance Rule Book. The 2019 Rule Book can be downloaded for free by anyone from the Concours page of the JCNA website. The URL is https://www.JCNA.com

The JCNA Concours Rule Book primarily deals with North American market cars but it includes a lot of detailed information that should be applicable to most other markets.

Paul

oo thats interesting. That looks like the XJS started fitting the Pirelli P5 between '75 & '81.

I think the P5 came out in '77. However what seems odd, is that Pirelli have made the 225/65R15 P5 https://www.longstonetyres.co.uk/classic-car-tyres/jaguar/xj12/225-65wr15-pirelli-cinturato-p5.html but according to that list that was never fitment, which seems odd.

There is a chance that Pirelli will make a 205/70R15 P5 & a 215/70R15 P5 in the future.