I decided to dig a little deeper as to inflation on Superblue’s 15" Cooper Cobra GTs, in light of that possible “quandary”, VK.
Checking both Discount Tires’ and Tire Rack’s websites (NTB does not show max PSI settings for the tires sold on their website) as to the indicated size and type Coopers for Superblue (which are in fact the same ones on her), they both show the max. cold inflation pressure for same @ right at 44 psi (i.e. the same pressure rec as what Jag indicates for “other” brand tires). Same for two other listed “generic” brands of tires indicated for '94 XJS 4.0… I haven’t actually looked at what Superblue’s tires have stamped on them, but unless both websites are wrong on that max. pressure, it looks like 44 psi should work. Interestingly, Tire Rack’s website mentions something about 44 being the usual cold max. inflation pressure for 15" tires, but that this amount is not recommended as the usual pressure “unless indicated otherwise by owner’s manual or tire placard w. the particular make/model of car”. It then adds something about some car manufs. recommending that 44 lb. max. inflation pressure for their tires nevertheless due to unusual high performance handling, cornering or speed characteristics for their cars. Apparently Jag believes the 4.0 XJS fits into that category (?) So again, 44 lbs. seems to be the magic # for Superblue w. her Coopers.
Oddly enough, both Tire Rack and Discount Tire do state a max. cold inflation pressure of 36 PSI for B.F. Goodrich tires for the same size tire, not 44 PSI. Note that this is the same rec PSI for “normal” riding characteristics rec by Jaguar for the OEM Goodyear Eagle GT tires, at least in the rear. This makes me wonder if, had Jaguar made the tire call today, being that Eagle GTs are n/a now, whether it would consider the Goodriches to be an acceptable substitute for same. ?
I found it interesting too to discover that none of the 3 sources I mention recommend Pirelli for the 4.0 '94 XJS anymore, something which they all did, up until very recently. Is this b/c Pirellis are n/a anymore in that size, or is something else going on there?
I just bought a set of vitour galaxy r1 235 60 r15 they are rated to 158mph 89.00$ a piece. They are a summer performance tire. I only run the car from late spring to early fall.
Rather odd-looking tread … no cross channels at all in the middle to “wick” away water to the edges in wet weather conditions. Don’t know if I would trust them then … Where did you buy them, btw?
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
28
Lots of tires look like that these days. Apparently the big straight grooves – four on this particular tire – are intended to let water pass straight through the contact patch and out the back, not out the side.
Performance Plus Tires they’re out of California I have Goodyear asymmetric on my X-Type with pretty much the same tread pattern never had any trouble in the rain I also looked into the Cooper cobras but they weren’t speed rated
I found them on PPT’s website, after I posted that. PPT shows them as supposedly V-rated - if so, they’re the first V-rated tires I have seen in a LONG time for 15"ers, other than Pirellis … All the others (BF Goodrich, Cooper Cobra, and the 2 “generic” brands that I mention above) are all T-rated. Seems strange that a tire THAT cheap (i.e. less than all the others) would nevertheless have a full V speed rating. Oh well, give them a year or two of driving and then please report back on how they turned out for you.
btw, PPT is kinda like Tire Rack, but one thing I saw on there I didn’t like is they, unlike T.R., do not provide a list of “approved installers” for their tires in your locale, once you receive them via mail … at least I couldn’t get their site to pull up anything here in the Dallas area …
Well, when and IF I ever get Superblack up and running () I may go with a set of them vs. for the Coopers. Again, though, I’ll have to find a place to install them that won’t squawk about it or charge me out the wazoo … I don’t happen to have a tire changing machine or balancer hanging around my place …
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
35
We had a Sam’s Warehouse here that sold and installed tires. The price and selection of tires was OK, but the installation left something to be desired. As a result, several tire shops in town advertised that you could buy a set of tires at Sam’s and they would install them for a reasonable fee.
First, last, and only time Sam’s installed tires on one of my vehicles I got service above and beyond. A young man informed me that he had installed my front tires. He saw one of my calipers did not move as freely as the other so he took them both loose and lubed the pins for me
That was very nice of him and he got a tip from me. Five miles away pulling off the highway into my subdivision I noticed a scraping/ticking sound at one wheel. Drove three blocks to my house and removed the wheel. A caliper bolt had backed out and was gouging my rim. The other had fallen off. Discount tire ever since.
NOW you know why they are not supposed to do anything but install tires (and batteries). They show “Lubrication” too on their sign out front of at least one of their bays at our local store, but I have a hunch that = changing engine oil/filters only. I have wanted to take Superblue in there and say, “O.K., she has 10 Zerk grease fittings in the rear suspension that need to be hit with some all-purpose lithium grease via the 'ole grease gun”, and I bet they would be totally clueless as to my request. Same for checking the level of the gear lube in the rear differential box or toping up same.
Frankly I would never take my Jaguar or Land Rover to a Sam’s or Costco. These guys are rough and not really properly trained imho. They seem disinterested in service and there is a lot of turnover. I’d rather use my Jaguar mechanic or either Goodyear or Direct Tire.
Are you gays kidding me there are a million tire shops just ask people you work with or find some one thats been in business for more than a year or some one that guarantees there work
Interestingly, Tire Rack’s website mentions something about 44 being the usual cold max. inflation pressure for 15" tires, but that this amount is not recommended as the usual pressure “unless indicated otherwise by owner’s manual or tire placard w. the particular make/model of car”. It then adds something about some car manufs. recommending that 44 lb. max. inflation pressure for their tires nevertheless due to unusual high performance handling, cornering or speed characteristics for their cars. Apparently Jag believes the 4.0 XJS fits into that category (?) So again, 44 lbs. seems to be the magic # for Superblue w. her Coopers.
Where did you buy them, btw?
Pirellis … 
) I may go with a set of them vs. for the Coopers. Again, though, I’ll have to find a place to install them that won’t squawk about it or charge me out the wazoo … 
I don’t happen to have a tire changing machine or balancer hanging around my place … 
They show “Lubrication” too on their sign out front of at least one of their bays at our local store, but I have a hunch that = changing engine oil/filters only. 
Same for checking the level of the gear lube in the rear differential box or toping up same.