Hi

How many of your cars fitted 235/60R15 tyres as OE?

what tyres are you fitting currently?

Do you fit 225/65R15 Pirelli Cinturato P5 that has just been made instead?

Submitted by Anonymous (not verified) on Fri, 04/27/2018 - 11:16

I had the dilemma of locating the original tires, 235/60R15 for my 1994 Jaguar XJS. Since I was able to locate the Pirellis and Cooper tires. I went with the Cooper Cobra Radial GT 235/60R15. They were about $105.00 at Discount Tire. So far same ride and handling as original tires that came with the car.

Regard

Submitted by Anonymous (not verified) on Wed, 04/25/2018 - 08:59

Consider an inaccurate speedometer (being electronic, this will distort accumulated millage on the odometer), a non-OEM tire size, and considering the 225 would be an aftermarket addition it will take away from its Fair Market Value. Besides, the OEM Pirelli P600 235/65R15 is a speed rated tire up to 168 mph. Do you really plan to drive that fast? This OEM Pirelli tire is still available at the Tire Rack for about $265 each plus about $13 shipping per tire. Good luck.

Regards

PS: the 235 mm or 225 mm specification is a reference to the sidewall (height) dimension which affects the rolling diameter on the same size wheel which means a 225 turns faster than a 235 at the same speed. Your speedometer will record a faster mph and cause your odometer to increment faster distorting actual accrued millage. There is no speedometer gear correction (replacement) for this condition in the TH400 GM transmission since GM never used a 235 mm tire on any GM produced vehicles. Make your cars life less complicated and stick with the Pirelli P600's.

I am assuming yours is an older Jaguar equipped with the GM TH400 3 speed automatic transmission as most Jaguars using the 235/65R15 were so equipped from the factory.

Regards

Submitted by Anonymous (not verified) on Mon, 04/30/2018 - 04:10

I think it is well worth having the right speed rating on a car like an XJS. I don't see the point in having a car like an XJS i don't see a point in having a car like that and jeopardizing the handling by fitting a tyre that isn't developed to suit a car like that, some soft sided comfort tyre would be a waste of a good car like an XJS.

The 225 or 235 is descriptive of the width of the tyre that next figures; the aspect ratio describes what percentage of the width is the height:
65% of 225mm = 146mm
60% of 235mm = 141mm

So they are all effectively the same size.

the speedo thing is a tricky one, because of course the overall diameter of a tyre varies with the wear of a tyre. You have probably 8mm radius of tyre made up by tread so a nearly bald tyre can be over half an inch smaller in diameter.

If you look back Jag tyres since the e type, they had 640H15 crossply tyres which then changed to 185R15, so with the series 1 e types you could ask to have 185VR15 Pirelli Cinturato CA67 fitted which they still make today, or if you couldn't afford the Cinturato, but wanted radial then there was a Dunlop SP41, but that wasn't much cop and you had to have the cars speed restricted, because at the time the Dunlop wasn't up to it. Then in 1968 Dunlop developed the SP Sport, which was a much cheaper speed rated radial, so Jag fitted it as OE in the size 185R15. and at the same time they fitted ER/70VR15 (205/70VR15) to the XJ6. They didn't fit low 70% profile tyres to the e-type because it spoiled the handling until they fitted power steering to the series 3 e type.

However the point i'm getting at, is these tyres had the same diameter
a 185VR15, (be it the earlier Pirelli Cinturato or the much later SP Sport) are not listing an aspect ratio therefore it is 80% so 80% of 185mm = 148mm
70% of 205mm = 143.5mm

In overall diameter the tyres on 15" wheels are between 562mm and 576mm. When they briefly went onto the millimetric TRX wheels it was the same diameter, if you follow the maths:
220/65VR390 = 220mm wide 65% of which = 143mm X 2 = 286mm + 390mm wheel diameter = 676mm

they did vear slightly off the mark with the V12 cars when they went for 215/70V R15 so that would mean the radius is 7mm taller, but the fatter and taller tyre would diminish wheelspin and give slightly longer gearing.

All these dimensions are theoretical but my longstone Tyres web site lists all the actual dimensions of these tyres if you go onto the product pages.

I would also be careful about date codes of the 235/60R15 P600, though i think Pirelli have just made a batch.

the Pirelli Cinturato tyres such as the 225/65R15 P5 are available through Lucas Antique tyres in the States

i don't think Jaguar ever fitted 235/65R15.

Dougal