Have the stock 275's on now and getting ready to change all four, want to keep the 35 height and changing to the 295's, looking for ride quality this round, anybody do this, can it be done? Going to the 255's up front.

 

Just read this throughout, so gathering info here...

 

Stock 20" wheels sizes are 295/35 (rear) and 255/35 front, but Jaguar OEM 20" wheels are 9" and 10.5" wide front to rear. Your 19s are 8.5 and 9.5.

The wheel/tire fitment guide lists 275s as the largest tire you should mount on 19" wheels 9.5" wide. To do what you want, the best solution would be to go to 20s. You can find good deals on those here:

Home | OEM Wheels | Wholesales Wheels | Wheel and Tire Packages

 

^That website is painfully slow.

There is no set standard with tires and sizing. For example, I used to run BFGoodrich G-Force Sport Comp 2. I ran a 255 in the rear but due to the way they are manufactured, it came out to almost being a 275. The old Bridgestone Potenza S-O3s in a 225 measured to be approximately 255. Its similar with treadwear. There is no set standard..its just designed to give the consumer an idea. A Bridgestone with a treadwear rating of 220 may still wear faster than a Continental with the same rating.

That being said..lets say you have a 19x9.5 rim. Every tire manufacturer has a set range of rim sizes you can mount the tires on. For example. If you wanted to mount the Michelin Pilot Super Sports sized 295/35/19 on a 19x9.5 sized rim, you can. Michelin states that the approved size ranges is on rims with widths of 10-11.5 inches.

Can you mount a 295 tire on your rim? Yes. Can you successfully do it without rubbing your fenders or suspension components? Thats up for debate. Things like offset, alignment settings, etc can impact it.

 

That is correct, but I know TireRack for one displays the exact section/tread width of the tires (independent of the sidewall size marking) so you can see what should or shouldn't fit for the wheel of choice. I'm not sure if other tire sites display that information. I have to do this for my racing tires has Hoosiers are almost a full inch wider than other manufactures using the same sidewall size markings.

 

Yup. When I ordered tires for my s2000, I always checked to see the largest tire I can cram on my rim and jam under my fenders. TireRack FTW!

 

However, you will be losing some of the benefit of the larger tire by squeezing it on a smaller wheel not within the specified range. The curvature of the sidewall will increase, and the contact patch will be smaller.

That's why I said the best bet is to go with wheels within the recommended range, but if you're budget doesn't allow, yes you can probably do it.

 

There is some truth behind that. If you mount a tire on a smaller rim, you may notice your handling being compromised a little bit as the weight of the car is supported more by your sidewall rather than your rim. It shouldn't impact your contact patch.

 

Just to clarify...what diameter are your rims? That will affect the answer. I'm assuming now 19" given the width of the originals.