Looking for experience or feedback on going from a SL tire to an XL. Currrent tire is the Firestone Desty Highway AS, 32 lbs, 105S.
My interest is in the Cooper ATP 4S, which for the P245/65/17 only comes in XL. It's weight is 37 lbs., with 111T indices.

I live on top of a mountain, with gradients btwn 3-18%, snow, ice, and gravelly macadam. I do not tow or load anything excessively, except for gravity and alternate btwn 89&93 octane. The vehicle has 172K, and while we've both taken care of each other, there is significant rust on the undercarriage. I understand I may see a drop in MPG(until a highway trip balances it out), but a stiffer sidewall may nudge up the handling. However, I am curious what a heavier tire will do to the braking or suspension system, if any. Is 5 lbs a tire negligible? Thanks.

I went from a Goodyear GT something tire on a BMW touring I used to have to the same tire but with an XL rating. Speed rating was down from ZR to VR, but as I never had it over 120 and I think it was electronically limited to 129 anyway, it was a non issue. I got 45K life out of the regular tires, pretty good in a car known to have tire wear issues. I got 76K out of the XLs. And even then I could have gotten more if alignment was better.

I didn't notice any difference in the way it drove. More rotating mass or unsprung weight isn't a goal, but percentage wise it's small. I wouldn't worry about it. Go for it if those are the tires you want.

Tks for the input, Mike.