Nuke

IF you put them on, post some pics. I'd love to see the sidewall along with the RWL's on an S197.

V6Vin

Actually gas mileage will increase going to a larger diameter tire.(less revs per mile/distance, higher ratio, blah,blah). I have considered these myself but can't find anyone who can say "for sure" they will clear on front and back.
'cause I'll run 'em if they will fit, love the RWLs. (some of us just drive our cars, not race them) hahaha.

What these will do is fill in the fender wells without having to lower the car.

Nuke

Unless you're doing 75% or more highway cruising per tank, what you'd gain in cruising with the larger OD tires you'll lose every time you accelerate to any given speed. If you're driving mostly city, you'll lose fuel mileage.

V6Vin

90% highway, 10% city. I could go with 3.55 rears and be about the same as stock size tires with 3.31s, lol.

Of course I may just go with 255/50/17 and some tire paint, hahaha.



The paint used in the above photo looks like good stuff, but VERY hard to get.

Link- http://www.mbzponton.org/valueadded/other/tirepaint.htm

He says it only gets 50% hard when dry and stretches like a balloon.

howarmat

255/50 would be the way to go for sure. I use them for winter tires and it works well

V6Vin

Also I think the 255/50 is close enough in diameter it does not need a speedometer calibration?

Sorry JD, didn't mean to go off topic, maybe someone will post up pics of the 255/60s on a car or at least tried them to see if they rub or not.

howarmat

yes 255/50 is OE diameter in my book

V6Vin

Thanks for the confirmation Matt.

Another thing to consider with the 255/60 is that with a bigger diameter tire your shift points will all be at a higher MPH.
Say your car shifts into OD at 55mph now, with the bigger tires it will shift at like 60 or so. Now, correct me if I'm wrong on this guys, but isn't there a certain speed/rpm combination that the car will shift in and out of OD with just small hills and such?
I never really noticed where mine drops out of OD.

Probably not enough change to worry about, just saying it will change some.

howarmat

remember he will reprogram the size of the tires so alot of this is not going to be a problem. The 4x4 look and possible rubbing would be his real worry

V6Vin

After some calculations it seems that with stock tires you run 60mph at 1750rpm.

With the big tires at 1750rpm you will be running 64mph.

Or 1625rpm at 60 mph.

Changing the computer will fix the speedo but not the rpm/mph, just like when you go with 4.10 gears your rpms go up like 400 at 60 mph.
I guess the computer will fix the shift points though.

I considered this and worked it all out last week, decided to just run the 255/50s. (Eagle GT) Not a lot of all season performance tires in that size.

Good luck JD. If you do put them on, shot me a PM and let me know if they work. (or post for inquiring minds)