bplein

Don't use a generic calculator. Use the manufacturers specifications because 2 different tires with the same approximate size can (and do) vary.

Tirerack shows the manufacturers specs for revs-per-mile. That's where I found that data.

tom__w

So basically I am screwed if I don't have a bunch of spare tires and spacers to play with.

Bigger won't fit in the front and smaller won't fit my 11.5" X 19 wheel in the back.

SH*T

bplein

The Michelin's I linked to will fit your rear tire. May not be optimal but you aren't looking for optimal by your own admission, you are just looking to get it driveable.

You can use the Michelin examples I showed you. Pricey tires, summer only. You can possibly find another tire manufacturer that can do it, but be sure to check THEIR revs/mile, not some calculated number. Tire widths are really +- 5mm or more (notice there aren't 300s, just 295s and 305s). They don't make the tire to the exact sidewall spec, the sidewall labeling is the closest width to a "standard" number that ends in a 5!

Aspect ratios are off by upwards of 2+ percent (i.e. a 35 could be 32.5-37.5, they always round them to 5% increments, not making them exactly that size in 5% increments).

bplein

What brand and model are your current front tires? Are they in good enough shape to keep them if we can help you find a close match on the rear?

I don't want to try and match the calculated revs, I'd like to see if the manufacturer lists a size for them.

tom__w

They are in like new shape..

Bridgestone Potenza S04
235 / 35 / 19
https://www.tirerack.com/tires/tires...8aAuVeEALw_wcB

bplein

If the rears are also the same tire, then WOW. The fronts are 818 revs per mile, and the rears (assuming S04s) are 775.

You can get them closer by going to 305/30-19 at 793 revs/mile (and good with 11.5" rims) or with 295/30-19 S04s at 801 revs/mile (but recommended wheel sizes are up to 11"). But you are running 285s on 11.5s and they aren't recommended either. You might even be able to do a 285/30-19 at 808 revs/mile but that's even harder for the tires to fit on the 11.5s.

The good thing about going less wide in the back is less chance to rub.

tom__w

And here are the rears: https://www.tirerack.com/tires/tires...um=835YR9PSSZP

This guy has run flats on here!!

bplein

The lowest cost option is to try the 295s I mentioned. Same tire type is a good thing. Mismatching brand and model front and rear is just sloppy. Sometimes people get stuck with limited choices especially near year end when tire stock runs low (manufacturers revamp their lines in the new year). TireRack has fewer options for our cars in december vs April.

Grab an a set of the matching 295s and cross your fingers. It’s a lot closer match for revs per mile and you can look st going to 18s down the road.

tom__w

I'll probably just go on the cheap with these:https://www.tirerack.com/tires/tires...omCompare1=yes

800 Revs is a lot closer to 818 than to 755. I don't think fitment will be a problem as the spacer in there gives a lot of room all around already.