Yet another rear tire question

[maclonchas]

Folks,

I have combed the internet and both forums and still do not have a clear answer on the correct tire size for the rears of my MK4 build. I am not looking to autocross, drag race or any competition with this car. I am in Florida, so the weather can get down to 30 and yes we will have rain. My plan is not to drive in the rain, but Florida always has the pop-up rain shower so the tires must have moderate grip to get around on with careful driving.

I have 18 x10 rims from OEWheels: https://www.oewheelsllc.com/Mustang-FR500-Wheel-Anthracite

The SPECS are as follows:

Wheel Size 18x10
Wheel Offset 22
Bolt Pattern 5-114.3
Hub Size 70.6
Back Spacing 6.37

I know a 315/30 will not fit on this rim and is made for 10.5-12 inch rims. I have read that the max size for this rim is 305/30, but I have not seen any manufacturer with that size readily available. I am sure there is someone that makes that size tire, but I am not looking for that one off tire. I am trying to understand the which of these 18 inch tire sizes will work, 305/35, 305/40, 305/45 limitations for the rear tires. Conversely do I need to go smaller size tire like a 285/40?

My fronts will be 255/40/18 or 245/40/18. I believe the 255/45/18 is too big a tire for the front. Is that correct?

Thanks for the help in advance.

Bill

[Jeff Kleiner]

I'd be comfortable with a 315/30 on a 10" rim. On a tire of that width the rim being just slightly narrow won't cause it to crown excessively. Keep them to around 22 psi and they'll have a full contact patch. Yes, 255/45 will be too tall in the front.

Jeff

[maclonchas]

Jeff,

Thanks. I sent you a PM on undercoating.

Thanks

Bill

[F500guy]

Added advantage, a little bit of tire sticking out past the rim so hard to scuff the rims.

[CraigS]

I would put a 315 on a 10 rim all day long. Guidelines are great but sometimes a little fudging is just fine. If you are concerned, you can go to Tire Rack web site and look up all the 315s they have and look at section width and tread width. You may be surprised at the variation. Choose one of the narrower ones.

[Alan_C]

I had the Halibrand look alike wheels from FF. They were a 9x17 and 10.5x17. I ran a 255 front and a 295 rear Kumho XS initially and they looked and functioned great. Your move to a 18" wheel makes all the sense in the world today with good performance tires getting harder to get in smaller wheel diameters. The guy who purchased my car went to a 315 on the rear when he wore out the first set with no issues.
I agree, a 315 on the 18x10 inch wheel is not likely to be an issue. I would imagine you are not using a 10" wheel on the front. Typical sizes up front for 9x17 inch wheels were 245 and 255 with some using a 275. The width you can run at the front often is based upon the spindle used.

[BEAR-AvHistory]

Run NITTO 275X40X17ZR - 315X35ZRX17. The NT-01 are not used below 40*F which means a lot of good driving days in NC. Fla should be even better with warmer temperature.

https://g80.bimmerpost.com/forums/picture.php?albumid=13527&pictureid=90524

Tires fit inside body & do not rub. Everything is stock, (no donor parts) including FFR wheels with no modifications to get the tires to fit. Tire run 22psi + or - a pound using shoe polish to check the contact patch.