315s on 18" rear wheels?

[cc2Arider]

Hey Y'all,

I've seen some tire posts before about 315's on 17" rear rims, but didn't see a lot of discussion about putting them on the 18" rims...maybe I just don't have the patience to navigate back thru all the posts :rolleyes:

It looks like a 315/30-18 has a similar overall height as the recommended front tires....so does anyone run them on their Roadsters?

Any fitment issues?

Any problem "staggering" rear/front overall height with 313/35-18? Would that be too-tall?

If you run the FFR recommended 295s, did you feel the need for spacers to fill out the wheelwell?

Appreciate your feedback!

Craig C

PS: I'm using the FFR 18" rims

[Papa]

I am running them with no issues. I think pretty much everyone with the FFR 18" wheels are running a 315 on the rear.

https://thefactoryfiveforum.com/attachment.php?attachmentid=115112&d=1569708513

https://thefactoryfiveforum.com/attachment.php?attachmentid=123262&d=1582751182

[CraigS]

Looking here I see FFR recommending 315s.
https://www.factoryfiveparts.com/15812-18-halibrand-style-replica-wheels/
I ran 315s on my MkII on 17x10.5 wheels so, since the 18s are 11 wide, I see no reason to run 295s.

[cc2Arider]

Thank you Papa and Craig!

I wondered why I got confused yesterday, since I tend to try to reason thru my decisions: I was dead-set on the 18" rims when I ordered, but then looked at the glossy order form yesterday and noticed the 295 width recommendation. I also noticed less variety/availability of the 315/30-18 as compared to the other options while looking thru the typical tire retailers...

Papa,
It's always nice to see your motivating pictures :) which brand/model did you end up using? I see a lot of recommendation for the Nitto 555 G2s, but only noticed the 315 size for the sticky autocross model NT01s...

Thanks again!
Craig C

[Jeff Kleiner]

315/30-18 rear (25.5" O.D.). In front you can use 255/35-18 (25.0" O.D.), 245/40-18 (25.8" O.D.) or 275/35-18 (25.6" O.D.). If you want to stick with a 200 treadwear range tire I'd suggest that you look at Falken RT660 or Yokohama AO52

Jeff

[cc2Arider]

Thanks Jeff! I was doing "research" at work and arrived at the same realization :)

Any feedback about the (similar parent company to Nitto) Toyo Proxes R88R?

Craig C

[Papa]

Thank you Papa and Craig!

I wondered why I got confused yesterday, since I tend to try to reason thru my decisions: I was dead-set on the 18" rims when I ordered, but then looked at the glossy order form yesterday and noticed the 295 width recommendation. I also noticed less variety/availability of the 315/30-18 as compared to the other options while looking thru the typical tire retailers...

Papa,
It's always nice to see your motivating pictures :) which brand/model did you end up using? I see a lot of recommendation for the Nitto 555 G2s, but only noticed the 315 size for the sticky autocross model NT01s...

Thanks again!
Craig C

I have Michelin Pilot Sports. I don't know if they are still available in the sizes I bought, but they are a great street tire.

[Hoooper]

Thanks Jeff! I was doing "research" at work and arrived at the same realization :)

Any feedback about the (similar parent company to Nitto) Toyo Proxes R88R?

Craig C

I run 315/30R18 rear and 275/35R18 front in R888R, it is a great setup for me. I love the tires and have about 3k miles and a few track days at sonoma raceway on them. I cant imagine wanting to run a less sticky tire personally.

[Jeff Kleiner]

Thanks Jeff! I was doing "research" at work and arrived at the same realization :)

Any feedback about the (similar parent company to Nitto) Toyo Proxes R88R?

Craig C

That's what I am running currently. Before these I ran the Nitto NT-01 (2 sets I think). Very similar tires as far as performance...not good for cool temps or wet, last about 4,000 miles, stick like a cat on carpet in dry warm conditions. Since your previous comment made it sound like you were ruling out the NT-01 I didn't mention the 888.

Jeff

[cc2Arider]

Thanks to all who replied :)

It's nice to have options -- I especially appreciated the mileage report on the sticky tires! This mileage doesn't seem out-of-the-ordinary for sport motorcycle tires (as a comparison) :cool:

Craig C

[CraigS]

Go to Tire Rack and find their tests on summer only tires. Also look for Grassroots Motorsports magazine and find their tests on 200 TR tires. Not being sure where you live, please note Jeff's comment about the 200TR tires not being good in cold or wet. Cold doesn't mean 30s, it means anything below about 50 degF. My wife's 15 Mustang daily driver came w/ summer only tires. About end of Sept she said the tires seemed slippery to her. I drove it that weekend, whoa. She says I can just go easy on the gas. I said if it won't go, it won't stop either. The summer tires still had 1/2 tread but 2 weeks later we had new tires on her car.

[Hoooper]

Ive driven my R888Rs around at 45F and the traction was fine. Not as good as when warmed up, but you arent going to go just randomly careening off the road simply because its cool out and you werent doing anything wrong. Just dont let them get to be 8 years old and heat cycled to oblivion.