New Tire Dilemma

[JMWarren]

There is a lack of available OEM sized tires suitable for my MINI JCW GP to use at Autox.  I am running the original 225/35R18 Hankooks and would like to move to the Yokohama A052s, but no one knows when they will be available. I am considering moving to a 225/40R18 to expand my options. My question is will this adjustment to the sidewall impact my car's handling/performance?  Any recommendations on suitable replacement tires would be appreciated. Right now I'm leaning toward the new Bridgestone Potenza RE-71RS.

[jw1]

Going with a shorter sidewall will result in less speed in gear (there are calculators to help on the diff) while also providing a little better acceleration.

If your car is fairly stock I wouldn't run A052s as cars without a lot of camber will wear them out pretty quickly. RE71Rs or RT660s would be a good choice.

[morbid]

That is a goofy size.  For 225/40R18, there's also Kumho's ECSTA V730.  GRM says it warms up quicker than the RT660, can handle the heat better, and wears better, but slightly worse wet traction (as the tread pattern would predict).  I was thinking about giving them a try for my next tire set.

They give some good thoughts about a bunch of tires, and have a neat chart near the bottom to compare them.

https://grassrootsmotorsports.com/articles/track-tire-buyers-guide/

Edited August 10, 2022 by morbid

[Bob B.]

I just put v730s on the Miata.  I really like them.  My perception is they're a little less grip than RE71s, but they MORE than make up for it in my case as they tolerate ham fisted over driving and the heat it generates a lot better. 

I'd have to confirm by looking at my historical times, but I usually swing a second between runs as I figure the course out, and as the tires heat up I have to be real careful with my inputs.  With these I was a half second or less between runs, and dropped about a full second faster on my last run.

By the time I got to my time only runs, I'd dropped another second.  Since we run timed and TO back to back, that usually doesn't happen for me, tires are usually a bit too warm at that point. 

I run 205s, but as these run narrower than the RE71s and RT615ks, I wish I'd gone with 225s.

Not sure where that leaves you size wise and what you want competitively, but, maybe a bit wider and less sidewall if they have something like that. 

They're worth a look, imo.