Hi guys,

I have gen 2 xidas on a track only car. Lowered to 4" up front and 4.2" in the rear. I have done my research. But no one has explicitly said they run 205's on 9" (+35) rims. Do they even fit? are they faster than 8"?

I am looking to buy some new rims and the 8" are out of stock. I run with a group of miata friends. We have a friendly competition going at the track. We run very loose rules but must keep 205 tires and near stock power. In general we are pretty close. But its not very serious.

 

They fit, they aren't measurably faster.

 

205 Hoosiers on 9s. All other 205s on 8s.

 

Edit: Good lord multi post. I was late to the party. +1^

 

Been running 205 RC-1s on 9's just fine, tad stretched but it gets the job done.

 

+1, also run 205/50 RRs and 205/50 NT01s on 9s. All fine, no reason to do it over an 8" wheel unless all you own is 9s (like me).

Lots of time on 205/50 SM6s, those really need a 9.

 

Thanks guys. And another question on tires. BFG r1-s don't get talked about to much. I run them because I have been told they are the next fastest after Hoosiers. But can take about 10 heat cycles. Is this true? I was able to get them for $660 a set. But now I am guessing national inventory is low because a set is ~$800. What's the best value tire closest to SM6's lap times?

 

If you're looking for the speed potential of 205/50 SM6s with better value, you want 225/45 RRs.

 

I saw Discount has a $40 rebate this week for NT01's. Other than that, I suspect it's tough beating the value of the SM6/7.

 

So wrong it hurts. There is minimal value in an SM6/SM7. They are expensive, gummy, and wear out insanely fast. I suspect the best value is in the Maxxis RC-1, followed by the NT-01, followed by the Toyo RR.

 

Whats the typical life of a Maxxis RC-1? Lets say 205.

i.e. Do they heat cycle out before running out of tread, are they easy to overheat? Are they consistent?

 

RC-1's last and are super consistent but not nearly as fast as a Hoosier. Closer to a NT-01. As Andrew mentioned, value-wise, the 225/45 RR is your best bet to get close to 205 SM6 performance for less $. If you have more than say, 180whp, 245 RC-1's would be another option. Less power than that and you're better off with a narrower, stickier tire. The 225 RR/RC-1/NT-01 et.al. are all about the same tread width as a 205 Hoosier.

 

Since we are talking hypotheticals:

Would the 225 RR or 245 RC-1 be faster on a 9" wheel on my car all things equal (~300whp, xidas, caged NA @ +/- 2350 loaded, Aero, etc)?

Which would would last longer in track day/time trial use?

How much faster than the 225 NT-01 and how much faster will either wear out?

Would I be better trying to find 205 Hoosier scrubs assuming I don't pay for mounting and balancing?

 

We didn't test the production 245/40/15 RC-1 on 9's because racecar. Nothing last longer than an RC-1. You should be on FA scrubs (fronts) if you're thinking about used tires.

 

I don't know anyone in FA so scrubs were more of a passing thought. I'm going to pull the trigger on some 245s for the 9s. I'm assuming that will be faster than the same tire at 225 on the same wheel. If a reputable race shop were to have 10" wheels in stock, I might consider buying a set and doing it right.

 

https://www.google.com/webhp?sourcei...20race%20tires

 

For what it's worth, the SM7 is much better value than the SM6. It lasts longer, doesn't heat cycle out, and is slightly faster.

At $171, it's $4 cheaper than an RR, about a second faster per lap, and doesn't wear out all that much faster. And if you're competing, contingency is WAY better for the Hoosier. That and their decals look cooler

 

You know, you would sell more 10" wheels if you didn't point out that shipping 4 scrubs is under $70... It would be better to get them from the tire guy at the track by the pickup load but a set at a time would be OK too.

 

About how long do SM7s last before they go off? Will you make it to the cords? PTE power/weight.