I have 8" wide wheels. Do the 225s look narrow enough to be better than the 205s on my 8" wide wheels for track/autocross use?

Out of curiosity I measured the two contact patch widths of the 225/45 on our 15x9 6UL. Not the casing or molded tread width, but the actual area that wears.

~214mm Rival-S
~200mm V720

V720 is rounder so molded tread width difference is closer to 8mm, as opposed to the nearly 14mm difference in contact patch. We raced this tire intermediate rain conditions plus 200miles of highway driving at 26psi. I suspect the V720 might roll over more and use more contact patch in full dry conditions. Just the same, it is most definitely narrower than the Rival-S.

8"= 203mm so the 225 may do ok and be faster than the 205 on a 8" wheel. I am not sure.

I'd say 225 is almost always faster than a 205- all else being equal (tire/wheel width/car)etc.

If you are not class limited to a tire width- run the widest tire you can on the widest rim that you have.

My experience goes like this:

205 on 8" rim- feels sharp, slowest
225 on 8" rim- feels slightly less sharp, lap times are faster than 205 on 8" rim
225 on 9" rim- feels sharp, fastest



If it was me- I'd get the 225 and run it on whatever rims you have.

Yeah, especially for autocross use. Hell, people use to run 275 Hoosiers on 6 inch wheels in Stock classes. Was it ideal? Hell no, but it was faster than anything else you could put on there.

--Ian

Emilio, thanks for pointing this out. For a reference, I measured the contact patch of a 205/50/15 Nitto NT05 on a 7.5 inch wheel. I sprayed the tire with water and moved the car and then measured it on asphalt with a tape measure. The NT05 contact patch was 6.5 inches, on the drivers rear, with 200# of driver. So there seems to be quite a difference between various manufacturers sizing. Star Specs and Yoke AD08 also seem to be on the wider side.

You did it different then.

"I measured the two contact patch widths of the 225/45 on our 15x9 6UL. Not the casing or molded tread width, but the actual area that wears. " -Emilio

We should set a standard and start creating a database before we get too much misinformation

Two of the same size/model tires will have different worn widths depending on type of use.

That's a valid point, in my case, the tires have only been street driven. Wouldn't front tires tend to have more edge wear due to turning?

Then your worn tread width of same tire model/size would be less than driver B's worn tread width who does competitive driving... or has less tire pressure... or more weight... or significant downforce... etc.

I would hypothesize that the rears could see just as much edge wear as the fronts on some cars. Depending on driving style, car set up, weight balance...

Are these tires really fast enough to warrant being in the +6 category by NASA?

Seems like they're just a budget 200TW tire, not a "cheater" tire with a 200TW rating, or autocross compound like the Rival S.

I'd love to save ~$80/set over star specs, but I need a +2 tire...

I was about to order a set of these for this spring... So no one here @ MT has seen any delamination issues (aside from those 2 tire rack reviews) from doing trackdays and HPDEs on the 225/45/15 V720s? Looking to those in warmer weather that might already be out abusing them...

I guess if they're good enough for Emilio they're good enough for me, lol.

I just talked to someone at Discount Tire Direct today, and they told me that the V720 was a Tire Rack exclusive.

My local shop has had no problems sourcing them...I'm calling BS.

Your local shop has a tire rack wholesale account?

When I bought my Dunlop ZIIs they were a TR exclusive. My local Discount Tire ordered them from TR, and gave me TR's price... :D

Hmmm...
Kumho Ecsta V720 Review - RX8Club.com

That's not looking kosher. If all goes according to plan this week, we should finally have a chance to try out the 720's this weekend on the ND.

I ran a pair of these this past weekend at AutoClub Speedway on the back of my car with a set of older RS3s in the front.

I'm not super fast (2:05.xxx/street car) and I didn't try to beat he shit out of them; they held up great. Sticky and felt like they let go very progressively. Actually a little more progressive than I remember the RS3s when they were new.

No delaminating at all and ran them at 34 psi hot.

Thanks, appreciate the reviews.

On the rx8club thread, it sounded like that fellow got a bad set of 720's, some kind of manufacturing defect I guess, since Tirerack apparently took care of him and Kumho actually wanted them back to look at. Hopefully that means that whatever that issue was is now fixed...