New shoe decision!

[Rich]

I'm planning on competing in the local street tire class this summer (autocross). The A048s aren't legal for that due to their low treadwear rating. I think I've decided on the Hankook R-S2s, which are supposed to compete with the Falken Azenis and Kumho MXs. The new Azenis aren't out yet in the right 17 inch size, so they're out. I can't find the old Azenis, and I don't like the idea of upsizing the fronts 2 sizes (215/45 R16 is the closest). The Kumhos don't come in the right size either. That leaves the Hankooks as the most likely tire that will be competetive in street tire classes. The only other tire I'm even considering is the Goodyear Eagle F1 GS-D3, but I'm concerned that it may be too balanced a tire. In other words, I fear that they may have given a bit of ultimate grip for low noise and good water evacuation.

Are there any other tires I should consider?

So, if I stick with the Hankooks, the question is size. There are a number that would work. The close sizes are:

Front:
205/45 R16 (1.75% smaller circumference, .207 inches lower)
215/45 R16 (0.25% smaller circumference, 0.03 inches lower)

Rear:
225/45 R17 (same size as stock)
235/40 R17 (2.29% smaller circumference, 0.285 inches lower)

The idea I'm tossing around right now is to go with the 205/45 R16s in the front and the 235/40 R17s in the rear. This accomplishes a number of things. Since I'll be upsizing the fronts, I worry that I may induce a bit of extra oversteer. I like the balance of the car as-is. If I upsize the rears to the 235s I'll keep the front/rear "spread" the same. I hope that will keep the balance about where it is.
Also, by going with a lower aspect ratio I'll lower the car a bit and will increase the torque at the rear wheels. Especially at 5,000 - 6,000 feet the engine is a bit weak down low. I've had trouble staying above 6,200 RPM on the tight courses we've had, so any extra torque is welcome.


So, what's wrong with this idea? What haven't I thought of? Comments please!

(I've always wanted to use this icon.)

[Stan]

Check the street tire rules carefully or ask for a clarification...although the treadwear number of the A048s is likely the problem, they are very streetable on the Elise and and the car ***comes delivered that way***. Some local clubs allow for the OE aspect so that you don't have to buy new rubber right away, which is part of the idea of the street tire class. (Of course folks buy the "right" tires anyway - that's racing!) I think that tires like the Azenis, KD, KDW2 etc are comparable to the A048 based on my datalog results. BTW the KDW new tread design comes in 205/40/16, 205/45/16, 225/45/17, 235/40/17 and 245/40/17. It's almost as grippy as a KD and gets decent tread life. I haven't heard many results from the new Hankook, but they sure seem to be right there from the specs.

[Rich]

Originally Posted by Stan

Check the street tire rules carefully or ask for a clarification...

I helped write the rules - or more correctly I helped determine which set of successful rules to adopt that had been developed in another region. We follow the 140+ treadwear rating rule that the National classes follow.

[Stan]

>>>I helped write the rules - or more correctly I helped determine which set of successful rules to adopt that had been developed in another region. We follow the 140+ treadwear rating rule that the National classes follow.<<<

That's what most groups follow. Around here some use treadwear 160...and some allow you to use any tire the new street car came with as OE. So for example at our no-r-compounds-allowed Rookie School / Autocross LSS Elises could run. Otherwise they'd have to buy/change rubber.

[ConeFusion]

Ok... delayed response. The only problem with the Hankooks is that I haven't seen any serious test data and feedback yet. They should be good tires, but we won't know how exactly they compare to e.g. the Azenis RT-615 until the rubber hits the road (literally).

215/45-16 and 235/40-17 sounds like a good size combination. If you're worried about too much oversteer, your idea of using the smaller front tires should work, too. Or add a stiffer front swaybar.

The Azenis RT-615 do come in 225/45-17, so the rears wouldn't be a problem. The only 16" size is a 205/40-16, which is quite a bit shorter than stock. According to theory, I believe that would add oversteer.

GS-D3: I wonder if anybody has seriously tried them. I think they could have potential. I only ran them in a dry auto-x once, and finished 2nd in index (not a very strong event, though). They were sticking much better than I expected. A bit squishy in transitions, but that would be less of a problem on a light car like the Elise. You would probably want to get the shaved for dry use, the tread is very deep.

Another one to look at is the Falken FK-451. This was the winning tire in STX at National last year. They come in countless sizes, and are relatively cheap. People normally get the shaved, though, not sure how well they work unshaved.

Other options I thought of don't come in a good 16" size (Kumho MX), or not in 16" at all (Pilot Sport PS2).

[Rich]

Originally Posted by ConeFusion

Ok... delayed response. The only problem with the Hankooks is that I haven't seen any serious test data and feedback yet. They should be good tires, but we won't know how exactly they compare to e.g. the Azenis RT-615 until the rubber hits the road (literally).

Either one will be a bit of a guess, from what I've heard. I haven't seen much hard data on either, although some folks over on the sccaforums have had positive comments so far on both. http://www.edgeracing.com/ sells both Falkens and Hankooks and is supposed to do a comparison on Monday. I really would like to get them in time for an even on Saturday, so I probably won't wait. Or maybe I will, I don't know yet.

Originally Posted by ConeFusion

215/45-16 and 235/40-17 sounds like a good size combination. If you're worried about too much oversteer, your idea of using the smaller front tires should work, too. Or add a stiffer front swaybar.

Thanks, that's exactly the kind of comment I was looking for. I'm going to wait on other mods for a while. I really like to get a few events in before I start changing too many variables. I've found that my driving style needs to change from car to car, and I'm not good enough to read everything after just a few runs. At my first event I tought the car was understeering a lot. By my 2nd event I figured out that some things I got away with in my Miata weren't working in the Elise. After changing my line and braking points I found that the car only understeers if I do something wrong. It's spectacularly balanced as-is, and until I understand it I'm going to refrain for playing with sway bars, shocks, or anything more than tires. This car is teaching me a lot!

Thanks a lot for the comments. I think I'll go with the Hankooks for now and see how they do. They're dirt cheap ($81 and $104), supposedly designed for street tire autocross, and I like the size choices. If they suck I'll just be out a few hundred bucks and some points that I can easily make up for later in the season. I'm not doing this too seriously, so I don't mind being the guinea pig.

[Highlander]

I had a set of R-S2's mounted up on my S2000 last wednesday. Although I haven't autocrossed them, I have driven them pretty hard through the local twisties. Unfortunately, the old Azenis were not offered in S2000-friendly sizes so I cannot comapre them. I have been running Kumho MX's for the last year and a half, though and the R-S2's are every bit as good as the MX's on the street. I have not pushed the car hard enough on the street to determine their limits. I was supposed to autocross on them today, but the timing chain tensioner started making an awful noise and I decided to not push the car until I can get that repaired. There's a 2-day event the 9th and 10th, though and I should be runnig there. I will say that at full tread, there is noticable tread squirm, but that is to be expected. I am VERY happy with the R-S2's. They are a fantastic tire given the price -- $385 delivered for my S2k.

[ConeFusion]

I'm actually considering the Hankooks as new summer tires for my WRX. Has anybody seen feedback on how well they would do in rain? I think I'll get either these or the FK-451's (unless I get a shaved GS-D3 to replace the one with a sidewall puncture ). In either case, they won't be used for auto-x much now that I have the Elise.

[Highlander]

Originally Posted by ConeFusion

I'm actually considering the Hankooks as new summer tires for my WRX. Has anybody seen feedback on how well they would do in rain? I think I'll get either these or the FK-451's (unless I get a shaved GS-D3 to replace the one with a sidewall puncture ). In either case, they won't be used for auto-x much now that I have the Elise.

It rained all day one day last week, and they worked GREAT in both a downpour and standing water.

[ConeFusion]

Thanks for the rain feedback, Highlander. I just ordered a set (235/40-17) for my WRX. They might see some auto-x action in 4 weeks, we have a Divisional in Oklahoma City, and I doubt that I'll drive the Elise that far. So maybe I'll try to defend my STX win from last year.

[Rich]

Originally Posted by ConeFusion

Thanks for the rain feedback, Highlander. I just ordered a set (235/40-17) for my WRX. They might see some auto-x action in 4 weeks, we have a Divisional in Oklahoma City, and I doubt that I'll drive the Elise that far. So maybe I'll try to defend my STX win from last year.

Well, I decided to give them a try. I hope to have them mounted Friday, and I have an autocross on Saturday. I don't know if I'll be able to drive off the mold release compound by then (the Azenis took almost 600 miles, from what I've heard). I'll give some feedback however it turns out.

[John Stimson]

The Azenis RT-615 will be available in 215/45-16 in September.

Preliminary autocross results from my inside source in San Diego have the ST-615 significantly faster than the RT-215. 4 weeks from now, you should be able to see some more conclusive results from the Atwater National Tour.

The Goodyear F1 GS-D3 is still mushy (and I mean really mushy) on a car as light as a '99 sport Miata (195/50-15). A size with a lower profile might sharpen up the response a bit, but it's not the tire I would choose for a car that's renowned for its razor-sharp, lightning-fast handling.