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Discussion Starter #1
Just got back from my 3rd autocross today. Have to say that it is quite fun and I think I'm hooked. Anyway, several people mention that the tires make a huge difference. I drive a 2001 MR2 Spyder with tires that has a treadwear of 440. These are the second set of tires and not the originals. I don't want to get a racing tire since I drive the car on the street and don't want them to wear out too fast but I do want a stickier tire that may cut some time off. Will a lower treadwear tire really make a big difference and how much? Say the course takes about 50 seconds, will it save a second, two, or three? Any suggestions on a tire or what to look for in the tire?
 

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Tires make a huge difference, to expect 2 or 3 seconds on a 50 second course is reasonable assunming the driver is good enough to exploit the tires. Remember though in most autocross series a tire with a traction rating (UTQG) of 140 or under will move you into a different (read faster) class.
 

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Cantwait,

You will definitely do better with a lower treadwear rating. The other thing to look for is sidewall stiffness. Most R compound or near R compound tires are much stiffer to give better response. I will give my vote (at present) to the Falken Azenis. I am currently using these for a summer street tire. They are inexpensive, and have decent grip. Many in SCCA street tire classes use the Azenis. It does not quite have the grip of an R tire, but it is a step up from a street tire. Another benefit - the Falkens are quite inexpensive. The size for the Miata is in the $50 ea range (195-14). I expect to get ~8-10k miles from them. It is probably worth 1-2 sec per run. I agree with James on the improvement range.

Stepping up a notch, I know quite a few people who run either Toyo RA-1's or Kumho Victoracers in the summer. I have heard people getting 4-8k miles on them. These are real R compounds, just a little slower than the stickiest R tires.

In my area, we run SCCA rules, so there are limited street tire classes (we don't run the new STS2 class). So your MR2 would run against R tired cars in C Stock. Higher performance tires do make for a more enjoyable driving experience.

Have fun and keep on autoxing!

Steve Brown

'94 Miata CS
'05 Elise (the wait is getting tough!)
 

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Discussion Starter #4
Thanks for the responses.

Brownsa5,

I looked up the Falken Azenis for my car and they are reasonable($60-65). Another question I have is what is the street tire class? I tried to look it up but can't find much info on it. I'm in c stock right now. Will the Azenis put me in a different stock. If so, how will that affect my pax time? Also, if my tire has a tradwear of 440 right now, would that put me in a street tire class and would it help my pax time vs. c stock?
 

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Street tire classes are set up by local clubs based on whatever rules they think are good. The only nationally recognized classes that run street tires are STS, STX, STU, and STS2. The MR2 Spyder isn't eligible for any of those.

In C Stock, you can use the Azenis, and you can even use stickier tires like the Kumho Victoracer and Hoosier A3S04. You can expect as much difference between the Hoosier and the Azenis as there is between the Azenis and your current tires, at least on some courses and sites. However, the Falken tires are roadworthy, will last longer, are cheaper, and are a better tire with which to learn how to handle your car.
 

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Discussion Starter #6
I think I'm narrowing my options down but have another question. Since my rear tires are getting worn and I'll need to replace them soon, I thought I might go with the Falken Azenis on the rear and leave the Cobras up front. How will such two different tires affect the car? I figure it's more important to have the stickier tires in the rear(rear wheel drive) since these will be powering the car. The Azenis are not available in the size I need for the front and I don't think I want to go with the same size tire all around since it didn't come that way.
 

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cantwaitforelise said:
I think I'm narrowing my options down but have another question. Since my rear tires are getting worn and I'll need to replace them soon, I thought I might go with the Falken Azenis on the rear and leave the Cobras up front. How will such two different tires affect the car? I figure it's more important to have the stickier tires in the rear(rear wheel drive) since these will be powering the car. The Azenis are not available in the size I need for the front and I don't think I want to go with the same size tire all around since it didn't come that way.
This is unlikely to be a good setup. Putting sticky tires on the rear and leaving the harder street tires up front is going to make the understeer that your car is probably already predisposed towards much worse (I've only driven an MR2 Spyder once and I remember it being pretty neutral with a bit of understeer but may be remembering wrong). I would imagine that the car will push terribly with the setup you propose.
 

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Discussion Starter #8
NMRJock said:
This is unlikely to be a good setup. Putting sticky tires on the rear and leaving the harder street tires up front is going to make the understeer that your car is probably already predisposed towards much worse (I've only driven an MR2 Spyder once and I remember it being pretty neutral with a bit of understeer but may be remembering wrong). I would imagine that the car will push terribly with the setup you propose.
Do you have any suggestions on front tires? The fronts are 185 and rear are 205. Some have suggested putting 205s all around but this might make it oversteer as I've been told. Is it best to find a manufacturer that makes the correct size needed for both front and back? I've read about a Yokohama and Bridgestone s-03 Pole. I liked the Falkens since many recommended them and they are inexpensive.
 

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You're fortunate to be on a board run by an MR2 expert. I'm a bit surprised that Randy hasn't piped in yet. I don't know a whole lot about the spyder, though if it were mine I would look at what people that know what they're doing are using. I'm guessing that putting the bigger tires on all around and making some alignment adjustments probably gets you a pretty neutral car.
 

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Urban legend about the same size tires being an instant death trap.

You can dial in with alignment less oversteer. Simple.
 

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Discussion Starter #11
Randy Chase said:
Urban legend about the same size tires being an instant death trap.

You can dial in with alignment less oversteer. Simple.
Randy,

If I go with the 205s all around, is it easy to get a shop to set up the alignment as you speak? What do I have to tell them. I'm new to this autocross and have heard a lot of different opinions. I was ready to go with these 205s all around but someone on spyderchat got me a little worried. I consider myself a decent driver. I don't drive crazy on the street so I'm not too worried. I would like some tires that would make me a little more competitive in autocross. Right now I'm in the middle of the pack of novices but feel these hard tires I currently have may be a disadvantage.
 

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Spyderchat, for all that is good about it, is full of people that have no clue. Listen to the national level autocrossers there. The key is to know which ones those are.

Yes, you can dial in a little more toe in on the rear to reduce oversteer. Also, I highly recommend getting the SANER Peformance Fabrication 1" front swaybar. The fatter front bar will be the key to you being faster. It increases understeer, so that solves the tire thing. And it acts as a limited slip.
 

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Discussion Starter #13
Randy,

I'm only going to have this car another 6-8 months, so I don't want to put a lot of money into it. Are you talking about replacing a sway bar already there in the back or is this a different one? Is this sway bar expensive? Will is take me out of c stock? Who puts these in, Toyota? Is it a simple thing I can do? I can do simple things with good instructions. If you think putting 205s all around is good, I'll probably do that. I know I'm asking a lot of questions, but I do appreciate your advise.
 

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Discussion Starter #14
I just looked up the sway bar, $180, not bad. I just need to figure out where it goes. It doesn't look too hard to install but I don't know much.
 

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Here's a second to Randy's suggestions.

My current street setup:

- 195/205 width tires front/rear (AVS Intermediates)
- Max negative camber all around with Dot2 crash bolts up front (about -2 degrees in the front)
- Slight toe out in front, neutral toe in the rear
- Saner 1" front swaybar (you can find stiffer) set to stiffest setting (very easy install)
- Koni Yellow strut inserts that I installed myself in an afternoon. Note: I am not a dab hand with car work and while this installation was nerve wracking it really wasn't hard.

For autocross I run in C stock and I currently have ~8 year old Hoosiers in 225 width all around. They had been sitting around and were unscuffed until my first event on them last month.

When I first put the AVS 195s on the front the car did feel a bit different (I had not yet put in the swaybar or the Konis). Soon after the tire change I spun the car on the highway when cut off at 80 mph but was lucky to have nothing worse than a scrape on my bumper from it. While the car's balance was somewhat changed by the wider front tires I believe the spin was more my fault than the car's (duh...don't lift and jerk the wheel at the same time...I was tired, that's my excuse and I'm sticking with it). The car handles significantly better now with the swaybar, Konis and alignment and has nice balance throughout a corner. With the current setup in the car I believe the likelihood of a spin in the same 80mph highway conditions is lessened although I haven't tried it again. :)

I have only autocrossed the car once with the 225s all around and I was very happy with it and had zero spins.

So, the car is still drivable with same sized tires on it although you may notice some changes in the balance that can be dealt with both with improved driver input and some suspension tweaking.

As for trying to get better times...you can do that regardless of the tires and setup. I didn't have this car even close to well set up for the first 3 years I autocrossed it (it still isn't really very close to the best C stock allows). On a few occasions I have had a friend who has won a national autocross title drive the car and he has thrown down faster times than people in much better prepared cars. Of course it is good to improve the car if it is hindering you, but don't forget that the most important improvement you can make is in your driving.
 
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