Next set of tires for autox and limited track

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moto_bruce
Posts: 9
Joined: Thu Mar 24, 2005 1:00 pm
Location: Newport, RI

Next set of tires for autox and limited track

Post by moto_bruce »

Hello from grey and cold Newport RI. Just got more snow yesterday. Fun meter is pegged.

Soon, I'll be starting my 3rd season of auto-x. I did my first season in San Diego and I used street tires, good enough to learn on. My second season, half in San Diego, half in New England, I used Azenis. My last couple of auto-x's up here before the happiness of a winter wonderland set in were within 4-5 seconds of the top CSP times (them on R compounds, me on Azenis). I installed a torsen towards the end of last season and only got a couple of auto-x's in, so I am still adjusting to it. Last year, I also got a track day at Streets of Willow, and two days at Watkins Glen. No IS2 class out here, so I am driving in CSP, my car is a 95.

I am considering moving to R-compound tires. I will try to get about 12 auto-x's and a couple of track days. I am considering Khumo Victoracers or Toyo RA-1s. I am leaning towards RA-1s to break me in gently to R-compoundland.

More background: In San Diego, I lived about 7 minutes (including lights) from the Stadium. Out here, I live about 1 hr 45 min from the auto-x site. I prefer to arrive and drive, mostly because I am lazy, and stuffing a set of tires in my car means taking out the front seat (still need to test fit that one). Khumos certainly mean changing tires at the site.

Here are my questions for you smart, seasoned, salty dogs of auto-x and motorsport lifestyle:


1. Can I drive the RA-1s to the site without completely destroying them by the end of the season?

2. What kind of mileage are you seeing on RA-1s if you are driving them dual duty, street and motorsport?

3. Is progressing from Azenis to RA-1 to more dedicated rubber next year a bad plan, ie, should I just go with more dedicated rubber this year?

4. Should I do another season on Azenis and work to close up the gap on the top CSP time to a smaller amount before moving to R compounds? The new Azenis aren't as cheap as the old ones...

Thanks for your answers.
moto_bruce
Brian
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Post by Brian »

There are lots of Toyo RA1 users out there driving to events. I have used them for events at Laguna Seca and that is a 437 mile drive each way and they have held up very well event after event. They really do not get that warm for long freeway drives so the wear is not very significant. Driving on them every day would be a different story and that will bake them long before the tread wears out yet many miata drivers have done this with the RA1s for years with decent results. So, my recommendation is that if you want R compound grip then indeed go for the RA1 but drive on them only to and from the events and between events take them off the Miata and seal them up in plastic bags to preserve them between events and you should get a full season out of them.
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
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Post by Guest »

Thanks Brian. I went with the RA-1s in 205/50-15. Hopefully I will get them this week.

This last weekend, I did the Evolution phase 1 and it was great. I used the Azenis that I used all last year (about 7 auto-x's, a test and tune and 2 track days). I stored them in the garage, but didn't put them into bags. They have definitely given up their best grip. I think it was due to the heat cycling and storage (4 months). I used them on the street very little, so they might have about 2000 total miles (over 200 at Watkins Glen :twisted: ). I'm guessing about 80 auto-x runs total.

I still measured about 5/32 tread left across the tire, but the is no useful life in them. The first braking zone into the 180 at Evolution, I completely blew it overshot by 15 feet. I was worried that my skills atrophied big time during the winter. Then my instructor did exactly the same thing on his first run. Didn't feel so bad after that. Tires are toast.

I'll be mounting the RA-1s on Motegi Trak Lites. They'll get bagged between events.
moto_bruce
Posts: 9
Joined: Thu Mar 24, 2005 1:00 pm
Location: Newport, RI

Post by moto_bruce »

Update.

I have been running on the RA1s and have 4 auto-xs and a test and tune (total of about 50 runs) and about 1100 transit miles. They are working out great.

I have about 5.5-6/32 of tread left. The first event, I drove (about 220 miles round trip), made my three runs and came home. I checked the tread wear, and I burned up about 1/32. I was concerned the tires weren't going to last long, but I didn't heat cycle them before using them that day. Since then, I really haven't burned up much rubber and it looks like they might last into next season if they don't get heat cycled too many times.

There is a lot of advice (even from the Toyo website) that says you don't need to heat cycle and I think that is fair. But I think taking them out and driving on them on the highway for a couple of hours then bagging them for a few days would make that first time out around the cones a little smoother. I found my first time out, the tires weren't very confidence inspiring, I was wishing I was on my burned up Azenis. I think the tires weren't cured enough and the advice I got on tire pressure didn't work for my driving style (38 psi).

The next event was in the rain, and grip was good. I ran with 35 psi and I was really impressed with the wet traction. My set up was good for the conditions (which tells me it ain't so good for the dry). A friend stuck his G-tech in my car and the playback showed pulling about 1g in lateral acceleration. Not bad.

I struggled with tire pressure at the next event in the dry then got some good advice from another club member on tire pressue. Took his advice to go lower (32 psi) and did really well at the test and tune.

The last event I drove, the tires felt great and I was comfortable putting the car where I wanted. Confident grip. There were no street tire drivers close to my times, although I was off the pace of the hotshoes with Hoosiers, Kumhos. But I also didn't have to change tires, or trailer my car.

I believe it takes a while to break in RA1s. I think 3-4 good heat cycles are needed, but I am new with R compounds so this is my guess. I don't think heat cycling is absolutely necessary for the health of RA1s, but after a few events, they have more grip and wear very well. I saw no measureable wear from the last event (180 miles transit, 8 runs, sunny high 80's, black top). To preserve my tires during highway transit, I pump them to 38 psi (less carcass deflection, keep them cool).

Additionally, Toyo's advice on camber is that more is better with RA1s. I'm running -1.4 F / -2.0 R and the center of my wear pattern is outboard of the center of the tire. I'm not working the inner part of the tread and getting more wear on the outside. With Azenis, I was seeing pretty even wear with these numbers. I will try a new alignment for the next event with more negative camber.

Based on wear, I guess I can get another 150 runs before running out of tread, but not yet hitting the cord (unless the tires are heat cycled to death by then). That would also be another 3300 miles of transit. I don't think I can get that many runs up here in New England before the season ends so I expect the tire to last into next season.

I have caught the R compound bug.
moto_bruce
Brian
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Post by Brian »

Good update there... Indeed the RA1 start a little greasy with a little wiggle from the full tread depth but quickly become useful after a few runs of wear. Assuming they don't bake out too much (which seems to be more a factor of age with the RA1s than anything else), the RA1s are still at their best 10 minutes before you hit the cords.
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
moto_bruce
Posts: 9
Joined: Thu Mar 24, 2005 1:00 pm
Location: Newport, RI

Post by moto_bruce »

Another update.

After much pontificating, I came up with some new camber numbers. I went with -2.0F/-2.5R. Toyo recommends -2.0 to -5.0. The most I could get in back was -2.5.

The difference in grip is significant. I did quite well at the next auto-x, finishing 2nd in CSP. Strange, the winner was also on RA-1s, in front of the Hoosier and Kumho guys. I think the weather had something to do with it, it was near 100% humidity and upper 80s.

The new alignment inspires confidence and that alone is worth some time. The car just doesn't let go, even under trail braking. I was able get on the brake later, knowing that the traction was there when bending the car into the turn.

It will be some time before I can really check for even tire wear. I know my set up doesn't yield perfect tire articulation, but then again, that is a holy grail.
moto_bruce
moto_bruce
Posts: 9
Joined: Thu Mar 24, 2005 1:00 pm
Location: Newport, RI

Post Season Update

Post by moto_bruce »

Well, auto-x season is over in New England. I just did my last event 2 weeks ago and have more information on how the RA-1s are holding up as well as my opinion on their performance and drivability.

Durability/Longevity: This season I put 88 auto-x runs on the RA-1s, and 2230 transit miles. Highway miles seem to wear the tires very little. I run my pressures on the highway higher than usual (36-38psi) to keep the tires cool. Tread depth is as listed below in 32ndths of an inch, measured across the tread in the 4 major circumferential grooves:

Driver side Front 4 5 5 3 Passenger side Front 3.5 5 4 2.5

Driver side Rear 3.5 4 5 3 Passenger side rear 3 4 3.5 2.5

Grip has not gone off. My last set of auto-x tires were RT-215s and their grip was gone with a similar number of auto-x runs, but they did get stored over a New England winter which I am sure contributed to their death. I will be storing these tires in black bags, sealed as best I can, in a garage which I will keep hopefully above 45 degrees.

Based on my wear rates, I expect to get another full season and auto-x school out of the tires.

Performance: With the temperature swings through the season (cold in the spring, hot in the summer, cool in the fall) when it is cold out, getting heat into the tires is difficult if not impossible. The last event, the temps were in the low 50s overcast and I only saw about 1psi change in pressure over a 40 second run, so grip was never great. When temp is lower than that, grip is reduced further. I tried lowering pressures to get more heat into the tire, didn't help at all.

During the summer the high heat and high humidity help keep the tires closer to operating temp. RA-1s heat up quickly, but don't overheat. Dedicated auto-x tires (hoosier, kumho) come up to temp quickly but don't seem to give off heat as well and can overheat and get greasy over a 75 second run (typical Miata club length). But this is why they are good, they heat up quickly and keep the heat. This is meerly my observation. I do not have experience driving those tires. The difference in heat capacity when it is hot out is worth real time out on the course. I would guess the heat was worth about 1 second to the RA-1 (maybe more, they felt very good) and the overheating and greasiness slowed the dedicated tires (hoosier, kumho) by up to 1/2 second. As mentioned above, there was one event where the top 2 CSP cars were Miatas on RA-1s. I am usually top 4-5, so I can only attribute the jump in standing to the conditions and tires.

In the very wet at full tread depth, I found grip to be very good with a g- tech reading of 1.1g sustained and no aquaplaning at auto-x speeds. Haven't used a g-tech for any other testing.

Drivability: Since I bought the tires unshaved, their grip was obviously higher than a street tire, but because of the tread design and tread blocks, their breakaway and progressivity at full tread depth were very similar to a street tire. In a way I felt they were more progressive than the RT-215 I drove the prior season. They don't squeal like a street tire, but the feeling through the seat and torque through the steering wheel clearly communicates what the tire is doing. The bonus with starting on RA-1s for R-compounds is that they behave like a street tire at first, but as the tread wears, there are less voids and the tire gets less forgiving, but only as it wears. No surprises to the driver. Grip goes up, progressivity goes down. My tires now have more grip but a smaller envelope of tolerance to driver input. But that is okay since I have got here gradually.

Overall, RA-1s have been a great first step for me into R-compounds especially living in New England. I bought them unshaved, and was able to drive them to events. I got a lot of auto-x runs out of them, was able to use them in heavy rain, light rain, cold, high heat and humidity. I'll get 2 full seasons out of them, so that is less money spent. Not competitve in all conditions, but versatile enough to be a one tire compromise in all auto-x conditions. At my level of the game, they are perfect.
moto_bruce
Brian
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Post by Brian »

Hi Bruce,

Thanks for the comprehensive report...I am sure others will find this helpful.
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
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