Dedicated track tires vs. all-around tires

[lancer360]

Originally Posted by FlyLo

"It is unsafe to operate any Hoosier Racing Tire including DOT tires on public roads. The prohibited use of Hoosier Racing Tires on public roadways may result in loss of traction, unexpected loss of vehicle control, or sudden loss of tire pressure, resulting in a vehicle crash and possibly injury or death."

http://www.tirerack.com/tires/tires....r&tireModel=R6

Unless I totally misread something, I don't think anyone was promoting the use of R6's on the street.

[Purist]

So what would be the most compelling reason to choose RA-1s over R6s as a dedicated track tire? I'm leaning towards the 205/245 option as there's a good chance I'll supercharge in the not too distant future.

[lancer360]

Only thing I could figure is that the RA1's should last longer, but I don't have any hard data to support that just the fact that the softer the compound the faster they wear. RA1's are a tread ware of 100 and Hoosiers are only 40.

[FlyLo]

Originally Posted by lancer360

Unless I totally misread something, I don't think anyone was promoting the use of R6's on the street.

It's relevant if you're going to drive to/from the event.

[YAUDI]

Here is how my set of full tread RA1’s have held up:
225/45R15:
68 sessions, and still at least another 10 session still in them
245/45R16:
51 sessions when I replaced them, probably could have gotten a bit more
out of them
I also drive on them talmost everywhere too, since I like the gunmetal Rotas.

For reference, here is what I got on my A048’s:
195/50R16:
Stick went away around 20 sessions, never could wear them all the way down, so just bought new ones when I replaced the rears.
225/45R17:
Center about gone around 30 sessions. Wish I could take back the 4 sets I bought.

Few reasons I like phat RA1’s:
-Very consistent over the life of the tire
-Since they are phat, they take a lot more abuse before they really get really hot. Actually, I typically never really over heat the edges like I could with the A048s. My A048s would have that bluish hue on the outside, esp on the fronts.
-Braking is so much more consistent, ABS is much harder to get into. A048 bicycle tires were terrible, esp after you get around 20 sessions on the fronts and over any mild undulation
-Wear across the tire is so much better, esp the rears. I’d run like 17-18 psi cold on the rears of the A048’s and still the center would wear out. With the RA1’s, I’d shoot for around 38 psi hot and drive as hard as I felt like. Still can over heat the rear RA1’s in the tail end of a session, but that just makes the ride more fun for the passenger.
-They look phat, it’s like the amount of rubber the car should have come with.
-They are cheaper and last quite a bit longer than A048s
-If you use all the available grip, RA1’s are definitely faster
-All the kewl guys here in TX run them

[Purist]

Hmmm...myelise is saying 20+ days on the hoosiers and yaudi is saying around 60 "sessions" on the Toyos. yaudi, what do you consider a "session?" Do you shave?

I would definitely get the RA1s over the Yokos...I'm trying to decide between the RA1s and the Hoosiers. Unless I can expect the RA1s to last significantly longer than the R6s (doing about 12 autox and 6-8 track days a year), I'll probably go with the Hoos.

[ace10]

purist, i don't recall you mentioning if you have a trailer or some other way to get the hoosier's to the track.

[lancer360]

For what it is worth, I shave my RA1's to 5/32's. They will have more grip if you shave them to 4/32 to completely remove the tread, but 5/32 will get you a little more life out of the tire without having too deep of a tread and overheating the tread blocks causing chunking.

I currently have 3 track days on them (12 sessions) and a couple of autocross events and the rears are between 3/32 and 4/32 and the fronts are right at 4/32's.

Originally Posted by Purist

Hmmm...myelise is saying 20+ days on the hoosiers and yaudi is saying around 60 "sessions" on the Toyos. yaudi, what do you consider a "session?" Do you shave?

I would definitely get the RA1s over the Yokos...I'm trying to decide between the RA1s and the Hoosiers. Unless I can expect the RA1s to last significantly longer than the R6s (doing about 12 autox and 6-8 track days a year), I'll probably go with the Hoos.

Sessions are a much better way to gauge the life of the tire as each session runs the tire through a heat cycle. In one day at the Lotus Track day at VIR I put 5 sessions on the tires.

[UKphil]

Gentlemen,

I have been following this thread because of my own plans.

Can I just summarize what I believe is the consensus - please let me know if I have misunderstood anything.

I want to go to a dedicated track tire next year.
I will buy separate rims and change at the track.
I will have base suspension - upgraded with nitrons (or possibly Ohlins)

I want the best performance tire - not the most economical.
I would like it to survive around 15 track days (3x 25min sessions)

I don't want to "over tire" the car and could do with a little less oversteer

So - am I right in thinking 205 front / 225 rear Hoosier R6s?


Thanks for your input.

[YAUDI]

One session to me is a lapping session of ~25 mins. I’ve run my first full set of RA1’s and my first rear RA1 replacement starting from full tread. It's a little tricky in the beginning, but any good driver can adjust and have just as much fun wearing them down to the good stuff.

As hard as I’ve driven, I never overheated or caused chunking of my RA1’s. I’ll point out, I shoot for around 38 psi hot., which seems to be the consensus of our local track rats.

lancer360, you just reminded me about something I meant too say, with 68 sessions and over a year on my front RA1's, they are just about as good as they've always felt.

[kverges]

As a counterpoint, I would never use unshaved RA-1s except in the wet - and really wet at that. I find the tread squirm unbearable when hot. My only experience was when Vilven sent me new, unshaved rears by mistake and I used them anyway. I had to use opposite lock in every turn after the intial turn in and spun the car 3 times in one session. I thought the lug nuts were loose or a supension component had failed. I use my SM Toyos take-offs for the front so I really need comparable rear tires.

[YAUDI]

Originally Posted by kverges

As a counterpoint, I would never use unshaved RA-1s except in the wet - and really wet at that. I find the tread squirm unbearable when hot. My only experience was when Vilven sent me new, unshaved rears by mistake and I used them anyway. I had to use opposite lock in every turn after the intial turn in and spun the car 3 times in one session. I thought the lug nuts were loose or a supension component had failed. I use my SM Toyos take-offs for the front so I really need comparable rear tires.

Keith, was this on your Elise with base suspension? I found base suspension much less forgiving anywhere near the limits compared to LSS, esp with trailbraking.

When I got my replacement set of rear full thread RA1's, I had so much front grip, it let me practice lots of opposite locking techniques, some successfull, some not so much...

[kverges]

OK i will take the suspension excuse too as part of my spinnosaurus maximus demonstration

[lancer360]

Originally Posted by YAUDI

lancer360, you just reminded me about something I meant too say, with 68 sessions and over a year on my front RA1's, they are just about as good as they've always felt.

That is good info to know that are cars appear to be light enough to not cause the chunking at full tread if you want to run them that way. I'm really curious to get back to the track and start checking my tire temps. I'm really surprised to hear such high pressures. I have only checked my tire temps at an autocross and the tires were running around 100 degrees with ambient air at 75. Based on the tire temps across the face, I need to reduce my rear camber a bit and the pressures worked out to be f24/r29 to keep the temps across the face of the tire even. This was with the 225/245 RA1 setup.

[YAUDI]

I remember finding this info when I was searching the web on RA1's, granted it is kind of specific to Miata's:

RA-1 Care and Feeding
--------------------------------------------------------------------------------
1) Toyo Proxes RA-1's may be "flopped". That is, the tires can be rotated on the rim so as to move the inside shoulder to the outside shoulder position. This is actually a good way to increase the life of the tire if you are experiencing excessive outside or inside shoulder wear. If you are experiencing excessive inside or outside shoulder wear, you should flip the tires on the rim at or a little before the tires are half worn to maximize tire life. There is no difference in construction of the inside sidewall vs. the outside sidewall like the old BFGoodrich Comp T/A R1 tires, so doing this is not a problem. Also, if you are running in dry conditions, the tire can be run rotating in the opposite direction. This can be handy if for example you want to rotate the left front to the right rear position during a race weekend. Even though the tread pattern is directional, this is mostly for better water drainage. If you are running in wet conditions, they should definitely be run in the proper direction of rotation.

2) The RA-1 does not really require heat cycling. The compounding is formulated to be very stable from the beginning of the tire's life to wear out. This is one of the reasons why many racers love the RA-1 for enduro's. Also, the compound is not very sensitive to the number of heat cycles you put on it. So even if you put a lot of short easy stints on them, they will not turn rock hard. So you CAN race on green tires. But if you are running at a very fast track such as Willow Springs in California, you may experience blistering if running full tread depth.

Here are some tips when running the RA-1. I have to emphasize that these are only recommendations. Setup boils down to making the car comfortable for each individual driver.

1) The optimum operating temperature for the RA-1 compound is about 200 degrees F. A general minimum operating temperature is about 160 F and a maximum of 220 F. Because tires cool off fairly quickly, you should be reading slightly lower temperatures when checking the tires in the hot pits. So, if your pyrometer is reading 200 F or higher in the pits, you're probably running too hot out on the track.

2) Target HOT pressures are the low 40's. For the 205/50R15, if you start around 34-PSI front/31-PSI rear COLD on the Miata, you should be getting up to around 43 PSI HOT. Hot pressures in the low 40's may be a lot higher than what you are used to, but (cautiously) give it a try and see how it feels to you. A lot of times people run the RA-1 too low. Hot pressures tell you how the tires are working. Adjust cold pressures to reach the optimum hot pressure.

3) As a general rule of thumb for camber setting on the Miata, max out negative camber on the front and use about 1 degree less in the rear (-3 degrees front, -2 degrees rear for example).

4) If you are running at a high speed track with high ambient temperature (again, using Willow Springs for example), you should run shaved tires in dry conditions. Having full tread depth may lead to excessive heat retention causing the tires to overheat, performance to drop off, and then eventually blister.

5) The RA-1 has slightly softer construction then some of the other competition tires out there. One comment I hear from a lot of guys is that you can push them a lot harder than you initially think. As you get used to the tire and how it feels, you may find that the limits are higher than you initially thought. Of course, please be careful when exploring those limits!

6) Just as a side note, one misconception that a lot of beginning racers have is that even tire wear reflects optimum tire setup. That's not necessarily the case. You usually make up the most time on the high speed sections of the circuit. Therefore, you should adjust your setup to optimize tire performance in those high speed areas. This often means more negative camber to optimize the tire contact patch when the suspension is heavily loaded. What you may find is that this leads to greater inside shoulder wear vs. what you are seeing on the outside shoulder since most of your heavy braking is done in a straight line.

I hope this information helps. If you feel this information is worth wile, please feel free to post it on any of the Spec. Miata bulletin boards. Let me know if you have any other questions. Thank you for trying out the RA-1. We'll be doing our best to support you guys. Good luck, and good racing!

Thomas Okihisa
Staff Engineer
Technical Service Department
Toyo Tire (U.S.A.) Corporation

[codymac]

Originally Posted by YAUDI

I remember finding this info when I was searching the web on RA1's, granted it is kind of specific to Miata's:

...

Thomas Okihisa
Staff Engineer
Technical Service Department
Toyo Tire (U.S.A.) Corporation

Interesting. I've tried on more than one occasion to get ahold of anyone at Toyo related to motorsports and been stonewalled - in fact, they've been complete asshats more than once.

[jordantii]

As I was reading that long post I was thinking to myself "that sounds a lot like my friend Thomas Okihisa from Toyo.

Whadaya know..

[Purist]

Wow...thanks for the great input, folks. I will have a trailer for next season, so driving to event on the Hoosiers is not an issue. As far as life goes, the only two data points I have are myelise who says he gets 20+ days on the R6s, so assuming 3 sessions per day, that's 60+ sessions (is 3/day accurate?). Yaudi got 51 sessions on the rear RA1s (more on the fronts), but he also drives them on the street. But then again he runs them at full depth which I wouldn't do (did that on a 968 and hated it). So I guess it sounds like life might be a wash. Can anyone compare the performance of the two? Do people go with the RA1 so they have the option of street driving on them?

Thanks everyone,
Tom