Street Tires vs Dot R Tires

[Drew_K]

For equivalent sized tires, how much of a difference do Dot R tires make? The tires I'm thinking of are the S03's vs a Dot R, particularly the Toyo RA1's. For example, assuming a 60 second autocross course, how much time can the Dot R save?

I'm due for new tires soon and I'm trying to decide whether to (i) buy S03's and use them for everything, or (ii) buy something like Dunlop SP9000's (longer wearing and comfort tire) for everyday and then some track tires on my extra rims. My main question is the performance advantage vs $$$, particularly for autocross.

[orbmedia]

Tires are the single biggest improvement you can make. For an 60 second autocross for a good consistent driver the benefit is about 4-5 seconds. That's a huge amount.

[Drew_K]

Orb, thanks for the feedback. Followup question:

What about SO3's on 17 inch rims, 205/255 vs. Toyo RA1's (or comparable Dot R) on 16 inch rims, 205/225?

The RA1's aren't offered in the sizes I need for my 17 inch rims, so I'm going to be stuck using the 16's for track tires and 17's for street tires.

[addictionMS]

I have used Toyos a lot on a 1988 Carrera, and I have a set of Dunlop SP8000, the SP8000 are like being on ice compaired to the Toyos. But the Toyos will only last about 10K miles if you street them and track them. I have used Toyos on a RX3 Enduro car, and they lasted an entire 12 hour race at Thunderhill. So if you can afford Toyos, I would get them, plus 16" smaller diameter tires can give you a quicker acceleration and closer feeling gearing. I have also tired Yokahama A032R, they are pretty good as well, last longer than Toyos, but not quite as good. also very limited in size.

[Drew_K]

Thanks guys, that's exactly what I wanted to hear. Coincidentally, I'm running Dunlop SP 8000's now, so it's great to hear a direct comparison. I'm going to order the RA1's tomorrow. I'll be ecstatic if they drop at least 2 seconds off my autocross times. Unfortunately even dropping 4 seconds won't put me at the top of my class (A stock is VERY competitive; best times are usually about 60 secs), but it at least levels the playing field and I'll be pretty close.

[This message has been edited by Drew_K (edited 10-01-2001).]

[911driver]

Drew you may also want to check out Hoosiers if they come in your size, they have applications for autocross and track, I'm not sure how they would compare with the R1s and Toyos, but should be quite a bit faster than A032s (very good street tires) but not last as long.

[Drew_K]

Addiction (or anyone else), what type of tire pressures are you running on your Toyo's? What are typical pressures for DOT R tires? Thanks.

[Peter Kelly]

I recently put RA1's on my 89 carrera (16" fuchs) for a 3 day event at the glen. After 3 days (about 5 1/2 hrs total track time), the left side tires are almost shot, particularly the left front. Lap time improvemnt was about 3 seconds faster than decent street tires.

I am not sure if going a little (3 seconds faster) is worth having to buy new tires for every other track event. Does anyone know how the hoosiers hold up?

[patalive]

You are starting the long climb up.
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I understand that the Toyos RA1 wear better than the hoosiers and others. I ran AVS Sports before I went to the Toyos. My times also increased significantly, but outside tire wear is significant primarily because R rated tires are designed to run with more negative camber than street tires. If you want to extend the track time of your R rated tires, you need to go to the maximum negative camber that your stock suspension will allow, about 1.5 degrees I believe. Even that is not enough - the R rated tires are designed to run at between 2 and 3 degrees negative. Of course, running your street tires on the street at these settings will destroy them after a period. Everything is a compromise or expensive.

Chuck
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