Best TW200 & TW100 Tire Size for Tracking an STR NC

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Best TW200 & TW100 Tire Size for Tracking an STR NC

Postby skeeler » Wed Jan 29, 2014 6:33 pm

I'm planning to take my STR-prepped NC* to a few HPDEs this year (once I get a real roll bar in the car**). I currently have 225/45-17 R1Rs for my street setup and 245/40-17 Rivals for autocross, both sets are on 17x9 wheels. This brings me to two questions:

I'm thinking the Rivals may be the best choice for the track; 245 seems like overkill on the track, but I'm worried the R1Rs will overheat. Any thoughts on this?

Also, once I wear through the current tires, I plan to get a set of treadwear-100 tires, like the RA1s, R888s, or NT-01s for track work. What would you suggest for the best size for an NC at my weight and power levels? I know the Spec MX-5 and MX-5 Cup cars run 225/45-15, but they are on stock 17x7 wheels and Hoosiers. I'm thinking 235/40-17 would be a good choice. Suggestions?

* Intake, full exhaust, tune, dampers, springs, sway bars, wheels, tires.

** Yes, I know a real roll bar will require soft top removal which will kick me out of STR, since I don't want to run the externally braced bar, and since I need an instructor to be able to ride with me (and thus can't use the petty bar).
2009, STR & DD. 1995, HPDE. 2004 MSM, sold. 2010 Mazda3, hers.
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Re: Best TW200 & TW100 Tire Size for Tracking an STR NC

Postby Brian » Thu Jan 30, 2014 6:36 am

I agree the 225/45-17 R1R likely your fastest choice of what you currently have. I have used R1R at the track and they work great (no overheat issues, as you go faster and faster there is more and more air flow over them to keep them cool). Once you are buying a 100 treadwear choice then I really like the Nitto in 235/40/17.
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Re: Best TW200 & TW100 Tire Size for Tracking an STR NC

Postby skeeler » Thu Jan 30, 2014 8:10 am

Brian, thanks for your reply. I guess I will reconsider using the Rivals and try the R1Rs instead.

I'll be back here in a few months to order the Nittos in 235.
2009, STR & DD. 1995, HPDE. 2004 MSM, sold. 2010 Mazda3, hers.
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Re: Best TW200 & TW100 Tire Size for Tracking an STR NC

Postby skeeler » Fri Jan 31, 2014 7:35 pm

Brian wrote:I agree the 225/45-17 R1R likely your fastest choice of what you currently have.


What starting pressures would you recommend for an STR-weight (2400 lb with full tank) NC on 225/45-17 R1Rs? Thanks again.
2009, STR & DD. 1995, HPDE. 2004 MSM, sold. 2010 Mazda3, hers.
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Re: Best TW200 & TW100 Tire Size for Tracking an STR NC

Postby Brian » Fri Jan 31, 2014 9:15 pm

skeeler wrote:
Brian wrote:I agree the 225/45-17 R1R likely your fastest choice of what you currently have.


What starting pressures would you recommend for an STR-weight (2400 lb with full tank) NC on 225/45-17 R1Rs? Thanks again.


You might be surprised how low I would start. Since that 225mm wide tire is so well supported on the 9 inch wide rim I would start with 25psi cold because I want some feel. Figure once hot it will be 30ish. Adjust from there as you like. If you had less rim supporting it I would start higher to prevent tire rolling over too much.
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Re: Best TW200 & TW100 Tire Size for Tracking an STR NC

Postby skeeler » Sat Feb 01, 2014 6:56 am

Brian, thanks for taking the time to reply. I am indeed surprised by how low your suggested pressure is. I'll start there, though, and see how it goes.
2009, STR & DD. 1995, HPDE. 2004 MSM, sold. 2010 Mazda3, hers.
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