dp1 tires (reference/research/reviews)

[dp1]

Originally Posted by Sleepless

I found 35 to be optimal

Thanks - what cold pressures do you start with at which ambient temp? Camber?

[Sleepless]

Originally Posted by dp1

Thanks - what cold pressures do you start with at which ambient temp? Camber?

I start at 30 cold and then adjust after the first session. Camber is 3/2.5.

[dp1]

Originally Posted by Sleepless

I start at 30 cold and then adjust after the first session. Camber is 3/2.5.

This was a great suggestion, thank you. Ended up at 29-30psi cold and 35-36psi hot in 75-85F ambient. Didn't push too hard on a new track but used up about 1/2 of the NT01 tread in 3 days at Palmer Motorsports Park. Need more than -3 camber up front (will go back to -3.4 next season) and -2.5 is about right in the rear. Definitely buying these tires again, they like heat and are predictable at the limit.

[icesilvermetallic]

Got to test drive BF Goodrich g-Force Rival S, the new Bridgestone Potenza RE-71R, and Kumho Ecsta V720 with the Hankook RS-3 Version 2's being the 4th tire.

RE-71R & V720's are super close, BFG's a step back and less direct, RS-3 Version 2's are another step back.

Bridgestone Potenaza RE-71R's and Kumho Ecsta V720's are the way to to go. They will wear fast though. Ism.

[GSpeed]

We ran 245/40/17 RE71Rs this past week for the first time. Car was stock other than camber bolts giving us -1.2° camber in the front. Picked up 4.8 seconds (1:32 to 1:27) with no other changes. Slight rubbing on 17x9+45.

After 20 minutes on track, front right tire was showing over 200F on outer shoulder and times dropped off by 1.5 to 2 seconds. Hot pressures were 34psi, which gave us a nice temperature gradient as measured by a probe in hot pits. Ambient temperature was 85F, track surface was 95F.

All in all, a very fast tire, but may drop off times under hard driving. Great tire for DD use and beginner DE users.

[dp1]

Originally Posted by icesilvermetallic

Got to test drive BF Goodrich g-Force Rival S, the new Bridgestone Potenza RE-71R, and Kumho Ecsta V720 with the Hankook RS-3 Version 2's being the 4th tire.

RE-71R & V720's are super close, BFG's a step back and less direct, RS-3 Version 2's are another step back.

Bridgestone Potenaza RE-71R's and Kumho Ecsta V720's are the way to to go. They will wear fast though. Ism.

Thank you - please provide some info about the car setup, temperature, pressure, length of time driving each tire, course - ax/track/skidpad, driver - experience, etc.

[icesilvermetallic]

Originally Posted by dp1

Thank you - please provide some info about the car setup, temperature, pressure, length of time driving each tire, course - ax/track/skidpad, driver - experience, etc.

I work for a major tire retailer. We use F30 BMW test cars on an autocross course but what I experienced should transfer to the FT86 (I run leftover Michelin Pilot Super Sports myself on my BRZed). Our head test driver is writing a formal report that should appear online in the next few weeks. This report will have hard data. Work will get mad at me if I throw too much information out there. Probably said enough as it is. Ism.

[solort]

I would think the Rival would be better than the Rival S for track days with the harder compound that handles heat better. But I may be mistaken. Would be an interesting test...

[DarkSunrise]

Originally Posted by PST

We ran 245/40/17 RE71Rs this past week for the first time. Car was stock other than camber bolts giving us -1.2° camber in the front. Picked up 4.8 seconds (1:32 to 1:27) with no other changes. Slight rubbing on 17x9+45.

After 20 minutes on track, front right tire was showing over 200F on outer shoulder and times dropped off by 1.5 to 2 seconds. Hot pressures were 34psi, which gave us a nice temperature gradient as measured by a probe in hot pits. Ambient temperature was 85F, track surface was 95F.

All in all, a very fast tire, but may drop off times under hard driving. Great tire for DD use and beginner DE users.

Thanks for the writeup. Were you seeing a lot of front outer shoulder wear at 34 psi hot?

[GSpeed]

Yes, the front right was worse than the front left, as it's a counter clockwise track.

[DarkSunrise]

Originally Posted by PST

Yes, the front right was worse than the front left, as it's a counter clockwise track.

Yeah that makes sense. I have a similar setup (-1.5 degrees front camber on stock suspension) and was seeing a lot of front shoulder wear at 36 psi hot with Nitto NT05's. I inflated to 40 psi hot to stop the shoulder from rolling over, but gave up some grip. Sounds like the RE71's are probably similar in terms of sidewall stiffness, maybe a bit better.

[7thgear]

Originally Posted by icesilvermetallic

I work for a major tire retailer. We use F30 BMW test cars on an autocross course but what I experienced should transfer to the FT86 (I run leftover Michelin Pilot Super Sports myself on my BRZed). Our head test driver is writing a formal report that should appear online in the next few weeks. This report will have hard data. Work will get mad at me if I throw too much information out there. Probably said enough as it is. Ism.

between the RE71 and V720, which had the stiffer sidewall and better response?

[icesilvermetallic]

Originally Posted by 7thgear

between the RE71 and V720, which had the stiffer sidewall and better response?

Between the RE-71R and the V720, I couldn't feel a difference in steering response or sidewall stiffness. Our head test driver, a better driver than I, will cover this in his formal report. Ism.

[rx3]

I've meanwhile had the opportunity to compare the Michelin S5B (super soft racing slick) with the Toyo R888 on the same slalom course.
Even though the Michelin S5B already heat cycled out, it was still almost 5% faster than the R888.