emilio700

iTrader: (3)

Did some testing at SOW last week. Hot day, average around 95° ambient, 112° surface temps. Very windy. Steady 15mph and frequent gusts to 25mph. Wind direction shifting through about 60°. As our test car had significant aero, the wind rendered much of our lap time data invalid. So we concentrated
on subjective feel. We also noted behavior when pushed to fade then backed off just enough to regain full grip. So we won't publish exact lap times as the data is corrupt and full of noise from the changing wind. One lap the car would be tight entering a turn, next lap loose in same spot due to a freak wind gust.
We were there with all the equipment, track paid for so we decided to get whatever data we could.

VIDEO - click to play

click to play

Nankang AR-1, Toyo RR, Maxxis RC-1
Test car was Vegas, our S1 Supermiata. 220whp, 2300#. All tires 245/40/15 on 15x10 6UL. 24psi cold pressure. 1st cycle used to get pyrometer readings and optimized pressures. Hot pressures ranged from 30 to 35psi, each corner different. Don't ask us final pressures because every car/track/weather/driving style is different. Buy a pyrometer. Start with low pressures to get readings and optimize each corner for your car on a given day.

Like any high performance tire, each was fastest on 2nd or 3rd lap when leaving the pits on stickers. Usually around .5s faster for that "magic lap" then they settled in for the remaining cycles. Lap times were nearly a wash throughout the day. The AR1 and RC1 hovering within a tenth or two all day. The RR was consistently faster but only by about .5s over the other two. Lap times varied from 1:21.4 (sticker RR) to 1:23's (3rd heat cycle in hotter part of the day).

All three exhibited good brake modulation, the RR being the best, AR1 a tiny bit better than RC1.

The RR ran coolest, RC1 a bit higher. The AR1 freaked us out a bit by returning tread temps above 250°. Our opinion is that the extreme tread and casing heat of the AR1 could lead to somewhat reduce heat cycle life. Only very light and thin casing pure racing slicks can tolerate that kind of heat very long without torching the tread rubber. Maybe we are wrong but damn, those are some high tread temps.

Steering response, the RR was the clear favorite. The RR had the characteristic of being more sensitive to little changes in weight transfer when the driver tried to adjust the line. This made the RR's easier to place on line. We also noticed significantly lower steering effort with the RR compared to the other two.
This also contributed to the ease of placing the car precisely.

Now to the part we really wanted to learn. How they behave when pushed at full race pace. This was not sloppy driving or deliberately sliding. Simply trying to drive as quick laps as possible. So clean but using all the tire as one would do towards the end of a w2w race.
Once we go to the 3rd heat cycle on each, their fastest laps were generally 2nd or 3rd lap. Nothing unusual there. The RR seemed to manage heat the best, being difficult to get to fade. We never really got a big drop in lap times on the RR, just a tick slower then stabilized.

The RC1 would slowly fade after about 5 full speed laps then drop .5s. It would take a minimum of 3 corners to cool off enough to stop the predictive from bleeding.

The AR1 would take about the same 4-5 laps to fade then drop roughly .5s. It would take the AR1 a bit longer, about 1/2 lap to stop the predictive bleeding. Both the RC1 and AR1 could be yo-yo'd like this. Push until fade and predictive starts showing big + integers. When either was cooled by backing off slightly, they would go only 1-2 laps full gas before beginning to fade again. The slight difference between the two is the RC1 coming back noticeably quicker than the AR1.

We did not measure wear but the AR1 was noticeably more chewed up than than RC1 or RR. The RR in particular looked like it ran half as much as the other two and we actually put the most laps on the RR by about 20%.

Conclusion is that any would make a good HPDE, TT, w2w or enduro tire. The RC1 gets the nod for enduro by being really consistent, nice steering, long wearing. The RR gets the nod as the w2w tire due to the way its shrugs off heat. The AR1 seems like a good TT tire choice as our data and observations indicated it would wear the quickest. For HPDE, the factors are not just behavior but cost, longevity and consistency. The RC1 wins that battle mainly because its inexpensive, lasts and is consistent.

ddwelch

Awesome info! Thanks.

hornetball

iTrader: (4)

That's been my experience running through several sets of RC1s and RRs. In the end, my HPDE cost was lower with the RRs because they wore much better and I had to replace them less often. Even with ELBJs, I couldn't find a camber/roll bar setting/inflation pressure that would prevent the RC1s from chewing up the outside edge. So I would end up tossing tires that still had plenty of meat otherwise. The RRs, OTOH, would wear even across the tread and last longer despite lower initial tread thickness.

k24madness

iTrader: (6)

Props for excellent write up and testing! Surprised the 245RR didn’t get more press. We’ve all been waiting years for a cheaper in between Hoosier DOT slick type tire. I’ll give it a whirl on my next open track day outing.

ooja3k

iTrader: (1)

Last track day at Buttonwillow the RR's seemed night and day better than the ar-1's. Could have been that it was also approaching 100 degrees later in the day and I had started with the RR's when it was cooler in the morning...

emilio700

iTrader: (3)

Please don't take offense but it's better not to add data points unless you have well, data. If you were recording lap times, tire temperatures, heat cycles surface temperatures things like that then it's all very useful. Otherwise it tends to muddy the picture and that's what this thread was pointedly trying to avoid. Carry on.

ooja3k

iTrader: (1)

Totally understand. I have 3 sessions worth of pyro data, starting and finishing pressures, and lap times. Didn't take track surface temps though. I'll post more specific data when I go get the notepad out of the trailer eventually.

emilio700

iTrader: (3)

Ah, cool. So your conclusions were based on numeric values, seat of the pants or a little of both? In for data *****.