333pg333

265x645x18 f and 285 r R80 all round.

I was very impressed. They seemed to come up to heat pretty quickly. I'd say within a couple of laps on a short twisty track just about did it. My previous experience with slicks is limited. Mostly I have run on R888s and NT01s. I have also used both R6 & A6 which are very good.

On the day I had some pretty poor understeer, push, scrubbing when first riding around on the Nittos. I am not entirely sure why, but I suspect that as we had to knock a decent amount of caster out just to gain clearance for the taller slicks, that this may have upset the geometry. I know that if you adjust camber, you have to re set toe. How about with caster. Does that also effect toe?

Apart from being able to turn in and corner better, I was most impressed at how much deeper I could go in under brakes. Especially without ABS the impression of increased modulation and feel was wonderful. I was only able to try these at the end of the day's event as that was on R spec only. I wanted to stay out there for a lot longer to get more practice in, but as I was concentrating and going faster each lap, I missed a braking point at the end of the straight when watching a guy in a 911 spin in front of me...so I flat spotted one of the fronts. D'oh!! Gotta hate doing that to a brand new tyre.

I have to really think about putting the old factory abs unit into this car or not. Some say it's better to leave them out and I am getting more attuned to life without abs...but it's damned expensive and frustrating when flatting tyres.

Managed to have a bit of fun with one of the quick EVOs. Saw him coming down the straight so I let him pass and we had a few quick laps around this short but quite demanding little track 2.5 hours south of Sydney. This was just after the first two laps warmup and then into it. I kept turning in using the R spec points and found that not only was it ducking now too early, but in parts I wasn't using the whole track as there was much more grip. Got better later on. Notice how I can close way up on him under brakes. To the point where I lose momentum waiting for him and then the 4wd rocket takes off and I get left behind. Good matchup all the same.

http://www.youtube.com/watch?v=0xSnau43PiE

aj986s

Nice runs! I run a 1984 944Cup car, which is NA and no ABS, so definitely slower than yours. Early on I was flatspotting tires when learning to drive on the Hoosier R6's. But I've been learning to brake a bit softer to better manage weight transfer, and use more trail braking to enter a corner a bit faster. Lately been locking up a lot less.

I think you did a great job keeping up with the Evo. Although it may have looked like closing under braking, remember that as speed decreases, "timed space" between two cars decreases. IMHO, some of the "closing" was simply getting closer due to decreasing speeds.

jrgordonsenior

Great driving on what appears to be a really fun track. What hot temps did you shoot for on your new Hoosier's?

PS: I kept waiting for the polo ponies to come cantering by......

Gary R.

Love the track, wish it was a little closer..

333pg333

Yes definitely a learning curve without abs. Good point about braking 'appearances' and one I make myself. In this case there were certainly places that I do catch him a bit though, to the point where I'm sort of stalled by him, but then he just takes off with all the power/traction. The EVOs are an amazing car to be behind. They just look so nervous, but they keep going forwards very quickly.

Thanks JRG. It is a fun track, if not a little bumpy in a few places. For a short track it's actually very hard on brakes. I didn't have any time for testing of the Hoosiers. Just wanted to slap them on and have a go and also heat cycle them once. Started out with 30psi and got to between 34-36psi hot after running around with the EVO for a few laps. Even though the Hoosier site has said to have them up to 40psi or thereabouts, I don't like this idea so I'm aiming for 32-34psi. Not sure on temps yet.

You're not far off on the Pony reference. This is a very rural area so animals are nearby. Wouldn't be surprised to see a Kangaroo hop across the track oneday.

Meh, just pack your car and come on down. Driving on the correct side of the road should be fun for you.

jrgordonsenior

No wonder you came up to temp so quickly, you were already there. You have incorrect information on pressures. That sounds like their recommended pressures for the A6/R6 tires not their slicks. 30 hot is the usual target; here read this: https://www.hoosiertire.com/rrtire.htm

Click on GT in the pink left margin, then "Set Up Information" under the lising of tire sizes....

333pg333

Found that info on Bob Woodman's tire site. Thanks for that clarification JRG. That makes much more sense.

jrgordonsenior

Think how much fun you'll have at 30 hot
That might explain locking up that front tire....

jakermc

FWIW, in my 996 cold pressures of 23F/21R generally get me to 30 hot.

333pg333

My car is about 3000lbs with me in it. Front engined. In general, I need them to get to heat quickly for short sprint events (3-4 hotlaps) so I'm thinking starting at about 25psi cold.

jrgordonsenior

Maybe if they're dead cold that would be OK for a short sprint. Don't you get a warmup session before your sprints. If so you should get them to temp then bleed them off to 30 hot and you're good to go for the sprint race. You really don't want slicks with excessive pressures or temps....

Reminder to me to call Bob Woodman tires tomorrow regarding their Hoosier slick pressure recommendations. Almost positive that's copied in error from their A6/R6 page....

333pg333

Yes, generally what they do is we run a 15 min session in the morning to determine the speed groups. If there's say 55 cars entered on that day that can take an hour and a bit to get through. Then we go out in speed groups for 1 outlap, 3-4 sprint laps, 1 cooldown. Not sure quite how long they hold heat/pressure but I get what you're saying. I would imagine based on the link you posted for a 2650lb car and 30psi, then mine would be best at about 32psi +/- but temps will help determine this. Can't wait to try these again. Have a full day booked in 2 weeks. Just have to repair the car after crashing it on the way home...but that's another story...

Garylimey

Great driving Patrick, love the track!
Makes me want go see my relatives "down under". Maybe do a little driving while I'm there especially as I prefer shifting with my left . When I was last home I wish there had been time for a drive at Brand's.

jakermc

Remember that heat and pressure are two different things.

Lower starting air pressure will actual generate heat in the tire more quickly than higher pressures. Think of the air as a heat sink for the heat that is generated by the tire's contact with the road. More air absorbs more heat and causes the tire to heat more slowly.

We usually associate high pressures with high heat, but that association is really about the change in pressures from cold to hot. A hot tire will heat the air and cause it to expand, thus showing a larger change in air pressure during the length of the run.

For such a short run, you will need to find a balance between hitting the optimal temperature range with hitting the optimal pressure range. The former will impact mechanical grip and make the tire as sticky as possible, the latter will impact grip by maximizing the tire contact patch and to some extent impact your spring rates.

A one hour break between sessions is not very long and I think you'll be able to carry residual heat from that session. I would try to get to 30-31 hot in that session or a touch over, then bleed down to your desired pressure immediately when you get off. Then don't touch tem and race at that pressure. Then check again after the race and see if it worked.

Good luck!

333pg333

Thanks Gary. Well you could import a rhd car and continue driving on the 'correct' side although I think you'd get your fair share of quizzical glances!
Personally I like having my strongest arm on the wheel...just in case.

Thanks Jake. Of course you're right. Sounds like a delicate balance between heat and pressure. Bit of trial and error I'm guessing.
Can't wait to get back out there on these tyres....at a lower hot psi than I was running just to see the difference.