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20 Heat Cycled R888?
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TOPIC: 20 Heat Cycled R888?

Re:20 Heat Cycled R888? 15 years, 4 months ago #4885

Based on all the info I have accumulated, it is safe to say that shaved is the way to go with the 888's. Simply put, they heat cycle out before they wear out.
MICHAEL MADUSKE
2009,2010 Southeast 944-SPEC Champion

Re:20 Heat Cycled R888? 15 years, 4 months ago #4886

I experienced the heat cycling out issue this weekend, and it happened fairly quickly. We had a three race weekend. Won the first two, and by the 3rd one, couldn't keep the same guy I beat in sight the whole race. He ran the same lap times, I was off by 1.5 seconds. No set up changes. Because the tires came with the car, I'm not sure exactly how many HC were on them (some of them were also in the rain). They still had a lot of rubber on them, however.

Joe, your thought of setting up the car to understeer more is a good one, if less fun. I came in with rear pressures up about 2 lbs over the fronts, so I was overheating the rears. Wear was even, and I'm running the same camber setting as you.
One interesting tidbit is that wear was more even on this car than my last one. Alignment settings were the same, but the current car has much stiffer sway bars (Tarret vs. Turbo), and a late offset suspension. I suspect this means less dynamic camber loss in corners, leading to better wear. Something to consider - softer cars, especially those with higher ride heights, may need more static camber than stiffer cars.
Eric Kuhns

National Director Emeritus

2007, & 2008 National Champion
2011, 2012 2nd

Re:20 Heat Cycled R888? 15 years, 4 months ago #4892

I have not shaved the R888's. I have only run them full tread. I have noticed going back early last year that you can run fast times on full tread R888's. The tire doe feel heavier, but it has grip so you can get good times. Remember these tires are more sensitive to overheating. The RA-1 could over heat and 2-3 corners later come back. The R888 can over heat and never come back until you either slow way down for a lap or two or wait till next session. I have feeling beating harder on over heated tires will cause them to go away even more possibly reducing their overall life.

When took camber out I also seemed to get better consistancy. I think what happened on my first set that went 14 HC was that I ran them like RA-1's. Thus I repeatedly over heated in insider rears. I did this by tossing and catching the car at turn 2 at PIR. The RA-1 technique was to brake, pitch the rear end and catch the side when point in the right direction. The probelm was that technique was hard on the rear tires. Not an issue with RA-1's, but damageing to the R888's. The tires stiffer sidewall also meant that my effective camber was even more this working the insides more than on the RA-1. Result was overdoing the rubber there resulting both fast wear and heat cycling of compound.

When I started running my 16 HC set I started to concentrate on rear end sliding. I made some sway bar adjustments and a few HC in adjusted camber. All this was intend to prevent sliding the rear and spinning the rear on corner exit which is somehthing an open diff car is prone to do.

The result seemst to be a car that I don't want to pitch and catch, but want to have it stick to be fast. Feeling balance between front and rear is now more critcal. With the RA-1 you could have the car rear end loose and just drive the slide. In fact there was not enough grip in the RA-1 to do much else and be fast. A fast RA-1 car is sliding all over the place.

The R888 however has more grip. The trick is that you need adjust the car to use that grip. If you do nothign to an RA-1 car and drive it the same you will slide it and overwork the tires. If you simply back down to where you don't slide you are slow. So to maximize the R888 you actually need to have the car more balanced since if the rear slides rather than just driving it you need adjust to gain balance.

So if the an RA-1 car has a little too much oversteer no big deal. If an R888 car has too much oversteer bye bye rear tires and you are slow. However if you dail the balance right you have ultiumatly more grip than you had before.

So that has been my goal to get the car have the perfect balance so that I am not sliding the front or the rear and using the grip of the tire to get lap times. This will also tend to preserve life since sliding wears downr rubber and locally overheats that rubber. My biggest issue is that Turn 2 at PIR is a very important corner I have been driving it pitch and catch for so long that it is hard to change technique there. It is ingrained my head to do certain things and doing that on R888 is not good for the tires.

I frankly feel I will have better time on R888 on track I don't have as much experience on. No bad techniques I need to unlearn. This is one reason I think I will be good at Miller.
Joe Paluch
944 Spec #94 Gina Marie Paper Designs
Arizona Regional 944 Spec Director, National Rules Coordinator
2006 Az Champion - 944 Spec Racer Since 2002

Re:20 Heat Cycled R888? 15 years, 4 months ago #4893

I have been changing my setup as well . I run 350# front springs and 30mm rear bars. As of our last event i have my rear sway bar adjusted all the way back to it's lightest/smallest setting. When the tires get hot the car still oversteers but not as bad.
Next event I will be putting in some front bar.

Re:20 Heat Cycled R888? 15 years, 4 months ago #4895

Chuck I have been doing the same. Softening the rear bar and stiffening up the front bar. Right now my sway bar and camber settings would make a understeering pig on RA-1, but seems to nice on the R888. In fact I am consider 400lbs front springs instead of the 350's. My concern is if I have move both sway bars too much to get the balance I need I am really under or over sprung on the front. Rear has 30's so no changing there.

Still I don't have enough data to determine if I want 400's yet. The biggest issue is that just swapping to 400's can change all what I have done for camber, ride height and sway bars. It could be a case where it is faster, but between now and National I don't have the track time to set-up 400 with any confidence. So feel better off making the 350's work as I feel like I am slowing dailing them in.
Joe Paluch
944 Spec #94 Gina Marie Paper Designs
Arizona Regional 944 Spec Director, National Rules Coordinator
2006 Az Champion - 944 Spec Racer Since 2002

Re:20 Heat Cycled R888? 15 years, 4 months ago #4902

YEP ! I am buying 400# fronts for my new car and will swap them with the #67 and test it out.
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