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Discussion Starter #1
Following quite a few recomendations, I began using Toyo R888s this Spring for my DE's. I have 8 DE days on the tires already and I'm quite pleased with the wear qualities. However, I still find myself chasing a good cold tire - hot tire set up. I've asked around the paddock and pressures recommendations vary widely.

I'm interested in feedback from this group on your findings at DE's:
Toyo R888's only - What's working for you at the track?
Front tire cold pressure
Front tire hot pressure
Rear tire cold pressure
Rear tire hot pressure
 

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I haven't tracked on my R888s yet; only two AX's. There was a thread with R888 in the title on the Racing/DE forum on rennlist that discussed tire pressures a while back.

On that thread, early reports suggested shooting for around 38/39 psi hot. Some said they liked them in the mid-30s better, as they start to slide a bit around 40 psi. Toyo's own initial recommendation was high 30s to low 40s, but now they recommend 32 to 35. That's quite a change in recommended pressures. In short, different people seem to like different hot pressures.

We can't tell you what cold pressures to set; depending on ambient temps and how hard you work the tires, you'll have to guess what pressures might produce the hot pressure range you're aiming for. I'll probably start out shooting for 35 to 37 the first time out. That range has worked for me with a variety of R-comp tires in the past.

One other thing; from what was posted on that thread, you might want to mark the edge of your tires next to the valve stem so you can tell if, or how much, the tires are "spinning" on the rim under hard acceleration and braking. Some suspect such tire movements on the rim are due to poor bead design. The cure may be to use hair spray on the bead prior to mounting. Too late for me on that, but I only got about 1/2" movement on the rears from two AXs (nothing on the fronts, but not much braking torque in an AX).
 

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Discussion Starter #4
You're confirming what I'm getting track side...a wide range of preferences. I'm still interested in hearing from others.

Toyo R888's - What's working for you at the track?
Front tire cold pressure
Front tire hot pressure
Rear tire cold pressure
Rear tire hot pressure
 

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This is dependent on so many conditions that there is no "one size fits all" setting. I've started with 31F, 33 R COLD and left them there all day (resulting in 39/41 HOT.) When they were worn out, the rears corded in the middle of the tread, so perhaps that was a little high. Try 30F/32 R COLD, first thing in the morning, before you drive an inch. Check the little arrows on the sidewalls (or use white shoe polish, as suggested) to see where the tread wear marks end up after a couple of sessions, and adjust pressures accordingly. The key point is, once you've found a good hot pressure (somewhere between 36-40 psi, with perhaps a +1 to +2 psi higher rear pressure,) let the tires cool overnight and check the cold pressures the following morning. That will be your baseline starting point. Hope this helps.
 

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When I first started using R888s, I was running 36F and 38R Hot. With more time on the tires, I find I am running lower pressures. I am now in the range of 30-32F and 32-34R Hot. I use a pyrometer and the temp data looks good at these pressures. Cold pressures will naturally be much lower, probably about 8# lower. I hope to collect more data next Wednesday and will report any new info.
 

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Discussion Starter #7
Thanks, this is helpful. I believe my cold pressure is too high at the start. I have detailed notes after every run for the last four days (8 sessions). My front tires range from 38 psi to 37.5 psi Hot and the rears are coming in at 43 and up to 45 psi hot.

The better I'm getting at our local tracks, the more I'm beginning to slide around. I'm hoping that going for lower hot temperatures will provide more grip.

BTW, I have been marking the side walls at the wear triangles. I'm hitting the triangles at the top, but certainly less than mid point.
 

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I would suggest you also use a pyrometer to help you find the optimal tire pressure. All tires not only have a recommended hot pressure, but they have a recommended tire temperature as well. That being said, you may be in Toyo's range for hot pressures, but your tire temps may exceed what is recommended. You need all this information to make the correct pressure adjustments to have the tires work well.
 

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I think all the R-comps I've ever run on tend to get slippery when the rears get much over 40 psi hot. I don't remember ever getting the fronts that high, but some who force push through corners might.

I get scrub to the tip of the pointers (little triangles) too, but that's only a rough indication of being in the right psi ballpark. The sidewalls are so stiff that you probably won't get scrubbing below where you already are even with a few psi less.

I've been doing DEs for over 20 years, and I still wonder where to set cold pressures for the first session. Even at the end of the day, I wonder if I should have settled in at a few psi more or less than I ended up with. I like to get to settings I'm comfortable and confident driving on.
 

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Discussion Starter #10
Prior to purchasing the CS and tracking it, I had 15 years experience between racing and DE's on motorcycles. I really got the mfg./tire pressure/hot temps dialed in on bikes. As this post indicates, I'm still looking for the optimal set up with the CS.

BTY, I have now purchased a pyrometer so that I can bring tire temperatures into the equation.
 
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