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Toyo Tire Pressure...Help

1,022
97
Exp. Type
HPDE
Exp. Level
10-20 Years
Texas
If anyone is running Toyo R888's on their Boss I am trying to figure out what the right tire pressure is. I am currently running 40 PSI hot on all four tires at the track.
 
367
1
I know I'm not much help with these comments, but careful with those tires.
They get greasy quick and don't like much heat.

Used them on a 2400lb car running 30psi and it got greasy after about 4 hard laps at my local circuit. I think something like 40hot front, 38hot rear is a good starting point.
 
Ive got the 888's as well, i couldn't find ant info on pressures when i first took them to the track so set them to the normal boss pressure which was 34 i think

The book says 41, what did you find as the best pressure now you have had them for a while
 
1,022
97
Exp. Type
HPDE
Exp. Level
10-20 Years
Texas
I have been running 38 front and 36 rear...I found that works out pretty good. I was running 40 front and 38 rear and that worked pretty good too. I wouldn't go any lower than 36. Hope that helps
 

isrboss

One of the things I like about Toyo is, they put out info on their tires. I had to call Bridgestone to discuss optimal temp and to get a good idea of hot pressure for my RE-11's.

Click set up & care
http://toyotires.com/tire/pattern/proxes-r888-DOT-competition-tires

Also depending whether your set up under steers or over steers would determine if you run less psi in the rear. If you have a set up that oversteers then keep pressures even or run slightly more psi in the rear, opposite for understeer.
 
3,806
3,745
IMO start with 29-31 in front, 25-27 rear cold, don't exceed 40-42 (or the mfg recommendation) hot. What rear sway bar are you running?, if it's stock, go smaller. One of these days I'm going to write a technical post on this whole tire deal.
 

isrboss

blacksheep, please put together a tire help thread and offer your technical help. Tire pressures are very important to get right when on track. This would be a great help to the BMO community.
 
1,022
97
Exp. Type
HPDE
Exp. Level
10-20 Years
Texas
On the Toyo site it recommends 32-38PSI hot...I found that running any lower than 36 with a heavy car like the Boss causes the car to move around a lot because of sidewall flex. I have experimented a lot with the tires and for my setup I like 38 front and 36 rear. I might go 36 front and rear for a session this week and see if that cures some of the understeer. I am going to dial in some more negative camber as that helped also in previous track days.
 

ArizonaBOSS

Because racecar.
Moderator
8,552
2,392
Arizona, USA
boro92 said:
I know I'm not much help with these comments, but careful with those tires.
They get greasy quick and don't like much heat.

Used them on a 2400lb car running 30psi and it got greasy after about 4 hard laps at my local circuit. I think something like 40hot front, 38hot rear is a good starting point.
Agreed, the R888 does not like heavier cars like the Mustang. AI reverted to the RA1s after trying to switch to the 888s. They just go away too quickly
 

isrboss

Flyboygsxr said:
On the Toyo site it recommends 32-38PSI hot...I found that running any lower than 36 with a heavy car like the Boss causes the car to move around a lot because of sidewall flex. I have experimented a lot with the tires and for my setup I like 38 front and 36 rear. I might go 36 front and rear for a session this week and see if that cures some of the understeer. I am going to dial in some more negative camber as that helped also in previous track days.

Just work one thing at a time. If you are going to add more neg. camber, then run the same hot temps you liked the best. If camber fixed it, then you know this. If you still have understeer, then you can start adj tire pressures. If you have understeer now, I would not suggest lowering the front tire pressure, this will increase your slip angle in the front, and may increase your understeer. Unless you are taking temps and finding the front tires are not getting up to optimal temps. What is the max cold psi reading on the sidewall of the r888? Even though the website states their recommendations of 32-38 hot I would take the front to 40psi hot, if the sidewall cold psi max will correlate. From what people are saying these get greasy and don't like heat I would lessen the slip angle as much as possible by adding psi. This should run the tires cooler and allow you to get more laps prior to them dropping off. The only proper way to do this though is by getting off track hot, taking tire temps across each tire and pressures. Here a couple charts I found that sums up a lot in a small amount of words. These helped me tremendously with setting pressure.

Center hotter than edges Tire pressure too high. Reduce 1 psi for each 5° F delta
Edges hotter than center Tire pressure too low. Add 1 psi for each 5° F delta
Inner edge hotter than outer Too much negative camber
Outer edge hotter than inner Not enough negative camber or too much toe-in
Tire below ideal temperature range Tire pressure too high, tire too wide, or springs/sway bars too soft at that axle
Tire above ideal temperature range Tire pressure too low, tire too narrow, or springs/sway bars too stiff at that axle
Front tires hotter than rear Under steering (pushing). Too much front spring/sway bar, not enough rear spring/sway bar, front pressure too low, rear pressure too high, front tires too narrow, rear tires too wide
Rear tires hotter than front Over steering (loose). Too much rear spring/sway bar, not enough front spring/sway bar, rear pressure too low, front pressure too high, rear tires too narrow, front tires too wide

Guide To High Performance Handling
Adjustments Decrease Understeer Decrease Oversteer
Front Tire Pressure Higher Lower
Rear Tire Pressure Lower Higher
Front Tire Section Larger Smaller
Rear Tire Section Smaller Larger
Front Wheel Camber More Negative More Positive
Rear Wheel Camber More Positive More Negative
Front Wheel Toe Toward Toe-Out Toward Toe-In
Rear Wheel Toe Toward Toe-In Toward Toe-Out
Front Wheel Caster More Positive More Negative
Front Springs Soften Stiffen
Rear Springs Stiffen Soften
Front Anti-sway Bar Soften (Thinner) Stiffen (Thicken)
Rear Anti-sway Bar Stiffen (Thicker) Soften (Thinner)
Weight Distribution More Rearward More Forward
 
3,806
3,745
isrboss said:
blacksheep, please put together a tire help thread and offer your technical help. Tire pressures are very important to get right when on track. This would be a great help to the BMO community.

Let me get back from the glen and I'll put something together
 

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