I run a 225/50/15 on my turbo eg. Street setup is 427whp, and 557whp on q16. I just ordered a set of r888s. been running the Mt et streets. love them, tho they don't last very long, wanted to give the toyo a try. any psi recommendations for street use and for drag strip use?

 

I run them on the road and for highway use at 30psi. The side walls are very stiff ( I believe they are made for road racing and auto X ) , So at the track they wont flex like a slick will, They do hook up pretty well on the road and are not bad in the rain if you get caught it in. I also ran MT ET and had the same issue they dont last long. I have ran my r888's for about 3 years and not much wear on them for normal driving and highway pulls.

 

I don't expect no where near that kinda life. lol. 6 months to a yr tops I'd be happy. I just talked to a guy that had a 700whp hatch runnin these, he said 18psi

 

I guess it depends how you are with them. I have 600hp and they hook up on summer nights over 50mph with 30-32psi for me. 225/45/16

 

when we roll race on them we go as low as 15

 

I dig race and roll race on the street, usually from 40 or below, so less psi makes more sense, want as much traction as possible. but ultimately I guess I'll have to just experiment with different pressures

 

I usually run mine in the 25-30psi range because I like to corner too. I've had 3 sets, 225/45/16, 235/50/15, and now 225/50/15. The 225/45/16 was probably my favorite size appearance wise, the 225/50/15 on my 15x8's seems to be a nice compromise between the 235 50 15 and 225 45 15, and the 235s hooked (marginally) the best but I had to jack up the car and it still rubbed at full lock.

 

I run the 225/50/16 and have ran them as low as 15 but tend to run the car at 18-20 when i drag race it and the street run at 30 give or take.

The difference between say 30-20 psi on lowering the car is at least .5" inches. The car gets quite a bit lower, and a hell of a lot harder to turn at low speeds lol

 

anyone ever try the 275/50-15 nitto nt555r 101v tires ?

 

Yep, that info is in the Nitto 555 thread, tho....

 

I have the R888's (P225/45R15) on my supercharged hatch... third gear, 45mph and up is just fine with pressures around 32psi. First and second require a lot of pedaling to keep from knocking the tires off. Never hit it from a dig though. I really like them.

 

Dropping the pressure in a Toyo R888 will not increase traction.

Your best bet is to get a Pyro meter and figure out your alignment and pressure setting by looking at where the hotter spots on the tire are.

Ive never run the 225/50/15, but 32psi is really the lowest you should go on the 225/45/15.

 

agreed 100%!!!!
a stiff sidewall tire, especially track/autocross tires like the r888 that are even stiffer than standard performance tires, should be run at or around the STOCK tire pressure recommendation. the entire purpose of altering tire pressure is to achieve the same pressure from the tread to the ground across the full width of the tire. too little tire pressure, and the center of the tire has less pressure on the ground than the sides of the tire. too much pressure, and the sides of the tire have less pressure to the ground than the center of the tire.

the only reason you'd ever want to drop the pressure to some stupid low number is if your car weighs 1,000lbs less than stock, and/or if you're measuring the pressure with the tires cold and your actual race run wil get the tire temps super sky high. for example, I run my hoosier A6's at 26-28psi hot, which drops down to around 13 when they cool off to ambient temp.