I am getting the 555R Xtreme II's in the front, and since my last set of tires wore the outside edges rather than the center, I want to know what pressure I should run these ones at in order to get even wear.

What pressure for the street?

Also, what pressure should I run the DR's at while at the strip???

All help is greatly appreciated. Thanks,

Brian

 

I don't have my notes with me, but I believe I was at 27 front and 24 rear, cold, for track use.

Not sure what the hot temps were ... somewhere around 30-32, I believe.

I was using a pyrometer to measure tire temps and those pressure got me to within 5 degrees across the face of the tire.

 

Okay. What should I run on the street?

 

24psi cold.

Any more an you'll get excessive center-wear, especially with higway driving (where the tires warm up a fair bit). Took me about 10,000 miles to learn that one the hard way. Finishing up my 3rd set now... and I can tell ya that the occasional burnout will also wear the center much faster than the sides... way more than Z-ratged rubber would of.

At the drag strip I find 23-25psi is ideal aswell, although some guys go lower and don't mind the increased side-to-side motion. As with any radial I wouldn't go lower than 20psi, so if you get close (and are bleeding them between runs/passes/laps, make sure you top them off before they cool or else you'll be running 15psi or worse the next morning. This tires are more sensitive to heat than normal street tires, so keep that in mind when you're picking a tire pressure.

Nitrogen gas would be a great asset for this tires, although I'm not sure how accessible it would be (water vapor in air amplifies expansion under heat, Nitrogen is much drier).

 

24 on the street? For the DR's, and the Xtreme II's? Just wondering. Thanks for the helps,

Brian

 

yeah sorry about that... ~24#s (cold) for the street on Drag Radials (555R) will give even wear. I havn't heard any high-wilage wear reports on the 555R-II's just yet, although considering the compound similarities I imagine the highway-speed warming/stickyness/wear would be about the same.

Try 24# and check the tread bars accross the tire every month or so to nail it down.

Also, if I did more stop/go driving I'd probably run 25 or 26 since they probably wouldn't heat up as much as when I commute 35 miles.

On a autocross or "spirited" driving I'd try ~40 or 42 psi (cold). The max rating is ~44psi I believe (and those typically have a safety margin), so I wouldn't want to heat them up past that. On the street it feels great, but wear is obviously going to be off.

I'd bet more than a few DR guys said the same thing... prompting the 555R-II idea in the first place Stiff sidewalls feel good with the 555R compound/design.

 

I ran my last set of 555RII's at 30-31 front and 25-27 rear, with some negative camber, and they wore very evenly. That was mostly street driving, but I ran the same pressure for autox.

 

OHH! OOHH! What were your alignment specs? I need to know I can never get my fronts to wear evenly. Thanks,

Brian