CDRAD51

I have Sumitomo HTR 200 215/50/13 tires on my '85 GSL. I got them from Tire Rack, and when I bought them I got recommended to keep them at max presure, I forget the rationale about it, but it had to do with the tire dimensions. Anyways so that's how I've kept them, 50 psi front and rear. Looking in the forum I haven't found any data to back that up. Is that pressure insane? Also, the tires will need replacement soon and so I have a choice of changing the dimensions on the tires. I'm going with Yokohama this time. I use my car as a daily driver, but I like to drive fast whenever I can, and I feel with the current setup of tire sizes and pressure I get an inmense amount of traction in turns, even with these not-the-greatest tires. Any recommendations?

drifter

Do you get guard rub with 215's? I do with Yokohama 205's but I don't have a stock tiller. 50psi does sound high, but I'm not sure about 215/50/13's, so I can't give an accurate comment. Your gonna get less grip with too much pressure, but you may not be noticing it due to the width of the tyres.

CDRAD51

No guard rub. Tires clear everything in their vicinity. Got it on the pressure, maybe i'll try several different lower ones and see what's the best one.

i'm still trying to remember the exact rationale I was given by the tire rack guy I talked to when I ordered these tires...

Viperx7

I do believe that's high. When I used to have 205/60/13's, I ran them at about 26-29 lbs with no problem. Tire wear was very good. I wore out several sets of tires running anything higher, before finally finding the right pressure. I use 205/50/15's now and only run 32 lbs.

CDRAD51

and what about measuring performance? what was the best pressure?

10,000

Hey CDRAD51, I have made the mistake of buying these same tires and i have never been more disappointed. Yes, I know they are too big for the stock rim. But if the sidewalls were not made of Jello pudding, they would possibly be road worthy. I have experimented with many pressure settings to no avail. fortunately i have only mounted 2 of the 4 that i bought and I will be returning the 2 new ones to tirerack.com. now i have a pair of these tires mounted on stock rims that are sitting in the corner of my shop because I hate them. worst tread squirm and sidewall flex ever. I think these would suck even on a 13x7 rim!

CDRAD51

I agree that the sidewall is not the hardest one in history, however I don't know how long you used them, because it was only until the end of the break in period that I was able to experience its full capacity. I can take corners at 40 mph without the slightest screeching sound from them, I can change lanes in a highway really hard and the tires simply respond. But true, when I had just mounted them last year it was a bit scary on the wobly feeling, especially since I had just had BFG tires that are incredibly rigid.



For reference, here's some photos that show clearance of the tires.



http://f1.pg.photos.yahoo.com/ph/c_duran@s...ir=/RX7&.view=t