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?

REVHED

Yes, that's insane.

cdrad51

any specific disadvantages with that pressure?

inittab

How's the side-wall flex on those 215/50/13? Well..... I guess at 50psi there shouldn't be much. LOL

I've been thinking about going to that size. How many miles have your tires lasted at 50 PSI?

Bayce

wow.
I have 26 PSI im my 185x70x13's (On the 7)

faye x7

When I bought my car there were some unheard of brand tires on them. 205/60/13s and my tire pressure is around 40.

anthrax

Dude dorp the the tire pressure down to 35 psi.

I used to work in a tire shop. Tires filled up to the max pressure cause premature ware on the tires.

If you keep them at max pressure at all times the centers of the tire will ware out and cause the tires to need to be replaced prematurely.

There is generally no worantey at this point either.

The door plate on the car recomends like 28 psi (I think), but if you set the pressure to 30-35 psi you will be fine.

IMHO any thire pressure under 30 psi is too low, and anything over 35 psi is too high for daily road use.

In general with passenger tires, tire size is not related to tire pressure.

Any way that is just my opinion

flames can go to /dev/null

Good luck

anthrax

MosesX605

215/50/13 is way too big for the stock rim. IMHO. My 205/60/13 Sumitomos were too big really, though it was a manageable size. For street driving, I set my tire pressures to 35 PSI, and for autocross, I typically set the fronts to ~45 and the rears to ~47. If I forgot to lower the pressure after the event, the ride quality was somewhat lowered.

anthrax

Man I am glad MosesX605 pointed out that you have thoes tires on the stock rim.

They are way too big for the stock rim.

They must look like doughnuts on there.

The tire is too wide for the stock rim. The stock 13" rim is a 5.5" thoes tires should be on like a 7" or 8" rim

Any way

82transam

iTrader: (18)

Will 215-50-13 even fit on the stock rims and not rub the springs? my 205-60 sumitomos just barely clear everything, and if you turn the wheel all the way they will chirp up against the body a little bit.

brianw

Way too high. How did oyu get all that rubber on a stock rim?Can't work right, too much rubber for the rim. The sidewalls gotta be hanging all over the palce.
((The door plate on the car recomends like 28 psi (I think), but if you set the pressure to 30-35 psi you will be fine.) I think the door plate only applies to stock size tires.

anthrax

The purpose of the 28 psi on the door plate is to give a tire pressure that gives the "most confortable" ride quality.

It has nothing to do with tire size

cdrad51

that's right, not much side-wall flex at that pressure. 15,000 miles so far, and predict another 5,000 by the time I replace them. However as I mentioned, I like to drive fast around corners and burn some rubber at stop lights every now and then...

theweasel

Actually the 28 psi is the amount of pressure needed to carry the load of the vehicle. Tires do not hold your car up, air pressure does. The higher the tire pressure, the more weight a tire is capable of handling.

brianw

Actually the 28 psi is the amount of pressure needed to carry the load of the vehicle.
The door tag only applies to factory size tires as well, I don't think that they are suppose to apply to ANY tire a person could EVER put on that car. Also I hate to be this way but psi applies to tires not vehicles so the door tag really don't mean **** if you don't have factory size tires.
Feel free to correct me if anyone knows different.

cdrad51

Nope, the tires do not run into anything. I will take some pics and include it in the next posting.

SCCA racing V8 RX7

My Bridgestone GTU race tires say 4.0kg/cm2 Max air presser. All most 9 lbs. And that’s what they will get.

Rutnick

I disagree. I bought some P225 55 16s Dunlop SP5000s for my maxima. The maximum rated pressure was 50psi. Anything BELOW 45 psi cause the side tread to wear funky and the center tread to not wear at all. It looked like crap. Just because you "worked at a tire shop" doesn't mean you know about performance tires. EVERY single time I went to that place they lowered my pressure because "that is what the sticker on the door said". I was like...well the sticker also shows I am running P205 65 15 but as you can see I am not. Believe me when I say this that anything below 45psi on the 225 55 16s that I am running wears my side tread PREMATURE on my performance tires. When the Tire Rack shipped the wheels and tires, they were actually around 50psi. That car also handles like crap with anything below 40psi.

I would tell the person in question to run his tires at 40psi or higher.

Rutnick

sounds about right to me.

cdrad51

as promised...

http://f1.pg.photos.yahoo.com/ph/c_d...r=/RX7&.view=t

Ritch

Tire pressure is something you adjust by it's affects on tire wear and performance. Both require testing time and miles. To be really good at it you should consider a tire temp. tester. However, your suspension and alignment tuning will also affect your tire temp differentials. Closest I can describe here in a few sentences is that temp reading higher in the center of the tread area indicates an excessive pressure. Higher temps on both inside and outside edges of the tread tends to indicate low pressure. Again however excessive toe in and bad camber adjustments and cause similar readings.
If you don't care to go to the extremes of track time and a temp tester just go with the tire manufacturers suggestion. You are at least within warranty then.

theweasel

It would seem that everyone does have their own opinion here. The door placard does apply only to the original tire size. The pressure is designed to carry the load of the vehicle. 28 psi will carry x amount of weight with the given 18570r13 tire. If you change sizes there is a load and inflation table to consult to determine the needed pressure to carry the load. When you enter the performance element, throw it all out the window!

Cloud

215's on a 5.5" rim make baby jesus cry.


But...so does over 40 psi on any of the tires described in this thread (for the street), so....oh well.

inittab

The center's are more worn than the sides but for 15k miles those Sumo's don't look half bad. I just might try that size next time around.

Rx7carl

: rofl:

Yea Im gonna try them tires too. Cant beat the price.