Who is using PS (non runflats) on their car?

[Kai SRT10]

I'm frustrated by the (lack of) tire choices for my car.

I'd like to run the new PS2 tires, but they don't make them in any Viper sizes, unless I want to go to a 20 inch (335) rear and 19 inch front. I'm trying to reduce rotational mass, not increase it, so I really don't want to go with larger wheels. 20 inch rears would also increase the already tall gearing.

So . . .

I could buy new 18" wheels, but even then, my choices are limited to Pilot Sports or Pilot Sport Cups. I don't see any other street/track choices in a 345/18 size for the rear wheels. (I'm not interested in drag radials.)

I'm not excited about running Pilot Sport Cups for street use although they look good for track days at tracks that are close by. With regular use, I would probaly go through 3 or four sets of Sport Cups in a year, and I don't have a trailer, so if I'm driving to an event (which might be 1000 miles away) I've likely worn out my tires before I've even driven back home from the race.

So it appears that my only real choice is between Pilot Sports and Pilot Sport runflats.

For those who are using Pilot Sports, how much real difference can you see (on the street and at the track) between the regular and runflat versions?

If there is a substantial performance difference, I'd be willing to trade the peace of mind of a runflat for the extra performance. If they are so close that you can't really tell the difference, however, I'll just stay with the runflats. I like the ability to drive to get help, and I also figure that they would probably do better in a decompression at very high speeds.

Any help?

Kai

 

[Hans Christian]

Kai,

I think by going to 20/345/25 actually reduces your gearing - there was a message about that some weeks ago (if I remember correctly but couldn't find it)

 

[Kai SRT10]

Kai,

I think by going to 20/345/25 actually reduces your gearing - there was a message about that some weeks ago (if I remember correctly but couldn't find it)

I'm sorry, I wasn't clear. What I meant is that the gearing is already tall, and that bigger tires will increase the "tallness" of the gearing, making the 3.07 gears seem like 3.00 gears.

Kai

 

[glenn hofstetter]

I had run flats on my Vet. They are heavier than regular tires, stiffer and a lot less predictable. They stick, stick, stick, and sudden let go without warning! The guys on the Vet board call them "run craps" for good reason.

 

[Brian E]

Kai, I am running the Pirelli P Zero tires on my HRE wheels.
The original equipment 345-30-19 rear tire is 27.150 in diameter.
The Pirelli 345-25-20 rear tire is 26.791 in diamter.
I added a link to a tire calculator for you to check out.
http://www.rx7.org/Robinette/tire_diameter.htm

 

[SCLSSRT10]

Kai, I have been running the non run flats all year this past summer. I did five Viper days events, the tires are far better than the stock run flats. When driving the car on the track and really pushing it the run flats will be toast in one weekend. If you are planning on any V.D. events you can only run the Pilot sports, the cup tires would move you up to the unlimited class. On the street the non run flats make the car feel softer on bumpy streets. I highly recommend the non run flats, Besides they are about $5-600,00 cheaper per set than the run flats. FYI, Michelin is now making both front and rear in non run flat.

 

[Skip White]

Kai, if you are interested in reducing rotational weight, you may want to check out the SSR Comp wheels. They are very light and strong. They are not only light, but being one inch smaller, puts there moment of inertia number lower. There are so many tires available to meet your needs. Just for your information the oem tire diameter is 27.2 I think. Tire rack has a specs on all there tires. This is very handy when sizing up. There are some killer tires on the market, that will give you great perfomance. I wish they made the Goodyear Eagle F-1 in more sizes. This is a fabulous tire. I run then on the front, and as you know Nittos drags on the rear.

The weight reduction of non run-flats is approx. 5 pounds less. That is a huge amount IMO.

Skip White