I love mine!

 

Good info. It did make me wonder something. Could that psi setting need to be different for a tire from another mfg or different style? For example, those folks that do switch to non-runflats. Once you go non-runflat you are outside the OEM setup, and I'm wondering about the differences in sidewall strength/support (I'm sure there is a term) between those two styles. Could non-runflats need additional pressures to provide additional cornering support? Maybe that isn't a factor at all. Just wondering.

 

Another vote for the Michelins! I just switched from BFGoodrich KDW's and was shocked at the difference. I feared the ride would be harsh going back to a run-flat but I was wrong. The ride quality and sound level is much improved even over the non run-flats I had.

 

It's a valid and good question, and a little "tricky":

The Tire and Rim Association Yearbook is the standard to which all tires must meet in order to see public pavement in the U.S. (although we do accept the European Tire and Rim, and JAPNA (Japan's)... which parallel our standards. These standards dictate the load range of a particular tire size, amongst all the other dimensional characteristics to which the tire manufacture has to meet, with a very small tolerance for tread width, sidewall height (rolling diameter..which is why you dont mix brand designations on the same axle... )

"The purposes of the Tire and Rim Association Inc include the establishment and promulgation of interchangeability standards for tires, rims, and allied parts for the guidance of manufactures of such products, designers and manufacturers of motor vehicles, aircraft and other wheeled vehicles and equipment, and governmental and other regulatory bodies."

When an O.E. vehicle manufacture goes out searching for the O.E. fitment tire, they do so by offering all the tire manufactures a shot at it, including price or course,...they usually narrow the playing field down to 3 or 4 and do final testing to see which do the best job for that particular vehicle. Sometimes they just award the contract to the single best performer, sometimes.... there may be 3 that all do the same job..then low bid comes into play. So tire construction plays a major roll, yes......... but not where the load range comes into play... no matter what the construction, the load range must meet the parameters of the Tire and Rim Assoc. Inc. And yes, the load on the tire dictates the size of the contact patch, and how the tread blocks and tread design react to directional changes and how the cord body reacts in flexing in order to provide the necessary action to maximize the performance of the tires components for handling, ride, water shedding, and tread wear.

Most manufactures of speed rated tires in a particular size designation will design the tire knowing what vehicles its marketed at..therefore, they are going to try at minimum, provide a tire that matches the performance of the O.E. fitment tire... then there are those who provide a better tire..and some use the info "why" in advertising, going after a certain vehicle "maximize the performance of your Corvette, add the _______________________ tire and take on new highlights"... etc..... ...... but the cold inflation pressure is still that what is dictated on the door jam... if its not, the tire manufacture will make a separate recommendation, which is rare, because of the load range issue... it could open the door to litigation if there was an tire failure resulting in an accident with injury or death. By maintaining the O.E. pressure recommendation for that size dictated on the door jam, and meeting Tire and Rim Assoc. standards Inc.... they are safe unless there is a tire design manufacturing flaw.

So... clear as mud? Could there be a better pressure for a particular non O.E. tire fitment? maybe... but testing would be the only way to find out, and that would include thermodynamics if the pressure were to be lower to insure there is no dangerous heat build up....

 

Outstanding. Thanks for the info.

 

You must drive really fast cause you certainly live dangerously

 

I got a set of theses.. I think their great !! They run quiet, corner well (street use).. Very smooth riding compared to the GY OEM supercar RF's..
Would buy again !!

 

That's what I have road hazard insurance on the tires for.

 

I also went with the Michelin Pilot Sport All Season ZP's. Here's the Tire Rack page....

http://www.tirerack.com/tires/tires....andard%20Model

I bought mine from Costco.

 

It seems (to me) the intent of the wording is that if the tire is driven deflated for more than 50 miles and/or operated @ over 55 MPH then the tire is unrepairable. I know the GYs were repairable as long as the puncture/damage was over an inch away from the sidewall.

I guess this would be a good question to pose to Firestone itself.

 

Answer to my own question:

from: http://www.firestonecompleteautocare.com/tires/faq.jsp

WHAT IS THE REPAIRABLE AREA OF A NON-RFT (RUN FLAT) TIRE?

We only repair tires in accordance with the RMA (Rubber Manufacturers Association) recommended procedures. Some punctures cannot be seen with the naked eye and other measures are taken to find such punctures (soapy water and tire water tubs).
WHAT IS THE REPAIRABLE AREA OF AN RFT (RUN FLAT) TIRE?

No tire, regardless of its design or quality, is indestructible. RFT tires can be ultimately rendered unusable due to a puncture or other road hazard as well as from improper run-flat or low pressure operation. Some punctures may be repaired under certain circumstances, with restrictions and subject to prescribed procedures.

When driven flat or with low pressure, factors affecting reparability include vehicle speed, load, handling and maneuvering; the amount of inflation pressure lost; and ambient temperature. In any situation, the extent and location of direct damage from a puncturing object or other road hazard are also critical factors.

RFT tires are not repairable in any of the following situations:

* If the tire is described as, "Do Not Repair" on the sidewall.
* If the tire was operated with inflation pressure less than 15 psi (100 kPa).
* Abrasion or other damage is present on the exterior tread, sidewall or bead areas.
* Abrasion, wrinkling, or separation is present on the tire interior.
* Any condition or damage is present that disqualifies repair of a conventional tire.

Run-Flat Certified Retailers will fully inspect your tire, inside and out, to determine if the tire can be repaired. Tire damage is not always visible from the outside and the tire must be removed from the wheel for a complete inspection.

Note: Some vehicle manufacturers recommend not using repaired tires. Such recommendations apply to RFT tires. Use of RFT tires deemed non-repairable may result in damage to the vehicle, injury, or death. Consult your vehicle owner's manual or contact the vehicle manufacturer before operating a repaired tire on your vehicle.

 

 

LOL... Im awaiting a call back from a good bud at BSFS on this. But it kind of reminds me of speed rated tire repairs....... if you repair a speed rated tire, it loses its speed rating and is down classed to an S speed rating......

So if you repair a run flat, it no longer is a run flat.... hence forth, you cant repair a run flat cause it wont be a run flat.......hahahahahahaha

 

I have had the Firestone's Run Flats for a year now. Like them better than the Goodyear that the Vette came with. They handle well. OK on the track, but you can only push them so far.

Just acquired a slow leak in the right rear tire and have been losing about 6-7 psi every day. So after a few days of pumping the tire up in the morning, I finally got to Firestone today. They were able to fix it. Said I had a nail in the tire. If there was any damage to the sidewall, they said they would not have fixed the tire.

 

I heard about the speed rating issue before, actually in Germany. Back in the 90s they wouldn't repair tires at all but in 8 years I never had a nail or whatever go into the tire. Not the same in the US where crap is on the road everywhere you go.