Run Flats Ran Flat

[Gersh]

The critical item for tire survival is not damaging the sidewall, which typically means heat. The sidewall flex of the EMTs is less than the standard tires (and much less than taller tires), so they don't heat up as easily. Rolling flex means heat, but standing flex doesn't add heat--shouldn't be a problem standing overnight. Also remember that rolling faster means more heat, so consider over-inflating just a bit for those 180 MPH excursions...
Gersh

 

[Ghost]

The critical item for tire survival is not damaging the sidewall, which typically means heat. The sidewall flex of the EMTs is less than the standard tires (and much less than taller tires), so they don't heat up as easily. Rolling flex means heat, but standing flex doesn't add heat--shouldn't be a problem standing overnight. Also remember that rolling faster means more heat, so consider over-inflating just a bit for those 180 MPH excursions...
Gersh

Well said. I have run flats on my current vehicle (not a Corvette, which is still on order!) Heat is the big killer of tires. Typically a tire under normal inflation will gain about 10% of its psi when hot. So, tires running at 30 psi cold would typically increase to about 33psi. That 10% could also increase relative to the ambient temp too. It could increase more here in SoFla or other hot climates.

The biggest complaint (and its not really a big one with me) I have about run-flats is the very firm ride compared to non-RF tires. My$.02...

 

[C-INRED]

Always put air in the tire and run it inflated to the extent it will hold pressure. This will avoid sidewall damage. Even though it is possible to run on 'flat' runflats...it is better not to.

Often the leak created by something in the tire will be very slow and you can hold air for quite sometime (hours anyway).

 

[BigMike5]

run flat update

Took a road hazard hit from a boulder some kids threw into the roadway late afternoon on the 4th of Nov. I was following a SUV at 35 mph and he suddenly swerved left to avoid it but once I saw the problem my swerve did not miss it and it hit the right front. About 20 seconds later the message came on that the right front was flat - 0 pressure. I was now about a mile or two from my local tire shop, so I went there and the sidewall where the "F1 " symbol is located was destroyed. The ride was no problem at 45-50 mph and a little noisy at the slower speeds. The car sat in the garage since then. My shop finally got a new GY F-1,GS emt, in today [$344 installed] and the sensor reset to the new pressure without the magnet being needed. The tech at the shop who has a C-5 Z06 recommended 39 psi, and that is what he put in all the tires, but I plan on dropping it back down nearer 35. I had been running 29-30 psi since I got it on the dealer's recommendation. The tech thought that was too soft. He runs 40 psi in his Z06. Any thoughts?

 

[thesurvivor]

Goodyear is the only run-flat maker whose tire can be repaired after a puncture incident (as long as the puncture is repairable). We ran over an object at 80mph and the tire survived that and a 30 mile run to an EMT-capable Goodyear dealer (we were outside Topeka). The other makes, while quieter and perhaps a bit better handling, cannot be fixed. A land line call to 1-800-runflat gets connected to the closest EMT-capable dealer. We, too, got the work done with no wheel damage. It took a 20 minute ride to get the sensor to read again, but were back up to Interstate speed directly thereafter.

 

[catbert]

Took a road hazard hit from a boulder some kids threw into the roadway late afternoon on the 4th of Nov. I was following a SUV at 35 mph and he suddenly swerved left to avoid it but once I saw the problem my swerve did not miss it and it hit the right front. About 20 seconds later the message came on that the right front was flat - 0 pressure. I was now about a mile or two from my local tire shop, so I went there and the sidewall where the "F1 " symbol is located was destroyed. The ride was no problem at 45-50 mph and a little noisy at the slower speeds. The car sat in the garage since then. My shop finally got a new GY F-1,GS emt, in today [$344 installed] and the sensor reset to the new pressure without the magnet being needed. The tech at the shop who has a C-5 Z06 recommended 39 psi, and that is what he put in all the tires, but I plan on dropping it back down nearer 35. I had been running 29-30 psi since I got it on the dealer's recommendation. The tech thought that was too soft. He runs 40 psi in his Z06. Any thoughts?

The recommended 39 psi is above both GM and Goodyears' recommendations, and I don't see any advantage to boot. You tech probably has non-runflat Supercars on his C5 Z06, so he may be a little confused. 30 psi cold is a good place to start, and unless that doesn't work out for some reason, I'd leave it there.

 

[thesurvivor]

We took a trip to Vettes on the Rockies last year---the flat occurred on tha way home from that. I read posts about increasing air pressure on trips, so I took them up to 33-34 psi cold. The trip brought the hot readings to 38-39. I did feel a change in the ride quality. I think the sensors show a high pressure warning above 40psi....so I was a bit uncomfortable. I did not really detect an advantage. So on our trip to Carlisle this year I only took them up to 32 cold. Ran 35 psi hot...the patched tire, right rear, was perfect.

 

[koolkatprez]

I had the unfortunate problem of being involved in an accident with my '98 coupe a few years ago. To avoid a guy that was travelling considerably faster than I on a freeway onramp, I stood on it only to get the back end loose. It was in a spinout when I got control but the front left wheel hit a curb and put me "backasswards" up an embankment at 85mph. The back of the car was in the air and when it landed it actually dislodged the rr tire from the rim. Got it on a flatbed wrecker and when we got to my house I drove it off the truck and up into my driveway. Only one side of the tire was attached to the wheel rim. I blew out the dirt with my compressor, aired it up, and it was fine!!

 

[BigMike5]

Catbert

I think you are right. I plan on checking the cold air temp tomorrow and then dropping them to 33-35 psi. The door jam sticker says 30 psi and I've tried to stay right at that figure, but it fell as low as 25 psi one cold day last year and set off the warning, so I guess 33-35 psi would be ok for winter months.

 

[abc]

The recommended 39 psi is above both GM and Goodyears' recommendations, and I don't see any advantage to boot. You tech probably has non-runflat Supercars on his C5 Z06, so he may be a little confused. 30 psi cold is a good place to start, and unless that doesn't work out for some reason, I'd leave it there.

When measuring tires when it is cold what figures do you go by? DIC indicator or tire guage?

So don't get the non run flats like BF Goodrich KDW's?

 

[BigMike5]

run flat inflation

Got the tire pressure gauge out last weekend and dropped the pressure on the run flats back from 39 psi to 33 psi per tire [cold temp]. Will see how that holds as it gets colder and adjust downward if necessary to get closer to the recommended 30 psi. Of course I have noted no noticeable difference in the feel or ride at 38-39, 33, or 30 for that matter. I can feel the difference in ride on the wife's Caddy but I attribute that mostly to the suspension rather than the tire inflation setting.

On which measure to use, I have a gauge, a good one that even allows bleeding the air while it is in use, and I have found it to be really accurate. I go by that mostly because the car has to run some distance [can't recall how far] before the DIC kicks in with the correct perceived psi, before that you get a reading of what was left on the car when used last.

 

[abc]

Got the tire pressure gauge out last weekend and dropped the pressure on the run flats back from 39 psi to 33 psi per tire [cold temp]. Will see how that holds as it gets colder and adjust downward if necessary to get closer to the recommended 30 psi. Of course I have noted no noticeable difference in the feel or ride at 38-39, 33, or 30 for that matter. I can feel the difference in ride on the wife's Caddy but I attribute that mostly to the suspension rather than the tire inflation setting.

On which measure to use, I have a gauge, a good one that even allows bleeding the air while it is in use, and I have found it to be really accurate. I go by that mostly because the car has to run some distance [can't recall how far] before the DIC kicks in with the correct perceived psi, before that you get a reading of what was left on the car when used last.

The factory calls for 30 PSI cold. Why did you increase PSI? For better handling and fuel economy? The ride will deteriote when increasing pressures.
How do you measure? Use DIC info or a good tire guage?

 

[MMFaber]

EMT experience

Interesting comments on the tire pressure. I too, had the same experience after picking up our 2002 Coupe. Not ever experiencing EMT's, I inserted 40psi in the tires cold....it didn't take 10 miles down the road before the monitor mentioned I had tire issues (over pressure). Since then, I keep them at 32psi and have no problems. Systems works fine for me!

 

[abc]

Interesting comments on the tire pressure. I too, had the same experience after picking up our 2002 Coupe. Not ever experiencing EMT's, I inserted 40psi in the tires cold....it didn't take 10 miles down the road before the monitor mentioned I had tire issues (over pressure). Since then, I keep them at 32psi and have no problems. Systems works fine for me!

On C-6 I believe when it gets to 44 PSI you will get the over inflated mesage on DIC. Isn't this the max (44 psi) for tires on our factory Goodyears?

 

[Gburg]

I did a search for tire recommendations from both the Tire Rack and Discount Tire web sites, and got two interesting responses.........

On the Tire Rack website, I selected the following tire brands: BFGoodrich, Bridgestone, Dunlop, Firestone, Goodyear, Hoosier, Michelin, Pirelli, Uniroyal, Yokohama.

Selected the top three grades of all season performance tires, with Z, W, and Y speed ratings. Selected: Include runflat tires. Tire Rack recommended: Goodyear Eagle F1 A/S-C EMT, which I believe came on my C6 from the factory. When I selected: Exclude runflats, I got the message that no tires meet my search criteria.

Discount Tire search results:http://www.discounttire.com/dtcs/sea...86&rd=19&ar=35

I got four different tire suggestions from Discount Tire, when I selected matching tire sets. Received even more tire suggestions when I selected front or rear tires only. Front: 24 tires suggested, including Goodyear F1 Eagle GS-D3 tires. Rear: just two tires were suggested. I would not buy the suggested Continental tires because of the poor tire wear characteristics on my 2005 Chryser 300C, and the experience of other 300C drivers. Chrysler no longer puts Continental tires on cars produced in 2006.

Gburg

 

[abc]

Never heard of continental tires.

 

[Norseman]

Tire Pressures

The factory calls for 30 PSI cold. Why did you increase PSI? For better handling and fuel economy? The ride will deteriote when increasing pressures.
How do you measure? Use DIC info or a good tire guage?

The factory manual states 30 PSI max. Use a tire gage to set them at 30, after driving a few blocks they should read 30 PSI. If you inflate them to more then recommended you run the risk of wearing out the center of the tire. I think that is what is causing a lot of the poor and uneven wear problems. 32-35 PSI probably should be the max pressure without causing uneven wear. The 30 PSI on the door was probably chosen for the most comfort and quietest ride and best gas mileage compromise.

I had the exact same problem with a screw in center of my LR, I noticed it coming out of a bar last week, just happened to look at my tire and there it was a shinny silver screw with a built in washer. I just left it there for 2 days as the pressure read 27 PSI like all the other tires. After 2 days it read 22 so I drove it to NTB and they had no trouble plugging it. It cost $50.00 and took about 45 min. Runs like new. I think run flats are a great idea but I will probably try Dunlop's next time and invest in a portable air compressor. I don't know why GM doesn't build one right into the car like they have done with Pontiac for several years. Just push a button and inflate your tires to a desired pressure. :eyerole Oh well, maybe on the C7.

 

[abc]

The factory manual states 30 PSI max. Use a tire gage to set them at 30, after driving a few blocks they should read 30 PSI. If you inflate them to more then recommended you run the risk of wearing out the center of the tire. I think that is what is causing a lot of the poor and uneven wear problems. 32-35 PSI probably should be the max pressure without causing uneven wear. The 30 PSI on the door was probably chosen for the most comfort and quietest ride and best gas mileage compromise.

I had the exact same problem with a screw in center of my LR, I noticed it coming out of a bar last week, just happened to look at my tire and there it was a shinny silver screw with a built in washer. I just left it there for 2 days as the pressure read 27 PSI like all the other tires. After 2 days it read 22 so I drove it to NTB and they had no trouble plugging it. It cost $50.00 and took about 45 min. Runs like new. I think run flats are a great idea but I will probably try Dunlop's next time and invest in a portable air compressor. I don't know why GM doesn't build one right into the car like they have done with Pontiac for several years. Just push a button and inflate your tires to a desired pressure. :eyerole Oh well, maybe on the C7.

I already know all of the above you mention but I go by my tire dial guage and when I do that the DIC reads two pounds above that reading when cold. In other words the DIC reads 32 when in fact it is 30 psi.

 

[Larry's Yellow Rdstr]

Run flats saved me a 13 mile walk a couple months ago. I don't care if the ride is a little harsh or noisy, run flats were designed to do a specific job and they do it well.

 

[abc]

Run flats saved me a 13 mile walk a couple months ago. I don't care if the ride is a little harsh or noisy, run flats were designed to do a specific job and they do it well.

:cool As long as you don't end up upside down.