Is it ok to run front tires without runflats but leave the rears alone with them?

 

I would say no. Bad idea.

Cheers!

 

Should be no problem... front will just be a little softer (runflats are harsh due to stiff sidewalls). You should really do this only as a temporary measure until you swap out both front and rear to normal non-runflat tyres.

I have runflats due to my tight-*** and not wanting to throw them away when they still have 80% tread.

 

I've got run flats in the front but regular's in the back and have no problem. Run Flats only mean there is a thick steel band in the side walls which make the sidewalls stiffer, so that in the event of a flat you can go approx. 50 miles to get somewhere to have it fixed. I can see the runflat's with the steel belt being a good thing in a road course event since it has a stiffer side wall, but a bad thing in drag racing.

 

Does it throw a error code when starting the car?

 

Seems to me if you did any aggressive driving you may find the balance of the car is out of wack. You could have either an over steer or under steer condition just wait to rear its ugly head in a corner taken too fast (or what ever your normal speed is).

If your doing this as a short term measure until you can buy 4 matching tires just take it easy.

Tom

 

I asked this same question a week ago...

http://forums.corvetteforum.com/showthread.php?t=855247

Most of the responses from people that have never done it were "DON'T"

The responses from almost all people that actually did it, were that they didn't notice any difference at all.

But after all that, Michelin replied back to me, "You have a high performance car, due to the differences between the two tires and their technology, we would NOT recommend using the two different tires."

I figured the difference in the wheel sizes I had been planning on getting weren't worth the chance of losing handling. I ordered the smaller front wheels so I could stay with the runflats all around.

 

But, that is just my opinion.

 

I am no expert but I have to believe that at close to the limits
they will have different characteristics and adversly impact
the handling of the car.

 

The car is seeing different characteristics all the time... the tires are all the same... but the front's steer, the back's push... you never see the front end fish tailing.. the g and lateral forces are different all the time.. No tire manufacTURER WOULD NEVER SAY IN PRINT THAT ITS OK TO mix TIRES.
the compound of the tire and the tread design have more to do with their performance.. whether a tire is run flat or not is not as crtical as the belt design and tire performance rating... and the application of the tire:drag racing , auto cross, spirited highway, etc...

 

A goodyear EMT can go 200 miles at a speed of 50 mph...without issue... not 50 miles as previously mentioned... a Goodyear EMT can be patched, still maintain it's run flat capability, but it will lose it's 160 mph rating...I would be interesed in knowing what % anyone on this forum has maintained a speed in excess of 160 mph, compaired to their whole C5 driving experience...
There are some inferior run flats (Firestone) that will infact let you drive 50 miles, but the manufacturer says you can not repair or drive on one that has been fixed... so you need to buy a new tire...I had two plugs in one of my rear Goodyear EMT's.. I drove it for 43,000 miles that way with never an issue... but I do have to say, I don't think I ever hit 160 mph after pluging the tire...

 

why not the tires are not going to fall off.

Rears will have stiffer sidewalls but all they do is go straight.

Go with 275's up front and 295's in the rear

 

The biggest rule to follow in runflats is not to have a non-runflat on the left side and a runflat on the right side. Front to back is okay but side to side does upset the performnace handeling. You'll lose coinfidence quickly in a left side right side scenario. I know the runflats can roll the side steel belt if cornering at high speeds. I would take a non-runflat tire any day over runflats. You will get better handeling all around, I have heard before that when runflats are at a high rotation speed a tire with a out of balance steel belt will cause a nice vibration. Runflats were devopled for a security blanket in a flat tire scenario. Non-runflat tires on a car that has the functionallity does not trigger codes, the way companies market the cars with runflats are deceiving, the runflat just means there is a stiff sidewall steel belt that will hold up the tire for 50-200 miles when there is low PSI or no PSI in the tire. The readouts you see in the cars cabin on air pressure at each tire comes off of a sensor in the valve stem that monitors PSI and sends the data to the PCM for the read out. A car that has the PSI readouts will still show you PSI information when the tire is not a runflat.

Running at 150 MPH + for a sustaned time with runflat tires is interesting, a recomendation if you attempt to run fast like this is not to turn, you think its easy to kick the *** end around when slamming the accelerator going into a corner, you'll see how much easier it is when your over 150, the problem is that its much harder to correct a slid at 150 than say 45-60mph.

Also a note boys your racing series such as IRL, NASCAR don't use run-flats, and they doing nothing but turn at high speeds. Nascar at some tracks will run a inner tube to help when a tire blows, That way they can make it back to the pits for a tire change with a higher probabilty of less suspension damage only if the inner tube holds though.

So if I'm going to buy a new set of tires for my C5 I would increase my sizes to a 275series in front and a 295 in the rear but making sure it's a low profile tire. (which just means a shorter side wall, this will give you a lower center of gravity which makes your C5 suspension really come alive). Good luck