Stock Run Flats + Track Day =

[RMBSRT]

Waste of time!!! The stock run flats get VERY SLIPPERY when they heat up. I had to cut my day short because the tires were just not holding up. Now I know why the 08 does not have run flats....these things are dangerous!!!

So I guess its new PS2's or Sport Cups? Any suggestions?

 

[Fast Too]

Nitto Invos

 

[Vipermann]

I'll call them run-craps too, but I think they are not as bad as many believe. I drove on-track with them twice in Vipers at Skip Barber schools and also on the track at VOI9. I think it's a matter of what you're used to before you drive them in a Viper on the track. At Barber, you spend a bunch of time in controlled skids and practicing corner slip angles, so by the time you get behind the Viper wheel, they don't seem that bad. But if you get a Viper on the track, after just some mild street driving, and maybe your other daily-driver is a well-composed BMW, you will enjoy the Viper experience of the 'sit 'n spin' game.

All that said, I'm looking forward to the new tires.

 

[black mamba1]

Call Jon B at Parts Rack for the new PS2's. It will make a WORLD of difference in both traction and handling.

 

[Flyntgr]

I could've bought a set of PS2's, but really only needed rear tires, so I got two new rear runcraps. Two weeks ago, these rear runcraps, about 6 months old, with NO track usage whatsoever, gave way, skidded as I maneuvered to avoid instant death, and caused me to "lose it" into a bridge rail, totalling the car. If I had it to do again, no way would I have runcraps on my car. PS2's would've stuck as well or better than my Pilots on my longgone GTS. YOu're RIGHTm RMBSRT: runcraps ARE DANGEROUS!!!!!!

 

[black mamba1]

I could've bought a set of PS2's, but really only needed rear tires, so I got two new rear runcraps. Two weeks ago, these rear runcraps, about 6 months old, with NO track usage whatsoever, gave way, skidded as I maneuvered to avoid instant death, and caused me to "lose it" into a bridge rail, totalling the car. If I had it to do again, no way would I have runcraps on my car. PS2's would've stuck as well or better than my Pilots on my longgone GTS. YOu're RIGHTm RMBSRT: runcraps ARE DANGEROUS!!!!!!

The run craps are very dangerous and I am shocked Chrysler put them on these Vipers. But again, they were probably the best thing going in 2001 and 2002 when the design was being finalized for Gen 3. The entire suspension is tuned and the run craps are part of that suspension. They follow the road and take a long time to warm up for any semblance of proper traction. GET RID OF ALL OF THEM and put on PS2's. The car will seem like a much tamer and more predictable vehicle, thereby giving your more confidence as a driver.

 

[SylvanSRT]

I have been told by someone who has worked on this project and by switching to PS2's with out other changes will not help, but hurt road course times. The '03-'06 suspension is tuned around the runflat pilot sports. I was told that on a given track(not sure which one it was) the times got slower with just putting the PS2's on and not makeing other changes(reach CC sway bar and possibly some others). I have had no problems with my runflats, on my third set actually. and if you take long road trips the comfort of having the runflats is good piece of mind. How many local tire stores just happen to have Viper size tires in stock??

 

[RMBSRT]

I cannot believe that going to a normal tire with a softer compound would not perform better at the track. It just does not make sense that the runflats would be the crucial elelment of the suspension.

Using runflats for a road trip is great, using runflats for performance driving is VERY DANGEROUS.

 

[SylvanSRT]

I have done 4-5 track day/driver ed. events a year for the past 4 1/2 years in this car with runflats. and to say they are dangerous is wrong. If properly inflated they are just as safe as anyothere tire. As i said above i was told by someone who does driving and development testing that '03-'06 handling will suffer by going to PS2's alone with no other changes. The factory suspension settings, shocks, alignment, sway bars are tuned to work with the runflats and their handling characteristics. Just repeating what i have been told, by someone who knows.

 

[SylvanSRT]

Actually some people here have just switched to the non runflat version of the Pilot sport and gone back to run flats due to negative effect on handling

 

[GR8_ASP]

Actually some people here have just switched to the non runflat version of the Pilot sport and gone back to run flats due to negative effect on handling

Who? First I have ever heard of that.

I have had the stock run-flats. Pilot Sports (non run-flat) and Sport Cups. The guy who said that (and I said the same to you in person) is all wet. I suppose putting on full slicks will slow it down even more as they are even more compliant than Pilot Sports.

Now to optimize a tire change may require commensurate adjustment of the alignment, shock/springs and maybe even sway bars. But to say they are incompatable is not right.

 

[SylvanSRT]

didn't say incompatable i just meant optimized for the characteristics of the run flats. There was a thread/post about someone who went with non-runflats and switched back quite a while ago, because they felt that the handling was affected negatively.

 

[DocAdam]

I don't understand how you can say using the run-flats for performance driving is dangerous, perhaps having you as the driver for performance driving is the danger?

You are blaming tires for your issues, do not blame the runflats and say you left the track early because they were too slippery. I have seen guys run DRs on a track day, it wasn't bright but they did just fine.

I have run 4-5 track days a year for the past 3 years on run flats and they are the exact opposit of what you describe, they come alive as they really heat up. There is nothing wrong with the run flats once they are at temp, the scary time is when they are cold.

I have only left early one time and that was due to blowing a shock (completely drained of oil, I was bottoming out after any kind of bump).

 

[RMBSRT]

I don't understand how you can say using the run-flats for performance driving is dangerous, perhaps having you as the driver for performance driving is the danger?quote]

OK do you want me to post my resume so you can be the judge? I guess your 3 or 4 track days in the past couple of years makes you a pro?

I have been driving some type of race car since before i got my drivers license....

I have a owned many sports car and dedicatated race cars so I do have a "little" experience when it comes to performance driving.

The day in question was in Texas and it was 95 degrees out. I was doing a combo track event, tight road course onto a super speedway.

In regards to the runcraps, they are good when the get heated up (at first)...then they fade fast. I would not recommend anyone spend a day at the track on these tires. They will bite you when you least expect it. There is very little warning, they just fade. Maybe that is why so many Vipers spin off the track?

Just my opinion...you can take the warning if you want.

 

[DocAdam]

I congratulate you for driving race cars since far before you got your drivers license and I am also thankful that I was nowhere near you.

I had a horrible childhood with parents who would not let me drive prior to being legally allowed, so I do hereby bow to your superior racing knowledge and will never do another track event until the Viper comes stock with both non-run flat tires and the added measure of traction and stability control.

Thank you for setting me straight with your many years of race car driving experience.

 

[RMBSRT]

You bet Doc...anytime!

BTW ... i started with go carts. (now called shifter carts) You might try it, you could learn a thing or two on how to drive.

 

[black mamba1]

I simply find the Viper difficult to control and unpredictable w/ run flats. The car follows every nook and cranny in the road w/ the run flats, and that makes for very dangerous driving on narrow and crowded roads as the car can **** w/ a road groove suddenly to one side w/ little warning. It takes intense concentration to keep the Gen 3 Vipers straight on some roads, and I have read about this problem in many car mags as well.
And I have personally found hard cornering and acceleration to be tenuous w/ the run flats. Now that I have switched to the PS-2's I can do more aggressive driving w/ much more confidence, the car sticks really well.
I have no proof, but personally I think the run flats are probably responsible for many Viper crashes that would have or could have been avoided w/ a more predictable tire.

 

[Kenny]

I don't understand how you can say using the run-flats for performance driving is dangerous, perhaps having you as the driver for performance driving is the danger?quote]

OK do you want me to post my resume so you can be the judge? I guess your 3 or 4 track days in the past couple of years makes you a pro?

I have been driving some type of race car since before i got my drivers license....

I have a owned many sports car and dedicatated race cars so I do have a "little" experience when it comes to performance driving.

The day in question was in Texas and it was 95 degrees out. I was doing a combo track event, tight road course onto a super speedway.

In regards to the runcraps, they are good when the get heated up (at first)...then they fade fast. I would not recommend anyone spend a day at the track on these tires. They will bite you when you least expect it. There is very little warning, they just fade. Maybe that is why so many Vipers spin off the track?

Just my opinion...you can take the warning if you want.

Well, if you think runcraps give no warning before they let go, then don't run Hoosier VRLs or most other slicks. I agree that the stock tires **** bigtime and have no business being on the car, but even when they get hot and greasy, they usually let you know before they go. My guess is part of what you were experiencing was the stock diff, which is scary as hell and also has no business being in the car.

In any event, if you do go to full track tires on 18" rims, the best tires I have run are the Toyo RA1s. They wear like iron compared to Hoosiers and really give a lot of feedback. Just a great tire.

But you may want to settle down a bit, you're not the only guy to turn more than a few laps here and opinions may differ.

 

[RMBSRT]

I have no proof, but personally I think the run flats are probably responsible for many Viper crashes that would have or could have been avoided w/ a more predictable tire.

Very well said ....

With the lack of any electronic nannies on the car..traction control, yaw control, etc... the tires are crucial for the Viper. Normal, everyday driving, they are fine...anything more than that...you are gambling with trouble.

Again...just my opinion.

 

[Yellow32]

I cannot believe that going to a normal tire with a softer compound would not perform better at the track. It just does not make sense that the runflats would be the crucial elelment of the suspension.

Using runflats for a road trip is great, using runflats for performance driving is VERY DANGEROUS.

Actually, not dangerous at all, not in the least, if you know that you must air them up. The "recommended" stock pressure of 29lbs is a *joke*, the minimum COLD temp for track days is 34lbs, I used them many times on my '05, no problem at all.

One time I did try dropping them a little and BAM, greasy, useless.

Here's the thread on that one:

http://forums.viperclub.org/showthread.php?t=576386

-J

 

[Yellow32]

I simply find the Viper difficult to control and unpredictable w/ run flats. The car follows every nook and cranny in the road w/ the run flats, and that makes for very dangerous driving on narrow and crowded roads as the car can **** w/ a road groove suddenly to one side w/ little warning. It takes intense concentration to keep the Gen 3 Vipers straight on some roads, and I have read about this problem in many car mags as well.
And I have personally found hard cornering and acceleration to be tenuous w/ the run flats. Now that I have switched to the PS-2's I can do more aggressive driving w/ much more confidence, the car sticks really well.
I have no proof, but personally I think the run flats are probably responsible for many Viper crashes that would have or could have been avoided w/ a more predictable tire.

Yep, the stock "recommended" pressure of 29lbs is SQUARELY to blame for the 'unpredictability'. I first experienced it running 27lbs pressure on a twisty road and the car slid sideways here and there. When I got back I check the pressure, annoyed it was at 27lbs and that 29lbs was recommended (this was just after I bought the '05 and before I ever took it to the track). Anyway, aired them up to where they should be (34lbs cold pressure) and never had another unpredictable moment again.

-J

 

[black mamba1]

Yep, the stock "recommended" pressure of 29lbs is SQUARELY to blame for the 'unpredictability'. I first experienced it running 27lbs pressure on a twisty road and the car slid sideways here and there. When I got back I check the pressure, annoyed it was at 27lbs and that 29lbs was recommended (this was just after I bought the '05 and before I ever took it to the track). Anyway, aired them up to where they should be (34lbs cold pressure) and never had another unpredictable moment again.

-J

So...instead of simply changing the recommended tire pressure on run flats, Chrysler decided to spend millions more and go w/ a completely new tire and re-tune the suspension to the new tires because......?????

Because the run flats sucked maybe?? Because many in VCA were screaming for a better tire?? Maybe, just maybe.

 

[Yellow32]

So...instead of simply changing the recommended tire pressure on run flats, Chrysler decided to spend millions more and go w/ a completely new tire and re-tune the suspension to the new tires because......?????

Because the run flats sucked maybe?? Because many in VCA were screaming for a better tire?? Maybe, just maybe.

There's no doubt a run-flat tire is subject to suboptimal handling characteristics. After all, you are literally 'riding on rails'.

I was speaking to how run-flats can be 'made predictable', I was not speaking of anything else.

-J

 

[RMBSRT]

Yep, the stock "recommended" pressure of 29lbs is SQUARELY to blame for the 'unpredictability'. I first experienced it running 27lbs pressure on a twisty road and the car slid sideways here and there. When I got back I check the pressure, annoyed it was at 27lbs and that 29lbs was recommended (this was just after I bought the '05 and before I ever took it to the track). Anyway, aired them up to where they should be (34lbs cold pressure) and never had another unpredictable moment again.

-J

What was your HOT pressure? Did you adjust after each session?

 

[Yellow32]

What was your HOT pressure? Did you adjust after each session?

HOT pressure after 30min running @ 80-85F ambient was 40-41lbs with cold pressure @ 34lbs, no I did NOT adjust pressures at all, next morning cold pressure was back at 34lbs.

-J