*** is up with runflats?

[CAS]

Ok, we all know the SRT is (mechanically speaking) a bad-*** ride. The styling is a bit, ah, controversial <FONT size="1">read: ugly</FONT s> *ducks from impending smack from Mike*

. But, undoubtably, the car is gonna be fast. Knowing this, why in the HELL would DC put 19" runflats on their new flagship automobile? I know there's no spare, but aren't these the type of tires that the 'Vette guys call "runcraps"? The tires on the Vette are from Goodyear, but the Michelins probably have the same tread charechteristics. Won't these tires hamper performance and lateral g #'s?

Has anyone else thought of this?

Clint

 

[Craig 201 MPH]

Clint,

supposedly these are a new generation run-flats where traction isn't compromised by the run-flat design. I guess we'll just have to wait and see how they perform when the mags can finally test the car and give us numbers. I don't think DC would give the car mediocre boots as you're car can only be as good as your tires are.

 

[Steve Ferguson]

Clint if you have any specific questions, please list them and I will get the tire guy (Brian)from Michelin to see what he can tell us?

 

[Mike Brunton]

Clint,

The Vette guys call them "runcraps", but what empirical data is there that these tires are not good? The C5 *vastly* outhandles the C4 in any quantitative test I have seen. The complaints usually center around the rough ride characteristics which are a result of the super-stiff sidewalls.

I heard (so it may or may not be true) that Michelin was late to the runflat game because they were not willing to compromise the ride quality of their tires in order to make a runflat version. I have also heard from some folks at Michelin that these are not your daddy's runflat tires.

So, to answer your question... the reason they went with runflats is that they are more convenient, and they save weight over standard tires. In addition, the negative aspects of runflat tires have supposedly been reduced or eliminated in these tires.

So I guess the question would be - why NOT go with runflats?

 

[SRTRICK]

Steve, I have got a specific question - What is the actual weight of the new run flat tires as compared to an equivalent size of the standard issue Pilot sport. I would like to know the actual front and rear weights, not a general comment about "little difference" or such. I can come up with the standard pilot weights myself, if necessary.

edit: While we're at it, would anyone tell us the weight of the new standard wheels? That way we can figure how much total unsprung weight could be saved with a set of light wheels and tires.

 

[Venom Lover]

Clint,
A very good question that I have also been wondering about!

Mike B,
What "empirical data" have I heard from the Vette guys about runcraps? Namely that they hook up for sh** at the drag strip. I don't see a lot of &lt;2 sec 60' times for standard (non-Z06) C5's out here, and most seem to be around 2.2 sec. (Is that empirical enough for you?) I'm surprised in your extensive experience drag racing you wouldn't have heard C5 guys complaining about hooking up on the runcraps. If the sidewall is really stiff, as you claim, then you have your explanation why.

Steve,
Specific additional questions I would have for Michelin on the runflats for the Viper are: (1) what is the tread wear rating, (2) what is the void ratio, and (3) what is the stiffness of the sidewall compared with Pilot Sports and MXX3s?

 

[Steve Ferguson]

I just called Brian and asked that he come to the site and take a look at all the questions? Great job on them by the way!

 

[Mike Brunton]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Venom Lover:

Mike B,
What "empirical data" have I heard from the Vette guys about runcraps? Namely that they hook up for sh** at the drag strip. I don't see a lot of &lt;2 sec 60' times for standard (non-Z06) C5's out here, and most seem to be around 2.2 sec. (Is that empirical enough for you?) I'm surprised in your extensive experience drag racing you wouldn't have heard C5 guys complaining about hooking up on the runcraps. If the sidewall is really stiff, as you claim, then you have your explanation why.<HR></BLOCKQUOTE>

Well, that's not hard data - just an observation from a source that may or may not know what they're talking about. In the interests of hard data, there are several guys at my track who run the stock runflats who are in the 12's in their bone stock C5 Corvettes (not Z06's). In addition, people say MXX3's **** when they start to wear... but mine were down past the wear bars and I was still able to run sub 1.7 60's times on them. I've heard of guys complaining of hooking up the runflats, but I've also seen guys running 12's on them - so I tend to chalk it up to yet another excuse why they weren't running faster then they were. And the C5 does pretty nicely in lateral acceleration and slalom tests, so it would seem the runcraps aren't as crappy as people seem to think.

 

[SRTRICK]

Mike - FWIW, the Z06 doesn't have standard tires for no reason, the run flats the standard car uses are simply not as sticky as other available tires. However, It is my understanding that the Michelin run flats are considerably better, perhaps even better than standard Pilot Sports. I am currently running my S2000 on Michelin Pilot Sport Cup tires, and while they are not run flats, they are a newly introduced example of what Michelin is capable of, and I am very impressed with them. As a matter of fact, I am hoping that Michelin will make these available in the 19" rear size for our new cars. The 285 x 18" they already have available should fit the front just fine!

 

[SRTRICK]

Clint - I believe that the weight savings attributed to the run flat tires are related to the abscence of a spare tire, not the actual weight of the tires themselves.

 

[Steve Ferguson]

Here are the only facts I can give you at this time:

The weight is coming in at about 10% higher than the standard tire.

The tread wear has been the same as a standard tire.

The plan is to have Sport Cup tires for the Viper racing league and Challenge series participants, and once they are satisfied, the remainder would become available to club members.

As for how the car will preform? The testing has gone much better than anticipated (what, did you think Michelin would let us down?), and unlike the Goodyear brand, The feeling is that most of the owners will be more than satisfied with the overall performance of this tire. The big question mark seems to be the drag races, since most development test revolves around turns and not straight line runs?

Hope this helps. BTW, Our information source is going out of town for about a week, so don't expect any more answers. He did welcome more questions, but asked that you be patient for the response.

 

[Mike Brunton]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by SRTRICK:
Mike - FWIW, the Z06 doesn't have standard tires for no reason, the run flats the standard car uses are simply not as sticky as other available tires. However, It is my understanding that the Michelin run flats are considerably better, perhaps even better than standard Pilot Sports. I am currently running my S2000 on Michelin Pilot Sport Cup tires, and while they are not run flats, they are a newly introduced example of what Michelin is capable of, and I am very impressed with them. As a matter of fact, I am hoping that Michelin will make these available in the 19" rear size for our new cars. The 285 x 18" they already have available should fit the front just fine!
<HR></BLOCKQUOTE>

Rick,

On the Z06, GM claimed they were abandoning the runflats because of weight savings. How true is that? I dunno. I certainly believe the runflats are inferior to, say, Pilot Sports.

However, just as you mentioned the new Michelin Run flats are much better - I had heard the same thing. A friend of a friend is employed by Michelin in their racing program and I've heard the new Michelin run flats are vastly superior to the F1's.

I guess my point in rebutting the "runflats on the SRT? that *****" train of thought is that I've heard these runflats are going to impress alot of folks.

I will be real interested to hear Steve's data.. I am not in the least worried about runflats on the SRT!


P.S. Steve, being the selfless type of person that I am, I will gladly test the SRT in a straight line, if DC or Michelin will pay my plane fare to Michigan, and put me up in a 5-star hotel. Hell, I'll even go 4-stars for them, just because I'm that kind of guy.

 

[Steve Ferguson]

Mike, only people wearing the Michelin Man costume get that kind of treatment!!! That being said, and since my body resembles him (thus eliminating the need for that costume), I guess I am the new tester?LOL

 

[CAS]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
Supposedly these are a new generation run-flats where traction isn't compromised by the run-flat design.
<HR></BLOCKQUOTE>
Craig, that's what I'd hoped.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
I don't think DC would give the car mediocre boots as you're car can only be as good as your tires are.
<HR></BLOCKQUOTE>
I agree 100%.
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
Namely that they hook up for sh** at the drag strip.
<HR></BLOCKQUOTE>
Mike B., this is what I was talking about.
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
So, to answer your question... the reason they went with runflats is that they are more convenient, and they save weight over standard tires. In addition, the negative aspects of runflat tires have supposedly been reduced or eliminated in these tires.
<HR></BLOCKQUOTE>
Great, I agree with DC's descision completely if this is the case. As you stated, there would be no reason NOT to equip the SRT with Michelin runflats. One thing I am suprised about; that they save weight over standard tires.. Oh well, 500/500 should be able to smoke 'em nonetheless

!

Regards,
Clint

P.S. The wheel weight questions are GREAT. Thanks for bringing them up! And also thanks to Steve for talking to the Michelin guy, hopefully he'll post.

EDIT: <BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
Mike - FWIW, the Z06 doesn't have standard tires for no reason, the run flats the standard car uses are simply not as sticky as other available tires.
<HR></BLOCKQUOTE>
I guess that's all the "empiricle data" that's needed.

 

[SRTRICK]

Steve - the news about the Pilot Sport Cup tires is great news, they are really linear in their response which should be a great thing in combination with the more predictable handling.

Any way to get the info on the wheel weight???

 

[Venom Lover]

Steve,
Thanks for getting the info. Did your connection at Michelin mean that the tread wear rating is similar to the Pilot Sports or to some other tire?

Mike,
Thanks for the daily reminder of your phenomenal drag racing abilities and your time slip with a 1.7 short time on bald MXX3s. Once again, I revere you as my god.

Now, sorry Mike, but you offered no hard data either. There are some guys in stock C5's who can get in the 12's at NED. So? That does not prove that Goodyear runflats are good tires. Also, that's a very limited data sample, and one chosen to help your point (as much as mine was chosen to help mine). Didn't your friend run a stock '01 Z06 to a 12.003 at that same track? So, it sounds like the Z06 tires hook up a lot better than the runflats, because I bet there's a big difference between the short times on the high-12 stock C5 runs vs. the 12.003 Z06 run. Obviously the 35 extra hp helps too, but I bet if you compare time slips, you'll see a 1.7 sec short time for that 12.003 run vs. 1.8 or 1.9 for your bud's in stock C5s....

In short, it doesn't really matter to me what god-like drag racers are able to do on runflats, because I am not a god-like drag racer. What matters to me is how the car hooks up and handles with an average Joe like me behind the wheel. Since the prevailing wisdom in the C5 world seems to be that their runflats ****, I think it's a valid concern to worry about them on the SRT.

I do hope that you all are correct that Dodge wouldn't have screwed the pooch in choosing terrible tires for their new baby, especially with all the hype about performance being the #1 priority on this car....

 

[Steve Ferguson]

I do not know who the wheel manufacturer is, and my main contacts at PVO are on vacation for a few weeks, so the answer would be no, on the weight thing.

Venom, the tire they compare to in wear are the Pilot Sports. FYI, they were very impressed with your questions!

To all, keep the questions coming, they really liked the fact that we care that much.

 

[VENM8R]

I do know from owning a 2001 C5 that the "runcraps" held up well and did what they were designed for. They did seem to have a more bumpy or "jarring" ride than normal tires. Until you get a large screw or nail in your tire in the middle of no mans land, you will not fully appreciate "runcraps".

 

[Steve Ferguson]

I guess the good news is that the plan calls for a tire that is a much better performer than the one Goodyear has on the C5! Based on what many of the C5 owners have said, the possibility for a great overall tire may be just what we get? Remember, the Viper is viewed as a great launching vehicle to announce new technology, so lets hope this new tire preforms up to the improvements we have been accustomed to Michelin providing us?