Hi guys,

have moved from Virginia over to Germany/Munich in October.
My 2011 Grand Sport has received new GY Gen 2s before we moved.
Have run the car some 300 mls still in the US in warm to hot weather conditions.
The Gen 2s were a big improvement and I was extremely happy.
Now, after moving to Germany and under rather cold (but not extremly) conditions around 35 F, everything seems to be very different.

- I have to add, that after the container transport to Germany, the (one of Germanys best) Corvette Shop, which made the conversion to European reglementations, checked the car and found the steering gear (play) and all 4 stabilizer links worn. Transport damage. Steering gear and 4 links replaced, alignment was done.

Still, the tires work badly under colder weather conditions. I know those tire aren't made for winter conditions, but these seem to work extremely poor.
When parking the car, over moving it slowly with high steering angles, the tires are vibrating heavily. Knew this effect before, but way less strong and rather at temperatures around 15 F.
The slightest grooves in the road makes the front wheels go in all directions, big impact in steering.
Traverse grooves in front of a traffic light when accelerating with very little throttle gives wheel hop and the back snaps...

Has anyone made the same kind of experience with the new GY Gen 2s in the Grand Sport tire size (275 front, 325 rear)???

Take care

Mirko

 

Our car is a base Z51 coupe, but "tires is tires". All tires, even A/S, lose grip in colder temps. It's just that the A/S don't lose as much. There may be other tires that will work better for you at low temps, but the difference might not be worth the cost.

We had Firestone runflats on our C5, and Michelin PS2 runflats now on the C6. Neither of them could get up our slightly inclined driveway with less than 1" of snow on the asphalt. The Firestones also turned to "stones" at low temps, driving on bare/dry pavement at -10'F was like driving on ice. The PS2's seem to do a bit better on temp but I haven't driven them below about 25'F.

OTOH, our Michelin A/S runflats easily handle 2" of snow and cold temps.

The tire shudder you are experiencing may just be normal, but increased due to the colder temps.

Setting up our car with a little toe-IN, front and rear, made it much more stable over bumps, undulations, and grooves.

Good luck, I think you may be screwed for winter driving most of the time. Hopefully, someone has better ideas.

 

Hi Jim,

the strange thing is I have driven C6 s incl. Z06 since 2008 in Virginia (Alexandria) as daily drivers incl. winter. No big problems apart snow. Tires have always been the GY Supercar runflats 1st generation. I was so enthusiastic about the Gen 2s in summer...

Take care

Mirko

 

Colder temps usually mean there has to be an adjustment in tire pressure, I usually have to run a bit lower pressure to conpensate for the cooler temps. The vibration that you feel may be be attributable to an out of balance tire or bent rim.

Once you have check the aforementioned then we can discuss the wheel hop issue

 

I drive my 2005 C6 all year round in Ontario, Canada. My wife also drove a C4 all year round until it burned to the ground last fall. She now has a base 2006 C6.

When it gets cold (temps under freezing) we switch to winter tires. The summer do get really really slippery and the cars would be undrivable in true winter conditions with them.

I tried A/S's for one winter (Yoko's on the front and Avons on the back) and it was DANGEROUS in snowy conditions (anything more than a inch or two).

we now use Pirelli Winter tires (winter sport 210 on the C4 and Sottozeros on the C6) and the cars are completely drivable in snow storms and cold weather with them. However, it may be very very difficult to find winter tires in your sizes. For the rears (285/35-19) on the C6 we found one and only one winter tire and that is the Pirelli Sottozero.

 

Yes, i had the same experience, even in Florida. I would start spinning when I hit about 4,000 rpms in 3rd gear with the GEN2's, when the temps got into the 50's at night.

I went to the Bridgestone runflats, and they hold very well in cooler temps, even into the high 30's.

Meaning, I have to try hard to make it spin in 2nd, and when it does, it makes a very loud bark.

If the roads are 60 and up, it just rockets and goes with the LS3 stock power.

 

Those G:2 tires (I have them as well), are EXTREME SUMMER tires, which is the most, well, extreme category of street summer tires. All are going to be crap in cold weather man. Since there's no all-season category of tires for the GS (not even ultra-high-performance, which is the best performing A/S tire), you should at least put max summer tires. The best rated is Michelin Pilot Super Sports (my next tire), but those are not runflats. For that, you might want Bridgestone RE050A RFTs. Both of those are going to be miles better in the wet, and significantly better in winter conditions. But again, it's unsafe to use those tires in winter, especially if not dry. Good luck.

 

Had the car in the shop again today. Checked everything together with the mechanic. Verified alignment again. Replaced front wheels with wheels with Michelins to isolate problem. The car showed the SAME problem with the Michelins. With high steering angle and parking like manoeuvres, the tension gets the front knocked up, the tire releases, knocked up, releases again, its a clunk, clunk, clunk sound.
Checked all suspension, took sway bar links off to verify front sway bar. Nothing found. Car runs like on eggs...
No cause found. Next step will be to start replacing one suspension part after the other.
Any ideas? Please help!

Mirko

 

The GM alignment has a huge range that is still "in spec", did the mechanic show you the numbers? The Pfadt street specs, available here through the Search feature, would be a good place to start. Just be sure you get some toe-IN, not toe-out.

Also, your description of the front end "knocked up" sounds exactly like the tire scrub we all experience, especially in cold weather with (usually) sticky tires.

 

Checked everything together with the mechanic. Went through all alignment numbers. Actually, was checking the numbers myself on the machine when the mechanic adjusted the car. We fine adjusted exactly on the spec value without any range. Its not the "normal" Vette tire scrub, it really bumps the car up.

 

That's normal man. Or did it start happening all of a sudden? That's due to aggressive camber and LSD. My '12 does that since day 1. At full lock, it seems like I stepped over a 2x4 or something. The better test is how the car feels under normal driving. Good luck.

 

Well, I'm stumped. Please post what you find.

 

It appeared after I got the car back from the transport company after the sea transport to Germany. Before, it was normal Corvette tire scrub, now its like it breaks the car.
Spent a full day with the mechanic in the shop to figure it out...
Could a diff problem be a cause for the front wheel hop?

 

Stop wasting time and money (with all due respect), and sounds like you are driving yourself crazy too. All C6's with huge tires do this, the tire slips, grabs and slips on high steering angles. You alrady have experinced this and know of it. The cold makes it lot more pronounced as the tire does not have as much traction and it will slip much more easily. As far as the play in the steering and the links, how many miles you have on your vette?. I do not know how this can be caused by a transport company. If it was that hard of a ride to cause this kind of damage, your vette's outside would be thrashed too. Also beware of mechanics who humor you and take your money. He must have a permenant grin on his face. I know of no sport car that is good in winter conditions, although doable, neither was my 79 or the 89. Get yourself a $2000 front wheel winter car ( a price of 4 good tires) you will sleep lot better at nights also knowing that no one person will slide and hit your vette.

 

Summer tires are just that... summer. Not all-seasons, not winters. Below about 50 degrees many suck. Every set of Goodyears I've had are also very prone to heat cycling quite quickly, becoming harder and less grippy with miles even when warm. Way back to Gatorbacks, GS-C's, F1 Supercars. Haven't driven G:2's, but suspect the same.

The hopping is what happens when the grip sucks, it's a scrub radius thing... runflats do it worse because of the super stiff sidewalls.

Yeah, get a set of winter tires, at minimum some kind of all-season (there are some pretty good Ultra High Performance All Seasons) at least they have compounds meant to work when it's cold. Trust me it'll drive better not worse.

 

I'm a little bit with gsflyer, tho not completely. You have several things going on it seems. First, do you really have a well-set, street alignment? Second, the tires, as said are extreme summer. Third, along with gsfly., I can't imagine what, in transport, could have worn out parts of your suspension unless they were/the car was tied down for weeks and bounced all over the place. Maybe, but I do tend to doubt it. Fourth, with that question above, whose parts did this shop install--who makes them?

If your car now rides unlike it ever did in Alexandria, VA in the cold weather (note: Alexandria does have 35 degree weather; it is that right now), and causes this almost cobblestone-street ride (similar to Prince Street in downtown Alexandria) at full lock (turning to the end of the turning circle), and the tires are not the issue since you tried different tires, nor is the alignment, then all I can guess is it is the suspension parts installed, and/or the method of tightening them down. This shop has possibly done something wrong, or used a wrong part. It is possible that something else is worn or broken but they would (might) have seen that in their first and subsequent inspections.

I do know that "bluewasp" (Springfield, VA) has been in Germany in the past with his Corvette. You may want to ask him who/what shop he has used, if any.

 

I had an '08 Z06 with GY Supercars and never had the thumping you described at cold temp. Just got a '13 Z06 with the GY G:2 and sure enough at < 40 degrees it thumps like you say at low speeds and turning.

To add to our pain I have seen GY bulletin(hopefully not fake) that DAMAGE can occur if driven in < 40 deg!!! Cracking on the tire. I have really limited my cold weather driving and may go back to GY Supercar like on the '08 Z06. Had the '08 for 4 years and no problems in cold----big loss of traction but I could manage that.

BTW I too love the G:2 in warm weather

 

Thanks for the info! Very interesting. First thought that the problem was not tire-related after replacing the front wheels with ZR1s and Michelins for test purpose and the effect was the same.
I have still the same problem after two shops and 5 alignments. Also winter weather is a problem as you can rarely test drive the car.
German Corvette Expert thinks that the bolts have not been sufficiently tightened as both shops only used 12 inch long wrenches, not a torque wrench.
Will make the next try when dry conditions are back.
Would be very interested in the bulletin!

@AORoads - the oversea transport by ship was actually more than 4 weeks! They started in Baltimore, went down to Mexico, back up to New Orleans, Wilmington and only then across the Atlantic...

Take care

Mirko

 

Do a search on---

Goodyear Supercar G:2 tires cracking in cold weather

it is on the SVT performance site---they use on G:2 as standard tire on 662HP 2013 GT500