Snorman

http://forums.rennlist.com/rennforum...n-reverse.html

991 911's seem to do it too, as I noticed last week.
S.

agapsdiver

Don’t feed the Troll. “Red Lightening” is obviously Torch2013C6 .
He apparently got a good price on a C6 back in March,2013. Good for him.
Instead of being content with his C6 he can’t stop bashing the C7 every chance he gets.
He blew his small wade on the C6, and now has “***** Envy”….errr
that’s “C7 Envy” and can’t help himself…his mission is to diss the C7.
“Red Lightening”, you really need to get well and enjoy life instead
of seeing how many ways you can whack off over the C7.

Bodene

Hi Folks! I am a new owner of a C7 and look forward to this website and forum. I have noticed a bad rumble noise and nasty feel leaving the parking lot when the wheels are cranked left. I figured it was cuz I had it in Sport mode and the car was messing with the suspension. No biggie but now I know it may be the cold tires. Only other complaint is a rear brake squeal but the car has less than 400 miles on it so I'm hoping it's just a breakin issue. Does anyone have any recommendations for an outdoor car cover (other than GM)?

rcallen484

Jethro:
1. Tell us all about your car
2. Pictures are MANDATORY

Jeffe65er

reducing front grip- worst of all worlds.

FrancisDGarcia

My tires dance turning hard both ways when cold and I am now just starting to get used to it. Normal for this car/tire combo. My brakes used to squeal as well. But not anymore that I have over 2000 miles on my C7 already. I heard that some hard braking after the 1500 mile brake-in also helps eliminate the squeal.

ByByBMW

As well as the 981's (new Caymans and Boxsters)

Aaron Keating

My Gen 4 Firebird did it in cold weather.

C4 doesn't (cause I currently have all seasons on it. Otherwise oh yes it would be chittering. probably worse than the bird ever did)

Dusty Starbucks

Why would someone have to break in the car before hard braking? The break in mileage suggested is for the engine/drive train, not the suspension and brakes. Just curious why as I have heard that before and doesn't make sense to me.

Regarding wheel hop. I am curious if the nonZ does it and if it does is it as bad on the nonZ? In theory it shouldn't be as bad due to taller sidewalls and more give, but not sure in practice.

JerryU

All 3 of these comments are very good. Even pulled out my old Fred Puhn, HP Book! No question the C7 has the shudder problem more than my C6 did when I pull out of the garage, which requires a full lock, very slow turn. (In fact I thought the C6 issue also had something to do with the electric enhanced steering it had, but probably was all the above issues.) I believe the tighter C7 turning radius is big part of the issue. It feels worse than it looks at full lock. So I find I just don’t turn as sharp and back-up twice like I did with the C6! If my wife drove the car (she doesn’t, prefers her higher seating Cayenne) I believe she too would want me to bring it to the dealer!

FrancisDGarcia

With the 1500 mile break-in comes enough application of brakes as part of normal driving. That is how it makes sense to me.

CRABBYJ

It is just as bad with my non-Z51 C7 as was with my '05 C6 Z51 Coupe.
I just refrain from making hard turns in either direction. No big deal IMO. You just need to understand the physics of what is going on.


1986C4Z51
CF Senior Member

Garage is empty, add now
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My Corvette Photos
Member Since: May 2013

I haven't seen anybody actually explain why this happens, so I'll give it a shot.

During a sharp turn the outside tire has to travel a much farther distance around the center of the turn than the inside tire. Both tires are turned about the same number of degrees because they are mechanically linked through the steering rack. Assuming that the outside tire is turned as far as it can go, that means the inside tire is not turned far enough and is sliding sideways across the pavement.

With a wide, grippy tire it becomes very noticeable as the tire grabs and releases like in a shudder.
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ByByBMW

Neither my 05 C6 nor my two 08 C6's had "electric enhanced steering". Is that something that came in the later MY's? I ask because this is the first I have heard of it. Thanks.

GARYFINN

You don't have a GS,it doesn't do it with smaller tires.

BRCC

If the problem still exist after a reasonable period your brakes may need burnishing. Refer to the owners manual Section 9 pages 8 & 9.

theseal

you don't know what you are talking about.

i have *measured* ackermann on a c5 and 6z... they do not have reverse ackermann, which is not something you would ever want in a street car (some high speed race cars on fast tracks use it to compensate for turn radius and desired front tire slip angle. i personally have never seen a car that wasnt faster with some ackermann in it).

however, the c5 - 6 cars, and i presume c7, do not have much ackermann at all, which is a compromise, and one that i disagree with. i believe they did it for packaging reasons rather than as a performance choice.

of course the cars handle pretty well, but they would autocross and take tight tracks even better with much more ackermann angle. they also would not hop around parking lots like the OP was worried about.

drive a mercedes, they usually have lots of caster and ackermann, and small kingpin angles, and they grip very well in tight turns rather than fight themselves as the C5-6 front end does.

in laymans terms, ackermann effect is when you turn the steering wheel, the inside tire turns MORE than the outside tire, to account for the difference in radius due to the width of the car, as well as the desired slip angles of the tires. reverse ackermann would be the inside wheel turning LESS.

i dont have my notes handy, but i seem to recall that on the c5 and 6, the inside tire turns about 2 degrees more than the outside tire at full lock, when to work best in a tight parking lot it would need around 8-10 degrees. there is no situation on modern tires, IMO where this tiny level of ackermann is ideal for performance... but overall, ackermann is not one of the more critical issues for most situations.

theseal

to add one bit of clarification, as the wheelbase gets longer, if nothing else changes, ackermann decreases by implication, so the c6 and 7 would actually have slightly less than a c5.

packaging reasons mean to get more ackermann you have to start pushing the outter tie rod outboard from the kingpin line, or otherwise moving the steering rack around, to get more ackermann, which puts pressure on other design parameters.

i think they chose to live with it for packaging reasons and to prefer other parameters over ackermann, but i can promise you if you added ackermann in a c5 or c6 on any track, without compromising other things (which is possible by the way), it would start getting very slightly faster, and the difference would get greater and greater the tighter the turn. it was not a performance choice by GM.

Bodene

RCALLEN - I have a crystal red 2LT w/51. Tan and black interior, 19 & 20 chromes, perf. exhaust and trans. top. Brought it home on my 57th birthday. First new car I've ever owned. Will try and figure out how to post some pics.

z06fun1

I can't believe no one mentioned the differential. A stiff rear diff is going to very much cause the tire skipping on tight turns. It will be worse in the cold simply because of the drastic change in grip that can happen with the typical high performance tire compounds found on a corvette.
I'm going to guess those with a C7 z51 may not really have it happen nearly as much, IF the ediff can go to a full (or at least very) open condition.

Bodene

Thanks, DCBE!