mikedee

Hi I'm Just seeing if anyone else has noticed that while backing up and turning the steering wheel a noise coming from the rear of the car almost acts like the rear end has locked up. I have talked to other Z-51 owners and they say it's the tires. 1st time it happened to me the car only had 30miles on it.

theanswriz42

You talking about when you turn the wheel all the way to one side and drive slowly either in forward or reverse? Yeah, it's normal.

WKMCD

Annoying but normal and harmless.

time2run

Slightly worse with colder tires. Didn't even notice it during the summer.

Zax

It is most likely normal (tire hop) but since you mention it's coming from the rear end you may want to verify as it could be low fluid or an issue with the eLSD.

JerryU

As we get colder, it gets much worse. The simple comment “normal,” which is what you’ll get from GM does not come close to what you’ll feel below ~40F! Had my C7 Z51 since October 2013. When it got cold (~40 F) in SC it was very concerning when turning full lock backing out of the garage in the morning. A poster said when backing out of a mall parking spot on a cold night the car shook so bad he got out and looked underneath to see what broke! His wife wanted him to call the dealer and have it towed and not drive it!
After a year and a lot of forum posts I believe the two main causes are the tires (particularly on the Z51) and the fact that the C7 has a 2 foot tighter turning radius than the C6. (C6 had the same tire width but less turning radius.) Folks installing All-Season tires said it goes away. Much worse than my ’08 Z51. (the '08, C6 had the same tire width but less turning radius.) Made a 4 page PDF from what I found. Describes Ackerman steering, tire slip angles, etc. http://netwelding.com/Wheel_Chatter.pdf
I use a simple solution you’ll want to consider if your have a friend in the car and don’t want them to laugh at your “piece of junk!” Just don’t use full lock when it’s cold, use a K turn! The PDF will help explain what it is and that Chevy says “it’s normal” if you forget and maybe your passenger can explain when he tells others, while laughing!




GM Calls it Tire Chatter, You'll Say, What Broke if Below ~40F in a Very Tight Slow Speed Turn!

Steve_R

This isn't specific to Z51, it happens on all C7s. My C6 did it as well. If you don't like it don't turn the wheel all the way when turning.

Glen e

My brother's 2014 911 does it too, same intensity, same sound...

rramjet

My wife's IS350C Lexus does it as well. Dealer didn't have a clue and test drove a new one which did the same thing. Once I learned of the C7 doing the same thing and the owners manual describing it as normal I informed the Lexus dealer.

I have to say now that I own a C7 it's much more pronounced than her Lexus.

Woodson

Only one comment regarding it coming from the rear, not the front? The sound never comes from the rear on mine.

Even though I knew about it ahead of time, I was still surprised how "intense" it was.

For OP and anyone else interested, it does not do it at all with my winter tires mounted (same sizes), and I've read it doesn't with the all seasons either.

Paul R

From the description, it sounds to me like the limited slip differential in the rear. It is normal for the clutch packs to grab and slip some...more when it is cold and the diff fluid is thicker.

The sharper you turn, the more difference in the rotational speed between the left and right sides and the more sounds you will hear.

-Paul

JerryU

When it first happened last Fall, I thought it did feel like it was coming from the rear and perhaps it was the clutches in the Positraction like what occurred with the 9” rear in my Street Rod. With it, I drained the fluid and installed new lub with the proper additive and the chatter was gone.
However the Z51 rear end does not have Posi clutches in the rear end! It has automatic transmission like clutch packs on each side of the differential that operate with separate high pressure fluid from an electric driven pump (called eSLD.) They activate independently many times per second by computer control and probably are not a factor in on a slow speed turn. Finally realized the sever vibration was coming from the front but did shake the car allover at cold temps on concrete, in my case. Worse if it’s wet.
The comment from Woodson (# 10) validates the issue, particularly with the Z51 tires but the base tires as well, that a primary cause is the high performance tire compound, slip angels and overall tire constrution.

KenHorse

Apparently we need a HUGE sticky at the top about this.

This makes what? The 100,000th time this has been asked (and answered)?

theanswriz42

We could just use a sticky suggesting people actually use the search function, not that anyone would read it.

KenHorse

Good point.....

Greg00Coupe

Forget the sticky.....Folks just want to know what is going on!!!!!!! The veterans knew this was coming as folks are just experiencing cold weather for the first time with their new cars.

Of course they are concerned!!! My wife said I know what they say but this can't be right!!!! It's that bad.

Assuming the original poster is truly having the " soft race tires get hard in cold weather and skip" syndrome, and not a limited slip issue.....yea it will get worse with cold weather.

I'm changing my tires out for cold weather it is that bad!!! No problem > 50 but ugly getting colder.

Not back to the sticky concern........ to those who don't want to help a fellow member who may be new here........ just back out of the post and dont comment!!!! Telling someone to do a search......if we all did that there would be no new posts!!! Few topics on here have not been asked before!!!

Zax

There is a sticky already (https://www.corvetteforum.com/forums...-and-tips.html) but the OP said the noise was coming from the rear so that would eliminate tire hop/chatter. I suspect he's mistaken and it is exactly this, but there are other possibilities.

sharpseadog

I took delivery of my Z51 Vert. Exactly a week ago. Fortunately I had read about this on the forum. Also, there was a tag on the shift lever that explained it and says it's normal. Otherwise, had I not known, I would have been very alarmed because it is very loud and you can definitely feel it.

JerryU

I agree: I fell the same way, someone getting into cold weather for the first time could be very concerned and the GM, “It’s Normal” is not much help! What’s normal?? The car feeling like it is falling apart! None of my other Vettef felt like that! My ’08 C6 Z51 (same size tires) was in the same garage and I used full lock to get out every morning. Felt a small shudder but not like the C7. I don't even like the feel so use a K turn now! I don’t mind posting, especially for someone who is not a gear head like I am and I was concerned! I only partially joke when I say if you have a friend in the car be sure not to turn full lock when it’s cold or they will laugh and tell all your friends about the "piece of junk you bought!" It’s that bad!
See your in Canton, I lived in Ashtabula Ohio, on the Lake and would defiantly get different tires for the winter even if you never drive in the snow. I am starting to feel the “chatter,” as GM refers to it, at 55F. Tomorrow night it will get to 35 and I live near Myrtle Beach, SC! We’ll use the wife’s SUV!

mikefeeser

I have experienced this 'chatter' on the few cool morning that I have encountered, but today it was 39 degrees when we took off and it really did make a lot of noise, yes, I have the Z51 version - but the PDF that was posted (JerryU) on this thread really does a great job of explaining the problem - thanks. Also I have sent the PDF to my son who just bought a Lexus 350.