News: Vette's thumping rubs some drivers the wrong way

[Rob]

Vette's thumping rubs some drivers the wrong way

RICHARD TRUETT
Automotive News

November 16, 2013 - 12:01 am ET

Chances are you have never heard of Georg Lankensperger, a 19th-century German wooden-wheel maker. He solved a problem nearly 200 years ago that Corvette engineers chose to live with in the redesigned 2014 Stingray.

Take a Stingray for a low-speed spin around a parking lot, turn the steering wheel at a sharp angle, and you'll feel a bumping-jumping-rubbing noise, as if a tire is skipping over the pavement. This sensation is called the Ackermann Effect, named for Rudolph Ackermann, who patented Lankensperger's steering system in Great Britain in 1818.

Lankensperger figured out how to make a pair of wheels turn smoothly in two separate arcs. You see, when you turn the steering wheel of your car all the way to the right, for example, the left or outer wheel travels in a larger circle than the right or inner wheel.

Lankensperger figured out that if the inside wheel is turned at a greater angle than the outside wheel, it won't skip over the pavement and make that thumping noise that's prevalent in the 2014 Corvette.

Full Story: http://www.autonews.com/article/201...rubs-some-drivers-the-wrong-way#axzz2kqjYrdOC

 

[Jride]

Thumping gone!

Vette's thumping rubs some drivers the wrong way

RICHARD TRUETT
Automotive News

November 16, 2013 - 12:01 am ET

Chances are you have never heard of Georg Lankensperger, a 19th-century German wooden-wheel maker. He solved a problem nearly 200 years ago that Corvette engineers chose to live with in the redesigned 2014 Stingray.

Take a Stingray for a low-speed spin around a parking lot, turn the steering wheel at a sharp angle, and you'll feel a bumping-jumping-rubbing noise, as if a tire is skipping over the pavement. This sensation is called the Ackermann Effect, named for Rudolph Ackermann, who patented Lankensperger's steering system in Great Britain in 1818.

Lankensperger figured out how to make a pair of wheels turn smoothly in two separate arcs. You see, when you turn the steering wheel of your car all the way to the right, for example, the left or outer wheel travels in a larger circle than the right or inner wheel.

Lankensperger figured out that if the inside wheel is turned at a greater angle than the outside wheel, it won't skip over the pavement and make that thumping noise that's prevalent in the 2014 Corvette.

Full Story: http://www.autonews.com/article/201...rubs-some-drivers-the-wrong-way#axzz2kqjYrdOC

I changed tires from the OEM Z51 Michelins to the Z51 All Season tires...and the thumping stopped....the ride also improved...only caveat no run flats for the As's yet. Z51 2\LT Black with Kalahari Black Wheels and Black Calipers VIN #1313

 

[Hib Halverson]

I think the Automotive News story is poorly researched.

My belief is the problem has nothing to do with the amount of Ackerman in the steering geometry.

It's that certain tire designs have stiff casings and tread design and, when you turn sharp, that the outside of the tire tread needs to move a different distance than the inside of the tread causes the tread to "hop" or "snap" as it rolls.

I had the same problem with the Michelin PS Cup times on my '12 Z06. When I took off the Cups and replaced them with PS2s (I did that because I was going to drive the car in bad weather) the problem went away.

If you've ever driven a road racing car with slick tires, you've undoubtedly felt that hopping or thumping from the front tires when you try to turn the car sharply in the pits.

I'm going to try emailing the author of that AN story and see what he says.

 

[Agent White]

My C6 did the same thing, especially snaking through the parking garage at work. I just tried to avoid sharp turns.

 

[motorman]

My C6 did the same thing, especially snaking through the parking garage at work. I just tried to avoid sharp turns.

I believe that there was a TSB on C-6

 

[frio69]

glad to know im not hearing things/ feeling

glad to know im not hearing things/ feeling
thanks for the info.
tom

QUOTE=Rob;1139105]Vette's thumping rubs some drivers the wrong way

RICHARD TRUETT
Automotive News

November 16, 2013 - 12:01 am ET

Chances are you have never heard of Georg Lankensperger, a 19th-century German wooden-wheel maker. He solved a problem nearly 200 years ago that Corvette engineers chose to live with in the redesigned 2014 Stingray.

Take a Stingray for a low-speed spin around a parking lot, turn the steering wheel at a sharp angle, and you'll feel a bumping-jumping-rubbing noise, as if a tire is skipping over the pavement. This sensation is called the Ackermann Effect, named for Rudolph Ackermann, who patented Lankensperger's steering system in Great Britain in 1818.

Lankensperger figured out how to make a pair of wheels turn smoothly in two separate arcs. You see, when you turn the steering wheel of your car all the way to the right, for example, the left or outer wheel travels in a larger circle than the right or inner wheel.

Lankensperger figured out that if the inside wheel is turned at a greater angle than the outside wheel, it won't skip over the pavement and make that thumping noise that's prevalent in the 2014 Corvette.

Full Story: http://www.autonews.com/article/201...rubs-some-drivers-the-wrong-way#axzz2kqjYrdOC[/QUOTE]

 

[Corv63]

I think the Automotive News story is poorly researched.

My belief is the problem has nothing to do with the amount of Ackerman in the steering geometry.

As long as each tire is traveling in a true arc, it shouldn't matter what the other tire is doing. If both tires were driven in four wheel drive then one tire could affect the other because of the different lengths they would travel and the tires could be skidding.

 

[Tuna]

Wider tires and cold weather trigger this noise issue more also. I see this on both my Vette and my V Wagon but more in the winter when the temps are below 50.

 

[67vet]

My ZR1 does this when I am turning sharply out of my garage.

 

[catbert]

My ZR1 does this when I am turning sharply out of my garage.

Mine does too.

 

[froggy47]

My opinion (duly noted) is that of course the steering engineers are aware and looked at it (not just for the c7).

If they "fixed" it for parking lot turns they would likely compromise the geometry for high speed (track) handling.

I'll take the high speed optmization. I have driven track only cars and they are stupidly awkward to manuver in the pits, but sweet on course.

 

[USNA1969]

Vette's thumping rubs some drivers the wrong way

I heard the same sound, but assumed it was because the temperature was pushing 40 degrees outside. However, according to the Getting To Know Your 2014 Corvette quick reference guide that came with my new Vette (I've owned it about 22 hours),

"During hard, slow turns, such as parking, the difference in steering angle of the tires may cause one tire to slide or hop lightly to keep up. This hop of the wide tires may cause a chatter sound. The noise will stop as the wheels are straightened."

FYI, my new Vette is a Premier Edition coupe, #24/500, and it is AWESOME. It is SO different from my '72, but then 40 some years of technological advances will do that. I've owned cars from a Road Runner to a Porsche 911 with a lot in between, but I've never been as excited to drive a car as I am with my new Vette.