Rear wheel hop

[BangkokDean]

When I floor the vette in first gear the rear wheels hop like crazy when tires are cold(80*F).Rear spring is a mono 360lb bilstein HD shocks and a stock sway bar.
Tires are Hankook 265 60 17.

How can I stop the hop?:sos:

 

[DeeVeeEight]

When I floor the vette in first gear the rear wheels hop like crazy when tires are cold(80*F).Rear spring is a mono 360lb bilstein HD shocks and a stock sway bar.
Tires are Hankook 265 60 17.

How can I stop the hop?:sos:

Dean, I have had the same issue but I learned to slip the clutch more or ease off the loud pedal. Sorry if it's not much help.

PS - my set up is similar, a 400 lb. mono spring with Bilsteins and Firestones

 

[68/70Vette]

Dean, I have had the same issue but I learned to slip the clutch more or ease off the loud pedal. Sorry if it's not much helps

I thought Dean's cas was an automatic. I think someone with differential expertise should jump in. Is it possible that the differential carrier is worn? What I'm trying to refer to here is the "positraction"....the springs, shims, whatever. Could the positraction be "hunting", going in an out due to aging?.

 

[MYBAD79]

Check first if you can find something loose, like for example the front diff mount ....

 

[BangkokDean]

Dean, I have had the same issue but I learned to slip the clutch more or ease off the loud pedal. Sorry if it's not much helps

I thought Dean's cas was an automatic. I think someone with differential expertise should jump in. Is it possible that the differential carrier is worn? What I'm trying to refer to here is the "positraction"....the springs, shims, whatever. Could the positraction be "hunting", going in an out due to aging?.

It only does it when the tires are cold and only when I get on it in first gear.
I don't see anything loose and there is no shimmy or noise when normal driving. I am thinking it might just be the tires.

 

[MYBAD79]

it might just be the tires ..... how old are they ???

just saying: I like to rule out other stuff before spending money......

 

[blue71vette]

When I floor the vette in first gear the rear wheels hop like crazy when tires are cold(80*F).Rear spring is a mono 360lb bilstein HD shocks and a stock sway bar.
Tires are Hankook 265 60 17.

How can I stop the hop?:sos:

Wheel hop is a stick slip condition. When the left and right sides stick and slip at the same frquency they couple. One side excites the other... To address this you must seperate the stick-slip frequency of the left and right sides. A simple fix for C2 and C3 is to use the small (early) half shaft on one side and the large (later) half shaft on the other. BTW, current CTS-V and ZR-1 use different size half shafts for this reason. Cheers!

 

[denpo]

When I floor the vette in first gear the rear wheels hop like crazy when tires are cold(80*F).Rear spring is a mono 360lb bilstein HD shocks and a stock sway bar.
Tires are Hankook 265 60 17.

How can I stop the hop?:sos:

Wheel hop is a stick slip condition. When the left and right sides stick and slip at the same frquency they couple. One side excites the other... To address this you must seperate the stick-slip frequency of the left and right sides. A simple fix for C2 and C3 is to use the small (early) half shaft on one side and the large (later) half shaft on the other. BTW, current CTS-V and ZR-1 use different size half shafts for this reason. Cheers!

Wow, learned something today.

 

[7t2vette]

Wheel hop is a stick slip condition. When the left and right sides stick and slip at the same frquency they couple. One side excites the other... To address this you must seperate the stick-slip frequency of the left and right sides. A simple fix for C2 and C3 is to use the small (early) half shaft on one side and the large (later) half shaft on the other. BTW, current CTS-V and ZR-1 use different size half shafts for this reason. Cheers!

Interesting. I have a wheel hop issue that I would like to get rid of as well. Why does having the different size half shafts eliminater this? Would a dual-mount rear spring help? What about those "traction bars" that are sold by VB&P?

 

[blue71vette]

Wheel hop

Wheel hop is a stick slip condition. When the left and right sides stick and slip at the same frquency they couple. One side excites the other... To address this you must seperate the stick-slip frequency of the left and right sides. A simple fix for C2 and C3 is to use the small (early) half shaft on one side and the large (later) half shaft on the other. BTW, current CTS-V and ZR-1 use different size half shafts for this reason. Cheers!

Interesting. I have a wheel hop issue that I would like to get rid of as well. Why does having the different size half shafts eliminater this? Would a dual-mount rear spring help? What about those "traction bars" that are sold by VB&P?

Let's try to explain this a different way than my explanation above. The same size half shafts have the same moment of inertia and stiffness. Different size half shafts have different moments of inertia and therefore different stiffnesses. When they have the same stiffnesses they hop at the same frequency. Different stiffnesses mean they have different hop frequencies. So the left side hops at one frequency and the right side hops at a different one. When they hop at the same frequency they involve the entire rear suspension and the size of the hop continues to grow to a very large level. When they hop at different frequencies they do not involve the rest of rear suspension.

Dual mount rear springs and traction bars would have to be different left to right to help. However, with the same half shaft stiffness the left and right side would hop at almost the same frequencies. Different spring rates and/or traction bars would probabaly only reduce the amount of coupling left to right. (Involving the whole rear suspension).

Please remember, different size half shafts is the same fix GM uses to solve wheel hop on their high performance vehicles.

Here is an aftermarket kit for the original CTS-V that was notorious for is rear wheel hop.

http://www.shop.gforce1320.com/product.sc?productId=53

Cheers