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Old 07-19-2011, 03:13 PM   #1
Nessal


 
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What is wheel hop?

I know what wheel hop is. I have felt it before in my previous cars and I IMMEDIATELY let off the throttle. But I'm curious about why it exists and what causes it?
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Old 07-19-2011, 03:56 PM   #2
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Harmonics. It is a small vibration that resonates, reverberates through the suspension and driveline. It grows and then explodes into a violent potentially damaging condition.

In the 5th Gen a primary contributor to wheel hop is negative camber, riding on the inner shoulder of the rear tire. When the tire breaks loose it loads and unloads (think vibration). A good alignment with minimal negative rear camber brings the tire contact patch square to the pavement. A good solid rear contact patch more evenly loads the tire (think less vibration).

In Pedders Book on 5th Gen Suspension we identify the rear sub-frame bushes as low hanging fruit. The OE sub-frame bushes are NVH voided to keep things quiet, but allow the rear sub-frame to twist create uneven loads (think vibration) on the rear tires. Removing compliance i the sub-frame bushes changes the motion and the harmonics of the IRS. Keeping the tires more squarely planted on launch keeps the tires more evenly loaded (less vibration).

Movement in the toe link bushes would be the next weakest link. That can be corrected with a set of urethane bushings.

The rear strut damping and rear coil rate are additional contributors. A bit firmer and more aggressive damping map will help.

The 5th gen is an IRS. A monster sized super strong rear sway bar will help more evenly distribute the load on hard launch. Once again, the goal is to keep the rear tires square up to the track surface or street so they load evenly preventing wheel hop at the source (eliminating vibration)

We could continue to remove compliance through the entire IRS including differential bushes, but before we do that we want to address another source of wheel hop. The driver and launch technique. I have seen drivers complain of wheel hop and a different driver in the same car launch cleanly. In a 5th Gen, dropping the clutch at high RPMs is a prescription for wheel hop.

We can go one step further and discuss tire composition, track surface and tire pressures as they all are potential sources of wheel hop.

Wheel hop is a vibration that grows until it becomes destructive. You can PM PQ about that

I have not included parts numbers as solutions because your post didn't ask for what you should buy. It asked what wheel hop is. If I have not answered your question, please ask a follow up and I will do my best.
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Old 07-19-2011, 04:49 PM   #3
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Quote:
Originally Posted by JusticePete View Post
Harmonics. It is a small vibration that resonates, reverberates through the suspension and driveline. It grows and then explodes into a violent potentially damaging condition.

In the 5th Gen a primary contributor to wheel hop is negative camber, riding on the inner shoulder of the rear tire. When the tire breaks loose it loads and unloads (think vibration). A good alignment with minimal negative rear camber brings the tire contact patch square to the pavement. A good solid rear contact patch more evenly loads the tire (think less vibration).

In Pedders Book on 5th Gen Suspension we identify the rear sub-frame bushes as low hanging fruit. The OE sub-frame bushes are NVH voided to keep things quiet, but allow the rear sub-frame to twist create uneven loads (think vibration) on the rear tires. Removing compliance i the sub-frame bushes changes the motion and the harmonics of the IRS. Keeping the tires more squarely planted on launch keeps the tires more evenly loaded (less vibration).

Movement in the toe link bushes would be the next weakest link. That can be corrected with a set of urethane bushings.

The rear strut damping and rear coil rate are additional contributors. A bit firmer and more aggressive damping map will help.

The 5th gen is an IRS. A monster sized super strong rear sway bar will help more evenly distribute the load on hard launch. Once again, the goal is to keep the rear tires square up to the track surface or street so they load evenly preventing wheel hop at the source (eliminating vibration)

We could continue to remove compliance through the entire IRS including differential bushes, but before we do that we want to address another source of wheel hop. The driver and launch technique. I have seen drivers complain of wheel hop and a different driver in the same car launch cleanly. In a 5th Gen, dropping the clutch at high RPMs is a prescription for wheel hop.

We can go one step further and discuss tire composition, track surface and tire pressures as they all are potential sources of wheel hop.

Wheel hop is a vibration that grows until it becomes destructive. You can PM PQ about that

I have not included parts numbers as solutions because your post didn't ask for what you should buy. It asked what wheel hop is. If I have not answered your question, please ask a follow up and I will do my best.
+1
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Old 07-19-2011, 06:24 PM   #4
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Quote:
Originally Posted by Bruce@raymondsperformance View Post
+1
+another1

Here's a terrible example...



You can even see the resonant frequency in the smoke
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Old 07-19-2011, 06:40 PM   #5
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Here is an excerpt from the article Curing Camaro Wheel Hop on our blog that gives a pretty easy to follow description of what causes wheel hop.

Quote:
All the horsepower in the world will not make your car faster if it can not transfer that power to the pavement. 5th generation Camaro SS owners, especially those with cars that are extensively modified, are quickly learning this due to the dreaded “wheel hop”. Wheel hop is a violent and potentially damaging condition that typically occurs when the car is launched aggressively and has been described as feeling like the rear tires are driving rapidly over rail road ties. It is very simply a rapid and repeated loss and recovery of traction. When a car begins to accelerate various bushings and suspension/chassis components deflect. Under normal driving conditions this flexing is negligible but when the car is launched aggressively the deflection causes significant toe changes which reduce the contact patch of the rear tires. This leads to a reduction in traction and momentary wheel slippage which alleviates the toe changes and allows the rear tires to regrip. The vicious circle then continues as the suddenly improved traction again results in deflection and toe changes leading to wheel slippage. The frequency of the cycle is so rapid that it feels like the rear of the car is riding on jack hammers.
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Old 07-20-2011, 10:09 AM   #6
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Thanks guys!
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Old 07-20-2011, 11:52 AM   #7
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Thanks guys!
Exchanging information is at the heart of the Camaro5 community. Answering questions like yours is something I really enjoy doing. So thank you for asking!
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Old 07-20-2011, 04:11 PM   #8
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Thanks guys!
No problem, that is why we are here.
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