What's the cause of S197 wheel hop?

[Mojo88]

I've owned many muscle cars with leaf springs in rear, and I can totally understand why wheel hop is so common on leaf springs - 'spring wrap'............... The 100% cure for these cars was traction bars.

But on cars with coil springs it's totally different. There are no springs to 'wrap'. So can someone explain to me why a S197 car would wheel hop? And, in general, what's the resolution?

Thanks

 

[Weather Man]

Mushy bushings in factory LCA's allow oscillation. Pick up some aftermarket.

 

[BMR Tech 2]

There are a bunch of different factors that come into play with wheel hop. Basically, wheel hop is the constant grip and slip that you experience when trying to accelerate quickly. As the tire gains and loses traction, it will start to hop. In order to stop wheel hop you need to improve suspension geometry and increase grip. You'll see people claim a number of different things have helped cure their wheel hop, and I'll break it down a little bit for you.

Lowering springs:

People experience a lack of wheel hop after they install lowering springs with no other mods because they've changed the anti-squat and instant center values for their car. From the factory, these cars come with pretty lame anti-squat and instant center. The low %anti-squat and long instant center make the car squat and hits the tires very softly. Of course Ford would want to set a car up like that from the factory, so your granny that bought a V6 doesn't launch herself into a wall driving to the bingo hall. The LCAs are set to be parallel with the ground in stock form, so the tires will be pushed along the pavement instead of into the pavement, which would cause the tires to slip more. When you lower a car without correcting the rear end geometry, the LCAs don't stay parallel to the ground and end up angled up towards the rear axle. This causes the axle to lift during acceleration, reducing grip. Because the grip is compromised, the car will just burn the tires off instead of gripping/slipping and hopping.

Control Arms:

Getting rid of bushing deflection is pretty big when it comes to reducing or eliminating hop. A lot of my customers notice a pretty dramatic drop in wheel hop after they install LCAs or UCA on their car. Normally I suggest starting with LCAs because they're cheap, easy to install, and will generally clear up about 85-90% of wheel hop. Once the tires start slipping and the wheel hop starts up, the higher durometer bushings will help to reduce the amount of suspension oscillation and wheel hop. Factory arms have a ton of deflection, so once the hop starts, it's exacerbated by the squishy bushings and stamped steel arms.

Relocation brackets:

Adjusting control arm geometry before and after lowering a car can improve traction and reduce hop quite a bit. With the LCAs lower on the axle side than on the body side, your anti-squat % will get closer to 100% or above 100%. When you have anti-squat values above 100%, the rear axle will be forced down and into the pavement, increasing bite. These are especially necessary after the car has been lowered. Shortening your instant center and increasing your anti-squat value will almost always make the car faster, assuming you have a tire that can handle it AND shocks that are good enough to control body separation. If you can't control the body of the vehicle, you'll end up blowing your tires off OR as the car lifts you'll yank the axle up and unload the suspension.


Tires:

Stickier tires are less prone to slip, so you wouldn't have the constant traction/no traction that contributes to wheel hop. However, if you don't change your rear suspension geometry to be more aggressive, your car would ultimately be slower than a car with a proper suspension set up (all other things equal).

 

[Mojo88]

There are a bunch of different factors that come into play with wheel hop. Basically, wheel hop is the constant grip and slip that you experience when trying to accelerate quickly. As the tire gains and loses traction, it will start to hop. In order to stop wheel hop you need to improve suspension geometry and increase grip. You'll see people claim a number of different things have helped cure their wheel hop, and I'll break it down a little bit for you.

Lowering springs:

People experience a lack of wheel hop after they install lowering springs with no other mods because they've changed the anti-squat and instant center values for their car. From the factory, these cars come with pretty lame anti-squat and instant center. The low %anti-squat and long instant center make the car squat and hits the tires very softly. Of course Ford would want to set a car up like that from the factory, so your granny that bought a V6 doesn't launch herself into a wall driving to the bingo hall. The LCAs are set to be parallel with the ground in stock form, so the tires will be pushed along the pavement instead of into the pavement, which would cause the tires to slip more. When you lower a car without correcting the rear end geometry, the LCAs don't stay parallel to the ground and end up angled up towards the rear axle. This causes the axle to lift during acceleration, reducing grip. Because the grip is compromised, the car will just burn the tires off instead of gripping/slipping and hopping.

Control Arms:

Getting rid of bushing deflection is pretty big when it comes to reducing or eliminating hop. A lot of my customers notice a pretty dramatic drop in wheel hop after they install LCAs or UCA on their car. Normally I suggest starting with LCAs because they're cheap, easy to install, and will generally clear up about 85-90% of wheel hop. Once the tires start slipping and the wheel hop starts up, the higher durometer bushings will help to reduce the amount of suspension oscillation and wheel hop. Factory arms have a ton of deflection, so once the hop starts, it's exacerbated by the squishy bushings and stamped steel arms.

Relocation brackets:

Adjusting control arm geometry before and after lowering a car can improve traction and reduce hop quite a bit. With the LCAs lower on the axle side than on the body side, your anti-squat % will get closer to 100% or above 100%. When you have anti-squat values above 100%, the rear axle will be forced down and into the pavement, increasing bite. These are especially necessary after the car has been lowered. Shortening your instant center and increasing your anti-squat value will almost always make the car faster, assuming you have a tire that can handle it AND shocks that are good enough to control body separation. If you can't control the body of the vehicle, you'll end up blowing your tires off OR as the car lifts you'll yank the axle up and unload the suspension.


Tires:

Stickier tires are less prone to slip, so you wouldn't have the constant traction/no traction that contributes to wheel hop. However, if you don't change your rear suspension geometry to be more aggressive, your car would ultimately be slower than a car with a proper suspension set up (all other things equal).

Now THAT ^^^^^ is a Helluva fine reply to my question. Thanks very much. Ironically, I just bought a set of BMR LCA's yesterday, LOL!

Good stuff...... thanks again