Wheel Hop

[blewbyoutobad]

I have a new problem of wheel hop. I searched the forum but didn't really find what I wanted. Just finished the car with new wheels and tires. The car: 69 Dart Swinger 340, 4 speed. Everything is new with Mancini extra heavy duty leafs and stock shocks with extra length for the leafs. Wheel hop is bad. Gears are 3:23, làunch at 3500, cam power band is 3500 to 7000. I know I need more gear but I'm in the country and every where is 15 to 25 miles. The wheels are 17x8 with a summer tire 245x45x17. It is factory diameter at
25.7". This car never wheel hopped until I made this change. Before I was running 255x60x15 at 27.2" tall drag radials. I searched and searched for a softer shock with some added length for the heavy duty leafs. I have a set of new Competition Engineering shocks I could run. I run the car on the street and when launching at 3500 is smokes the tires and does the wheel hop. Any launch lower and it's bog because of the cam and gear ratio. Any help appreciated. Thanks FABO

 

[MOPAROFFICIAL]

......You have no sidewall Flex with the new dimensions....so the tire can't move like it did before...and therfore it just bites,breaks...bites n breaks over n over.

That's the only change you made, as you said , and now this problem occurs.

How many drag cars do you see that have 1.5" tall side walls....answer is N O N E

 

[blewbyoutobad]

......You have no sidewall Flex with the new dimensions....so the tire can't move like it did before...and therfore it just bites,breaks...bites n breaks over n over.

That's the only change you made, as you said , and now this problem occurs.

How many drag cars do you see that have 1.5" tall side walls....answer is N O N E

The side walls are around 3" but I get it. Funny thing is it didn't do it at first.

 

[Joey4speed]

Rear wheel hop?
What type of pinion snubber?
I also developed a bad rear hop (more like a bang, bang, bang) when I attempt a burnout.
Hop started after I changed to 15 inch wheels.
Never happened with 14s and same 3:55s and shocks.
Used to do control burnout nicely, but now it's a horrible and embarrassing.

 

[MOPAROFFICIAL]

The side walls are around 3" but I get it. Funny thing is it didn't do it at first.

Would you say these bite better?
If so you need adjust your springs and possibly...more than likely...your pinion angle. If its wrong... the springs get to their rebound force quicker in the launch and will fight the tire...and they will go back n forth-hop.

 

[MOPAROFFICIAL]

Rear wheel hop?
What type of pinion snubber?
I also developed a bad rear hop (more like a bang, bang, bang) when I attempt a burnout.
Hop started after I changed to 15 inch wheels.
Never happened with 14s and same 3:55s and shocks.
Used to do control burnout nicely, but now it's a horrible and embarrassing.

It's trying to hook and is probably doing a better job than the other tires...but it's not quite right.lol
Spinning ain't winning...hoping ain't poppin..
If you could never do a burnout again but were able to go wide open throttle from a dead stop n straight hook and lunch with no tire hop or spin.... would you care about burning out anymore? 'Outside of the wet burnout box of course'.

 

[blewbyoutobad]

Would you say these bite better?
If so you need adjust your springs and possibly...more than likely...your pinion angle. If its wrong... the springs get to their rebound force quicker in the launch and will fight the tire...and they will go back n forth-hop.

Pinion angle has been adjusted to remove some vibration I had. Smooth now and angles match. These do not bite better.

 

[MOPAROFFICIAL]

Pinion angle has been adjusted to remove some vibration I had. Smooth now and angles match. These do not bite better.

There's a required amount of nose down on the pinion in order to absorb the shock load of hard race launching. There is stock spec around 2*down and then race of 4-8+* down. If the pinion is almost straight to the Driveline stationary with no load then when you hit the gas and load it it's going to put it nose up and wind the Springs up and the Springs fully wound up will then resist and unwind breaking the tires loose and then repeating over and over

 

[blewbyoutobad]

Rear wheel hop?
What type of pinion snubber?
I also developed a bad rear hop (more like a bang, bang, bang) when I attempt a burnout.
Hop started after I changed to 15 inch wheels.
Never happened with 14s and same 3:55s and shocks.
Used to do control burnout nicely, but now it's a horrible and embarrassing.

No pinion snubber

 

[blewbyoutobad]

It's trying to hook and is probably doing a better job than the other tires...but it's not quite right.lol
Spinning ain't winning...hoping ain't poppin..
If you could never do a burnout again but we're able to go wide open throttle from a dead stop n straight hook and lunch with no tire hop or spin which would you care about burning out anymore? 'Outside of the wet burnout box of course'.

With the drag radials they would ßpin some but they also hooked better and went in a straight line. This gets a little squirrelly but doesn't hook. With that cam and gear there is windup time you until it sees the power bànd. Sounds like a gear is what it needs to get it moving.

 

[66340SEDAN]

Back in the day Direct Connection and Mopar Performance offered leaf spring clamps that you would put at the front of your leaf springs, I have some but packed away so I can’t show a picture...but they could be easily made....supposed to help eliminate axle windup and wheel hop....Dick Landy also talked about this during his drag clinics and in books...I found these 2’pictures doing a search on FABO

 

[Ironracer]

I had that problem when I rebuilt the 383 magnum, 4 spd 68 Coronet I had (!&@%$#, darn fool!) I used clamps in front of the leaf springs, then added an adjustable snubber. Beat the snot of my rear pan..

 

[blewbyoutobad]

There's a required amount of nose down on the pinion in order to absorb the shock load of hard race launching. There is stock spec around 2*down and then race of 4-8* down. If the pinion is almost straight to the Driveline stationary with no load then when you hit the gas and load it it's going to put it nose up and win the Springs up and the Springs wound up will then resist and unwind breaking the tires loose and then repeating over and over

I can install the drag radials on these wheels and get a set of 3:91s or 4:10s . I'm no stranger to low gears and highway driving. My 65 Valiant had 4:30s.

 

[blewbyoutobad]

It's trying to hook and is probably doing a better job than the other tires...but it's not quite right.lol
Spinning ain't winning...hoping ain't poppin..
If you could never do a burnout again but were able to go wide open throttle from a dead stop n straight hook and lunch with no tire hop or spin.... would you care about burning out anymore? 'Outside of the wet burnout box of course'.

Not into showing off with burnouts.

 

[blewbyoutobad]

I can install the drag radials on these wheels and get a set of 3:91s or 4:10s . I'm no stranger to low gears and highway driving. My 65 Valiant had 4:30s.

My bad my drag radials are 15" and wheels are 17". Would the competition engineering shocks help keep it planted.

 

[MOPAROFFICIAL]

My bad my drag radials are 15" and wheels are 17". Would the competition engineering shocks help keep it planted.

There's a soft medium and heavy setting on those shocks to control the extension rate..the main thing with them and why they're necessary is because they're longer and dont bind when using ss springs with their higher arch. You did say you already have extensions on the stock shocks, right?
Whatever you do I would make sure your pinion angle is right for the power level and what you're trying to do/launching and then move to everything else after that...like snubber....shocks...air pressure...

 

[blewbyoutobad]

There's a soft medium and heavy setting on those shocks to control the extension rate..the main thing with them and why they're necessary is because they're longer and dont bind when using ss springs with their higher arch. You did say you already have extensions on the stock shocks, right?
Whatever you do I would make sure your pinion angle is right for the power level and what you're trying to do/launching and then move to everything else after that...like snubber....shocks...air pressure...

 

[Locomotion]

Put stiffer shocks on it. Single adjustable Rancho shocks are good. I forgot the part # on my Dart Sport and car isn't here to check. You'll need to check your estimated compressed and extended lengths and look at Rancho's spec sheets for shocks with mounting ends that will fit.

The harder the tires are hit, the stiffer the shocks need to be to control the spring when it tries to wind up & unwind. I tried the Mopar 4-speed drag shocks on my Dart Sport with a 904 footbraking, but had a pretty high stall converter. Race only with 9" slicks, 2.74 low gear, 4.86 rear and 30" tall tires. It also had 002/003 SS springs! When traction wasn't good, it still wheel-hopped! With stiffer shocks, it sometimes spun due to track conditions, but it never wheel-hopped again. Always used a pinion snubber! Never saw a disadvantage to it.

 

[blewbyoutobad]

What I found was a shock that matches the CE drag shocks in length but they are not adjustable. Should I try the CE shocks again. They were a little to harsh on the street.

 

[MOPAROFFICIAL]

My bad my drag radials are 15" and wheels are 17". Would the competition engineering shocks help keep it planted.

Hop mostly isnt a shock issue unless they are binding, too short....and that's all that's left. ..as in all else is set up right. Stiffer will extend harder and help plant them...if that's the even the issue. We have no idea where your pinion angle is set..

 

[318willrun]

10 dollar swap meet traction bars... paint them the color of your flavor, set bumper of the traction bar 1/2" from the eye of the leaf spring bolt, wheel hop gone ... or more controlled

 

[33IMP]

Quickest and easiest experiment is tire pressure. My fox body five speed wheel hopped bad with 30 pounds, hooked good with 22.
And then I would sure try the adjustable shocks.

 

[MOPAROFFICIAL]

With the drag radials they would ßpin some but they also hooked better and went in a straight line. This gets a little squirrelly but doesn't hook. With that cam and gear there is windup time you until it sees the power bànd. Sounds like a gear is what it needs to get it moving.

View attachment 1715825619

Got to remember street tires are not going to hold it at a certain point. It could be JUST the tires but as I said we have no idea where everything else is

 

[blewbyoutobad]

10 dollar swap meet traction bars... paint them the color of your flavor, set bumper of the traction bar 1/2" from the eye of the leaf spring bolt, wheel hop gone ... or more controlled

slapper bars should not be used on Mopars. They are not designed like Chevys. Behind the eye can bend the leaf spring.

 

[318willrun]

slapper bars should not be used on Mopars. They are not designed like Chevys. Behind the eye can bend the leaf spring.

okay