Frame Flex

It happens with fords and most dodges... but no so much chebby's.

http://i11.photobucket.com/albums/a186/imelmo/truck%20pics/buntingpulling.jpg

what can we do to stop it?

Chevy's don't flex, they just snap in two.

I would rather have a little flex.

I guess you could box the frame.

may sound dumb but whose truck is that?

Nice Avatar Marty:DLOLLOLLOLLOLLOLLOLLOLLOL

Stop the flex to stop the bounce.

YouTube - Broadcast Yourself.

says the vid is private

Not so sure why i'm looking at this post, i don't make enough power to worry about frame flex lol

Is it not playing?

It doesn't work for me Kevin.

works now

Chevy's don't flex, they just snap in two.

I would rather have a little flex.

I guess you could box the frame.

:whs: Haven't seen many Ford frames crack or dent unless it was a hard used work truck.

may sound dumb but whose truck is that?

That's buntings truck when it was running.

i personally think it looks bad ass when an ol' '79 ford w/ a screamin big block gets all hunched up in the middle.

You actually want some frame flex. What you don't want is flex that stores energy and causes a rebound - that is where the bounce comes from. You can also make things too stiff and cause some bounce, and high stress problems. I'm helping a buddy build a full tube chassis for his pulling truck right now and this has been a large portion of our thought process and consideration - How to give it enough flex and not cause any bouncing......

semi truck frames are designed to flex so they don't crack

may sound dumb but whose truck is that?

another from that event

http://inlinethumb03.webshots.com/6786/2035048350045160794S600x600Q85.jpg

some on call bunting and buy that truck

I always did dig the truck.

some on call bunting and buy that truck

Its sitting in front of his shop. I wonder what he would want for it?

The right amount of frame flex is a good thing.

As to why the newer chevy's don't have it? I would have to guess that's the design of their frame. That big drop in the middle under the cab would be my bet.

You actually want some frame flex. What you don't want is flex that stores energy and causes a rebound - that is where the bounce comes from. You can also make things too stiff and cause some bounce, and high stress problems. I'm helping a buddy build a full tube chassis for his pulling truck right now and this has been a large portion of our thought process and consideration - How to give it enough flex and not cause any bouncing......


Very good post Jason. A friend that owns a body shop swears the Ford frame is the toughest to work with. It takes a lot to bend it and a lot to pull it back.

The flex and bounce seems to become an issue once you reach a certain amount of power. It will get to the point that the stored energy releases when the tires start to spin. That's when the bounce starts. If you have enough power to spin the tires sooner the frame flexes less. Less energy is stored, thus no bounce. Traction, be it from the tires or the track, plays a big roll in this. When your stuck in the middle, set up is critical.

I nearly broke something every weekend till I cough that video. Once I could see what was happening I could then address the issue. I tried everything and talked to anyone that would listen. Mostly, even the old Ford gas pullers said it was because the truck has leaf springs on the front. I tried every combination I could find. The only thing that worked for me was to stiffen the frame. Once I got past a certain power level it became less and less of a problem.

I think that video was 06.

Check out Jason's vids! he can tell you all about BOUNCE!!:hehe::hehe: j/k

Check out Jason's vids! he can tell you all about BOUNCE!!:hehe::hehe: j/k

And broken parts :doh:

Call me, we have rules issues to discuss......

Hey jason, have you ever paid attn. to my gas truck......? It never hops.......ever, Figured this out a couple a years ago......Its actually not very complicated at all, we have fixed many many different leaf sprung trucks, next time ya get a chance just look under the front of my gas truck.

Oh yeah, It used to hop like a jack-rabbit all the time.

Watch a dodge with good power pull, and if it hooks up to the track good you will see the frame flex hard enough that the cab and bed will almost hit at the bottom.You never see that with a newer ford. What needs to be done to a ford suspension to keep from bouncing?????

I tried different spring combinations, bump stops, front traction bars, you name it. I did some things under the frame to make it more ridgid. Take the flex out of the equasion. Choose the right tire and make it work for you.

WHEEL SPEED!

Bounce can come anywhere on the track. It starts when the track speed and tire speed begin to become equal.

Sorry have to go to dinner. :doh:

I have the most problem with bounce right off the line.Took care of alot of it by adjusting air preasure. My bounce always started at the front and moved back.

Hey jason, have you ever paid attn. to my gas truck......? It never hops.......ever, Figured this out a couple a years ago......Its actually not very complicated at all, we have fixed many many different leaf sprung trucks, next time ya get a chance just look under the front of my gas truck.

You have a gas truck?!?!?!? :poke: Yes I have watched it hook, and I have seen your front spring pack ;) I have discovered that my bounce is in the rear of the truck at the start of the track. I know what I need to do to fix it after I realized what was happening..... taking out a few leafs on both sides in the rear will help out a TON, in fact pretty similar to what you gas guys do on the front of your trucks.

I have the most problem with bounce right off the line.Took care of alot of it by adjusting air preasure. My bounce always started at the front and moved back.

I always thought the same thing till I got to watch a couple videos. I'll post another one. It's not the best but you can what happens.
Mine always started soon after the start. Sometimes slipping the clutch further would keep it from happening. All that did was limit the energy transfered to the frame, less flex and burn up the clutch. Get the tires to spin sooner and choose the right tire.
I run Truxus XTerrains. Some say they are too agressive or just don't work. It's what works for me. I'd like to try the STS's but their just not in the budget right now.

YouTube - Dayton Kevin 1

YouTube - Dayton Kevin 2

Don't look at the dirt, the weather has been terrible. The traction bars are off. They attach to the long, lower stud.

http://www.powerstrokenation.com/photopost/data/500/medium/DSCF11482.jpg

http://www.powerstrokenation.com/photopost/data/500/medium/DSCF11492.jpg

http://www.powerstrokenation.com/photopost/data/500/medium/DSCF11502.jpg

I watched videos. I had same type of bounce. One of the worst times was at the Big Butler Fair. I think there might be a video of that on youtube also.

I have severe bounce goin on in my 80 gas puller. I have dents in my roof from my helmet hitting so hard. I tried a set of F-superduty rear springs clamped together but still has bounce. Im thinking in my truck it is the swiss cheese 80 frame that has about 8 2" holes down the side of it and it is only 3/16 thick. I bought a 97 f350 frame and have trussed the inside of the frame rails using 1 1/4" square tubing. I trussed the frame from the rear shock mount up to the trans cross member. I hope this fixes the prob.
4651

That should be a good start. When you get it out take a video from the side where you can see the whole truck. Should show you what it's doing.

the dodge frames will and do crack ecspecially if they have traction bars. the best way to prevent this is to finish boxing the frame in.

More horsepower doesn't always stop the bouncing either. Sometimes the truck's just hell bent on it.

http://www.youtube.com/watch?v=EF9g929U9eA

I've never got the chance to look at the frame close on that truck to see what's done to it. HP and traction go hand in hand contributing to the bounce.

Still workin the bounce out of mine, it all revolves around my front end it starts there and works it way through out. On the list for this year is much stronger tie rod and drag link to keep it from actin like a dmax.

Bean your truck does some crazy stuff up front.

double overtime's problem was motor was too far forward in the frame causing poor weight transfer.

The only thing i can come up with on beans truck is that the fummins is sitting in the wrong spot and causing poor weight transfer but you would think with a full bodied truck etc that it would not be enough to affect it, Double overtime for instance has like 80 percent of its weight on the front axle.

Mine doesnt hop at all? guess i am lucky

lol

Travis

There ya have it Bean! Ford/Navistar came up with a fix a long time ago for front end bounce, it comes in a nice clean kit and if your lucky you can even get one already installed in a truck. Its call the PSD. Put it back in you quitter!

double overtime's problem was motor was too far forward in the frame causing poor weight transfer.

The only thing i can come up with on beans truck is that the fummins is sitting in the wrong spot and causing poor weight transfer but you would think with a full bodied truck etc that it would not be enough to affect it, Double overtime for instance has like 80 percent of its weight on the front axle.

Mine doesnt hop at all? guess i am lucky

lol

Travis


I moved it back 2"s last time I had the motor out cant tell any differance on the track. I just made a weight bracket so I can hang a few out front and stripped the hell out of the truck, hopin that will help some.

Auto's dont seem to bounce as bad as the sticks but it would also seem it has alot to do with how much hp you are puttin to the track. PSD dont bounce since its lacking in that area....:poke:

are you guys still running leaf spings in the front, if so that will cause hop also. i bet a coil sping conversion would help a bunch

are you guys still running leaf spings in the front, if so that will cause hop also. i bet a coil sping conversion would help a bunch

Have you ever seen an 05+ truck pull before :poke: :D

I haven't paid attention to the '05+ trucks...what happens when they pull?

LOL The front tires shake like a marble in a can.

and they get to bouncing like a pogo stick :)

:whs:LOL it real bad. dodges can be that way sometimes too.

i thought it was the same coil spring idea as the dodges. i never hqad any problems out of my dodge and i don't know of anyother dodges that have had issues. There is no axle wrap with coil springs, too much traction can cause bounce also

The Dodge has an upper and lower control arm. The Ford has a single arm with upper and lower bushings.

i thought it was the same coil spring idea as the dodges. i never hqad any problems out of my dodge and i don't know of anyother dodges that have had issues. There is no axle wrap with coil springs, too much traction can cause bounce also

Dodges have coil overs - Fords do not.

Dodges have coil overs - Fords do not.

i beleive in 05 ford switched to coil spings, my brother has an 07 f350 and it has coils

i beleive in 05 ford switched to coil spings, my brother has an 07 f350 and it has coils

Coil overs and coil springs are different - google it. FYI - I own a 2005 F350 as well.

Coil overs and coil springs are different - google it. FYI - I own a 2005 F350 as well.


Other than space requirements.... what's the difference to function if the dampener is inside the coil spring or next to it? Does the coil itself deflect badly without a shock tube to keep it centered?

What's the functional difference?

LOL I thought the same thing. The problem is how the front axle is attached. The Dodge has an upper and lower arm, four link style. The Ford has a single arm with an upper and lower bushing.

and spring rate has alot to do with it as well

Hang a little weight i guess bean, i can squeeze about 300 on mine

Travis

What year is Beans truck? I thought he had leafs up front.

Other than space requirements.... what's the difference to function if the dampener is inside the coil spring or next to it? Does the coil itself deflect badly without a shock tube to keep it centered?

What's the functional difference?

I don't think there is a functional difference. Regardless the front suspension set up on the Dodge is not the same as the 05 up Fords. That was the point. I just reread the posts and do not see where I mentioned there being a functional difference, so I'm not sure where you're getting that from.


Kevin I think Bean's truck is Sapps' old dually w/ 05 front end appearance (grill/lights/bumpers) - it was a 7.3 originally (Bean correct me if I am wrong).

What year is Beans truck? I thought he had leafs up front.

2002

Coil overs and coil springs are different - google it. FYI - I own a 2005 F350 as well.

when i think coilovers i think of the shock and spring as one unit. dodges have coil springs just like the fords, but they just use it in a different configuration. FYI-i've owned a 94,95,98 and 99 all dodge cummins and now a 97 f250

I don't think there is a functional difference. Regardless the front suspension set up on the Dodge is not the same as the 05 up Fords. That was the point. I just reread the posts and do not see where I mentioned there being a functional difference, so I'm not sure where you're getting that from.


Kevin I think Bean's truck is Sapps' old dually w/ 05 front end appearance (grill/lights/bumpers) - it was a 7.3 originally (Bean correct me if I am wrong).


I thought we were talking about suspension design induced hop/bounce. If the difference in spring/shock placement between the Dodge and Ford has no functional relevance, then I think you may have wasted our time bringing it up.

I didn't know, and still don't know this to be the case. My questions were genuine that I asked. I didn't know what the functional difference might have been.

Ya I am hoping to hang 300 for next year in 8k classes. Also have some things to try on the steering to get the wobble out of it, goin to hiems and cm instead of standard tie rods. If that dont work then on to the next trick.

when i think coilovers i think of the shock and spring as one unit. dodges have coil springs just like the fords, but they just use it in a different configuration. FYI-i've owned a 94,95,98 and 99 all dodge cummins and now a 97 f250
Correct - Dodges have coil overs. A coil over is a different configuration than the regular coil sprung hence why I said in the first place why they are different. See pic - Dodge w/ coil over. Ford has spring next to shock as Charles pointed out.
http://images5.ecarlist.com/photos/1198_254979/254979_003_7040.jpg

I thought we were talking about suspension design induced hop/bounce. If the difference in spring/shock placement between the Dodge and Ford has no functional relevance, then I think you may have wasted our time bringing it up.

I didn't know, and still don't know this to be the case. My questions were genuine that I asked. I didn't know what the functional difference might have been.

Haha well I wish I was more well versed in suspension, unfortunately for me I was just stating there is a physical difference. I can ask some guys who raced GT class @ 24hrs Daytona next time they are at our shop. I feel like there may be actual functional differences on race cars. Now, as far as our trucks go, I do not know. But maybe they will shed some light on something. One thing I can tell you from working on the german cars is that often times they swap to adjustable coil overs if they don't have them, instead of springs w/ shocks or non-adjustable coil overs.

DOT uses coil overs, I think Stroked Out might as well. I'd think DOT uses them instead of the 05 suspension for a reason. I wonder if adjustable coil overs would be useful in pulling?
Here's DOT
http://image.dieselpowermag.com/f/9105026/0802dp_12_z+2005_ford_f350+lift_off_front_ends.jpg

Charles, any chance you could ask the Supra dudes what they are running? Are they running adjustable coil overs? There's gotta be something to it - otherwise it seems like if you needed to swap shocks, or just springs, it'd be simpler to have them separated.

There's a very good chance I could be wasting your time but hopefully I'm not.

The shock configuration is not the problem. The problem with the late model Fords is how the front axle is attached. I listed the differences between the Dodge and Ford in an earlier post. #54

Based on personal expeirence and watching at the pulls, it seems to me as the ext cab short bed Fords always want to bounce. I have a freind I pull with all the time and we both have ext cab long beds and neither of us have ever had bounce problems except when he tried just running air bags and no solid stop. Both of us run a single traction bar and solid stops with no problems.

Last year i ran my extended cab short box ford, did like 6-8 fairs never bounced once, I watch the air pressure pretty close and run long single tube traction bars.

Not to hurt anyones feelings but most bounce comes with power, the more power transfer you get to the tires the more it wants to move everything around. I have seen plenty of chipped trucks with nothing on them at all pull with no hop at all. Try the same thing with 500+ hp and its a nightmere.

Not to hurt anyones feelings but most bounce comes with power, the more power transfer you get to the tires the more it wants to move everything around. I have seen plenty of chipped trucks with nothing on them at all pull with no hop at all. Try the same thing with 500+ hp and its a nightmere.

True
Thier is alot to be said about rear end transfer too, My rear ladder bar setup works perfectly, but it was desighned by someone with more pulling expierence then 5 of the known puller in this thread combined,

if you get 300 on in a 8k class i will be impressed i can get 300 in a 3200lb class lol

Last year i ran my extended cab short box ford, did like 6-8 fairs never bounced once, I watch the air pressure pretty close and run long single tube traction bars.

Im not saying its not possible, I just know several trucks Ive seen and helped with that happened to be ext shorties hopped like a rabbit. But like you said air press has some to do with it and theres that line where you can only help so much and the rest comes to personal preference (Air press) and driving sytle (Coming off the line etc)

Not to hurt anyones feelings but most bounce comes with power, the more power transfer you get to the tires the more it wants to move everything around. I have seen plenty of chipped trucks with nothing on them at all pull with no hop at all. Try the same thing with 500+ hp and its a nightmere.

Dont know if this was aimed at me or not(None taken if it was) but you do bring up a good point! With 530 hybrids, Id like at think im in the 450-475 rear wheel range, but havent got on a dyno to know. Also, if the budget allows, I want to send my H2E to ya to get modded sometime before June.

Coil overs and coil springs are different - google it. FYI - I own a 2005 F350 as well.

No, neither truck comes from the factory with coil overs.

The are both coil sprung front ends. Chrysler chose to put the shocks inside the coil for packaging reasons...save money on having a separate spring/shock perch.

Coilover shocks were developed in the racing industry, to allow user adjustability in ride height for various reasons: ride height, weight distribution, suspension geometry, main spring/tender spring ratios, etc. They are usually coupled with high end emulsion, monotube, or reservoir shocks that can be specifically valved for a particular application/course.

A lot of cases, the bounce comes from improper suspension setup, which includes spring rates, shock valving, ride height, etc.

Shocks with more rebound will control the hopping - springs that are stiffer/softer may have a different resonance - thus preventing the hopping that gets worse and worse.

just replacing bushings with heim ends may not solve the problem. The bushings in the applications have a certain durometer, designed to flex a certain amount for that application. Having zero deflection does not necessarily make it better.

The difference in the Dodge (5-link, or 4 link with a panhard rod) and the 05+ Fords (3-link) is the way the axle travels.

As the Dodge front end compresses, caster stays the same, but axle shifts, placing a huge load on all the joints, including the panhard rod. The upper and lower links start to act against themselves (push on the top, pull on the bottom, and vice versa), and it starts to death wobble...which will happen on a sled pull track at slow speeds, causing vibration and hop.

The Fords, with the 3 link, are nearly impossible to cause death wobble, as the joints do not act against themselves, pushing and pulling cyclically.

However, a lot of companies that offer a "4 link" lift like Rize, when jacked up that tall, with steep arm angles, will result in a perfectly fine truck having death wobble at speeds.

So...I hope I didn't rain on anyone's parade....:ford:

No, neither truck comes from the factory with coil overs.

The are both coil sprung front ends. Chrysler chose to put the shocks inside the coil for packaging reasons...save money on having a separate spring/shock perch.

Coilover shocks were developed in the racing industry, to allow user adjustability in ride height for various reasons: ride height, weight distribution, suspension geometry, main spring/tender spring ratios, etc. They are usually coupled with high end emulsion, monotube, or reservoir shocks that can be specifically valved for a particular application/course.

A lot of cases, the bounce comes from improper suspension setup, which includes spring rates, shock valving, ride height, etc.

Shocks with more rebound will control the hopping - springs that are stiffer/softer may have a different resonance - thus preventing the hopping that gets worse and worse.

just replacing bushings with heim ends may not solve the problem. The bushings in the applications have a certain durometer, designed to flex a certain amount for that application. Having zero deflection does not necessarily make it better.

The difference in the Dodge (5-link, or 4 link with a panhard rod) and the 05+ Fords (3-link) is the way the axle travels.

As the Dodge front end compresses, caster stays the same, but axle shifts, placing a huge load on all the joints, including the panhard rod. The upper and lower links start to act against themselves (push on the top, pull on the bottom, and vice versa), and it starts to death wobble...which will happen on a sled pull track at slow speeds, causing vibration and hop.

The Fords, with the 3 link, are nearly impossible to cause death wobble, as the joints do not act against themselves, pushing and pulling cyclically.

However, a lot of companies that offer a "4 link" lift like Rize, when jacked up that tall, with steep arm angles, will result in a perfectly fine truck having death wobble at speeds.

So...I hope I didn't rain on anyone's parade....:ford:

Good info!

No, neither truck comes from the factory with coil overs.

The are both coil sprung front ends. Chrysler chose to put the shocks inside the coil for packaging reasons...save money on having a separate spring/shock perch.

Coilover shocks were developed in the racing industry, to allow user adjustability in ride height for various reasons: ride height, weight distribution, suspension geometry, main spring/tender spring ratios, etc. They are usually coupled with high end emulsion, monotube, or reservoir shocks that can be specifically valved for a particular application/course.

A lot of cases, the bounce comes from improper suspension setup, which includes spring rates, shock valving, ride height, etc.

Shocks with more rebound will control the hopping - springs that are stiffer/softer may have a different resonance - thus preventing the hopping that gets worse and worse.

just replacing bushings with heim ends may not solve the problem. The bushings in the applications have a certain durometer, designed to flex a certain amount for that application. Having zero deflection does not necessarily make it better.

The difference in the Dodge (5-link, or 4 link with a panhard rod) and the 05+ Fords (3-link) is the way the axle travels.

As the Dodge front end compresses, caster stays the same, but axle shifts, placing a huge load on all the joints, including the panhard rod. The upper and lower links start to act against themselves (push on the top, pull on the bottom, and vice versa), and it starts to death wobble...which will happen on a sled pull track at slow speeds, causing vibration and hop.

The Fords, with the 3 link, are nearly impossible to cause death wobble, as the joints do not act against themselves, pushing and pulling cyclically.

However, a lot of companies that offer a "4 link" lift like Rize, when jacked up that tall, with steep arm angles, will result in a perfectly fine truck having death wobble at speeds.

So...I hope I didn't rain on anyone's parade....:ford:



Maybe on the street. Put them on some good clay and watch what happens.
Not near as bad if they can hang weight.

No, neither truck comes from the factory with coil overs.

The are both coil sprung front ends. Chrysler chose to put the shocks inside the coil for packaging reasons...save money on having a separate spring/shock perch.

Coilover shocks were developed in the racing industry, to allow user adjustability in ride height for various reasons: ride height, weight distribution, suspension geometry, main spring/tender spring ratios, etc. They are usually coupled with high end emulsion, monotube, or reservoir shocks that can be specifically valved for a particular application/course.

A lot of cases, the bounce comes from improper suspension setup, which includes spring rates, shock valving, ride height, etc.

Shocks with more rebound will control the hopping - springs that are stiffer/softer may have a different resonance - thus preventing the hopping that gets worse and worse.

just replacing bushings with heim ends may not solve the problem. The bushings in the applications have a certain durometer, designed to flex a certain amount for that application. Having zero deflection does not necessarily make it better.

The difference in the Dodge (5-link, or 4 link with a panhard rod) and the 05+ Fords (3-link) is the way the axle travels.

As the Dodge front end compresses, caster stays the same, but axle shifts, placing a huge load on all the joints, including the panhard rod. The upper and lower links start to act against themselves (push on the top, pull on the bottom, and vice versa), and it starts to death wobble...which will happen on a sled pull track at slow speeds, causing vibration and hop.

The Fords, with the 3 link, are nearly impossible to cause death wobble, as the joints do not act against themselves, pushing and pulling cyclically.

However, a lot of companies that offer a "4 link" lift like Rize, when jacked up that tall, with steep arm angles, will result in a perfectly fine truck having death wobble at speeds.

So...I hope I didn't rain on anyone's parade....:ford:

THNAKS!!!! i was starting to think that i didn't know what a coil over spirng looked like
http://www.desertrides.com/reference/images/terms/coilover.jpg

No, neither truck comes from the factory with coil overs.

The are both coil sprung front ends. Chrysler chose to put the shocks inside the coil for packaging reasons...save money on having a separate spring/shock perch.

Coilover shocks were developed in the racing industry, to allow user adjustability in ride height for various reasons: ride height, weight distribution, suspension geometry, main spring/tender spring ratios, etc. They are usually coupled with high end emulsion, monotube, or reservoir shocks that can be specifically valved for a particular application/course.

A lot of cases, the bounce comes from improper suspension setup, which includes spring rates, shock valving, ride height, etc.

Shocks with more rebound will control the hopping - springs that are stiffer/softer may have a different resonance - thus preventing the hopping that gets worse and worse.

just replacing bushings with heim ends may not solve the problem. The bushings in the applications have a certain durometer, designed to flex a certain amount for that application. Having zero deflection does not necessarily make it better.

The difference in the Dodge (5-link, or 4 link with a panhard rod) and the 05+ Fords (3-link) is the way the axle travels.

As the Dodge front end compresses, caster stays the same, but axle shifts, placing a huge load on all the joints, including the panhard rod. The upper and lower links start to act against themselves (push on the top, pull on the bottom, and vice versa), and it starts to death wobble...which will happen on a sled pull track at slow speeds, causing vibration and hop.

The Fords, with the 3 link, are nearly impossible to cause death wobble, as the joints do not act against themselves, pushing and pulling cyclically.

However, a lot of companies that offer a "4 link" lift like Rize, when jacked up that tall, with steep arm angles, will result in a perfectly fine truck having death wobble at speeds.

So...I hope I didn't rain on anyone's parade....:ford:

Thanks Denny! Where you been!? :poke:
:ford:

Thanks Denny! Where you been!? :poke:
:ford:

Out playing with my truck....water meth, nitrous, bigger turbo, injectors...

you know, the usual!

Getting' ready for sled pulling season!

To do away with bounce you can fluid fill your tires but then there is to much wt in the back. If you could find a suitable fluid that would not damage the tire and would not weigh much you would be set.

A set of rear tires filled with water would weigh a LOT!! But you could run tires a lil low to get a better ground surface and when the wt comes on they will not allow your hitch to go any lower as water don't compress. There would be zero recoil :)