Adjustable strut rods - durability for street use

[Ted265]

Hi all,
Seriously considering purchasing a set of QA1 adjustable strut rods for my hardtop. I have been doing some research and I'm convinced these will be a noticeable improvement to the cars handling but I have some concerns as to how these will hold up with heavy use and abuse on a high mileage street car.
First thing that jumped out at me with this design is the straight 9/16 thread at the control arm mount instead of the 5/8 shoulder on the factory rods, but i can easily turn up some small sleeves on a lathe to take up the gap at this mounting point.
Other concerns I have are how well the heim joints will hold up to shockloading from hitting pot holes at speed, railway crossings, cattle grids ect? And will the lack of a bushing induce cracking at the K-frame mount or pull the threads on the alloy stut rod? Also how much harshness do they add to the ride?
If I buy them I will get some rubber boots for the heim joints to keep road dirt out. I once had a LCA pivot pin shear on me at speed and it scared the crap outta me - not in a hurry to repeat the experience with a failed strut rod.
Would like some feedback from folks that have put a lot of street miles on them or stories of failures. I've talked to a bunch of guys running heim jointed rods on mustangs and they seem to love them - but their cars spend most of there time in the shed instead of being driven.
Cheers,
Ted.

 

[72bluNblu]

I ran the QA1 style adjustable strut rods on my Challenger for over 70k street miles using the car as my daily driver year round. Car saw dirt roads, mud, snow, etc. The heims were not booted and I didn’t do anything special to care for them. They’re the only part of that suspension to go the entire 70k miles, and there’s nothing wrong with them now. The same car ate the heims on the Hotchkis UCA’s I was running in 7k miles, and the second set has obvious wear after another 7k.

I also have a set of adjustable strut rods on my Duster, they were made by Dillenger chassis. They’ve got 30k + miles on them with no issues or visible wear. And no boots on them either. Both my Challenger and my Duster have 1.12” torsion bars. The Challenger ran 275/40/17’s up front for most of those miles, the Duster has 275/35/18’s. And 11.75” rotors on the Challenger, 13” rotors on the Duster. So lots of tire and braking loads on both those cars.

I wouldn’t run heims on the UCA’s of these cars again, but at the strut rods it’s not an issue at all. They’ll outlast any of the stock strut rod bushings hands down.

 

[RustyRatRod]

The QA1s are the ones I plan on getting for Vixen. They're nice, because they're double adjustable and you don't have to disconnect one end to make your adjustment. Cost is a bit more than some, but they're a quality product.

 

[Oldmanmopar]

Buy new 5 point seat belt harnesses with your purchase. Make sure your collapsible steering column is in place. Other then that you should be good to go. They are real pretty to look at though. I was thinking of painting my factory set gold. Keeping my wheels turned when parked so I can look at them and gloat over how pretty they look.

I have a set of adjustables here I pulled from a customers car. I use them to knock bearing races out . They mushroom over nice and protect your hand from the nammer The threaded end is nice to install a flat taper head allen so I can replace the edge to grab the race better. They are a nice rebuildable tool I'll have a long time. Great investment for a shop.

 

[Professor Fate]

Not directly answering your question, but before you invest in adjustable strut rods, be honest with yourself about your front end shop's abilities- most have no clue how to adjust a Chrysler t-bar suspension to begin with, and once you throw adjustable strut rods into the mix, they're totally lost. You're throwing another step into a process that they already don't understand.
So, unless you do your own alignments or have total faith in your shop, you may not get the full benefit from your investment.

 

[72bluNblu]

Buy new 5 point seat belt harnesses with your purchase. Make sure your collapsible steering column is in place. Other then that you should be good to go. They are real pretty to look at though. I was thinking of painting my factory set gold. Keeping my wheels turned when parked so I can look at them and gloat over how pretty they look.

I have a set of adjustables here I pulled from a customers car. I use them to knock bearing races out . They mushroom over nice and protect your hand from the nammer The threaded end is nice to install a flat taper head allen so I can replace the edge to grab the race better. They are a nice rebuildable tool I'll have a long time. Great investment for a shop.

And how many actual street miles have you used adjustable strut rods for? Zero?

Because I know the set you put on that hacked up drag race only K you copied from someone else has never sent any street or strip time, per your very own posts.

Just let it go man. You don’t have to use them. You clearly haven’t used them, since you keep posting things about them that simply aren’t true.

Not directly answering your question, but before you invest in adjustable strut rods, be honest with yourself about your front end shop's abilities- most have no clue how to adjust a Chrysler t-bar suspension to begin with, and once you throw adjustable strut rods into the mix, they're totally lost. You're throwing another step into a process that they already don't understand.
So, unless you do your own alignments or have total faith in your shop, you may not get the full benefit from your investment.

This is a very valid point. Most big chain alignment shops will not do the set up to install or tune adjustable strut rods to the proper length. You’ll need a race based alignment shop or one that does custom work. Or be willing to do it yourself. At the very least you should be willing to become familiar with how to do the install and tuning, because you will need to be knowledgeable about the process to make sure it was done properly.

They’re like any high performance aftermarket part- they can improve the performance and function of your car when used properly, but if they’re not used properly they can create issues. The factory stuff is low tech and leaves a lot of performance on the table, but it only installs one way so any moron can install them and there’s no adjustment to mess up. There’s also no adjustment to optimize your suspension. It’s like anything else, if you add a turbo to your engine you can make more horsepower and be more efficient. But if you just slap it on there you might puke your pistons all over the road.

 

[Ted265]

Haha calm down guys, I would rather not have this thread deleted before I can read the replies and learn something. It's OK to disagree and I will take on all information for and against these parts into consideration to help me make up my mind.

If you want to improve the suspension . The proper way to is to buy a complete fabricated suspension. eliminate the steering box and the t-bars.

This is not in my budget for this car, these aftermarket kits are very expensive to purchase over here in Australia and it gets a lot more involved than just a regular front end re-build.
Our registration laws are also fairly strict with regards to these types of modifications so they would want engineering reports, weld x-rays and such when I take the car in for inspection (more $$$). My daily is 2022 Kia Stinger GT so i will use that for when I want to do twisty mountain roads at high speed. For the valiant I just want to improve on what is there.
I have a set of bilstein shocks, MP 0.94" torsion bars, 27mm sway bar, roller bearing idler arm, variable ratio steering box, braced LCAs and bigger brakes to go on it. One of my STD struts has a bit of a bend in it and it's getting hard to find the rubber bushes now that's why I was looking at these vs stock replacement struts.
Have you or someone you know had a bad experience with these?

Not directly answering your question, but before you invest in adjustable strut rods, be honest with yourself about your front end shop's abilities- most have no clue how to adjust a Chrysler t-bar suspension to begin with, and once you throw adjustable strut rods into the mix, they're totally lost. You're throwing another step into a process that they already don't understand.
So, unless you do your own alignments or have total faith in your shop, you may not get the full benefit from your investment.

Yeah shop's that can do a propper alignment on these are few and far between. I have a shop semi-local to me that do a good job - couple of older guys that did their apprenticeship when these cars were still fairly new, so they are familiar with them. I'm not intending to use the adjustable struts as an alignment tool, more to free up movement in the front end (and replace my bent strut). I would like to have a go at doing my own alignments and have some good threads on here bookmarked to read through some more.

You’ll need a race based alignment shop or one that does custom work. Or be willing to do it yourself. At the very least you should be willing to become familiar with how to do the install and tuning, because you will need to be knowledgeable about the process to make sure it was done properly.

They’re like any high performance aftermarket part- they can improve the performance and function of your car when used properly, but if they’re not used properly they can create issues.

Not adverse to installing and setting them up myself - I would imagine one would start at the same length as the stock strut then adjust as necessary to keep the LCA perpendicular to the frame rail and be able to travel between the bumpstops without any binding?
Would the torsion bars need to be in place to help locate the LCA or is it done with just the spindle & upper/lower arms installed?
Did you notice a much harsher ride after installing them?
Any more feedback welcome.
Cheers,

 

[Ironracer]

Hi all,
Seriously considering purchasing a set of QA1 adjustable strut rods for my hardtop. I have been doing some research and I'm convinced these will be a noticeable improvement to the cars handling but I have some concerns as to how these will hold up with heavy use and abuse on a high mileage street car.
First thing that jumped out at me with this design is the straight 9/16 thread at the control arm mount instead of the 5/8 shoulder on the factory rods, but i can easily turn up some small sleeves on a lathe to take up the gap at this mounting point.
Other concerns I have are how well the heim joints will hold up to shockloading from hitting pot holes at speed, railway crossings, cattle grids ect? And will the lack of a bushing induce cracking at the K-frame mount or pull the threads on the alloy stut rod? Also how much harshness do they add to the ride?
If I buy them I will get some rubber boots for the heim joints to keep road dirt out. I once had a LCA pivot pin shear on me at speed and it scared the crap outta me - not in a hurry to repeat the experience with a failed strut rod.
Would like some feedback from folks that have put a lot of street miles on them or stories of failures. I've talked to a bunch of guys running heim jointed rods on mustangs and they seem to love them - but their cars spend most of there time in the shed instead of being driven.
Cheers,
Ted.

Glad That didn't hurt You, or any Passengers! Very good Questions also!

 

[Ted265]

Yes, very lucky no one was hurt and minimal damage to the car but could have been much worse. It was an aftermarket pin, I'm guessing wrong grade of steel for the application/sized incorrectly at the K-frame mount. Or I just got one with a flaw that slipped through QC.

 

[junkyardhero]

this is one of those situations where you need to honest with yourself and how you plan to drive the car and think about if you need them or if you want them.

if other components of your suspension have been upgraded these would be a nice addition and probably compliment the system well. if you have worn out stock stuff and you're rolling on 14" 205/70's that money would probably be better spent elsewhere.

the few sets that i've installed had no discernible noise in operation and showed no undue wear during routine safety checks.

btw, it's okay if you just want them just to have them. no harm in that at all.

ETA: i just looked back at your set up. yeah, i'd totally go with set with what you have cooking.

 

[Ironracer]

Yes, very lucky no one was hurt and minimal damage to the car but could have been much worse. It was an aftermarket pin, I'm guessing wrong grade of steel for the application/sized incorrectly at the K-frame mount. Or I just got one with a flaw that slipped through QC.

Man, that's just messed up! I had an 02 Ram with a 360 four-door with a tow package 85,000 truck, second owner, the original bearings got a little loose on the hubs at 285,000 so for $138 bucks I bought a different hub bearing, from Advance Auto, after a few thousand miles it separated in half, from my passenger front! Took the tire, rim, half the Hub, the brake caliper, part of the steering knuckle, and some other parts. I have pictures on Google photos. I was going to go to a friend's house and get on the Veterans Expressway he told me he was going to go ahead and do something else for the day I was driving up to the Walgreens I was doing three miles an hour and that thing separated! If I'd have been on the interstate man that it would probably killed a few people

 

[72bluNblu]

Haha calm down guys, I would rather not have this thread deleted before I can read the replies and learn something. It's OK to disagree and I will take on all information for and against these parts into consideration to help me make up my mind.

This is not in my budget for this car, these aftermarket kits are very expensive to purchase over here in Australia and it gets a lot more involved than just a regular front end re-build.
Our registration laws are also fairly strict with regards to these types of modifications so they would want engineering reports, weld x-rays and such when I take the car in for inspection (more $$$). My daily is 2022 Kia Stinger GT so i will use that for when I want to do twisty mountain roads at high speed. For the valiant I just want to improve on what is there.
I have a set of bilstein shocks, MP 0.94" torsion bars, 27mm sway bar, roller bearing idler arm, variable ratio steering box, braced LCAs and bigger brakes to go on it. One of my STD struts has a bit of a bend in it and it's getting hard to find the rubber bushes now that's why I was looking at these vs stock replacement struts.
Have you or someone you know had a bad experience with these?

Yeah shop's that can do a propper alignment on these are few and far between. I have a shop semi-local to me that do a good job - couple of older guys that did their apprenticeship when these cars were still fairly new, so they are familiar with them. I'm not intending to use the adjustable struts as an alignment tool, more to free up movement in the front end (and replace my bent strut). I would like to have a go at doing my own alignments and have some good threads on here bookmarked to read through some more.

Not adverse to installing and setting them up myself - I would imagine one would start at the same length as the stock strut then adjust as necessary to keep the LCA perpendicular to the frame rail and be able to travel between the bumpstops without any binding?
Would the torsion bars need to be in place to help locate the LCA or is it done with just the spindle & upper/lower arms installed?
Did you notice a much harsher ride after installing them?
Any more feedback welcome.
Cheers,

Yes, your thoughts on the install are right on. Start with the functional length between the K and the LCA being the same as with the stock strut rods for the adjustable strut rod and work from there. You want the LCA to be perpendicular to the frame, and you want it to be free of any binding when it travels up and down. Adjustable strut rods are not for adjusting the alignment specs, although you may see a change in the alignment numbers after installing them. The goal is the free movement of the LCA up and down, while reducing movement fore/aft.

You'll want to have as much of the suspension installed as possible while still being able to check for resistance/binding. So, torsion bars in, UCA's, spindle, LCA's installed. You'll need to removed the torsion bar adjusters so you can cycle the LCA up and down by hand. You'll also need the shocks out, and if you have a front sway bar you will want that disconnected as well. Then cycle the suspension up and down, from bump stop to bump stop, and check for binding. If you know where in the range of travel your ride height is that will be better too, since you'll want that to be the neutral spot. It takes a little trial and error, especially the first time, to get a feel for what is normal resistance and what is binding. When you think you have it good, put another turn on the adjustment in one direction or the other and see what that does. If you're right, it should be more binding, if you're not, you may get less.

I've found with my cars that the adjustable strut rod ends up being a bit shorter than the factory strut rod, but I also use Delrin or poly LCA bushings, so the LCA may be slightly farther forward with that arrangement than with the stock bushings.

Adding the adjustable strut rods will not make the ride harsher. If anything, it should smooth it out. The strut rods should not be affecting the up and down travel of the LCA, this is especially true for the adjustable strut rods. So the ride quality shouldn't change. What does change is the amount of forward/backward movement the LCA can have under acceleration and braking. That directly moves the lower ball joint, which means caster changes. With the adjustable strut rod there shouldn't be any forward and backward movement, except for the tiny amount built into the changes in the arc when the strut rods moves up and down. But that's at an angle to the LCA too.

This isn't my video, another member took this of his LCA and strut rod. It shows how much movement there is with the factory arrangement. This is just a drive around the block and a slow speed stop. Watch the front end of the strut rod, and how much it moves around. That's all fore/aft movement in the LCA. IMO, the adjustable strut rods are a great addition even if everything else is stock. It will reduce that caster change, making the handling much more accurate, without affecting ride quality.

Strut rod deflection

 

[Ricks70Duster340]

Yes, your thoughts on the install are right on. Start with the functional length between the K and the LCA being the same as with the stock strut rods for the adjustable strut rod and work from there. You want the LCA to be perpendicular to the frame, and you want it to be free of any binding when it travels up and down. Adjustable strut rods are not for adjusting the alignment specs, although you may see a change in the alignment numbers after installing them. The goal is the free movement of the LCA up and down, while reducing movement fore/aft.

You'll want to have as much of the suspension installed as possible while still being able to check for resistance/binding. So, torsion bars in, UCA's, spindle, LCA's installed. You'll need to removed the torsion bar adjusters so you can cycle the LCA up and down by hand. You'll also need the shocks out, and if you have a front sway bar you will want that disconnected as well. Then cycle the suspension up and down, from bump stop to bump stop, and check for binding. If you know where in the range of travel your ride height is that will be better too, since you'll want that to be the neutral spot. It takes a little trial and error, especially the first time, to get a feel for what is normal resistance and what is binding. When you think you have it good, put another turn on the adjustment in one direction or the other and see what that does. If you're right, it should be more binding, if you're not, you may get less.

I've found with my cars that the adjustable strut rod ends up being a bit shorter than the factory strut rod, but I also use Delrin or poly LCA bushings, so the LCA may be slightly farther forward with that arrangement than with the stock bushings.

Adding the adjustable strut rods will not make the ride harsher. If anything, it should smooth it out. The strut rods should not be affecting the up and down travel of the LCA, this is especially true for the adjustable strut rods. So the ride quality shouldn't change. What does change is the amount of forward/backward movement the LCA can have under acceleration and braking. That directly moves the lower ball joint, which means caster changes. With the adjustable strut rod there shouldn't be any forward and backward movement, except for the tiny amount built into the changes in the arc when the strut rods moves up and down. But that's at an angle to the LCA too.

This isn't my video, another member took this of his LCA and strut rod. It shows how much movement there is with the factory arrangement. This is just a drive around the block and a slow speed stop. Watch the front end of the strut rod, and how much it moves around. That's all fore/aft movement in the LCA. IMO, the adjustable strut rods are a great addition even if everything else is stock. It will reduce that caster change, making the handling much more accurate, without affecting ride quality.

Strut rod deflection

Just so I'm clear about this (my original strut rods are long gone); the strut rods should be lengthened just until there is some binding, then back it off a turn?

 

[MMissile]

Been running them on my `70 cuda ragtop, since completion. Zeros issues, thus far.

 

[72bluNblu]

Just so I'm clear about this (my original strut rods are long gone); the strut rods should be lengthened just until there is some binding, then back it off a turn?

They should be set so there’s no binding within the range of available travel. Once I achieve that though I double check it by changing the adjustment by a turn and seeing if it adds binding.

Start with them set so the LCA is perpendicular to the frame, then make small adjustments until you get them free of any binding. They usually end up slightly on the shorter side from that start point, but it will be set up dependent.

It takes some practice to figure out what’s normal resistance and what’s binding, you’re lifting the whole weight of all the suspension components and dealing with whatever resistance you get at the pivot points/bushings. If you have rubber bushings in the system they add some resistance. But when you actually feel binding it gets more obvious.

 

[360notch]

Haha calm down guys, I would rather not have this thread deleted before I can read the replies and learn something. It's OK to disagree and I will take on all information for and against these parts into consideration to help me make up my mind.

This is not in my budget for this car, these aftermarket kits are very expensive to purchase over here in Australia and it gets a lot more involved than just a regular front end re-build.
Our registration laws are also fairly strict with regards to these types of modifications so they would want engineering reports, weld x-rays and such when I take the car in for inspection (more $$$). My daily is 2022 Kia Stinger GT so i will use that for when I want to do twisty mountain roads at high speed. For the valiant I just want to improve on what is there.
I have a set of bilstein shocks, MP 0.94" torsion bars, 27mm sway bar, roller bearing idler arm, variable ratio steering box, braced LCAs and bigger brakes to go on it. One of my STD struts has a bit of a bend in it and it's getting hard to find the rubber bushes now that's why I was looking at these vs stock replacement struts.
Have you or someone you know had a bad experience with these?

Yeah shop's that can do a propper alignment on these are few and far between. I have a shop semi-local to me that do a good job - couple of older guys that did their apprenticeship when these cars were still fairly new, so they are familiar with them. I'm not intending to use the adjustable struts as an alignment tool, more to free up movement in the front end (and replace my bent strut). I would like to have a go at doing my own alignments and have some good threads on here bookmarked to read through some more.

Not adverse to installing and setting them up myself - I would imagine one would start at the same length as the stock strut then adjust as necessary to keep the LCA perpendicular to the frame rail and be able to travel between the bumpstops without any binding?
Would the torsion bars need to be in place to help locate the LCA or is it done with just the spindle & upper/lower arms installed?
Did you notice a much harsher ride after installing them?
Any more feedback welcome.
Cheers,

I imagine this will start a holy war, but my preference is adjustable struts (like Firm Feel) without heim joints, and rubber strut bushings. I have tried to be open minded about the benefit of heim joint struts, but have not gotten a good technical response from any of technical people I've talked to at 4 companies that sell them. So maybe somebody here can clear this up for me. The heim joint length makes the effective strut radius to the LCA shorter than stock, because the strut now rotates from the heim joint rather than from the K-member. As the LCA goes up and down, the struts push/pull sideways on the bottom of the LCAs because the distance from the bottom of the LCA to the heim joint changes, and the strut is a fixed length, aside from strut bushing give. The shorter the strut radius, the farther will be the sideways push/pull per vertcal distance of LCA movement. The original equipment, softer strut bushings allow some compliance to reduce that movement, but the stiffer bushings don't have much give. So, more push/pull from shorter strut radius, plus less bushing give, impedes LCA vertical freedom of movement and increases the amount of movement at the bottom of the LCA. Stiffer strut bushings probably give better steering wheel control when going over potholes and bumps than do the original factory bushing, but that could be achieved by stiffer strut bushings alone, without the heim joints.

Separate issue, heim joint struts and stiff bushings are wrong for drag racing, because they will hinder the unsprung weight from falling at launch.

 

[360notch]

I imagine this will start a holy war, but my preference is adjustable struts (like Firm Feel) without heim joints, and rubber strut bushings. I have tried to be open minded about the benefit of heim joint struts, but have not gotten a good technical response from any of technical people I've talked to at 4 companies that sell them. So maybe somebody here can clear this up for me. The heim joint length makes the effective strut radius to the LCA shorter than stock, because the strut now rotates from the heim joint rather than from the K-member. As the LCA goes up and down, the struts push/pull sideways on the bottom of the LCAs because the distance from the bottom of the LCA to the heim joint changes, and the strut is a fixed length, aside from strut bushing give. The shorter the strut radius, the farther will be the sideways push/pull per vertcal distance of LCA movement. The original equipment, softer strut bushings allow some compliance to reduce that movement, but the stiffer bushings don't have much give. So, more push/pull from shorter strut radius, plus less bushing give, impedes LCA vertical freedom of movement and increases the amount of movement at the bottom of the LCA. Stiffer strut bushings probably give better steering wheel control when going over potholes and bumps than do the original factory bushing, but that could be achieved by stiffer strut bushings alone, without the heim joints.

Separate issue, heim joint struts and stiff bushings are wrong for drag racing, because they will hinder the unsprung weight from falling at launch.

first sentence should have said, ", and with rubber strut bushings."

 

[Oldmanmopar]

I imagine this will start a holy war, but my preference is adjustable struts (like Firm Feel) without heim joints, and rubber strut bushings. I have tried to be open minded about the benefit of heim joint struts, but have not gotten a good technical response from any of technical people I've talked to at 4 companies that sell them. So maybe somebody here can clear this up for me. The heim joint length makes the effective strut radius to the LCA shorter than stock, because the strut now rotates from the heim joint rather than from the K-member. As the LCA goes up and down, the struts push/pull sideways on the bottom of the LCAs because the distance from the bottom of the LCA to the heim joint changes, and the strut is a fixed length, aside from strut bushing give. The shorter the strut radius, the farther will be the sideways push/pull per vertcal distance of LCA movement. The original equipment, softer strut bushings allow some compliance to reduce that movement, but the stiffer bushings don't have much give. So, more push/pull from shorter strut radius, plus less bushing give, impedes LCA vertical freedom of movement and increases the amount of movement at the bottom of the LCA. Stiffer strut bushings probably give better steering wheel control when going over potholes and bumps than do the original factory bushing, but that could be achieved by stiffer strut bushings alone, without the heim joints.

Separate issue, heim joint struts and stiff bushings are wrong for drag racing, because they will hinder the unsprung weight from falling at launch.

With the heims rotated in one direction they have more then enough travel to twist the opposite way. Actually more then needed. They allow for more of a drop if using the large heim with tappered spacers to let them travel.

Every sprint car relies on Heims for all suspension movement. Even the W link. That is all we use. You just have to know how to use them. Having removed the rubber bushing from the equation and only relying on the washer in front of the small heim will concave the k-member when hitting a pot hole. If making the strut rod solid, Brackets and bolts should be used to strengthen the k member as shown.

In the picture below the arms are on the stops and the heims are at full twist in that direction. When rotated they travel farther and easier then any other strut we have tested. been using heim ends for a long time. You just have to use them correctlB

 

[72bluNblu]

I imagine this will start a holy war, but my preference is adjustable struts (like Firm Feel) without heim joints, and rubber strut bushings. I have tried to be open minded about the benefit of heim joint struts, but have not gotten a good technical response from any of technical people I've talked to at 4 companies that sell them. So maybe somebody here can clear this up for me. The heim joint length makes the effective strut radius to the LCA shorter than stock, because the strut now rotates from the heim joint rather than from the K-member. As the LCA goes up and down, the struts push/pull sideways on the bottom of the LCAs because the distance from the bottom of the LCA to the heim joint changes, and the strut is a fixed length, aside from strut bushing give. The shorter the strut radius, the farther will be the sideways push/pull per vertcal distance of LCA movement. The original equipment, softer strut bushings allow some compliance to reduce that movement, but the stiffer bushings don't have much give. So, more push/pull from shorter strut radius, plus less bushing give, impedes LCA vertical freedom of movement and increases the amount of movement at the bottom of the LCA. Stiffer strut bushings probably give better steering wheel control when going over potholes and bumps than do the original factory bushing, but that could be achieved by stiffer strut bushings alone, without the heim joints.

Separate issue, heim joint struts and stiff bushings are wrong for drag racing, because they will hinder the unsprung weight from falling at launch.

You've got your theory correct, the shorter strut rod would create a shorter arc that can put more push/pull force on the LCA as it travels up and down.

If the strut rod was perpendicular the the LCA, that would have more of an impact. Since they're at an angle and both the strut rod and LCA travel in arcs, there is overlap. In that overlap there isn't any detectable binding.

The reality of it is that in the range of suspension travel that these cars have, ~5.5" total, the shorter strut rod does not induce noticeable binding if you tune the length correctly to the middle of the range of travel (which should also be your ride height, you can adjust the height and match the travel by altering the heights of the bump stops). I have set up several cars with the adjustable strut rods, I've had no issue getting the full range of travel to be free without binding. If you take out the bump stops and allow more travel, you can start to feel binding at the extreme ends of the range. But that's with more travel than should be allowed.

Stiffer bushings at the strut rod are a trade off. They do resist more fore/aft movement of the LCA, which is good because it reduces caster change. That kind of travel is in the video I linked above. The problem is that the stiffer bushing there will also add more resistance to the up and down suspension travel of the LCA, which you do not want. You want the LCA to move as freely as possible, so the suspension reactions aren't altered by stored energy unloading.

 

[360notch]

With the heims rotated in one direction they have more then enough travel to twist the opposite way. Actually more then needed. They allow for more of a drop if using the large heim with tappered spacers to let them travel.

Every sprint car relies on Heims for all suspension movement. Even the W link. That is all we use. You just have to know how to use them. Having removed the rubber bushing from the equation and only relying on the washer in front of the small heim will concave the k-member when hitting a pot hole. If making the strut rod solid, Brackets and bolts should be used to strengthen the k member as shown.

In the picture below the arms are on the stops and the heims are at full twist in that direction. When rotated they travel farther and easier then any other strut we have tested. been using heim ends for a long time. You just have to use them correctlB

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Moving the heim joint in front of the k-member is an excellent idea, because it lengthens the strut.

 

[jos51700]

My personal opinion is that for a street car, adjustable strut rods are a solution looking for a problem. It wasn't broke, but someone makes it for your car so you feel obligated to buy it.

 

[72bluNblu]

Moving the heim joint in front of the k-member is an excellent idea, because it lengthens the strut.

If it were necessary to lengthen the strut, but it’s not. Simply installing the adjustable strut rods that are commercially available would show you their range of motion is more than adequate to provide bind free motion through the whole range of suspension travel on these cars. The theory is sound, but it’s just not an issue in practice with the strut rods that are available.

My personal opinion is that for a street car, adjustable strut rods are a solution looking for a problem. It wasn't broke, but someone makes it for your car so you feel obligated to buy it.

You don’t have to build an engine with twice as much HP as the factory did either. Or run better tires or brakes either. But people do it don’t they?

The QA1 style strut rods on my Challenger had absolutely no issues in 70k miles, which is probably more miles than you’ll get out of any of the rubber replacement bushings currently available. And the adjustable struts absolutely help to improve handling. If all you do is putt around on sunny weekends and park on the grass at the local show, the rubber bushings will do just fine.

 

[360notch]

If it were necessary to lengthen the strut, but it’s not. Simply installing the adjustable strut rods that are commercially available would show you their range of motion is more than adequate to provide bind free motion through the whole range of suspension travel on these cars. The theory is sound, but it’s just not an issue in practice with the strut rods that are available.


You don’t have to build an engine with twice as much HP as the factory did either. Or run better tires or brakes either. But people do it don’t they?

The QA1 style strut rods on my Challenger had absolutely no issues in 70k miles, which is probably more miles than you’ll get out of any of the rubber replacement bushings currently available. And the adjustable struts absolutely help to improve handling. If all you do is putt around on sunny weekends and park on the grass at the local show, the rubber bushings will do just fine.

Yes, your thoughts on the install are right on. Start with the functional length between the K and the LCA being the same as with the stock strut rods for the adjustable strut rod and work from there. You want the LCA to be perpendicular to the frame, and you want it to be free of any binding when it travels up and down. Adjustable strut rods are not for adjusting the alignment specs, although you may see a change in the alignment numbers after installing them. The goal is the free movement of the LCA up and down, while reducing movement fore/aft.

You'll want to have as much of the suspension installed as possible while still being able to check for resistance/binding. So, torsion bars in, UCA's, spindle, LCA's installed. You'll need to removed the torsion bar adjusters so you can cycle the LCA up and down by hand. You'll also need the shocks out, and if you have a front sway bar you will want that disconnected as well. Then cycle the suspension up and down, from bump stop to bump stop, and check for binding. If you know where in the range of travel your ride height is that will be better too, since you'll want that to be the neutral spot. It takes a little trial and error, especially the first time, to get a feel for what is normal resistance and what is binding. When you think you have it good, put another turn on the adjustment in one direction or the other and see what that does. If you're right, it should be more binding, if you're not, you may get less.

I've found with my cars that the adjustable strut rod ends up being a bit shorter than the factory strut rod, but I also use Delrin or poly LCA bushings, so the LCA may be slightly farther forward with that arrangement than with the stock bushings.

Adding the adjustable strut rods will not make the ride harsher. If anything, it should smooth it out. The strut rods should not be affecting the up and down travel of the LCA, this is especially true for the adjustable strut rods. So the ride quality shouldn't change. What does change is the amount of forward/backward movement the LCA can have under acceleration and braking. That directly moves the lower ball joint, which means caster changes. With the adjustable strut rod there shouldn't be any forward and backward movement, except for the tiny amount built into the changes in the arc when the strut rods moves up and down. But that's at an angle to the LCA too.

This isn't my video, another member took this of his LCA and strut rod. It shows how much movement there is with the factory arrangement. This is just a drive around the block and a slow speed stop. Watch the front end of the strut rod, and how much it moves around. That's all fore/aft movement in the LCA. IMO, the adjustable strut rods are a great addition even if everything else is stock. It will reduce that caster change, making the handling much more accurate, without affecting ride quality.

Strut rod deflection

Regarding your travel experiment, with the torsion bar removed and using Delrin or poly bushings, isn't the LCA free to slide on the pin when the LCA is moved up and down?

 

[72bluNblu]

Regarding your travel experiment, with the torsion bar removed and using Delrin or poly bushings, isn't the LCA free to slide on the pin when the LCA is moved up and down?

The torsion bar should be installed when tuning the length of the adjustable strut rods, you want the suspension as fully assembled as possible so the binding represents what will actually happen when the car is on the road. So I check for binding with the suspension fully assembled with the following exceptions- torsion bar adjusters are removed, shocks are removed, and the sway bar (if present) is unhooked.

Regardless, the torsion bars don't keep the LCA's from moving about (although ultimately they would keep the LCA from coming completely off the pivot shaft). The torsion bar socket and anchor are further apart than the length of the torsion bar, which is done intentionally because the torsion bar itself will shorten and lengthen slightly when it loads and unloads. But that also means the torsion bar wouldn't keep the LCA from moving back and forth a bit on the shaft.

The LCA's movement forward/aft is constrained by the strut rod. The poly and delrin LCA bushings do allow the LCA to slide on the pivot shaft, but the distance is controlled by the strut rod. Which is why I always recommend adjustable strut rods with poly or delrin LCA bushings, so you can tune the length of the strut rod to correctly locate the LCA and prevent any binding.

With the factory rubber bushings at the LCA and strut rod, there will be more forward/aft movement of the LCA at the outer ball joint than with poly/delrin bushings and an adjustable strut rod. That movement will all be flex in the rubber, but the deflection will be a larger distance (again, you can see that deflection in the video clip I posted earlier). And if the strut rods were removed, the LCA's could travel far enough to destroy the rubber LCA bushings.

The idea that the LCA can slide off the pivot shaft with poly/delrin bushings is just silly, the LCA's are constrained exactly the same way as with rubber bushings because the rubber LCA bushing does not constrain the forward/aft movement of the LCA. If you remove the strut rod you can pry the LCA right off the pivot shaft, even with the OE style rubber LCA bushings. It requires more force than sliding the LCA off the pivot shaft with poly/delrin bushings, but the amount of force required to peel the LCA off the pivot shaft with rubber LCA bushings is still less than what the LCA sees in use on the car. Regardless, only a fool would remove their strut rods and go for a drive, so it's moot to begin with.

 

[360notch]

The torsion bar should be installed when tuning the length of the adjustable strut rods, you want the suspension as fully assembled as possible so the binding represents what will actually happen when the car is on the road. So I check for binding with the suspension fully assembled with the following exceptions- torsion bar adjusters are removed, shocks are removed, and the sway bar (if present) is unhooked.

Regardless, the torsion bars don't keep the LCA's from moving about (although ultimately they would keep the LCA from coming completely off the pivot shaft). The torsion bar socket and anchor are further apart than the length of the torsion bar, which is done intentionally because the torsion bar itself will shorten and lengthen slightly when it loads and unloads. But that also means the torsion bar wouldn't keep the LCA from moving back and forth a bit on the shaft.

The LCA's movement forward/aft is constrained by the strut rod. The poly and delrin LCA bushings do allow the LCA to slide on the pivot shaft, but the distance is controlled by the strut rod. Which is why I always recommend adjustable strut rods with poly or delrin LCA bushings, so you can tune the length of the strut rod to correctly locate the LCA and prevent any binding.

With the factory rubber bushings at the LCA and strut rod, there will be more forward/aft movement of the LCA at the outer ball joint than with poly/delrin bushings and an adjustable strut rod. That movement will all be flex in the rubber, but the deflection will be a larger distance (again, you can see that deflection in the video clip I posted earlier). And if the strut rods were removed, the LCA's could travel far enough to destroy the rubber LCA bushings.

The idea that the LCA can slide off the pivot shaft with poly/delrin bushings is just silly, the LCA's are constrained exactly the same way as with rubber bushings because the rubber LCA bushing does not constrain the forward/aft movement of the LCA. If you remove the strut rod you can pry the LCA right off the pivot shaft, even with the OE style rubber LCA bushings. It requires more force than sliding the LCA off the pivot shaft with poly/delrin bushings, but the amount of force required to peel the LCA off the pivot shaft with rubber LCA bushings is still less than what the LCA sees in use on the car. Regardless, only a fool would remove their strut rods and go for a drive, so it's moot to begin with.

Thank you for this information, but I'm only asking about your travel test. The simple question is, "Is it possible for the LCA to slide on the pin during that test?". Because if i can, it would never bind.