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Wagonstien taking fully independent suspension to the next level


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191 replies to this topic

#26 dwuollet

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Posted 12 September 2011 - 03:56 PM

Numbchux, so just to be perfectly clear... It's a bad idea to turn the tie rod ends over?

I have a two inch lift and there seems like a lot of pressure on the tie rod ends when the suspension is at full droop, I've been thinking that turning them over would relieve this. Other than lowering the drive train do you have a suggestion for a fix? Thanks.

#27 Numbchux

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Posted 12 September 2011 - 10:33 PM

semi-off topic: so verdict? tie rods flipped good or bad?\


RV


Numbchux, so just to be perfectly clear... It's a bad idea to turn the tie rod ends over?


IMO, flipping just the TRE over is a bad idea. If both sides compress simultaneously, the tires will toe-in equally, and it will stay fairly stable. But if one side compresses (you hit a bump on one side), that wheel will angle in, and the other will stay straight. Some simple geometry calculations could tell you exactly how many degrees the toe would change. It might only be half a degree, but it might be 2 or 3.


Full disclosure. I have not tried it. I love suspension geometry. I play with it in simulators (common driving games like gran-turismo and forza, and I do some ground-up vehicle design for the open-source PC game Rigs of Rods), and in real life. I love having soft suspension with a ton of travel. I run 17x8 wheels with low profile summer tires on my celica, and the only suspension mod I've done, is disconnect the front sway bar to reduce understeer. And as crew-chief for a stage rally team, I have some experience with suspension tuning. This is not something I would even consider on a vehicle that I planned to drive more than about 20mph. I might do it on a go-kart or something....but that's it.


I have a two inch lift and there seems like a lot of pressure on the tie rod ends when the suspension is at full droop, I've been thinking that turning them over would relieve this. Other than lowering the drive train do you have a suggestion for a fix? Thanks.


Nothing easy. Honestly, IMO if you're reaching the edge of the TREs travel on a fairly simple build (nothing like what this thread is talking about), you have too much suspension lift. Having the control arms at that angle will help your roll center, but effect the way the suspension transfers force into the body, and amplify the positive camber on the front end (none of these things are dangerous, but will hinder the way the suspension works). Also, you're probably pushing the range of the axle joints.


Couple options, but you're getting into drastic fabricating territory.

The fundamental idea behind the front geometry is that the control arm and tie rod stay parallel. So if you want to ease the angle on the tie rod, do the same to the control arm. You could flip the TRE like that, but then modify the crossmember to lower the control arm pivot the same distance to keep the 2 arms in phase with each other.

You could also raise the steering rack. Obviously engine/oil pan clearance will make that a challenge, but I think some changes could be made.

You could combine both. If flipping the TRE raises that by 2". You could raise the steering rack by 1", and drop the control arm pivot by 1". This would ease your angles AND improve the tie rod clearance without sacrificing control arm clearance much.


Another option, would be to cut and re-weld the TRE tab on the knuckle with an angle so that the TRE itself doesn't need to compensate. This is no small project, and IMO only for a VERY experience fabricator and welder. But I have seen someone shorten that arm to effectively increase the steering ratio and range (IIRC it was on a RWD-converted subaru for going slideways).


Or, use a heim joint. This would be the easiest to do, but you would gain no clearance, and you'd also gain the noise of having heims in the suspension. As well as the increased maintenance (keeping them lubricated). This is not a viable option for a Daily Driver, especially if you're in a part of the world that uses chemicals on the road to combat ice.

#28 Uberoo

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Posted 12 September 2011 - 11:38 PM

I did this on a vehicle that had a 2" suspension lift.Before as the suspension moved at all the steering wheel would go everywhere off road.Now the only time it really moves off road would be when I hit a large rock hard enough to pull a wheel in one direction.

flipping the tie rod end is only for suspension lifted vehicles.

I dunno if it really bothers you experiment on a spare set of spindles.I don't really have any problems offroad or on road.The only problems I have on the road come from my horrible alignment.take something offroad and the alignment will get knocked out of adjustment.that and my tie rods themselves are bent...


HOWEVER numbchux is correct as far has the tie rods raising the roll center of the car and increasing bump steer IN THEORY.in practice when the suspension is lifted the tie rod is at such an extreme angle already that the tie rod binds up pulling the wheels in.tie rod flipped only helps for offroad long suspension travel setups.

so like I said,try it on a spare set of spindles on a suspension lifted car and see how you like it.

#29 SmashedGlass

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Posted 13 September 2011 - 11:44 AM

So here's a noobish question then. Do the 2" and 4" lifts by, say, SJR create alot of bump steer problems when you are daily driving? As I understand it (limited knowledge of lifting at this point...) those kits are technically just body lifts. When I get around to mildly lifting my wagon, I really don't want to have to fiddle with geometry and still want a decent in-town/highway driveability.

#30 dwuollet

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Posted 13 September 2011 - 12:43 PM

numbchux: thanks for the great reply, very informative gives me the exact info i needed.

I might go the heim joint way, i don't have a problem with noise or regular lubing.

Thanks again:)

#31 VaporTrail

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Posted 13 September 2011 - 01:07 PM

So here's a noobish question then. Do the 2" and 4" lifts by, say, SJR create alot of bump steer problems when you are daily driving? As I understand it (limited knowledge of lifting at this point...) those kits are technically just body lifts. When I get around to mildly lifting my wagon, I really don't want to have to fiddle with geometry and still want a decent in-town/highway driveability.


the kits (from SJR an others) that provide same sized lift bocks for all suspension and subframe mounting points, keep the geometry exactly the same as stock. some kits provide tranny/radius rod blocks that are a half inch shorter to help with the shift linkage, but it's not enough to make a big impact on the placement/movement of the front end.

the only time I've seen steering issues with rigs with these type of lifts, is because really wide tires have been put on, and wide tires react to cracks in the road more on a light vehicle...

#32 SmashedGlass

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Posted 13 September 2011 - 02:10 PM

Thanks for the info McBrat. I'm not getting crazy with mine, just want to be able to get up into the mountains here in Colorado during weekends along some of the logging/mining/gas co. roads and some light off-road.

#33 Numbchux

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Posted 13 September 2011 - 06:28 PM

So here's a noobish question then. Do the 2" and 4" lifts by, say, SJR create alot of bump steer problems when you are daily driving? As I understand it (limited knowledge of lifting at this point...) those kits are technically just body lifts. When I get around to mildly lifting my wagon, I really don't want to have to fiddle with geometry and still want a decent in-town/highway driveability.


No, they will create zero bump steer problems. Honestly, it sounds like the problems that Uberoo is describing are symptoms of really abused, out-of-whack and worn-out suspension, and as the alignment changes through the travel of the suspension, it is getting "better". "Better" saying more about how bad it is at ride-height, than how good it is at compression :rolleyes:

I would take his experiences as an isolated incident. I daily drove 4" and 3" lifted EA82 wagons for years. The combination of oversized tires, and more control arm angle (better roll-center) means the body-roll is not bad, even without sway bars. It is worse than a stock car, and takes a little getting used to the feeling, but they're very stable and safe, even at freeway speeds.

#34 Gloyale

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Posted 14 September 2011 - 05:25 PM

There is a reason that Tierods are fitted with a tappered shank. It's so that the load of side to side motion of that post is spead out and there is not a fulcrum created. Also, the threads of the nut are just used for clamp force. there is no real change in load at the nut during usage.

By hoggin out the top of the hole, and mounting the TRE upside down, you eliminate the load spreading affect.

Now all the force is placed at a few contact points, and you are relying ENTIRELY on the threads of the nut to hold that post from wobbling back and forth.

THAT is WAAAY more scary than the changed geometry. And reason enough for me to call it completely dangerous and bad advice.

I would not touch a customer car that came to me like that unless I was replacing the knuckle and TRE with unmolested ones.

Uberoo, I pray for your safety.

#35 kanurys

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Posted 16 September 2011 - 12:20 AM

Well, if you think about it, when you drop the cross member 3" the control arm and the steering rack are dropped 3" together, so the steering geometry is preserved. If you push the suspension down 4" (1" more than the cross member) you still preserve steering geometry because it changes the tie-rod and control arm from the same point.

Maybe it's not "factory" ideal, but it sure lets me out jeep some jeeps in CO. Oh, and it's still stable at 60 mph on the highway.

Edited by kanurys, 16 September 2011 - 12:22 AM.


#36 smackvt

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Posted 16 September 2011 - 10:07 PM

hummmm yah yah ......how are those upers comming and whats going in those stacks ?:slobber:

#37 Ioku

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Posted 16 September 2011 - 11:27 PM

Still working on the uppers, been busy with work and had to order more heim joints, and make a trip to the pick and pull. I'm starting over on the front knuckles and building them from the start to use a heim as the upper ball joint.

And I still need to find some shocks to put the spring stack over and find a way the weld spring perches to them with out it exploding.

#38 Ioku

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Posted 19 September 2011 - 12:03 AM

Modded another set of knuckles, and got the upper arms built, now I need to find some shocks and a way to build the coilovers.

Posted Image

Posted Image

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#39 Uberoo

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Posted 19 September 2011 - 12:44 PM

There is a reason that Tierods are fitted with a tappered shank. It's so that the load of side to side motion of that post is spead out and there is not a fulcrum created. Also, the threads of the nut are just used for clamp force. there is no real change in load at the nut during usage.

By hoggin out the top of the hole, and mounting the TRE upside down, you eliminate the load spreading affect.

Now all the force is placed at a few contact points, and you are relying ENTIRELY on the threads of the nut to hold that post from wobbling back and forth.

THAT is WAAAY more scary than the changed geometry. And reason enough for me to call it completely dangerous and bad advice.

I would not touch a customer car that came to me like that unless I was replacing the knuckle and TRE with unmolested ones.

Uberoo, I pray for your safety.


when I did mine I payed close attention to the taper I was putting in to closely match the taper on the tie rod.I didn't just take a large drill bit and run it through.

#40 monstaru

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Posted 19 September 2011 - 03:17 PM

Whats the measurement from the tophat mounting area to the top of the upper a-arm?
It looks in the pics like the car is at ride height up front.IF that is the case then why not try to stuff a premade coilover in there.It looks like there is enough room.Say, like a Fox style coilover,dual rate springs and such.There are several other companies to choose from as well.
Just curious i guess.You are dealing with upper mount issues, of course unless you cut a bunch of sheet metal:grin:..The bottom shock mount could go on the upper a-arm, as simple as a plate and a couple of tabs sticking up.
If you can find one to fit then the tophat mount could be the same , only upside down...or the shock could protrude through the tophat mount hole, and have some missing hood , as mentioned before.
Just throwin ideas around.
cheers

Edited by monstaru, 19 September 2011 - 03:22 PM.


#41 Ioku

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Posted 19 September 2011 - 08:03 PM

Yeah thats the plan, going to make the lower coilover mount on top of the upper arms and the upper mount where the top of the strut would go, and yeah if I have to I'll just cut holes in the hood I think it would look bad rump roast to have to shocks come up though the hood. I need to look into some Fox coilovers, I just need to find some that are cheep enough, this is still more or less a budget build and I can't go spending 2k on coilovers.

#42 monstaru

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Posted 19 September 2011 - 11:01 PM

yeah, they are def. spendy. I have about 1200 bucks in air shocks down stairs.but i only paid about 750ish total for them.buy them in pairs, that either need rebuilds, or piece it out.
for a pair of 8" F-O-A single rates you can be out the door for about 400.
http://f-o-a.com/sho...er_of_uploads=0

They have a damn good reputation and are well priced.When i go to coilovers , i will get FOA.not that means anything.just been reading alot:grin:.cheers

#43 Uberoo

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Posted 20 September 2011 - 09:14 AM

What about using some rear coilovers from an EA82?Sedan rear coilover would probally work great for the front.Maybe modify them if needed to get enough flex out of them like the way bigo1966 did?

#44 Gloyale

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Posted 20 September 2011 - 10:56 AM

when I did mine I payed close attention to the taper I was putting in to closely match the taper on the tie rod.I didn't just take a large drill bit and run it through.


At best you might have half of the hole correctly tapered. Even still, now there is a point, about halfway down the stud that the bottom(threaded end) can fulcrum on. There is a reason for the taper full length. It's so the stud CAN"T wobble in the hole, the forces are not acting on the threads and nut, but rather on the ballpivot. Screw with that, and your tierod stud is now able to wobble.

Still totally scary to me. I'm a dad. There's no way I would ever consider modifying my rig like that.

It's a bad idea all the way round.

#45 monstaru

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Posted 20 September 2011 - 07:01 PM

What about using some rear coilovers from an EA82?Sedan rear coilover would probally work great for the front.Maybe modify them if needed to get enough flex out of them like the way bigo1966 did?

because crap suspension is crap suspension..........

#46 Numbchux

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Posted 20 September 2011 - 08:06 PM

Yikes, those A-arm angles are scary
Posted Image

before you hook up any springs or anything, cycle that through the travel a couple times and see how much your camber changes.

Also, with the upper arm that short, you will probably still have issues with that upper joint binding. Ideally you should move that pivot point in and up. The upper and lower arms should be pretty much identical and parallel.


because crap suspension is crap suspension..........


yep :rolleyes:

coilover shocks are dirt cheap compared to struts of similar quality.

#47 smackvt

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Posted 20 September 2011 - 08:47 PM

i say keep going .. kant wate to see the rear set up:grin:
dont be afade to use more than one strut/shock on a corner there r many anglels

#48 bigo1966

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Posted 21 September 2011 - 03:27 PM





Cheap, long travel coil overs. and easy to make really.

#49 Ioku

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Posted 21 September 2011 - 08:50 PM

Yikes, those A-arm angles are scary
Posted Image

before you hook up any springs or anything, cycle that through the travel a couple times and see how much your camber changes.

Also, with the upper arm that short, you will probably still have issues with that upper joint binding. Ideally you should move that pivot point in and up. The upper and lower arms should be pretty much identical and parallel.




yep :rolleyes:

coilover shocks are dirt cheap compared to struts of similar quality.


I know the angles are sort of weird but there is a reason for it, one being lack of space, in order to have the distance between the outer in inner pivot point be the same the pivot pints for the upper arm would have had to be in the frame or I would have to add 3 inches more lift and to put them under it. Also with the spacing equal like that the upper ball joint would be almost maxed out with the amount of droop in that pic. I would like the arms to be longer like the lowers but again theres no room with out starting to get in the way of the engine.

And when I cycled through the travel the camber goes very negative at full compression and a little positive at full droop, I don't see it being a problem. Also with the upper arm like that the upper ball joint has plenty of pivot, at full droop the limiting factor is the inner tierod and at full compression the inner pivots hit the frame first, still need to cut some of it away to fix that.

Edited by Ioku, 21 September 2011 - 08:56 PM.


#50 Ioku

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Posted 21 September 2011 - 09:00 PM





Cheap, long travel coil overs. and easy to make really.



Thanks for the vids, I was thinking up something like that too, sleeving a basic shock with something and wielding a lower spring perch to it. But how did it go welding to the shock any problems with it exploding or anything.




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