Steering...high steer, assist, full hydro

[cracker]

Another reason NOT to use a single sided ram.

Look at the difference (as Lincoln noted) of the steering forces on the SE ram from retract to extend and the DE is symetric.

This was from the PSC website

 

[hadfield4wd]

Given crackers' post is there a way to do a double ram with hydro assist? Can you just hook up both ends and plumb it? Seems like the only thing that would happen is the cylinder could rotate on the shafts.

 

[cracker]

Given crackers' post is there a way to do a double ram with hydro assist? Can you just hook up both ends and plumb it? Seems like the only thing that would happen is the cylinder could rotate on the shafts.

I had inquired about that a long time ago when I first looked into hydro assist and they (PSC) said it was possible but really didn't want to do it. They do custom rams so the possibility is there.

I was looking into it because I didn't have the real estate on the front axle to make it work perfectly. I compromised with a ram 'guard.'

 

[vetteboy]

Given crackers' post is there a way to do a double ram with hydro assist? Can you just hook up both ends and plumb it? Seems like the only thing that would happen is the cylinder could rotate on the shafts.

It's doable, but with a mechanical tie rod in there as well the mounting points on the knuckle would have to coincide exactly or else it would bind. It'd be like having two tie rods of fixed length and making them work together.

I'm sorta picturing how it would go together and it seems like an odd setup.

edit: what you'd need to do would be to have the tie rod connection and ram connection inline with the Ackerman lines for that particular steering setup. Not exactly coinciding with each other, but coinciding with those lines.

 

[BrettM]

you CAN run a double ended cylinder with assist. there are 2 ways to do it; either you connect just one end of the ram to a normal tie-rod and leave the other end not connected to anything, OR you use 2 small tie-rods from the ram to the knuckles with no tie-rod going all the way from knuckle to knuckle. the second method looks just like most full-hydro setups, except you still need a draglink attaching to the passenger side knuckle.

 

[vetteboy]

you CAN run a double ended cylinder with assist. there are 2 ways to do it; either you connect just one end of the ram to a normal tie-rod and leave the other end not connected to anything, OR you use 2 small tie-rods from the ram to the knuckles with no tie-rod going all the way from knuckle to knuckle. the second method looks just like most full-hydro setups, except you still need a draglink attaching to the passenger side knuckle.

The first option seems like a terrible use of space. Just having to position the thing so you've got a 8" or so open spot out the other side seems kinda funny. Might as well do something useful with the other arm, like connect it to an air pump and have a weird OBA setup...

I guess in the other one you're using the cylinder ram as the tie rod, and pulling or pushing on it via the drag link...that's intriguing. I didn't think of that. Hmm.

 

[BrettM]

yeah, the first method isn't very practical. the second method works just fine, if you want pictures a guy on Pirate did it (and later converted to full-hydro), I think his screen name is WanderingWillys and it's a 4 door Chevy truck on 44s.

 

[vetteboy]

if you want pictures a guy on Pirate did it

Not to discredit the idea, but this same statement applies to 99% of the things that can be done in the 4x4 world. irate1:

I can see it as being a good stepping-stone between full hydro and assist setups. However for a 'purely' assist kind of setup, like what I am running (and you too, I think), there's really no downside to having the single ended that I can think of. It's easier to package, easier to protect, and you have the...um...advantage of nearly 2x the steering force in once direction. :roll:

 

[hadfield4wd]

The first option seems like a terrible use of space. Just having to position the thing so you've got a 8" or so open spot out the other side seems kinda funny. Might as well do something useful with the other arm, like connect it to an air pump and have a weird OBA setup...

I guess in the other one you're using the cylinder ram as the tie rod, and pulling or pushing on it via the drag link...that's intriguing. I didn't think of that. Hmm.

I was thinking more along the lines of attaching one ram to the axle and one ram to the tie rod and allowing the cylinder to "float". This would give you pushing force in both directions. The cylinder would then be subject to rotating though. Seems like I would have to use a cylinder twice the length that I would need to get full pusing in both directions. Also I heard somewhere here that someone did a hydro assist on the pitman arm. Do you now who did it?

 

[FarmerMatt]

The shaft will lock the tierod to the axle not allowing it to turn at all & the cylinder will just float back & forth not doing anything...

 

[BrettM]

Also I heard somewhere here that someone did a hydro assist on the pitman arm. Do you now who did it?

I think hydro-assist with the fixed end mounted to the body is a TERRIBLE idea, especially on an XJ. People have enough trouble keeping the steering box attached to the XJ frame as it is, if you do that you are adding even more force to the box. By putting the cylinder on the axle you are taking load off of the steering box to frame attachment.

For assist, a single ended cylinder really isn't a big deal. You get a different amount of power (and speed if you pump isn't keeping up), but I've never been able to notice the difference.

 

[Goatman]

Using a double ended ram on a hydro assist system is dumb, I don't care who did it. It only makes sense if you know you're going to full hydro but just don't have the time to get the orbital installed in time for a couple of runs. It would be silly for anything long term. Sometimes too much is made of the differential from side to side on single ended ram installations. Before folks started using double ended rams everyone that went hydro used single cylinders. No doubt double ended cylinders are ideal for full hydro setups, but single ended cylinders will still work fine depending on what the goals are. For hydro assist, a single ended cylinder is all there is, and they work perfectly.

BTW, the only person I know who has put the assist cylinder from the frame to the pitman arm is Drew Burrows (goat1 on Pirate), undoubtedly one of the most knowledgeable people out there on suspension design. He made his own assist cylinder out of a shock body, and even made his own internal bypass coilovers for the front of his CJ buggy. Agreed that it's not ideal on most XJ's, but it can be made to work well. I've thought about this, and the cylinder would still absorb force and shock load lessening the leverage against the steering box and frame, but it would still push against the track bar. I'd rather have the cylinder pushing directly against the axle, since I've ripped both the steering box and the track bar mount off the frame multiple times each.

 

[hadfield4wd]

Thank you BrettM and Goatman. I appreciate your responses and insite. I guess I will be sticking with assist and a single ram.

 

[Goatman]

Hmmmm, just checked with Tera to see about getting arms like the one that came on my Tera 60 knuckle, just with the link hole in a different place. The arms are made by Tera, come with no hole for the link so you drill or ream it where you want, and they're $49.50 each.

I like these arms. Even though they are cut from 3/4" plate, and not machined from 1" billet, they are wider, and beefier around the three mounting holes. Also, they locate the link hole closer to the wheel so the Ackerman angle is better.

 

[Goatman]

Paul, I measured from the outside lip of the steel wheel (widest part of the wheel) to the edge of the Tera arm even with the lip of the wheel and it's 1 3/4". The bead of the alloy wheel is thicker than the steel wheel, but the steel wheel has that lip on the edge of the bead, so it should be about the same. My wheels are 2.5" backspacing.

I'm wondering about this arm correction issue.....that it might not be a bad thing. The D44 arm tilts inward, so a flat arm really makes the DL joint angle severe. They add correction to flatten the mounting surface for the links. With the inverted T like I'm running on the yellow XJ the only thing that matters is the tie rod mounting surface, so while my arm has correction, it should work fine without it. If we're now going to mount the DL directly to the arm, then if we use an arm with correction the angle of the DL joint will actually be less than it would if the arm was flat (since unlike a D44 knuckle, the top of our Tera knuckles are flat/level). With correction, the tie rod mount would have some angle in it, but the tie rod joint only spins, while the DL joint has to move. So, which is better, having a flat mounting surface (relative to the link) for the DL or for the TR? It should be better to have less angle on the DL since DL joint binding can be an issue. If that's the case, then we could use anyone's arm that will put the link holes where we want them, and we could use a raised arm to get a little more clearance.

AND, how important is the best Ackerman angle? It looks like the Tera arm will have the best Ackerman angle, but plenty of folks are running the other arms, including us on our D44's, and they seem to work fine.

I keep switching back and forth between the issues involved. Tie rod as high as possible above the arm but more forward to clear the pitman arm and in front of the drag link (but then the ram has to go behind the axle on a double arm). Tie rod lower below the arm and as far rearward as possible, directly below the DL, would have to use rod ends and can't use my aluminum DL and TR, but the current mount and position of the ram would work. TR below the arm and slightly forward of the DL and keep the 1 ton TRE's and the aluminum links, and the current ram position will work. Then......Tera flat arm made of 3/4" plate with good Ackerman, or a raised arm made from much thicker billet with correction (that probably doesn't matter) but not as good Ackerman angle. ????

 

[Paul S]

Based on your 2.5" BS wheels having 1.75" clearance, it doesn't sound like a 4.5" BS wheel will fit, especially since the diameter is smaller too.

I've also been thinking about the correction issue being a potential good think. Certainly would only help the DL. I'll mock something up tonight to see how 10* looks on the TR. I don't see any reason it would matter.

As you know, I'm pretty anal about Ackerman, I gave up a whole lot of clearance on my WJ knuckles due to the crappy characteristics of reverse Ackerman. Having said that, I don't think it's as simple as drawing a line from the TR through the KP axis to the rear axle. Based on this formula, my PMP arms are reverse Ackerman, but in reality they work great, Ackerman seems perfect, not at all like what I experienced with the WJ arms.

Paul

 

[BrettM]

As you know, I'm pretty anal about Ackerman, I gave up a whole lot of clearance on my WJ knuckles due to the crappy characteristics of reverse Ackerman. Having said that, I don't think it's as simple as drawing a line from the TR through the KP axis to the rear axle. Based on this formula, my PMP arms are reverse Ackerman, but in reality they work great, Ackerman seems perfect, not at all like what I experienced with the WJ arms.

Paul

Maybe the WJ stuff had worse Ackerman, but it really is as simple as TREs, through KP/BJ axis, to the center of the rear axle. plot it out on graph paper (or a CAD program if you've got it) and you can see how it effects turning.

 

[Jeff 98XJ WI]

I don't know if you could make this work, but I think putting a tie rod from high steer arm to high steer arm at like 5" from the ball joint centerline and then connect the drag link to the passengers side high steer arm at the normal 6.5" from ball joint centerline would work best. Then you could run an assist cylinder between the axle and the tie rod and keep it all behind the drag link. The drag link would be in front of everything during compression, full left turn, and full right turn. This won't work on xj's with real coils, because the tie rod would hit the coils at full turns, but you are running coil overs, so perhaps there is room? How about posting a pic or two of the Tera High Steer arm that you have? I'm just interested to see what it looks like. It does seem like a good price! Oh, one other thing that sort of setup might allow for is to put the tie rod end holes in the steering arm further out near the rim without having clearance issues since it is closer to the ball joint centerline which would then keep ackerman angles better. If the drag link end at the pitman arm is too close to the tie rod at full stuff with the wheels pointed straight ahead, perhaps one could move the steering gear forward an inch or two on the frame? This would require cutting all or a portion of the front XJ crossmember off, but you've got a welder, and the stock crossmember is a bent piece of sheet metal anyways, so who cares, just make a better one with steering box clearance. Jeff

 

[Paul S]

Maybe the WJ stuff had worse Ackerman, but it really is as simple as TREs, through KP/BJ axis, to the center of the rear axle. plot it out on graph paper (or a CAD program if you've got it) and you can see how it effects turning.

It's been a long time since I had the WJ knuckles, but IIRC, the histeer arms on my WJ knuckles were about the same distance in from the KP axis as my PMP arms. Before I bought my PMP arms I argued at length with Mike that his arms would have terrible Ackerman, he insisted that they wouldn't & finally offered to take them back if I didn't like them. He was right, they're perfect, but the KP axis is nowhere near what I'd call proper Ackerman.

Paul

 

[Goatman]

Well, now I'm figuring either use a raised arm if the tie rod is mounted below the knuckle and live with the correction (which could be good), or put the tie rod above the knuckle in front of the drag link. Have to check who would make an arm that would work.

I'm being stubborn about wanting to make use of my aluminum DL and TR, meaning I have to stick with the 1 ton TRE's, which I also think is a good thing if I can make it work. If that aluminum TR can take a hit, bend and then go back, that would be a real good thing and it should last for a very long time. Plus, I don't have to buy anything other than arms.