Heim Steering

[WarFab]

I don't know a whole lot about these upgraded racks, but I also want to look into something stronger once I increase tire size. I've already gone through a few racks, and I know larger tires will only make it worse.
On the Howe racks, is it full hydro with the servo built in, or is it actually a rack and pinion with hydro assist? I can't really tell. Sounds really expensive too.
Those Sweet racks look like there is some potential in there. Are they supposed to be pretty strong? I can't really tell the differences between them. All I could tell was width and travel (at least that's what I'm assuming the measurements are). I'd like to look more into these. I'm sure it wouldn't be hard to fab up some bracket to mount those.

That last idea of using a slider rack and swing setup could be an idea too. Less packaging space than a steering box. especially for you guys with the rack between the crossmembers up front. Mine is behind the crossmember, so I could potentially make room for a steering box. Would be fairly easy to add hydro assist down the line (which is probably what we really need when playing in the rocks).

Moving the rack doesn't effect scrub radius at all. Scrub radius is measured through the upper and lower ball joints and its relation to the tire contact patch. Unless you are talking about scrub in another term that I don't know of. It can mess up the ackerman a little, but bump steer is the big one.
View attachment 8666

Sorry wasn’t meaning to say the mounting point on the knuckle changed scrub, what I was getting at was the steering will change with his movement forward without moving the rack as well. The increase in the radius from center to outer tre means the rack (horizontal throw) won’t match as well as it did with less of a radius. So the steering angles are all going to be fucked off and pronounced.
(Why when building a swing steering matching the swing arms arc to knuckle arc helps improve feel and handling) I mean any rack will experience this but making the arc bigger like he did will pronounce it unless addressed elsewhere.

 

[WarFab]

Let me add disclaimer. My discussion on ifs steering is limited to experience with circle track cars, friends builds, lowered rides, and research or talks with ifs built friends.

 

[AssBurns]

Sorry wasn’t meaning to say the mounting point on the knuckle changed scrub, what I was getting at was the steering will change with his movement forward without moving the rack as well. The increase in the radius from center to outer tre means the rack (horizontal throw) won’t match as well as it did with less of a radius. So the steering angles are all going to be fucked off and pronounced.
(Why when building a swing steering matching the swing arms arc to knuckle arc helps improve feel and handling) I mean any rack will experience this but making the arc bigger like he did will pronounce it unless addressed elsewhere.

Gotcha! I see what you are talking about now. I can see how that might change how the steering behaves. I might have to draw that up to get a better idea of what issues it would cause with steering. Based on how I'm thinking of it, I think it wouldn't cause enough of an issue to be noticeable. The ackerman progression might change a little, but probably not enough for us to care. The ackerman might be reduced at full lock. That's about all I can think of as a problem. Bump steer is dealt with on a separate plane, so pushing the steering arm forward for more leverage without changing rack positions is probably not enough of an issue to worry about.

 

[AssBurns]

So I did a quick sketch of different length steering arms while keeping the steering rack in the same point. I did increments of 0", 1" and 2" either direction at the steering rack. For steering arms I did increments of 4", 5", & 6" long arms. This was just a visual sketch with parallel steering arms for the sake of simplicity.


This one is 4" long arms. You can see the ackerman angles are quite a bit higher than the other sketches.


This on is 5" long arms with the steering rack being collinear with the tie rod at a neutral position.



This one is with a 6" steering arm with the rack still at 5" from the pivot point. The ackerman angles are far less than the 4" arm. This would probably keep things the most consistent since the arms are longer, but less ackerman at full lock compared to shorter arms.



Now here is the 6" arm with the rack moved forward an inch to be collinear with the tie rod at the neutral position.

.

This one is the one to really look at. This is with the both the 6" arm sketches on top of each other. One has the rack at 5" and the other is at 6" from the pivot plane. Notice there really isn't much of a difference between the two. Makes me think it is safe to say making the steering arm longer is not as much of a problem as we thought as long as you keep the other dimensions in the right location to avoid bump steer.



Here is all of them stacked on top of each other. You can see the one with a 6" arm and the rack still at 5" from the pivot plane has the furthest steering point by just a hair.



I know this can get more complicated when factoring steering with actual ackerman steering vs parallel steering, but I think this gets the point accross well enough.

 

[WarFab]

So I did a quick sketch of different length steering arms while keeping the steering rack in the same point. I did increments of 0", 1" and 2" either direction at the steering rack. For steering arms I did increments of 4", 5", & 6" long arms. This was just a visual sketch with parallel steering arms for the sake of simplicity.


This one is 4" long arms. You can see the ackerman angles are quite a bit higher than the other sketches.
View attachment 8681

This on is 5" long arms with the steering rack being collinear with the tie rod at a neutral position.

View attachment 8682

This one is with a 6" steering arm with the rack still at 5" from the pivot point. The ackerman angles are far less than the 4" arm. This would probably keep things the most consistent since the arms are longer, but less ackerman at full lock compared to shorter arms.

View attachment 8683

Now here is the 6" arm with the rack moved forward an inch to be collinear with the tie rod at the neutral position.

View attachment 8686.

This one is the one to really look at. This is with the both the 6" arm sketches on top of each other. One has the rack at 5" and the other is at 6" from the pivot plane. Notice there really isn't much of a difference between the two. Makes me think it is safe to say making the steering arm longer is not as much of a problem as we thought as long as you keep the other dimensions in the right location to avoid bump steer.
View attachment 8685


Here is all of them stacked on top of each other. You can see the one with a 6" arm and the rack still at 5" from the pivot plane has the furthest steering point by just a hair.

View attachment 8688

I know this can get more complicated when factoring steering with actual ackerman steering vs parallel steering, but I think this gets the point accross well enough.

Cool to see the visualization. With the marlin kit I’m looking at his whole setup. Suspension and all. The setup moves centerline of suspension an inch forward and then the outer mount at knuckle is moved forward 1.5” iirc. So it’s 2.5” forward movement but the centerline moved as well so wasn’t sure what that does to the numbers as the steering link will be longer than suspension parts (if that makes sense) why I think the tundra rack style works well for him as it helps keep measurements right.

 

[AssBurns]

Cool to see the visualization. With the marlin kit I’m looking at his whole setup. Suspension and all. The setup moves centerline of suspension an inch forward and then the outer mount at knuckle is moved forward 1.5” iirc. So it’s 2.5” forward movement but the centerline moved as well so wasn’t sure what that does to the numbers as the steering link will be longer than suspension parts (if that makes sense) why I think the tundra rack style works well for him as it helps keep measurements right.

I think as long as the bump steer are good then the rest will be fine. Like we saw in the visuals I made, the worst it would do is mess up the Ackerman a bit but I think that’s the least of our worries

 

[Arcticelf]

I think as long as the bump steer are good then the rest will be fine. Like we saw in the visuals I made, the worst it would do is mess up the Ackerman a bit but I think that’s the least of our worries

Bump steer, and maintaining your turning radius. When I fixed my bumpsteer issue I lost turning radius. I can either live with it or I can sacrifice the ability to convert back to the original geometry, which I kept incase of a failure.

 

[AssBurns]

Bump steer, and maintaining your turning radius. When I fixed my bumpsteer issue I lost turning radius. I can either live with it or I can sacrifice the ability to convert back to the original geometry, which I kept incase of a failure.

True. Longer the steering arm, the less steering angle with the same rack. As much as I’d hate to lose steering angle, as long as it’s not too much loss, then I could get by. I already rub the frame rails at full lock, so I’m used to no having full turning radius. More would always be nice though

 

[Mike_taco4x4]

Where can I get a 3/4" tie rod that slims down like this pic? I was going to call camburg and kartek too. I have some from kartek and they are straight so they rub my coilover.

 

[Airdog]

JD fab makes them....ask for some.

 

[Arcticelf]

JD fab makes them....ask for some.

@AssBurns has a lathe...

 

[Airdog]

@AssBurns has a lathe...

So do I

 

[Stairgod]

JD fab makes them....ask for some.

Mine from JD are not tapered

 

[AssBurns]

@AssBurns has a lathe...

I actually don't have a lathe. I wish I did though. No space in the garage for it.
@malburg114 has one I am pretty sure. And a mill!

So do I

@Mike_taco4x4 here is your guy...

 

[Mike_taco4x4]

I actually don't have a lathe. I wish I did though. No space in the garage for it.
@malburg114 has one I am pretty sure. And a mill!

@Mike_taco4x4 here is your guy...

Would be way better if i can shave em down cause they werent cheap. Looks like kartek sent me HD tie rods so they are thicker which is the problem.lol.

 

[malburg114]

Send em to me and I can get em turned down some. Can add wrench flats too if they don’t have em