Now we are back on topic. And a good one. Recent Steering Problems
Howe is the only one with a 6 or 7" throw Rack, which seems necessary for IFS builds...using racks. The problem is that they were designed for a pinion that is horizontal. They were designed for 2wd buggies and trucks. Where a rack has to reside in a IFS is directly in front of the Diff case, which interferes. So all designers turn that rack so the pinion is up...which works...sort of. In the original configuration the top and bottom flat surfaces ride on a Teflon or UHMW skid. Most of the feedback from the uprights link which is vertically up and down (suspension travel) and those skids "can take it". The links from the uprights are also generally inline with the rack. There are only slight angles from turning and upright movement from front to back (minimal). In the 4x4 IFS configuration, the skids are not generally inline and only taking the offset pressure from turning. There is also a twinting effect whee the shuttle is actually "in line" but the "rack is not. It wants to lock. The now, top and bottom, surfaces are generally raw with no skids , but greased. Before portals, and early on, it was very common for the feedback to break all 4ea 5/8" bolts holding the rack. The racks are now indexed into the top bulkhead, so all the bolts see is droop torque with no shear. So now we know the limitations of the Howe designed, and others racks.
It is not necessarily the "****ty" rack. It is the "****ty" application of it. A 'rebuild" is about the same cost as a new one $3,800.
There is some shining light with portals is that it has allowed the crew chiefs to flatten the arms and shafts in the IFS because they get the ground clearance from the Portals. (Scherer) This reduces some offset angles to the rack...... But.
This has been a known problem for years. Some have tried to take on just the re-thinking of the rack design. And it is very apparent at both KOH and the desert that portals stress the steering systems even greater. As a starter, it would be good to know if it is the gearing feedback, or the 4" vertical offset, or the added weight increasing the pressure on the racks. If portals are going to be a thing, then something has to happen soon. Portal owners!!! Check your parts and figure out where the extra forces are coming from!!
I think I heard that Lorens rack blew out the seals in the cylinder. I have already had that discussion with Eric Ammato, Radial Design, how to buffer or relief valve the cylinder, if possible, from those new big hits. This might be OK to the rack guys but the SA hydro guys a killer. Literally.
The other common option out there is the standard OEMish steering box linked over to a swinger set that then has arms to both uprights. It is the favorite for the desert Trucks and Truggies. They overcame swinger failures when going to 4x4, and now again adding the portals. I fully expect the better solutions to come from the desert group as way more responsive to $$$$ needed to fix a problem. Whether we, as a KOH community, get to learn from that....Who knows.....But they would not be afraid to change something really quickly.
Joe Thompson has made a swinger design survive all the Gomez'. And the brothers just survive the hits and wait for more. I do believe that Joe is waiting for the thought to deal with the feedback from portals before rushing to them.
It was reported during Bronco testing in JV that the engineers had fully outfitted the steering assemblies with sensors to check pressures and forces. It is probably unknown if the KOH Broncos this year had the 74weld billet rack body upgrades. But they are now taking orders.
So: On the list for 4400 2024. More robust steering assemblies ... at least for IFS.
EDIT: It should also be remembered that SA cyclinders only take offset loads from steering. Not from articulation. So an easier cat to slay.
And on the old forum, bringing in rotary steering to a rack mounted to a SA was discussed. There was a lot of bump steer issues on articulation. Even with a rotary cable as used in some busses. A cable abot 1" in dia but would curve 90*. Pretty neat. but found to not work in models.
