Turning Radius

[Dokatd]

Did you measure what the turning radius (or circle) is now?

It's about 3-4ft tighter overall.

 

[Zimm]

The turns lock to lock I read as 3.85. I think my ford is something like 3.

I wonder if the choice to have that level of increased input precision presented the issue of the chosen off the shelf box running out of manufacturer recommended movement range, necessitating a premature stop of the steering angle. Which would have made it an engineering compromise for what the designer prioritized, not a design flaw. Anyone have a solid working knowlege of recirc ball design, that they could make an informed opinion on that? I don't see how that would affect a rack and pinion, but the ball box may be different.

 

[NQ94]

The turns lock to lock I read as 3.85. I think my ford is something like 3.

I wonder if the choice to have that level of increased input precision presented the issue of the chosen off the shelf box running out of manufacturer recommended movement range, necessitating a premature stop of the steering angle. Which would have made it an engineering compromise for what the designer prioritized, not a design flaw. Anyone have a solid working knowlege of recirc ball design, that they could make an informed opinion on that? I don't see how that would affect a rack and pinion, but the ball box may be different.

Recirculating power steering design. This will be near identical to the Grenadier steer system except for the vane pump being an electrohydraulic gear pump.

 

[Zimm]

Recirculating power steering design. This will be near identical to the Grenadier steer system except for the vane pump being an electrohydraulic gear pump.
View attachment 7898952

Well... if one increases the turns by making a change to the input via making a finer "thread" on "ball rack/shaft" assembly requiring more turns to move the rack, I don't see an issue. BUT if one were to increase the needed turns of the wheel to move the drag link "x" distance by adjusting on the output side, by merely making the pitman shorter, the rack would run out of usable travel. Minor corrections would also need much more input causing wandering sensation.

At least that what I see. correct me if I'm i'm in error.

 

[NQ94]

The diagram is the larger version of the ZF Bosch steering box manual for 5t truck. The Bosch unit in the Grenadier is a hefty unit and will follow similar a design with size and the mounting orientation and case position being the only real difference.
Likely to put excessive loads and shortening the service life of the torsion bar that is connected to the steering wheel when the piston is forced on the stops too often.

 

[Dokatd]

I do not believe the issue is the steering box limits. When you max out a steering box they hard stop internally. You cannot keep turning it, the torsion bar won't allow any additional rotation either.

A slightly longer pitman arm would both reduce slop and increase steering angle as well as reduce lock to lock rotation. I have seriously considered altering mine for some time, but my truck seems tolerable now with the stops opened up a bit. It easily reaches full stop as long as I am moving.

I think the primary killer is the programed stop of the pump based on steering wheel rotations. I truly believe the pump stops delivering pressure at the software stops. The mechanical stops on the axle are just to mechanically protect the drivetrain on minor impacts.

 

[INEOS OG]

I’m a late-comer to the party having only just seen the YouTube video on the topic. However, as I have to park my vehicle in some fairly small carparks for work, I decided to adjust the steering bump stops on my vehicle to see if it might tighten up the turning circle.
I have the non-adjustable Fox Steering Stabiliser fitted to my RHD Australian-spec Grenadier.
The first thing I would say is that even before I performed the mod, the bump-stops on my vehicle were absolutely pristine, with no evidence of contact with the corresponding flat area/stop on the axle casting. So despite performing many full-lock turns in both directions over the last 18 months, I had obviously never actually engaged the bump-stops. I suspected that there would be no appreciable improvement to the turning circle by burying the bump-stops even deeper into the front knuckle.
I didn’t go down the 2-washer path and decided just to screw the nut down tight on the bolt and tighten the bolt again.
After driving the car for a day or so, there really hasn’t been any significant change to the turning circle on my vehicle, despite performing several deliberately tight turns in both directions and the bump-stops still look pristine.
I think there are other aspects of the steering geometry that govern the turning circle on our beloved Grenadiers that are not able to be overcome by this simple mod.

I went with two 7/16 heavy duty washers this week (9 months after John with Agile posted the AO video “just in case”) and find the outcome well worth the effort.

I would say it improves the overall radius by about 6’ / 2M and has eliminated three point turns getting into parking spaces in the places I roam. The steering stop bolts have 19mm heads and unlike the Agile Offroad video required rattling them off with an impact driver.

 

[LRNAD90]

Surprised this hasn't been linked in this thread..

View: https://youtu.be/ukdVpGKw-es?t=852

 

[Mohs 9]

I went with two 7/16 heavy duty washers this week (9 months after John with Agile posted the AO video “just in case”) and find the outcome well worth the effort.

I like to go for that. What is 7/16 in metric dimensions? Seems there are 2 standards in the US, USS and SAE:

And they are different in thickness. The M12 washer (DIN EN ISO 7089) here in Europe has a thickness of 2.5 mm, which is thicker than the US washers. How this will effect the turning circle?

 

[alvan]

I'm currently rebuiding a Saginaw recirculating ball steering box. Research suggested that pushing these boxes to the maximum sector shaft angle at either end of their swing - even on the bench - can result in internal damage. I know the one used by Ineos is from a different manufacturer but the same caveat may apply.

And these considerations seem to confirm my concerns. I wonder, however, whether in a world so vigilant about every form of complaint and compensation claim, IA would have left that (very accessible) option open if it actually caused harm. It would be difficult to declare the driver's behavior inappropriate, as it merely involves exerting a slight additional effort on the steering wheel...

 

[alvan]

I don't know how it would be judged in the United States, but I'm sure that if I were to have a serious accident in Europe with a Grenadier with modified steering components, I would have a difficult time, both in terms of personal liability and with regards to insurance...