Range Rover Rock Sliders

The door bottoms and sill area are very susceptible to damage when hard off-roading.  The damage can result from a sideways impact into the door when driving through deep cuttings, or from bellying out on rocks or banks.  A limited amount of protection is given by the original plastic trim that sits under the door/sill area, but no where enough for the hard stuff.

When I set about making up a set of sliders for my Range Rover, I wanted to offer protection to the sill area and the door bottoms, and due to the extra lift height, provide a entry/exit step to the cabin.  They needed to be strong enough to support the weight of the whole vehicle when the vehicle bottomed out or when I needed to use the Hi-lift jack.

The sill area itself is manufactured from folded panel steel, and hence under point loading is quite weak. The nearest mounting point with any structural rigidity is the chassis rails.  The chassis rails are 400mm from the edge of the sill, and the bottom of the chassis sits slightly higher than the bottom of the sill.  There is clear space between the sill and the chassis rail just behind the front wheel but there is no available space in front of the rear wheel.  This means that the slider can only be attached to the chassis at the front.

To fabricate the sliders, I used 50x50x3mm galvanised RHS, and 38mm NB water pipe.  The fabrication and installation process went as follows:

1. The original plastic sill moulding was removed, leaving a nice flat bearing surface just the right size for the 50x50 RHS. 
2. As per the plastic moulding, a small cut out was made midsection of the RHS to allow for the shape of the centre pillar. This was plated in with some 2mm panel steel.
3. The RHS also had to have a very small kink bent into it approx 1/3 back from the front wheel to match the small curvature of the door bottoms.  To achieve this I hired a pipe bender, removed the dies, and jacked the RHS between the hydraulic ram and the die pins.  Use extreme caution here because the kink required is very small and it is easy to over bend it.  From memory, it only took one full pump on the bender hydraulics.
4. The RHS was then fitted up to the sill and clamped in place.  The location of the reinforcing folds in the sill panel work were marked out, and the appropriate location of the four 10mm horizontal through bolts marked on the RHS.  The holes were then drilled through the RHS and the sill. 
   These through bolts bolt through the finished sliders and the sill panel steel and provide horizontal clamping and vertical sheer.

5. To provide a good bearing area for the vertical forces of bottoming out, matching plates were made from 50x10 and 50x6 flat bar.  The plates were cut 100mm long, with the 50x10 being drilled and tapped for two M10 bolts and the 50x6 being drilled with 12mm holes at matching centres.
   The 50x10 was then welded to the bottom of the sill panel steel, and the 50x6 welded to the slider RHS.  A total of two plates per slider were fitted, one at the very rear of the slider, and on approx 400mm further forward.

6. To provide the protection to the door bottoms and the step into the cabin, I then fitted a 38mm NB pipe to the RHS running parallel to it.  Short radius welded bends were used to keep things compact and looking nice which gives the pipe a 75mm offset form the RHS when measured for outside to outside.  The bends were welded directly to the RHS.
7. To increase the structural rigidity of the front of the sliders, a 38mm NB water pipe stiffener was run between the slider and the chassis rail.  Due to the differing heights, this pipe had to be angled up to the chassis.
   As per the mounting plates on the rear bullbars, I have discovered that the best way to mount any attachments to the vehicle chassis is to use a 10mm mild steel plate with as bigger foot print as possible (100mm x 100mm), drilled and tapped for M10 bolts.  This plate is then welded to the chassis.  The stiffener is then welded to a 6mm mild steel plate cut and drilled to match.  Using this method, you don't have to drill and tube the chassis rails, and to date, even after some rather heavy impacts, no chassis deformation has occurred.

In practice the sliders have proved extremely effective.  With the extra 100mm of under body height that I have due to the suspension lift, I don't often bottom out, but when I do, the peace of mind that I'm not going to do damage is very reassuring. 
The real damage saver though is the 75mm off-set of the water pipe.  This has really saved the door bottoms, particularly when driving those off camber cuttings when the Rangie has to rub up against the banks.  The off-set is just enough to keep the rest of the Rangie panels clear of the bank.

Oh, and they definately make getting in and out of the cabin a whole lot easier!!