Although this is not a completely new idea (thanks to the link to the CMIQ forum from ennrico), this is my version of a significant rear skid upgrade for the SWT with torsion spring rear end.

Shocks:
The stock non-rebuildable C36 rear shock on the rear torque arm of the Expedition RCG is too soft for my purposes. The first thing I did was to lean on some old resources and had my good friend Denis Boivin send me up a pair of G-Force shocks from the composite ZX2 rear skid, complete with snowcross (stiff) damping and a king kong rear spring. One has the softer DB9 damping (reasonable), the other has the DB22 (snowcross) damping package, looks pretty stout. I would prefer a C46, but I have confidence in the C36 with a good damping set-up for consumer use. I did not touch the front arm shock yet. I figure going from no shock at all (SWT) to a front torque arm + shock should be a noticeable improvement as-is.

Widened arms:
Although I do a fair amount of work myself, I wanted these arms to be widened and perfectly true, so I brought to a friend of mine who owns a machine shop and had him do it for me. The front and rear torque arms were widened from 20.25" to 24.25" using machined collars that were partially inserted (rear) or sleeved on the outside of the tube (front) then plug and seam welded + corner braced. I also had him brace up and cheek plate the ear mounts on the upper rear cross shafts. I did this before on another sled and it resulted in a very strong part.

Here are some pics of the front arms:

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Hope to start drilling some holes soon....!

Some pics of the rear arm:

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Very nice improvement to a proven skid LB. How is the shock fit? Did you need to modify it at all? I have to laugh thinking about Red Rooster and his SWT rear skid experence in Labrador last winter. I will recomend that he borrows YOUR SWT next year. LOL I know how you love to lend out your gear.

K

Ya right! RR's not getting anywhere near my SWT! Do you remember a date in the Groomer shed with a chain hoist and a 10lb maul? LOL

My ears are still ringing.

Nice job on the reinforcements!

K now tell us more about the shocks LB. What mods did you have to make? How close are they for C to C opened and closed to stock?

BRP Stock:
Open C-C = 14 1/2"
Closed C-C = 10"

AD Boivin G-Force:
Open C-C = 13 3/4"
Closed C-C = 10"

I'm going to try it as-is. The closed height is the kicker, as long as that remains the same, we're in good shape, the shock itself limits the top-out height, so that'll be OK even if we do miss some travel due to the change. The upper and lower shock eyes are much larger on the G-Force compared to stock and I had to have two T-Bushings fabricated for each eye in order to work with the M10 bolts and stock mounts. When you compare the two shocks side-by-side, the 3/4" difference in stroke is hard to see, I honestly believe it to be less.

Hope to bolt everything up tomorrow.

Without looking that sounds very close to the center shock lenghts? That may be a great center shock as well. Especially on a rider forward (over the center shock) chassis. The C-46 does not have much clearence to the front arm with enlarged shock mount ears. The smaller diameter spring would work better here I think. HMMMM!

Possibly. I am surprised that the Rr/Fr torque arm shocks would be that close in open/closed lengths. The front shock looks much smaller than the rear shock.

This project has been dragging arse so bad...! I have the skid out, rear axle off and I am wrestling with the GD 135mm wheels. Boy they are hard to get off the older skids. Those plastic t-bushings really stick on bad. Hope to have the wheels on the new skid, holes drilled in the tunnel of the SWT and skid mounted by the end of the day on Saturday.

At long last, the RCG rear skid is in the track, the tunnel and all of the holes are drilled.

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I am very pleased with the use of the stock front torque arm hole. It kind of messed with my templates a little since I did an inch-for-inch swap from an SUV to a standard WT last Summer, but it only took a 1" C-C change in position all-around to make it work. I always cringed at seeing two front torque arm holes close together on the last swap I did, so I'd have to say that if I had to do it again, I'd keep using the stock front mount hole. I did not cut off the old rear drop brackets since it adds a great deal of strength to the tunnel and doesn't look like it will touch when the skid bottoms. Time will tell I guess.

I have the AD Boivin G-Force shock and 530lb/in rate spring all mounted up as well and it looks clean.

As an FYI, the front and rear torque arms needed to be widened to 24.25" in order to work with the SWT tunnel.

Just a side view and another rear-ish view.

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Looks like this skid was meant to be there, no? Perhaps BRP will follow-up wth an offering of this skid in the future.

I am happy with the result so far, hopefully the run tests this Winter will prove even better.

I will be drawing, .pdf'ing and posting all of the templates required to do this swap shortly.

Great Job LB. Can't wait to see it.


k

Looks much better than the skandic suspension, much higher, more clearance, less places for snow to clog, not to mention the softer ride, better all around I think. I don't know why BRP didn't put on that suspension at the factory? :

LB I noticed you have transfer rods on this RCG. Are they the ticket to couple the action in this skid??? Is it possible to run slightly longer open C-C lengths? The front arm I believe is 14" Could a 14.5" center shock and a 15" rear be utilized if the front suspention was aligning with more travel then stock?

k

The Yamaha-esque transfer rods are standard fare on the Yeti II chassis Expeditions, that's what this skid came off, so that's why they're there. I find that they wheelie less than the Rev-XU skid does, but then again, you're riding the front arm a lot more on the Rev-anything platform vs. the Yeti or Yeti II chassis.

As far as I can remember, the only limiting factors on skid opening are the limiting strap on the front arm and the geometry (somewhat) on the rear arm. If you're only talking 1/2"-1" additional open length, I'd say try it.

The big things to watch are:

(1) Track tension. When the skid is open (i.e. fully extended, no load), the track is tighter. With additional stroke, you may set your track comfortably at full open but at full compression, that sucker might be loose as a goose. Something to watch.
(2) Slide rail stab. The more extended your skid is, the further forward are your rails and the sharper your angle of attack. You want to be careful here as I have ruined one track like this and felt like an idiot. Oh well, I guess every mad scientist breaks a few beakers... LOL In all seriousness, a set of anti-stab idlers on your lower limiter strap cross-shaft will solve this.

Cool Thanks LB I have a big shiny (gold) gift from Aucoin but she's 15 C-C open. Rather then installing a spacer to shorten the stroke I was looking to increase travel as we did on the front suspention if possible. I will post some pics if she fits.

Oh my... that is a nice gift. Remote resi or piggyback?

Get that sucker in there and size it all up. You'll probably need some T-bushings made up for the mounting like I did.

Well, I am putting some miles on the SWTUV now and although it rides great, the rear shock does not open up big enough to fully extend the skid; this in turn lowers the rear of the sled and lightens the front end. I have hauled in the front limiter as far as I am comfortable with and it's still too light on the front, crap. I had a 1996 Polaris WT LX and that thing was so light on the front end that it was terrible for tight woods situations, which is where my SWT used to shine.

I will either have to swap in the stocker rear shock (yuck) or build a higher perch for the G-Force unit to compensate for the shorter initial C-C.

More work to do...

.....bravo! I read with a big smile on my face..look very good....that's what I want for christmas!!!!!!
..........skid(sky) is the limit!!!!