Pro-RMK Rear Suspension Mod Idea...

[m7ascent]

Working on a '11 Pro-RMK 155" and I have some ideas. So it ticks me off that the rear suspension is a good 1/4 to 1/3 compressed before I even step onto the sled. I've got the front track shock set to factory 8 1/2" cuz I'm a light weight and any stiffer makes it to stiff in the whoops, and the rear shock set to 10 3/8" which seems to be working ok. If I go any stiffer on the rear shock, I get to much ski pressure. I want to get the tunnel up out of the snow where it should be. Not exactly apples to apples, but my m7 with 4000 miles on the stock springs almost goes all the way to the top of compression when I step off of of it. If you notice, when you lift the rear of the sled up on the rmk, then lower it slowly, the rear of the track contacts the surface first, thus compressing the rear track shock a bit before the front shock even takes any load.

So here is my idea, I'm thinking about dropping the front rear suspension mount to the lower (assault) hole in the tunnel. I might possibly add an adjustable limiter strap or modify the stock one so I can suck it up just a bit if need be to keep the ski pressure in line. Also would go to an Assault style Rear Track Shock with adjustable compression so i can crank the rear spring up a bit/soften the compression so I get my ride height while retaining weight transfer. I realize this will make the sled taller/tippier but I doubt that will be an issue of any sort for my riding style. If it's to tippy, I can always go to the wide setting on the ski spacers.

I'm looking to try this mod because I feel like when climbing in steep and deep the tunnel being so low in the back creates a bunch of avoidable drag on the snow. My idea of an optimal setup would be to have the rear shocks almost all the way extended until I step onto the sled, and when the rear is lifted and lowered slowly, the entire track front to back would contact at the same time. What are your thoughts?

 

[roni87]

I've had my '11 standard rmk in the bottom mounting hole (assault) for the past two weeks. No issues with stabbing the track even though the rails aren't as curved on the rmk. Good weight transfer too. I don't have the sagging issue you describe though. I gonna move the front arm back to the top hole when I go back to the mountains this spring though...get a much better approach angle for the deep snow.

Make sure your suspension is greased good incase it is binding at all.

Much more fun to drive with the skid in the assault position, turns it into a wheelie machine

 

[winter brew]

IMO one of the reasons the skid (which is basically a Holz copy) works as good as it does is is because of how it sets....the Holz is the same way and this allows the skid to drop into dips as well as soak up the bumps.
The best deep snow sleds I've been around were very low slung.

 

[byeatts]

IMO one of the reasons the skid (which is basically a Holx copy) works as good as it does is is because of how it sets....the Holz is the same way and this allows the skid to drop into dips as well as soak up the bumps.
The best deep snow sleds I've been around were very low slung.

Agree the Poo skid work very well

 

[Huizenga]

Progressive rate suspension

 

[m8sandman]

love mine, sag or no sag. best stock skid i've ever rode by far...

 

[AKSNOWRIDER]

polaris went to a lot of work to make the pro jump up on ths snow and go..one of the main reasons is the skid geometry..why would you risk destroying that? if it bottoms hard on you get heavier springs, maybe even a quality revalve or even better shocks..but i wouldnt risk screwing up the stock geometry..it works right as is...

 

[assault11]

I dont recommend dropping it down a hole it will make trench more because it gives it a steeper approach angle. And the suspention collapses so easy so that the sled gets on top easier. When it collapses the approach angle gets less steep and that's what you want if you wanna get up on the snow. If you move it down a hole youll also get excessive ski lift

 

[hyperduc]

Duplicate...wtf

 

[m1kflyingtiger]

I dont recommend dropping it down a hole it will make trench more because it gives it a steeper approach angle. And the suspention collapses so easy so that the sled gets on top easier. When it collapses the approach angle gets less steep and that's what you want if you wanna get up on the snow. If you move it down a hole youll also get excessive ski lift

X2 the softer the set up the better it's going to get in the snow. In the past poo has always recommended 2" of sag in the rear suspension. On my m1000 I did the geo mod which added sag to the rear, didn't look as BA on the shop floor but it improved the way the sled got up on the snow a bunch. If your really ticked off about it give it a shot, but if it starts trenching like crazy don't discount putting it back to stock.

 

[hyperduc]

I think what everyone here is telling you in a not so round about way is: Go ahead and try it if you want your sled to look "cool", but don't be surprised when it digs holes and handles like $hit.

 

[The Fourth Wolf]

polaris went to a lot of work to make the pro jump up on ths snow and go..one of the main reasons is the skid geometry..why would you risk destroying that? if it bottoms hard on you get heavier springs, maybe even a quality revalve or even better shocks..but i wouldnt risk screwing up the stock geometry..it works right as is...

What he said.

The Pro skid works better than (just about?) anything else out there. Why mess with it?

 

[assault11]

If you just want it to look "cool" you should've bought an assault. If you want it to preform in the deep stuff leave it stock

 

[rookie]

The only real improvement you can do to this rear suspension (IMO) is a set or Holz valved Fox Shocks. I did.

~Rookie

 

[m7ascent]

If you just want it to look "cool" you should've bought an assault. If you want it to preform in the deep stuff leave it stock

Never said I wanted it to look cool, I could give a flip how it looks, only how it performs. Just was wondering if there was some performance left on the table by having the tunnel low in the snow...thus drag. That's why I asked what everyone thought.

 

[m7ascent]

polaris went to a lot of work to make the pro jump up on ths snow and go..one of the main reasons is the skid geometry..why would you risk destroying that? if it bottoms hard on you get heavier springs, maybe even a quality revalve or even better shocks..but i wouldnt risk screwing up the stock geometry..it works right as is...

Well lucky for me if I try this idea, it won't destroy anything, it will just go back to the factory settings if it doesn't work. Just because it's the best performing factory skid doesn't mean there isn't room for improvement. You ever notice sleds keep getting better every year? Look how far mountain sleds have come in the last 10 or 15 years. Sleds don't get better by leaving everything the same every year.