17 RMK Assault trenching..tips for suspension set up?

[Northshore705]

Hey guys looking for some feedback on my assault 155... Sled is fun to ride love it. We we're just out in the northern Ontario back country with some decent uphill skidder trails and I could climb but not as good as my buddy's PRO. I understand our front skid mounts on the assault are in the lower hole and the RMK and SKS are mounted into the upper holes by the footwells.. so the approach angle is different.. now I know all sleds will eventually get into a trenching situation now and then but I feel like I can get more out of this rmk assault 155 for climbing... I stiffened up my rear suspension as it was very loose and loosened up my front skid shocks as they were very stiff... Someone wanted to to do wheelies...lol but anyways that should help the matter a bit but I am just looking for other rmk assault owners input for tree riding and climbing.. I am also running the stock 2.25 peak track but I am willing to upgrade to the Challenger extreme 2.5... any rider input would be great..

 

[prowop]

Lots of things that you suggested are good starts. Having seen this comparison between these two sleds which are very similar in the rear suspension area I'd say your biggest problem is that track. It just doesn't work in steep and deep snow. I mean it is pretty ideal for northern Ontario but for slower tree riding and technical stuff in deep snow it just cannot hang with a 2.6 or even a 2.4 which I am running right now and seems to be a great mix between toughness and being light. My 600 15 pro rmk with a 2.4 walks all over a couple sks with the 2.25. I mean the sks will make it but the 2.4 is a lot easier just walk up over and the 2.25 is notorious trenchers. Hope this helps.

Cheers.

 

[Northshore705]

Awesome thanks for your tip... Looking at ordering a Challenger extreme 2.5 to upgrade.. would this be a good start ?

 

[prowop]

Lots of reviews of tracks on here.. sorry never mentioned I am talking about the Polaris 2.6 and 2.4. The challenger seems to be a solid track.. I'd look for a new take off polaris track which come up once and a while. Or trade ur 2.25 for a 2.4 or 2.6 with more of a trail rider..

 

[Northshore705]

Yeah I can get a CE 2.5 for $560 compared to 800-1000 on a new 2.6 take off..

 

[flying frenchman]

Go for the CE 2.5.
It's an awesome track and very durable too.

 

[indydan]

Hey guys looking for some feedback on my assault 155... Sled is fun to ride love it. We we're just out in the northern Ontario back country with some decent uphill skidder trails and I could climb but not as good as my buddy's PRO. I understand our front skid mounts on the assault are in the lower hole and the RMK and SKS are mounted into the upper holes by the footwells.. so the approach angle is different.. now I know all sleds will eventually get into a trenching situation now and then but I feel like I can get more out of this rmk assault 155 for climbing... I stiffened up my rear suspension as it was very loose and loosened up my front skid shocks as they were very stiff... Someone wanted to to do wheelies...lol but anyways that should help the matter a bit but I am just looking for other rmk assault owners input for tree riding and climbing.. I am also running the stock 2.25 peak track but I am willing to upgrade to the Challenger extreme 2.5... any rider input would be great..

Assaults are not designed in anyway to ride in powder...... they are hard pack jumping sleds.

It needs everything that the PRO has, running boards, track, set suspension set up like a PRO

its pretty much 100% anti-powder.

 

[Northshore705]

Not sure how much I agree with that statement. Yes they are set up a little different than the pros but they will always be classified as an extreme back country mountain sled...

 

[prowop]

I always thought the assault 155 was basically a pro rmk chasis with heavier front end and bracing in the tunnel area, different gearing etc.. assault 144 is a completely different beast..

 

[Northshore705]

This is from polaris website under rmk assault.

The RMK® Assault® 155 is a backcountry mountain snowmobile built for extreme conditions. The tough-as-nails sled, featuring Walker Evans® shocks, is perfect for dominating cliffs and jumps.

Yes it's different than the pro..but it doesn't have a front cooler.. it was made for the mountains...and hill climbs..

 

[tek9tim]

The stock comp track that comes on the RMK Assault is really bad in powder. Just swapping to a stock 2.4 track off an RMK is a big help. The shorter lugs are the smaller difference, the track is really stiff.

Getting an RMK Assault nowadays means a little wider front stance (narrow on the Assault = wide on the RMK), chaincase, piggyback shocks, higher clearance and one small brace. The weight difference is made by the track, shocks, and chaincase. The lineup now is muddied by the SKS, the kind of guy (like me) that spring ordered an Assault with the powder track back in the ProRide days would just buy an SKS now.

I loved my Assault, had no problem rolling it up with the wider stance, and never paneled out. And yeah, drill out the RMK hole for the front of the skid and run it that way. Not a crazy change, but noticeable.

 

[Northshore705]

Thanks for your input. I will def do the track swap first and continue to dial it in. By no means am I a west coast mountain rider but we do have some decent hills here we like to play on.

 

[skippy]

The first thing I did with my ASSAULT ROCKY MOUNTAIN KING was to put the rear skid in the same mounting location as the PRO. Which requires you to raise the front torque arm 1" higher up in the tunnel. Then I adjusted the rear suspension shock springs to exactly what the manual says for length for my weight. Once I got to the hill, I made a few minor turns on the front skid spring and all was good. It's very touchy to the littlest adjustment. Find a baseline and adjust from there. Mine pops up out of the snow just like the PRO..

My sled came with the 2.6 powder track and gets around in the hills just like the PRO. The clicker shocks on the ASSAULT are such an upgrade over the PRO shocks.

The last thing I did was installed one inch off-set spindles to narrow up the ski width 2" total to get the width closer to the PRO stance and all was good.

The only thing I notice different between the ASSAULT and PRO is the ASSAULT has the chain case and it requires more muscle in order to get the sled on edge versus the PRO with the belt drive. Other than that the sleds are pretty much identical. Oh and the ASSAULT has stronger A-arms.

Best of luck...

 

[Northshore705]

The first thing I did with my ASSAULT ROCKY MOUNTAIN KING was to put the rear skid in the same mounting location as the PRO. Which requires you to raise the front torque arm 1" higher up in the tunnel. Then I adjusted the rear suspension shock springs to exactly what the manual says for length for my weight. Once I got to the hill, I made a few minor turns on the front skid spring and all was good. It's very touchy to the littlest adjustment. Find a baseline and adjust from there. Mine pops up out of the snow just like the PRO..

My sled came with the 2.6 powder track and gets around in the hills just like the PRO. The clicker shocks on the ASSAULT are such an upgrade over the PRO shocks.

The last thing I did was installed one inch off-set spindles to narrow up the ski width 2" total to get the width closer to the PRO stance and all was good.

The only thing I notice different between the ASSAULT and PRO is the ASSAULT has the chain case and it requires more muscle in order to get the sled on edge versus the PRO with the belt drive. Other than that the sleds are pretty much identical. Oh and the ASSAULT has stronger A-arms.

Best of luck...

Awesome feedback this is what I was looking for. We're you required to drill out the upper hole and did you keep your stock skid as well?

Was also looking at offset spindles.. are they worth it??

 

[akmclean]

Assaults are not designed in anyway to ride in powder...... they are hard pack jumping sleds.

It needs everything that the PRO has, running boards, track, set suspension set up like a PRO

its pretty much 100% anti-powder.

The Assault he is speaking of is. It has all the same features as the RMK Pro except for a wider ski stance, chaincase, and slightly different rear skid geometry that can be changed to be identical to the Pro. In his case the track is the majority of the problem.

The switchback assault is another story.

 

[skippy]

Awesome feedback this is what I was looking for. We're you required to drill out the upper hole and did you keep your stock skid as well?

Was also looking at offset spindles.. are they worth it??

If I remember right, I drilled the hole from the inside of tunnel to the outside, drill bit self guides on the hole on the mounting bracket for the most part. Super simple and doesn't look bad with the extra original holes when done. Well worth it!

Yep on the using stock skid.

I do think that the offset spindles are worth it. Little on the spendy side for what your're getting, but way cheaper than buying all new arms and new shocks to go narrower.

 

[Cummins88]

Being from Northern Ontario I know what you mean about having a playful sled that can lift but also a sled that can climb.


When I first got my SKS with the 2.4 I was able to climb really well but it lacked that playfulness of picking up the skis.


I got RMK assault rails and a 2.5" CE and ran it in the bottom hole, the sled became a wheelie monster that would trench alot.. fun for an afternoon of flatland riding but no good in the steep and deep.


I now run the RMK assault rails in the top hole and the 2.5 CE track. It goes good but i do think that for the deep powder days the 2.6" polaris track is softer and would trench less.


If you want stock RMK/SKS rails to put on your assault I know a guy that would trade you rails, he's located in Hearst.

 

[Northshore705]

Being from Northern Ontario I know what you mean about having a playful sled that can lift but also a sled that can climb.


When I first got my SKS with the 2.4 I was able to climb really well but it lacked that playfulness of picking up the skis.


I got RMK assault rails and a 2.5" CE and ran it in the bottom hole, the sled became a wheelie monster that would trench alot.. fun for an afternoon of flatland riding but no good in the steep and deep.


I now run the RMK assault rails in the top hole and the 2.5 CE track. It goes good but i do think that for the deep powder days the 2.6" polaris track is softer and would trench less.


If you want stock RMK/SKS rails to put on your assault I know a guy that would trade you rails, he's located in Hearst.

I think with my suspension adjustments and the new CE 2.5 track I should be better off... The price of the CE from a place located in Ontario was $820 cdn... The price of a new Polaris 2.6 is almost double that... Small adjustments as we go.. my last thing to try will be drilling out that hole but as of right now I am hesitant to do so lol

 

[Killer Time Racing]

Assaults are not designed in anyway to ride in powder...... they are hard pack jumping sleds.

It needs everything that the PRO has, running boards, track, set suspension set up like a PRO

its pretty much 100% anti-powder.

WHAT????? They have the Exact same boards ,Same overstructure, same rear suspension ( different Springs ; lighter tension 100 VS 130 ) and mounted 1" lower in front !

The front Arms are obviously wide and have a spindle with less caster and way better shocks . But it is a 155 RMK 3" all the way just with more !!

And I usally agree with you 190% Dan !

 

[MKULTRA]

Hey guys looking for some feedback on my assault 155... Sled is fun to ride love it. We we're just out in the northern Ontario back country with some decent uphill skidder trails and I could climb but not as good as my buddy's PRO. I understand our front skid mounts on the assault are in the lower hole and the RMK and SKS are mounted into the upper holes by the footwells.. so the approach angle is different.. now I know all sleds will eventually get into a trenching situation now and then but I feel like I can get more out of this rmk assault 155 for climbing... I stiffened up my rear suspension as it was very loose and loosened up my front skid shocks as they were very stiff... Someone wanted to to do wheelies...lol but anyways that should help the matter a bit but I am just looking for other rmk assault owners input for tree riding and climbing.. I am also running the stock 2.25 peak track but I am willing to upgrade to the Challenger extreme 2.5... any rider input would be great..

I'd say change the track first