155 ASSAULT COMPARED TO 155 RMK RAILS... DIFFERENCES WITH PHOTOS

[HPJUNKIE]

The Assault front suspension has a inch more travel then the Pro, so measuring under the belly pan will not be accurate.

This is correct. The proper way is to use an angle finder on the inside of the track measured between the front of the rail & driver. Measuring on the showroom floor is one thing, does anyone know if the Assault has more sag built into it's suspension?

 

[mountainhorse]

HUH???

Clearance to the bottom of the bulkehad pan is a decent way to figure this out.

I'll see if I can get an answer from Polaris...

I belive that the PRO Assault, which shares the same spindle as the PRO RMK sits a bit higher in the front.

I will also make an educated speculation that if you were to lower the swing arm to the RMK position that you will cause more ski pressure and change the interplay of the front and rear suspension.

I do not believe that the Assault has any more or any less ski pressure than the RMK.

BUT>>>> I will check into this more and revisit this here this week.

 

[Freeride1]

It seems logical that Wider Stance = Longer A-Arms = More Travel = More Ride Height. And if those assumptions are true the front of the skid would need to be dropped lower than the RMK to allow similar track/ski pressure.

Moving the Assault to the upper location would make it steers hard with the added ski pressure compared to the RMK. Theoretically

 

[mountainhorse]

TTT-Bump

 

[MCIVER]

Freeride1,

you're correct, with the assault in the upper hole like the rmk steering is much harder. also when sitting on flat surface the assault rails are bent in a way that only the back section of the track is in contact with the ground cause the rails are tipped up so much at the front. I'm putting Ice age rmk rails on my assault to correct this.

 

[mountainhorse]

The Assault-RMK and PRO RMK use the same tunnel and bracket assembly.

The rear of the skid is in the same position, height-wise)... If you crank up the preload on the RTS.. you will have that tipping action...

Both rails are Flat and both suspensions use the same arms... only the rail tips and shocks are different.

The increased steering effort comes from dropping the front of the skid and placing more weight on the front arms.... and remember... the front arms and shocks on an Assault-RMK are longer.. the ride height in the front is taller.... drop the front end of the skid to the "RMK position" and you will have more ski pressure....simple physics...

If you have the shocks shimmed a bit (an internal shock mod that would need to be done by a shock shop) on the Assault shocks... you would maintain the RMK geometry but with the wider front end of the assault and the increased compression control of the "piggyback" shocks.

If it were as simple as having "position A... and Position B" on the tunnel of the Assault... with no other side effects... the factory would have left both holes drilled.

Again... I really recommend against running the PRO-RMK (non assault) in the lower "assault position" on the front arm of the rear suspension...

MCIVER... I really dont think that putting the RMK rails on the assault and running the front arm of the Rear suspension in the upper location will change your heavy steering effort.


Dems my 2 cents.





MH.

 

[adamg]

2012 SBA has both tunnel holes drilled from the factory.

 

[Snow Trooper]

On the assault rails every port or hole depending on what you want to call it is a slightly smaller area. The Pro has more material removed and therefore larger ports to reduce more weight. I have confirmed this numerous times and don't chalk it up to manufacturing variances.

 

[Skeld]

2012 SBA has both tunnel holes drilled from the factory.

The RMK doesn't.

 

[MCIVER]

.

MCIVER... I really dont think that putting the RMK rails on the assault and running the front arm of the Rear suspension in the upper location will change your heavy steering effort.


Dems my 2 cents.





MH.

I'll let you know what happens. I'm not trying to fix steering effort, only the fact that the rails do not sit flat because of the increased approach angle of the assault rails and the skid being mounted in the upper hole.

 

[Dartos]

So I just read the entire thread.

It appears the skid uses the same arms for the Assualt and RMK. If so then I should be able to use Assualt skid shocks on my RMK, correct?

 

[roni87]

Back assault and pro shocks same length

 

[mountainhorse]

So I just read the entire thread.

It appears the skid uses the same arms for the Assualt and RMK. If so then I should be able to use Assualt skid shocks on my RMK, correct?

Yes.. they are bolt in replacement.

 

[mountainhorse]

BUMP...best to read this thread from the beginning if you are just visiting it now for the first time.

The shape is different, RMK VS Assault 2012... pay particular attention to the nose of section of the rail and the turn-up there.
With the lower mounting position of the Assault front arm... the rails are tipped up in the front more to accommodate that change... the approach angle on an assault is steeper than an RMK.

.

 

[TRS]

MH, wonder if the Assault rails wouldn't be a better choice when installing the anti-ratchet drivers on an RMK. The Assalt rail attack angle with the 7 tooth drivers may be beneficial.

 

[mountainhorse]

Ya know... you may have a good point there my friend!!

 

[roni87]

Can you use a hydralic press to put more of a curve on the front of the rails? I have some iceage rmk rails that would be nice to put in my assault.

 

[TRS]

Can you use a hydralic press to put more of a curve on the front of the rails? I have some iceage rmk rails that would be nice to put in my assault.

Once you break the back on a rail they are junk. I have tried it without any luck.

 

[LoudHandle]

Can you use a hydralic press to put more of a curve on the front of the rails? I have some iceage rmk rails that would be nice to put in my assault.

Roni, it is cost prohibitive to do it correctly. Here is what would be required; remove the temper / heat treatment from the rails, do your bending, retemper / heat treatment the rails. You would likely be money ahead to just buy the assault rails. Unless you have an aluminum heat treater locally, shipping costs will run more than the new rails.

 

[TRS]

LoudHandle that would be the only way to do it correctly.
I watched the Yamaha R&D boys make a few saw cuts part way through then bend and weld. It's not advised for a permanent part. But would apply if you wanted to do a little R&D for a set of custom Ice Age rails.