Extended Mono Skids

[Stubbs]

I know there’s been more threads on stretching Mono’s than a guy can count, but here goes…..
Looking for experience from anyone who’s stretched out a Mono from 136” to 144”, 151”, further? whatever you’ve tried...
Did you go with tipped rails?
How did you find the ride?
How did it change the weight transfer characteristics?
How did it affect your handing?
What were your fave settings ie transfer rod, spring pre-load, limiter strap, etc. and why?

I’m running a 146” tipped rail Mono with the upper carrier wheels moved back into the 136” position, so essentially a 136” stretched to 146” with rail extensions.
My base settings started out as a carbon copy of my Vector LTX with the exception of the control rod. The Vec has always impressed me with a great ride with good bottoming resistance from a BOP dual rate spring. I don’t think my Apex works nearly as well set up the same way. After setting the control rod to very little transfer like the Vec it’s much better, but still not at the same level of comfort over a wide range of conditions. I love the added traction and deeper snow capability the 146” has given me, but just can’t figure out why I can’t get it to ride as well with an almost identical setup.
All opinions, theories, and experience with something like this are welcome.
Thanks guys….

 

[maim]

one thing i remeber guys telling me on extending those skids was that you could not run yamaha track tension specs as it would cause binding from not being able to move properly.

 

[Stubbs]

Track tension isn’t the issue, with the current set up I can remove the spring/shock assembly and the skid bottoms on the stops without a problem.
Next idea. Lol

 

[musselman]

How tight is the track as is compresses? It may compress easily but essentially add spring force to the suspension since it's acting as a rubber band. I struggled with this on a 144 M-10 with tipped rails, the tipped rails make it worse. To have correct track tension the angle of the front suspension arm needs to closely match the angle of the track going up over the rear top wheels.

Otherwise the shock calibration and spring rates are the same? Mounting points are in the correct location? I assume you had to replace the tunnel mounting plates.

How about ice buildup in the tunnel? It might be making more ice than the vec causing an inconsistent ride due to varying weight?

 

[Stubbs]

How tight is the track as is compresses? It may compress easily but essentially add spring force to the suspension since it's acting as a rubber band. I struggled with this on a 144 M-10 with tipped rails, the tipped rails make it worse. To have correct track tension the angle of the front suspension arm needs to closely match the angle of the track going up over the rear top wheels.

Otherwise the shock calibration and spring rates are the same? Mounting points are in the correct location? I assume you had to replace the tunnel mounting plates.

How about ice buildup in the tunnel? It might be making more ice than the vec causing an inconsistent ride due to varying weight?

Pulled the tunnel protectors so no ice build up, if anything the Vec ices up more, but wasn’t all loaded up the day I was doing my back to testing. Mounting points are correct, used OEM plates from an old 136 tunnel mounted in factory location.
I’m liking your suspension arm angle theory, that’s the only thing that makes sense because the the calibrations otherwise are almost identical. My rails have a 6* tip up, so you’re saying I need to shorten my front limiter to equalize my angle, or am I thinking about that backwards?

 

[musselman]

Unfortunately pulling the limiter will also change the angle of the track, they are mechanically connected through the rails. The only way to change that angle is to move the upper rear wheels further back until it gets closer/steeper. I think the upper cross shaft may bottom out on the rails though if you do that since they get taller towards the back.

A quick test you could do is back off track tension until you have like 2" of free hang (maybe more) and give it a try. If it changes the ride, then you need to address the track geometry.

 

[Stubbs]

I’m not using the upper cross shaft, made up some upper wheel mounts to mimic what Yammy did with the Mono II 136 skids. I’ll loosen the track tension some more before I head to Cochrane on Sunday and see how it feels. Worst case scenario I fab up some drop brackets in the off season to set those wheels another coupe inches rearward.

 

[musselman]

That should be much easier moving them then. Essentially the longer track should do everything the vec can do only better.

 

[Stubbs]

That was the theory when I started into this adventure. Lol

 

[bjowett]

Throwing sh#t at the wall… I am curious if moving the rear arm back could be of benefit? The old Ski Doo Sc3 moved the arm back for the extended length of the 136” Renegade models. The 136” Proaction on the Rage and Warrior models did the same. A longer shock and transfer rod would be required.

A rising rate linkage such as snocross Monoshock might help, too.

 

[Stubbs]

Throwing sh#t at the wall… I am curious if moving the rear arm back could be of benefit? The old Ski Doo Sc3 moved the arm back for the extended length of the 136” Renegade models. The 136” Proaction on the Rage and Warrior models did the same. A longer shock and transfer rod would be required.

A rising rate linkage such as snocross Monoshock might help, too.

In all likelihood I’m going to shorten the skid up into a 137” with correct geometry with a little more aggressive track and ride on. Even with the tipped up rails the sled feels “long” in certain situations and 95% of the time I’m on groomed trails anyway. I’m REALLY interested in the rising rate linkage set up though, that would be a lot of fun to play with. Could you shoot me a pm about that Brian?

 

[bjowett]

Yup.