Tweaking the Monoshock suspension - adjusting ski pressure

[ReX]

One thing I find with my 05 RX-1 is I wouldn't mind a hint of extra ski pressure (with the stock skis).

But - how can it be done????

It looks to me like the front/rear weight balance built into the skid is fixed. There is no way (I have seen) to move any pivot point to adjust ski pressure. There is no front skid shock spring to loosen off, etc.

For WOT both the front limiter strap and transfer rod can be used, but there doesn't seem to be a way to adjust ski pressure while cruising.

I thought about tweaking the ski pre-load, but that will also lower/raise the front and I want to independantly adjust height.

Another question I have is - what good is the front limiter strap on these? Has anyone played with the balance between front limiter and transfer rod settings? I'm wondering if the two will affect the transition points (amount of throttle) to good weight transfer.

 

[LazyBastard]

Tighten the strap to increase cruising ski pressure, raise position of transfer rod to increase on-throttle ski lift.

 

[ReX]

Tighten the strap to increase cruising ski pressure, raise position of transfer rod to increase on-throttle ski lift.

You'd have to tighten the strap an enormous amount to increase cruising ski pressure.

With the sled just sitting under it's own weight, there is at least 1" of free length on the front strap. If I lift the front end to the point where the skis are only just on the ground the strap is just starting to get tight. If I sit on the sled it's back to loose again.

In the stock setup I think the strap is only used to control maximum extension at the front of the track (riding over the top of a bump or in the air). The transfer rod controls the weight transfer pretty much completely.

I don't know, but my guess is if I tightened it enough to add some cruising ski pressure I would introduce other problems and it would greatly reduce the potential droop at the front of the skid. I might try it, but it doesn't seem like the right solution to me.

 

[Roadrunner]

Almost RX-1, Are you running the stock factory carbides ? More aggressive carbides should reduce the amount of front end push. Remember, if you crank down on the limiter strap say bye bye to your weight transfer. Try some more preload on the front springs, it's easy to do and just as easy to return to stock if you don't like it. Is the rear skid set up properly for your weight ?

 

[ReX]

Almost RX-1, Are you running the stock factory carbides ? More aggressive carbides should reduce the amount of front end push. Remember, if you crank down on the limiter strap say bye bye to your weight transfer. Try some more preload on the front springs, it's easy to do and just as easy to return to stock if you don't like it. Is the rear skid set up properly for your weight ?

I found changing the mono-spring's preload made no noticable difference in front end weight/push.

I started out with it on #4 (I'm about 210 - I figure 240 ready to sled) and then moved it up a notch at a time to #6 in order to reduce bottoming out on big bumps/2' of air. I also reduced the weight transfer a little to keep the skis on the ground more (I will reduce it more).

I usually find more preload on the front springs only works if at the same time I reduce the preload on the front skid shock - unfortunately this sled doesn't have one...

The way it corners right now:

Neutral throttle - the skis bite acceptably (just)

Light throttle/acceleration - the skis start to push too much

More throttle - skis push a little more

Heavy throttle - skis lift so they are just on the snow and the sled pushes a little more (riding primarily on the track).

The heavy throttle lift is almost acceptable. I think only a little more adjustment is needed there. The light throttle push/mild lift is what I'd like to improve. I doubt reducing the weight transfer setting will help the light throttle push as the skid doesn't rock back much at all (and so far reducing the weight transfer settings haven't made any difference).

I will replace these carbides with more aggressive ones.

 

[LazyBastard]

Believe it or not, when you're going into a turn the straps are being pulled tight by the tension on the track. You tighten those straps and you'll be able to power into and through corners.

 

[ReX]

Believe it or not, when you're going into a turn the straps are being pulled tight by the tension on the track. You tighten those straps and you'll be able to power into and through corners.

I can see this being possible - depending on the geometry. I'll give it a try.

You're thinking is this (I assume):

Hit the throttle any amount and the top of the track is in tension. At the other end of the "string" is the ground. Because the track wraps around the rear idler, there would be two times the track tension pushing the rear idlers and skid forwards. Because of the angle at the W-arm, this will push the skid downwards at the front, raising the front of the sled/extending the front of the skid.

The question is when does the limiter strap come into play vs the transfer control rod?

I guess the best way to find out is to try it...

 

[LazyBastard]

That is correct, that is exactly how the suspension works.

The strap sets how far down the front of the rails sit. The control rods set how high the back of the rails lift UP. They work together. The transfer rods are easy-adjust so you can change it several times a day.

 

[ReX]

I played around with it a little last night, but ran out of time to do a good test run (crazy evening - we had no electricity until after 10pm).

I think it will work. I ended up shortening the strap one position (moving it to the center position) and reducing the weight transfer adjustment to 1 marking from minimum.

Supporting the sled by the very rear of the track and hoisting the front end so the skis are just on the ground (same height as the rear support) the track is now parallel.

Shortening the limiter lets the rear spring push back up, increasing the weight on the front skis prior to hitting the weight transfer limiter.

Hopefully I'll get a chance to ride and tweak a little more tonight.

 

[banjo04414]

Keep us informed on how you make out. I'm thinking about fiddling with mine this week-end.