Lets talk suspension set up

[earthling]

Lol I live in southern Ontario, deep snow is a fairy tale for us. But. I would start with skis first as without the right skis you are on the losing end of the equation. Then loosening up the rear skid, less coupling, softer preload, limiter loose, etc as you want the rear to articulate. I am sure there are lots of guys here that can share their real world experience as I am more used to ice highways.

 

[Upstater57]

View attachment 169063

The Cross Country race sleds use the 14.7mm variety. This is one I have using for years. Be sure to order the bushing kit as well.

As far as I know these part numbers are still valid. They were a month ago when I ordered them.

 

[stevewithOCD]

has anyone ever scaled their sled to see the side-to-side weight distribution? Also, to measure exactly HOW much weight is moved front to rear by the front shock spring and/or strap? I may try it out of curiosity this fall.
I know testing and adjusting is the way to get the feel and ride you want but to put actual numbers to them would be interesting.

I have that info from I think SnoTrax.
I'll see if I can find it

 

[Yamifan]

has anyone ever scaled their sled to see the side-to-side weight distribution? Also, to measure exactly HOW much weight is moved front to rear by the front shock spring and/or strap? I may try it out of curiosity this fall.
I know testing and adjusting is the way to get the feel and ride you want but to put actual numbers to them would be interesting.

I'm in the infancy of the suspension setup on our new LTX GT's. I bought 4 digital postal scales placing them on good, flat plywood dollies then thin plywood on top of the scales and then sled on top. In stock form with no rider there was no left / right bias on skis. (around 180 per side) I don't have my numbers in front of me, but I seem to remember the bias was 55% front / 45% rear no rider...which flip flops when adding a rider and put the majority of the weight on the center scale. I took as much preload off the center shock spring as I could and then the bias spread 30# or so off the middle scale putting about 10# to the skis and 20# to the rear scale. Doing that oddly seems to change the left / right bias on the skis though? I've got to pull the skids out, lube everything and reinstall before I can start recording solid numbers. (so far, I've just checked the ski bushings when widening the stance and they appeared to only have rust inhibitor with no grease when assembled)

 

[Yamifan]

 

[Richard Hodgins]

Are you guys factoring in cornering ability/ ski pressure or just trying to balance the weight? With a 22 LTX GT Or any power steering model for that matter, to me the beauty of that setup will be to run super aggressive carbides and have tons of ski pressure to absolutely rail corners without noticing any of the weight.
In the past, on older procross non power steering models, i would typically have my center spring loosened right off to get maximum ski pressure which in turn leads to some heavy steering at times and picking the right carbide.
Now with power steering, I would imagine you want as much weight as you can get on the skis to allow it to carve even more and all this with ZERO compromise for heavy steering.

 

[STAIN]

Are you guys factoring in cornering ability/ ski pressure or just trying to balance the weight? With a 22 LTX GT Or any power steering model for that matter, to me the beauty of that setup will be to run super aggressive carbides and have tons of ski pressure to absolutely rail corners without noticing any of the weight.
In the past, on older procross non power steering models, i would typically have my center spring loosened right off to get maximum ski pressure which in turn leads to some heavy steering at times and picking the right carbide.
Now with power steering, I would imagine you want as much weight as you can get on the skis to allow it to carve even more and all this with ZERO compromise for heavy steering.

I would think you could do this to a point. At some point, I would assume, the front end will start to bite so hard the inside ski will want to lift.

 

[Yamifan]

Not to mention the tail end getting too loose.

 

[twyztid]

Did they use a pipe wrench on those spring collars & springs?? Wow! Those are tore up!

 

[sailor joe]

I was responding to @STAIN who was asking if anyone had measured the corner weights.

What this says; (probably) is that the sled has a natural right side weight bias. Because of the spring rates however and because the left and right sides are connected by the sway bar, it has little real world effect. If the spring rate is say 150lbs/inch then a 15 pound difference in weight isn't going to create much sag on one side. What it does mean however is that the sled will always act like there is 15 pounds more (or whatever the differential is) on the right side which means further that it will naturally turn right slightly easier and will naturally roll slightly more when you turn left but again, the difference is somewhat disguised by the spring rate/sway bars so... ignore it unless you want to really are hung up on having perfect balance.

I don't have a corner weight setup so no, I have not done this on my sled. Corner weight testing however will tell you a lot about what works and ultimately why it works. For instance cranking up the pre-load on your center (front shock) spring will show up as more load for that shock on the scales and less on the rear, this will allow the sled to pivot more but also could give you a harsher ride when the front shock engages first. When you are just playing with spring preload it isn't always intuitive what changing the preload does to the rest of the sled and this is further exacerbated by related issues like how you sit on the sled, how much you weigh, etc..

What I took away from the video;

The sled is naturally right side biased due to the extra 'stuff' hanging off the right side.
That natural bias probably has less effect than you might think because as the rider sits on the sled the entire left/right AND front/rear bias changes and becomes more balanced. This is a well setup design but... rider weight, position, and riding style matter.

The most important measurements are in order, the front/rear bias (with/without rider), and then the front shock/rear shock bias and then finally left/right bias. When you find something that works for you, those readings will make achieving your natural selection more repeatable because you know what works 'for you'. It will take some of the guesswork out of choosing spring combinations and preload settings. From there you attack valving because valving (and damping bias) only exist to control the natural frequency of the chosen spring rates.

pretty cool stuff Earthling, I dont know anyone with 4 scales that interact to one screen to give true weight distribution...and then adjust shocks accordingly...way over my head so hats off to you. I've been riding what the dealer gave me for set up...with my luck changing anything would probably end in poor results. Nice video!.

 

[earthling]

pretty cool stuff Earthling, I dont know anyone with 4 scales that interact to one screen to give true weight distribution...and then adjust shocks accordingly...way over my head so hats off to you. I've been riding what the dealer gave me for set up...with my luck changing anything would probably end in poor results. Nice video!.

Wasn't me, I only have two scales and both say I need to lose weight. The guy who posted the video I linked to was using a proform 4 corner system, @Yamifan did his own 4 corner measurement using postage scales and came out with very different numbers left to right. I am now sorely tempted to do what the same and buy some postage scales. The challenge with postage scales is that you have to be careful how you load them or they tend to get biased by their initial readings but I am sure it can be sorted out. Of course if I saw a proform for cheap I would buy that pretty quick but I am not curious enough or competitive enough to spend $1200.00-$1500.00 on scales.

 

[sailor joe]

Wasn't me, I only have two scales and both say I need to lose weight. The guy who posted the video I linked to was using a proform 4 corner system, @Yamifan did his own 4 corner measurement using postage scales and came out with very different numbers left to right. I am now sorely tempted to do what the same and buy some postage scales. The challenge with postage scales is that you have to be careful how you load them or they tend to get biased by their initial readings but I am sure it can be sorted out. Of course if I saw a proform for cheap I would buy that pretty quick but I am not curious enough or competitive enough to spend $1200.00-$1500.00 on scales.

yup, probably why I haven't seen them in my buddies garages..too expensive for a one time check...myself, I stay away for scales lol, however i jump on the scale in the doctors office before he gets in and tell him the numbers..

 

[1nc 2000]

Anybody else care to share their suspension setup for trail riding?

 

[number1kyster]

Mine isn't apples to apples, but I have a 129" with Fox Zero 1.5 Rc2 shocks up front, and tucker hibbert series shocks in the rear. The fronts have minimum preload on the springs. The rears have a 160lb spring with the torsions on medium.
The valving is a tad stiff at slow speeds, but when the trails get rough, these things just soak it up. The faster you go, the better it rides.

 

[Turboflash]

Wasn't me, I only have two scales and both say I need to lose weight. The guy who posted the video I linked to was using a proform 4 corner system, @Yamifan did his own 4 corner measurement using postage scales and came out with very different numbers left to right. I am now sorely tempted to do what the same and buy some postage scales. The challenge with postage scales is that you have to be careful how you load them or they tend to get biased by their initial readings but I am sure it can be sorted out. Of course if I saw a proform for cheap I would buy that pretty quick but I am not curious enough or competitive enough to spend $1200.00-$1500.00 on scales.

Hey earthling, is it easier to lose weight or add HP?! Lol. Oh yeah, with your rocket, you're probably all the way to the top on HP already so maybe you only have 1 option?! Lol