Jack_Shaft
TY 4 Stroke Junkie
As one of my other posts show, I have a 2003 Pro-X 136" rear suspension in my 2003 RX-1.
I was always very skeptical of the standard spring rate on the Pro-X skid vs. the weight of the RX-1, but really had no proof to support my argument. As it turns out, it looks like the initial rate of the torsion spring is the real culprit.
I can't get any weight transfer out of the skid b/c under the dead weight of the RX-1 (and/or once I get on), the rear scissors are right up against the rear scissors stop. No matter where I put the rear scissors stop block, the scissors are right up against it before I even get moving, so there is no opportunity for the skid to transfer at all.
The spring rate is ok once the skid starts to stroke, but by that time, I have already lost 3-4 inches of vertical travel, so there's not much left to give.
My theory is that once I install the stiffer springs, the "starting" rate will will be stiff enough to hold the rear scissors away from the rear stop block, then when the throttle is squeezed, the scissors will move back to the block (weight transfer), then the rear scissors will start to stroke.
The only bad thing about all of this is that I have installed the skid to work with the current ride height, so I'll probably have to move by drop brackets up an inch or so.
This make sense to you all?
-JS
I was always very skeptical of the standard spring rate on the Pro-X skid vs. the weight of the RX-1, but really had no proof to support my argument. As it turns out, it looks like the initial rate of the torsion spring is the real culprit.
I can't get any weight transfer out of the skid b/c under the dead weight of the RX-1 (and/or once I get on), the rear scissors are right up against the rear scissors stop. No matter where I put the rear scissors stop block, the scissors are right up against it before I even get moving, so there is no opportunity for the skid to transfer at all.
The spring rate is ok once the skid starts to stroke, but by that time, I have already lost 3-4 inches of vertical travel, so there's not much left to give.
My theory is that once I install the stiffer springs, the "starting" rate will will be stiff enough to hold the rear scissors away from the rear stop block, then when the throttle is squeezed, the scissors will move back to the block (weight transfer), then the rear scissors will start to stroke.
The only bad thing about all of this is that I have installed the skid to work with the current ride height, so I'll probably have to move by drop brackets up an inch or so.
This make sense to you all?
-JS
lippy
Pro
- Joined
- Nov 6, 2004
- Messages
- 136
I had the same problem when I installed the zr in mine. moved back holes 3/4 of inch closer. fixed everything!!!!!!! They need some preload on back spring to work right.
Jack_Shaft
TY 4 Stroke Junkie
You mean you moved the rear holes 3/4" forward, i.e. towards the front mounting point? That would certainly put a little bit of preload on the rear torsion springs, makes sense.
Seeing as I'd rather avoid swiss-cheesing my tunnel further, I think I can accomplish the same thing by installing a set of 77* springs instead of the stock 90* that are on there now. That should accomplish pretty much the same thing, right?
Thanks for the note, I appreciate it.
-JS
Seeing as I'd rather avoid swiss-cheesing my tunnel further, I think I can accomplish the same thing by installing a set of 77* springs instead of the stock 90* that are on there now. That should accomplish pretty much the same thing, right?
Thanks for the note, I appreciate it.
-JS
lippy
Pro
- Joined
- Nov 6, 2004
- Messages
- 136
yes. moved holes forward. dont know about springs for preload. when you move the holes forward you move the entire scissors to give you the preload. I put new springs on with more preload on spring and it still did'nt work. I had to move holes to do it right. just my two cents. hope it helps
ProX 136
Jack, did you use the exact measurement between the front and rear arms as the sled the skid came out of? It is probably the most critical of all.Here is what happened to me. I have an 03 RX1 which I converted to a 136" in 2004. I used Venture rails to lengthen my ProAction but was unhappy with the ride. I even purchased a set of Fox shocks from a guy on ebay but it still didn't ride like I wanted. I found a 136" Cat skid out of an 05 Pantera with 150 miles on it. The price was really good so I snapped it up. Now this is the part of the story you may find interesting. I installed it using the measurements I got from this forum. The problem is the Pantera suspension uses a slightly different front arm and the distance between arms is shorter than the ZR, ZL sleds. When installed using the ZR spacing the suspension collapsed and hit the coupling blocks as soon as I sat on it. Almost half the travel was used up already. When the skid coupled the remaining travel was very stiff and the ride was terrible. I went to the local Cat dealer where a friend fo mine works and measured the skid from an 06 Panther. I had verified using online Microfiche that it was the same skid with the exception it had softer springs. I checked the front to rear arm center to center distance and found the problem. I had spent considerable time fabricating drop brackets for the swap and like you didn"t want to have my tunnel look like Swiss cheese. What I did was move the front arm hole back and the result has been great. The approach angle is visibly improved. If you have followed the threads on Cat skid swaps you will remember that some guys recommended heating the front of the rails and bending them up to avoid wear on the rail end caps. This is not even a remote concern with this skid now. Now for the big surprise. The skid was much stiffer. I could jump up and down as hard as I could and the suspension would not collapse enough to hit the coupling blocks. I rode the sled and found things dramatically better. I did not bottom even once that weekend with the springs set to the softest position. Not being content to leave things alone, I ordered the softer torsion springs that come standard on the fan cooled Panther I took the measurements from. I rode the sled this weekend past with this setup. I have the springs on the softest setting. The sled has never been this good. The ride reminded me of the M10 I had in my Vmax 4. It was plush but only bottomed once or twice on some extreme bumps I didn't see becuase the snow dust was bad. Unexpectedly, the steering effort was much reduced compared to the ProAction and inside ski lift wasn't a problem at all. I had my doubts whether I had made a wise decision at first but now I couldn't be happier. The reason I made this long post is because I suspect you may be having second thoughts about your conversion. Give it a chance. There are things you can do before opening your check book. Check the CtoC distance on a sled with the identical skid first. If its OK then consider moving the spring slider block to a hole higher up and further back than stock.If there aren't any from the factory don't be afraid to drill your own. I don't know if Polaris has them but Cat sells a taller spring slide block that increases preload and only costs 3 bucks each. You can purchase rear spring adjusters that have higher preload settings for about the price of one torsion spring. I would not hesitate to move the front arm back one half inch if it were my sled. Before coupling came along we moved the rear scissors lower pivot ahead to soften the suspension and back to stiffen the suspension all the time. it didn't cause any problems.Now that rear arms are confined by coupling blocks this is not an easy option. Moving the front arm pivot by small amounts will accomplish similar things with a lot less hassle. By moving the front arm back a bit the suspension will be preloaded, act stiffer, forward couple sooner and not transfer as much weight to the skis when braking. This was the thing I hated about my sled. On tight trails when slowing hard for a corner I felt I needed the muscles of Hercules to turn the bars and then that inside ski would pop up. My friends on their Revs would just leave me in the dust. Not now though, huge improvement. Just be patient. Don't be afraid to experiment. Ask the forum questions and you will get what you want.
Jack, did you use the exact measurement between the front and rear arms as the sled the skid came out of? It is probably the most critical of all.Here is what happened to me. I have an 03 RX1 which I converted to a 136" in 2004. I used Venture rails to lengthen my ProAction but was unhappy with the ride. I even purchased a set of Fox shocks from a guy on ebay but it still didn't ride like I wanted. I found a 136" Cat skid out of an 05 Pantera with 150 miles on it. The price was really good so I snapped it up. Now this is the part of the story you may find interesting. I installed it using the measurements I got from this forum. The problem is the Pantera suspension uses a slightly different front arm and the distance between arms is shorter than the ZR, ZL sleds. When installed using the ZR spacing the suspension collapsed and hit the coupling blocks as soon as I sat on it. Almost half the travel was used up already. When the skid coupled the remaining travel was very stiff and the ride was terrible. I went to the local Cat dealer where a friend fo mine works and measured the skid from an 06 Panther. I had verified using online Microfiche that it was the same skid with the exception it had softer springs. I checked the front to rear arm center to center distance and found the problem. I had spent considerable time fabricating drop brackets for the swap and like you didn"t want to have my tunnel look like Swiss cheese. What I did was move the front arm hole back and the result has been great. The approach angle is visibly improved. If you have followed the threads on Cat skid swaps you will remember that some guys recommended heating the front of the rails and bending them up to avoid wear on the rail end caps. This is not even a remote concern with this skid now. Now for the big surprise. The skid was much stiffer. I could jump up and down as hard as I could and the suspension would not collapse enough to hit the coupling blocks. I rode the sled and found things dramatically better. I did not bottom even once that weekend with the springs set to the softest position. Not being content to leave things alone, I ordered the softer torsion springs that come standard on the fan cooled Panther I took the measurements from. I rode the sled this weekend past with this setup. I have the springs on the softest setting. The sled has never been this good. The ride reminded me of the M10 I had in my Vmax 4. It was plush but only bottomed once or twice on some extreme bumps I didn't see becuase the snow dust was bad. Unexpectedly, the steering effort was much reduced compared to the ProAction and inside ski lift wasn't a problem at all. I had my doubts whether I had made a wise decision at first but now I couldn't be happier. The reason I made this long post is because I suspect you may be having second thoughts about your conversion. Give it a chance. There are things you can do before opening your check book. Check the CtoC distance on a sled with the identical skid first. If its OK then consider moving the spring slider block to a hole higher up and further back than stock.If there aren't any from the factory don't be afraid to drill your own. I don't know if Polaris has them but Cat sells a taller spring slide block that increases preload and only costs 3 bucks each. You can purchase rear spring adjusters that have higher preload settings for about the price of one torsion spring. I would not hesitate to move the front arm back one half inch if it were my sled. Before coupling came along we moved the rear scissors lower pivot ahead to soften the suspension and back to stiffen the suspension all the time. it didn't cause any problems.Now that rear arms are confined by coupling blocks this is not an easy option. Moving the front arm pivot by small amounts will accomplish similar things with a lot less hassle. By moving the front arm back a bit the suspension will be preloaded, act stiffer, forward couple sooner and not transfer as much weight to the skis when braking. This was the thing I hated about my sled. On tight trails when slowing hard for a corner I felt I needed the muscles of Hercules to turn the bars and then that inside ski would pop up. My friends on their Revs would just leave me in the dust. Not now though, huge improvement. Just be patient. Don't be afraid to experiment. Ask the forum questions and you will get what you want.
Jack_Shaft
TY 4 Stroke Junkie
Low Flying Missile, I think you're seriously on to something. The only bad part is that now I have to do more work....!
I had an exact 27 1/4" from C-C of the mounting holes when I mounted the skid right up there in the tunnel, but then I found the ride-height to be too low, so I installed drop brackets.... straight down. I should have moved them forward a little bit. It certainly sounds like I have come across the situation that you describe and I will measure the C-C distance again today to see how far off I am.
Thanks for the note, I appreciate the guidance.
-JS
I had an exact 27 1/4" from C-C of the mounting holes when I mounted the skid right up there in the tunnel, but then I found the ride-height to be too low, so I installed drop brackets.... straight down. I should have moved them forward a little bit. It certainly sounds like I have come across the situation that you describe and I will measure the C-C distance again today to see how far off I am.
Thanks for the note, I appreciate the guidance.
-JS
Jack_Shaft
TY 4 Stroke Junkie
Replied to your PM there LFM
Jack_Shaft
TY 4 Stroke Junkie
UPDATE:
Since the rear skid was dropped too far out of the tunnel, I put the drop brackets back in there about 2", to the basic height that they were at when they were used for the stock skid. C-C of the two mounting points is dead-on 27.25" just as on the donor sled.
I installed the 0.401", 77* Polaris springs and now the ride height looks far more sano with the sit-in sag eliminated.
Rear scissors stays forward, looks like we're ready for weight transfer.
More details to follow once I get my clutch back together...!
Since the rear skid was dropped too far out of the tunnel, I put the drop brackets back in there about 2", to the basic height that they were at when they were used for the stock skid. C-C of the two mounting points is dead-on 27.25" just as on the donor sled.
I installed the 0.401", 77* Polaris springs and now the ride height looks far more sano with the sit-in sag eliminated.
Rear scissors stays forward, looks like we're ready for weight transfer.
More details to follow once I get my clutch back together...!
Jack_Shaft
TY 4 Stroke Junkie
UPDATE #2:
Clutch is back together, works great.
Even with the stiffer rear springs, I have about 1.5" sit-in sag, so I drilled two new rear holes and moved the RRSS back about 1" from the rearmost factory option to ensure adequate room for the scissors to move initially. Rear torsion spring preload is set to #2 to reduce squat as well.
NOW this sucker transfers! 16-18" of ski lift on acceleration from a dead stop, lifts the skis anytime I punch it and especially when trying to hammer a series of junk. Pro-X skid really, really rides well.
I am now very pleased with the install and finally have some great results.
-JS
Clutch is back together, works great.
Even with the stiffer rear springs, I have about 1.5" sit-in sag, so I drilled two new rear holes and moved the RRSS back about 1" from the rearmost factory option to ensure adequate room for the scissors to move initially. Rear torsion spring preload is set to #2 to reduce squat as well.
NOW this sucker transfers! 16-18" of ski lift on acceleration from a dead stop, lifts the skis anytime I punch it and especially when trying to hammer a series of junk. Pro-X skid really, really rides well.
I am now very pleased with the install and finally have some great results.
-JS
Where di you get the havier spring. I mounted mine today, and it is close to being ok with the stock .359 spring, but I was going to try and find some HD springs and try that. I am going to ride it tomorow, and see how it fells, but snow is a little scarce right now. Maxdlx
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