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Discussion Starter · #1 ·
I'm working on some modifications to my 90 EXT 530. Primarily I want a little more travel from the front suspension as well as more clearance at the belly pan. I'm going to build some longer A-arms, about 1-1.5" longer each. The stance on the 90 AFS is ~35" center to center. My 94 EXT is about 38". I want to keep it narrow for the side hilling and boondocking, so I may modify the spindle to offset the ski inward .5" to help make up for the longer arms.

But here's my question, does anybody know the spring rate for the main spring on the AFS suspensions? I think they are quite a bit heavier than those used in the AWS because of the cantilever design has more leverage on the shock. Has anybody seen anything like this done back in the day? I heard that there may have been a Brads Long Travel system for the AFS sleds, but have not found any information on the internet. Not even much on the AWS BLT from Fast.

Also, does anybody know of any place to buy coil springs in varying rates/sizes? If I get a shock from an AWS sled with a longer travel than the tiny shocks on the AFS, I'd like to be able to bump up the spring rate if need be.

Thanks, Brad
 

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Not to steal your idea or anything, but keep me posted on what you find out. I have modified my rear suspension to gain travel, and would love to lift the front up a little bit too. Thanks...Prowler
 

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Discussion Starter · #3 ·
Originally posted by Prowler@Sep 28 2005, 07:29 AM
Not to steal your idea or anything, but keep me posted on what you find out.  I have modified my rear suspension to gain travel, and would love to lift the front up a little bit too.  Thanks...Prowler
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No problem. What did you do to gain travel in the rear? I've swapped a newer skid under mine from a slightly newer 92ish Prowler/Panther or something of that nature. Compared to the very worn out original EXT skid it was night and day! Once I get the front end figured out I'm going to work on modifying a 136" skid for some more travel and to lift the back up to compensate for the higher front. I don't think I'm going to be able to loosen the front limiter strap enough to take much ski pressure off...which isn't going to do me any good for the type of snow I tend to ride in.

I've been putting some thought and taking some measurments and its starting to look like I may not need much more if any more spring than a typical AWSIII because in the AWS configuration the shock is layed down at less than a 45degree angle relative to the movement of the lower pivot. In the AFS arrangement, the shock is also laid down, but with the pivot of the upper arm it pushes almost directly towards the shock. So with a coilover from a T-cat for example it should be plenty. I'm going to have to compare shock lengths to see how much extra travel I would get from just swapping in the shocks.

I took some pictures showing the amount of travel the arm are capable of, but haven't had a chance to upload them yet. We'll see!
 

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Originally posted by chicksdigwagons@Sep 29 2005, 04:38 AM
No problem. What did you do to gain travel in the rear? I've swapped a newer skid under mine from a slightly newer 92ish Prowler/Panther or something of that nature. Compared to the very worn out original EXT skid it was night and day! Once I get the front end figured out I'm going to work on modifying a 136" skid for some more travel and to lift the back up to compensate for the higher front. I don't think I'm going to be able to loosen the front limiter strap enough to take much ski pressure off...which isn't going to do me any good for the type of snow I tend to ride in.

I've been putting some thought and taking some measurments and its starting to look like I may not need much more if any more spring than a typical AWSIII because in the AWS configuration the shock is layed down at less than a 45degree angle relative to the movement of the lower pivot. In the AFS arrangement, the shock is also laid down, but with the pivot of the upper arm it pushes almost directly towards the shock. So with a coilover from a T-cat for example it should be plenty. I'm going to have to compare shock lengths to see how much extra travel I would get from just swapping in the shocks.

I took some pictures showing the amount of travel the arm are capable of, but haven't had a chance to upload them yet. We'll see!
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I put in a long legs kit. Stock skid, and the kit is basically just the upper and lower rear arms from a 97 zl440, and the limiter strap. My stock setup is a fast track 8.5" and the 97 zl440 is a fast track 13.5" with similar tunnel mounting and did not use the TSL yet. It works out to be like a fast track 11.5" - 12". I used the lower holes in the tunnel front and rear, and moved the front limiter strap from the front of the skid to the crossmember closer to the front shock. On the rear arms I used the holes furthest back to mount the lower rear arm. I did NOT use the cross link to "couple" the rear skid. Here is a link to a write up about the kit. I do NOT recommend using Sherwood as I and a few friends had major problems with them, and I do not know if they are still around or even a cat dealer any more. Here is the article link:
http://www.off-road.com/snowmobile/reviews...s/longlegs.html

If you want to see the instructions (maginal at best) that came with it, I can try to e-mail them to you, or fax or something. PM me if needed. Prowler
 

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Look very closely in my avitar pic, one sled has the long legs in (left), and the other is stock (right). I know it is a small pic, I will try to load the full size one later if I can find it. You can see light through the one with the long legs kit in it, and check out the seat angle. It made such a difference, I had to crank the front shock springs up all the way, and I had to readjust my headlight too.

I will try to look up the numbers, but I had crossed a set of front shocks with the same eyelet sizes and a slightly longer eye to eye distance, and a touch (like 1"+-) more travel. It looked like the spring retainer ring was just mounted up a little higher on the shock body, so the stock springs may just work. Might have to do something with the sway bar, but I think it may still reach just fine.

Well, good luck, and lets keep each other posted on our finding. Thanks...Prowler
 

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Discussion Starter · #6 ·
Ahh, yes. I have heard about the Longlegs setup. Have you had any issues with ratcheting? Last year I looked into the longlegs concept, but what I never really found was any information regarding the actual differences between the ZL peices and the stock peices.

Is the upper rear arm just longer? If anybody had any pictures of the 97 ZL peices used for the longlegs kit, compared to the stock peices they replaced them with I'd be grateful! :love:
 

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Originally posted by chicksdigwagons@Sep 29 2005, 12:55 PM
Ahh, yes. I have heard about the Longlegs setup. Have you had any issues with ratcheting? Last year I looked into the longlegs concept, but what I never really found was any information regarding the actual differences between the ZL peices and the stock peices.

Is the upper rear arm just longer? If anybody had any pictures of the 97 ZL peices used for the longlegs kit, compared to the stock peices they replaced them with I'd be grateful!  :love:
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I kept the track loose and just adjusted tighter to get rid of ratcheting. Maybe it was a bigger issue with bigger power, mine is only a 440 :-(

I will lay out the pieces and show you the differences with a ruler in the picture for a scale. I will try to get to this tonight, but no promises. I will get to it very soon though and post up my findings.

If I can find a way to gain 1" in the front ride height and/or travel I will be happy with it.

I can say I have 2 of these sleds, one with the kit and one without, and I love the one with the kit in it in the nasty bumps, but the stock one is better on the smooth stuff (it just feels more stable), but I ride more bumps than smooth anyways. It is a different feel for sure, as most of the added "travel" is sag. When sitting there the long leg sled sits much higer up at the bumper, once sitting on them you do not see much difference, except the long leg one sags in 3" or so when you sit down, the stock one barely moves. The ride is much smoother too.

I'll see what I can come up with tonight and post when I can. :beerchug: Prowler
 

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Here are some pics of the parts used in the long legs kit.
I can't control the order of the pics, so if you have any questions, just let me know. Prowler
 

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The EXT's came with 2 stacked springs, one the 2" 750lb/inch and the other the 5.25" 520lb/inch spring for both the Mountain and standard version. In order to increase your travel, you would need to upgrade to a wider stock front end from another AFS models. I think some of the AWS models went up to 38", could be wrong though. Do you have a mountain EXT? 35" ski width seems pretty narrow. There is no BLT front end for the AFS sleds, only AWS.
 

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Here are your options

0603-196 2.75" 250lbs/in
0603-021 2.25" 350lbs/in
0603-132 7.25" 375lbs/in
0603-203 2.75" 380lbs/in
0603-127 7.25" 420lbs/in
0603-197 5.35" 430lbs/in
0603-019 5.25" 520lbs/in
0603-020 1.75" 750lbs/in
0603-173 2.00" 750lbs/in
0603-160 2.00" 880lbs/in
 

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Discussion Starter · #11 ·
Prowler, you are the man :ylsuper: That is exactly what I was looking for.

Also, Mike, thanks a LOAD for the specs on the springs. Now the million dollar question is how do those numbers compare with longer travel shocks from AWS sleds? I'll see if any of my manuals have specs...should have done that in the first place. :frech32:

As far as the BLT, I kinda figured there wasn't anything like that for the AFS sleds after looking for 6 months. So I'm going to build the equivalent. My sled isn't a mountain version, back then they all were pretty narrow. 35" IS very narrow, even for a modern day mountain sled, but consequently I can lay this thing down on its side in the powder no problem compared to the 2001 MC 800 I ride occasionally. This is a 16 year old sled after all. I don't know if the EXT special had longer arms, but I DO know they were nice tubular units for the 1990 model year. The upper and lower arms on my El Tigre are stamped and welded units, a monocoque design so to speak. I'm guessing I'm going to save quite a bit of weight by going with a tubular design even with longer arms.

Looking at the long legs design I'm also going to modify a skid I have to emulate that setup. I'm going to have to check the dimensions a little but I think its well within my means after seeing the fairly basic differences between the peices.

Here are some comparison pictures of the front end...


This is the front end completely compressed without shocks/springs.


Here is the front end at approximately ride height...

And completely dropped out.

It woudln't take much modification to the front bulkhead to increase the total travel, but the problem is a lot is unusable because of the harsh angles with the fairly short arms. So I figure with longer arms, longer travel shocks, I should be in pretty good shape. I realize fully that I am talking about polishing a turd, but its MY turd damnit! I'm kinda poor but I have some good fab skills so I'm going to use them. :smiley-faces7:
 

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Dang, those AFS sleds had a TON of drop-out front suspension travel! You could replace your 2" spring with the 880lbs/in spring to increase your front ride height and increase resistance to bottoming. That seems to be your only spring option with the stock suspension.
 

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Discussion Starter · #13 ·
Well, keep in mind the shocks are NOT connected in those pictures. So the droop is not in the shock, its in the arms themselves. But at full droop there is the problem both of the camber being off and the angle of those arms seems a little steep. If I want to see that kind of travel I'm going to have to get longer shocks in there, which is going to require longer springs of course. So I'm going to do some research to see what kind of spring rate a AWS IV era T-Cat has and if its going to be high enough for the AFS setup. Between the longer shock and the wider arms I'm going to build I think I'll have a pretty nice front end. Then I'll have to modify the back to suit...

Then I have to come up with a cheap 136" track.

EDIT: Did some more research. Turns out that even the T-cat only used a 10.5 110lb/in pound spring on the front...little soft for what I'm looking for. When using a dual spring setup how to you calculate the effective spring rate? Could I get away with using a pair of 5.25" 520lbs/in springs, that is if the spacer would reach the shock body. Hmm... I could also modify the geometry to allow for a lighter spring but at that point I might as well go with a conventional style front suspension rather than the cantilever deal. Or possibly find a manufacturer that makes springs, like hypercoil. They have a pretty wide selection of off the shelf items, but not much in the 2" ID. I wonder however if the later AWS springs are more like 2.25" ID? I'll have to check on that.

Thanks for all the help guys.

EDIT AGAIN: Found the formula. Spring1 * Spring2 / (Spring1 + Spring2) so...

So the stock setup is about 307Lb/in effective spring rate, if I moved to the longer AWS shock, with twin 520Lb/in springs I'd be at about 260lb/in, which incidently is WAY more still than the 1990 ElTigre EXT special had at about 158Lb/in effective rate, with a 250# and 430# spring. Something there just doesn't seem right to me? The EXT Special wasn't very much different from the regular EXT, remote res. shocks, tubular front arms and a couple cosmetic things, is there something big I'm missing as to why it needs half the spring rate?

I guess the moral of this story is I'm going to have a heck of time coming up with springs that are going to work with a longer travel shock :-( If I have to pay hundreds of dollars for the right springs it kind of defeats the purpose of cost-effective upgrades to my old beater. Time will tell!
 

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Originally posted by chicksdigwagons@Sep 30 2005, 11:56 PM
Prowler, you are the man  :ylsuper: That is exactly what I was looking for.
Hey, no problem. I hope it helps some :div20:

I have a different setup on my sleds, I do have AWS (2 i think) not AFS front suspension. I also have the fasttrac 8.5 rear, well kind of now. I am hunting for longer travel front shocks/springs, and I think I may have found an option. It looks like the front shocks/springs from an 01-02 Mountain Cat 500 & 600 would bolt right in to my sled. They would have 1" longer extended length, and a .125" shorter compressed length, which would gain me around an inch or so of travel and hopefully a bit more ground clearance. These MCs came with 110lb springs.

How did you find the spring rates? I am looking for the spring rates on my stock 93 prowlers, any help is appreciated. Thanks...Prowler
 

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I tried the long legs kit in my 93 580Z. I picked up all of the parts from a 97ZL 440 from a wrecker and found the instructions online. It sucked. I could never get rid of the ratcheting. I had to run the track as tight as a fiddle and even then under hard acceleration it still ratcheted. I removed all of the long legs parts and instead I installed a TSL skid from a 98 ZR 600. It is much better. I'm not sure if that skid would fit in a 1990 though.

Here are some pics



 

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Originally posted by KevinS@Oct 3 2005, 12:37 PM
I tried the long legs kit in my 93 580Z. I picked up all of the parts from a 97ZL 440 from a wrecker and found the instructions online. It sucked. I could never get rid of the ratcheting. I had to run the track as tight as a fiddle and even then under hard acceleration it still ratcheted. I removed all of the long legs parts and instead I installed a TSL skid from a 98 ZR 600. It is much better. I'm not sure if that skid would fit in a 1990 though.

Here are some pics




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Got a Long Legs kit on my ZRT1000, Ratchet city baby! :banghead: I wanna put a TSL skid under it but don't know the measurements.
 

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I also had ratchet issues at first, but after trying a few different setups it works without issues and my track isn't too tight either. I wound up changing the mounting holes on just about everything once or twice. Prowler
 

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Discussion Starter · #18 ·
I think a lot of the racheting issues might be geometry related. If you use the wrong combination of holes it will tend to loosen the track more than usual under compression...leading to the racheting. I'm sure with some adjustments that could be tweaked out, but it certainly wouldn't be a whole lot of fun. I'm sure I could get a TSL skid under my '90, but unless I found one basicly for free its not going to be an option. I need to save what little money I have for the parts I can't fabricate myself. Such as a new track!

Prowler, I used the parts fiche on browns leisure world to find the spring rates, not every one is listed, mostly just the newer ones. I would bet those shocks would bolt right up no problem. I can't seem to find a listing for the springrate for the prowlers though, I'd be suprised if they were very different from the ~110lbs/in that most everything else seems to be on the AWS sleds.

Try it out, and sell me your old shocks :-D
 

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Originally posted by chicksdigwagons@Oct 3 2005, 05:32 PM
I think a lot of the racheting issues might be geometry related. If you use the wrong combination of holes it will tend to loosen the track more than usual under compression...leading to the racheting. I'm sure with some adjustments that could be tweaked out, but it certainly wouldn't be a whole lot of fun. I'm sure I could get a TSL skid under my '90, but unless I found one basicly for free its not going to be an option. I need to save what little money I have for the parts I can't fabricate myself. Such as a new track!

Prowler, I used the parts fiche on browns leisure world to find the spring rates, not every one is listed, mostly just the newer ones.  I would bet those shocks would bolt right up no problem. I can't seem to find a listing for the springrate for the prowlers though, I'd be suprised if they were very different from the ~110lbs/in that most everything else seems to be on the AWS sleds.

Try it out, and sell me your old shocks :-D
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Indeed, I improved my racheting issues by changing the front arm mounting holes to move the skid forward some, which seems to have fixed racheting on my sled for the most part. It will still rachet a bit when landing very hard and on the gas. I think the rest could be cured by coupling the front and rear arms like the newer ones.

I think the 110lbs/in springs are going to be a lot stiffer than my stock ones are, as Mountain Cats do not use a sway bar so they have to run stiffer springs to compensate, and the other sled they came on was a bearcat which I know is a lot heavier then my prowler. It may work if I just disconnect the sway bar, but I am not sure if I want to do that or not yet.

I just really need to find out the stock spring strength so that I know which direction I am going in, and how much of a difference it will be, and there may be something that falls in between them too. Brown's only shows the spring rates on some sleds, and my prowlers are not one of them :dunno:

As far as my stock shocks, what are your eyelet diameters, my sled has .400" top and bottom. Are yours the same? I think my stock shocks are 14.25" extended and 10.5" compressed.

Well, best of luck. Prowler
 

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Man those EXT's bring back memories. What a machine in its day.

The center to center distance on the the EXT and wildcat was 39" and it used nice tubular arms. The EXT mountain cat and the smaller AFS machines use stamped steel arms and have a 37" center to center distance. Yours look like the 37" arms. Black magic made a set of 39" lightweight arms too.

I found the spring rates to be OK in mine, stiffer could have helped. But the shocks couldnt take much at all. You really need stiff shocks in the front, front of mine would always bottom out if it left the ground at all. I found the rear arm setup of the rear suspension was fine, but I eliminated the linkage in the front arm and threw in a coil over shock along with a ryde fx shock in the back arm. Also installed heavier springs in the back. Rear suspension was great, even by todays standards.

If you can come across a set of PSI pipes buy them. They make an incredible difference in that sled. I also had boyesean reeds in mine. I ran the needle in the leanest notch and was running 310 main jets I believe. Purple spring in the drive clutch along with a little steeper helix and 21/39 gears. Really ran great.
 
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