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Discussion Starter · #1 ·

im putting a 98 storm xtra 10 rear suspension in my 94 polaris storm.
does anybody know if or how far i have to move the mounting holes

44 Posts
Oh boy....

I've been asking the same question.... and getting a few different answers.

Check out look in the Polaris Discussion area for my name...

Some say no moves at all... sorry that doesn't seem right.

Some say follow

but, that's for a rolled chaincase, but I will be checking the numbers out from that... this one has the center to center distance at 23 1/2"

others say... leave the front alone, then move the back forward 2 5/8"

even others say, center the new suspension holes at 23 1/8" apart centered about the old holes....

Some people think, you move both holes 1.5"

One guy is going to measure a sled that has the xtra-10 on it and report tto me what the number he sees are...

I'm going to take all this information with the suspension laid out next to my old xc-100, some measuring tools and come to a conclusion...

I'll let you know what I decide, I will likely follow the measurements off an actual sled.

:withstupid: ???

626 Posts
i dont think it will fit its not just the mounting holes by buddie tried it on his storm and didnt fit

2,560 Posts
I just had a similar problem putting a 121", stretched to 136", Edge suspension under a Gen II SKS this weekend. Had to get dimensions from scratch. Turned out perfect. Heres how I did it:

On the new suspension, make sure the scissor arm is against the front stop, the front stop is in the low position, and the rear axle has been placed in the center of it's adjustment range. Suspension is fully assembled
and springs are installed.

With the new suspension flat on the floor, lean a level against the rear torque arm center. We need to get a vertical line going, from the new rear torque arm center, to the floor.

Measure horizontally back to the rear axle center from this line. This is going to be our "key" dimension. A mistake here can't happen. Get someone you trust to give you a "second set of eyes" here, and again at end of next step. Make sure arm and axle are located as described above.

Transfer this "key" dimension to the tunnel by starting at the rear axle bolt center on the original suspension, with track tensioned normally, and measuring forward the "key" distance, then up to the tunnel, again on a vertical line, (maybe using that level)? We're kind of "reversing" the way we got this dimension from the new suspension, and marking the tunnel for the new rear mounting position just high enough on the tunnel so there won't be a problem getting the bolt in (like maybe 3/4" or so up from the floor board). If your original brackets have extensions that extend below the tunnel, I'd plan on using those holes. Either location, as long as it is located on that vertical line, is ok.

Finding front torque arm mounting locations is much easier. Just measure front to rear torqe arm distance on new suspension and transfer dimension to tunnel, measuring forward from our newly marked rear hole. I would suggest you maintain hole height in tunnel the same as it was originally, unless going to new location on rear under floorboards. In that case you might want to drop the new front location 1/2" or so.

I don't know where you are going to wind up in relation to the original mounts. This process will tell you for sure. My installation was off from original by 5" in the rear, and a little over 2" in the front. This left me in areas of the tunnel that were not reinforced at all. Was forced to relocate original mounts by drilling original rivets and refastening original brackets at the new locations.

When I removed the original suspension, I laid it on the floor next to the new suspension, and lining up the rear axles, was able to confirm all my dimensions. This made me feel a little better about the whole project and gave me the confidence necessary to start drilling and riveting.... measure as many time as you need to convince yourself you will only cut once.

Total time to actually get dimensions, relocate brackets, install new suspension took me 8 hours. Lots of head scratching before that work actually started. Hoping I can save you some time there with these notes.

Best of luck, sounds like you are qoing to wind up with quite a ride. Feel free with questions. I'll do what I can to help.


44 Posts
Here is a TON of information on this....

I'm doing it on a 95 Indy Trail, Fan Cool, no heat exchangers to worry about... Original suspension was an xc-100, swapping to the xtra-10.

At the end you see that I have done a "dry fit" on this, my front mount is going to move forward and down a little. I am going to put in both mount locations that are approx 1" vertical so I may set at the lower for deep snow conditions and upper when I am riding groomed trails and looking for cornering stability.

Holidays have slowed the project latley, I may be able to get an eventing in the garage this week, if not Saturday at the latest I will be finishing the installation. I have a few parts in route that I would like to get before finishing up, but, my mount points are ready so I have no reason not to drill them.

If I really wanted I could possiable get away with leaving the front mount where it is located and just drilling a top postion mount hole off center of bracket, but, I would run out of bracket if I ever wanted to set the suspension to the lower position in the tunnel, so I think I will be moving the front mounts. The back mounts are a no-brainer, they have to move forward.

happy reading...

I did this swap last year with a 95 Indy 500. The best thing to do is get the measurements off the donor sled. What you need is the distance from the driveshaft to the front mount and the distance between front and rear mounts. I believe for the Indy trail (evolved chassis) there shouldn't be any need to relocate the front mount. The distance between the front and rear mounting spindles is 23 1/8, so I believe you will have to move the rear mount forward 2 5/8". This will require removing the rear mount on the machine and fabricating a new one, which is fairly simple. I used regular bolts and nyloc nuts to attach it. However, it was a very tight fit putting this in. One thing you can do to help is get a ratchet strap and compress the front and rear arms of the suspension, this will give you a little extra room.
After mine was installed the track tension was very tight. However, there is a world of difference between the Xtra 10 and the XC100. If you send me your e-mail address, I can forward you an email I received from someone who did this swap on an Indy trail, complete with pictures.
Good luck.

Ok, here is what I've measured from this past weekend,
First of all let me give you the sled info:

#1. 94 indy classic (evolved chassis)
#2. 96 indy 500 carb (evolved chassis)
#3. 2000 XC700 SP ( the coolest sled on the planet)

distance from: axle to front hole #1 11-3/16"
#2 11-3/4"
#3 11-1/2"

distance from: axle to back hole #1 36"
#2 34-3/4"
#3 34-1/2"

distance between front and #1 24-13/16"
back hole #2 23"
#3 23"

distance from: inside top of tunnel #1 5-3/8"
front hole #2 4-3/8"
#3 4-3/8"

distance from: inside top of tunnel #1 5-3/16"
back hole #2 5-1/16"
#3 5-1/16"

Now for the details, I learned a couple of new things:
1. Don't use the steering hoop to measure to anything. All three sleds had different measurements.
2. The rail profile changed on the extra-10 somewhere between 96 and 98. there is more rail towards the front tips of the suspension, about 1-1/4 inches.
3. Measurements taken from the driveshaft were measured from butting the tape measure up against the flat of the hex to the centerline of the holes and in a straight line.
4. Measurements taken from the top inside of tunnel were taken from butting the tape measure against the support piece (corner brace that runs the length of the tunnel) to the centerline of the hole and in a straight line.
5. There are some differences between the front suspensions of the classic and the 500, although I believe these are minor I will do some more measuring in this area. Don't think I have anything to worry about.

As far as moving the support mounting plates, I don't have to because by moving the holes up and closer together I have enough room to miss the old holes by quite a ways on the front and back.

So if you have any more questions, let me know


Now I thinks I have enough information to make the holes....

I haven't fully digested the measurements yet but, from what I have read here is my basic course of action...

From anouther reply I am told that the critical dimension is the distance between the mounts... 23.125" is the measurement I believe is correct. (I've seen 23, and 23.5... hence 23.125 is the mean)

Some people have left the front mount in the same location and just moved the rear mount forward, but, it seems this solution moves the tensioning adjustment near it's full forward position. This makes installing/removing difficult and you risk having too much tension in the track (and I have a brand new one to install), so I am going to adopt the suggestion to move the front location forward some. I will use Rat's numbers from the driveshaft to the front hole to determine that amount, it should land around 1" forward of the old mount hole, and down from the tunnel a little. Once this is set I will use it as a datum to set the distance between mounts, and move the mounting bracket to it's new position.

ok, more food for thought, I think if you move your forward hole closer towards the driveshaft instead of back you will be changing the angle that the track runs at on a level surface. I think that the front rails will be up in the air more than they need to be which will also effect ski pressure and related adjustments. Also when you accelerate your suspension moves forward and you don't want to move any further forward. Your track angle will be steeper than normal and that will rob some of your horsepower and speed up hyfax wear at the front of the slide rail. And by moving the back holes to match the 23" you will have more track tension adjustment. I don't see how this helps. I've never run out of track adjustment. And as far as getting the track in and out, moving the front hole forward won't help with installation. it will only change the angle that the track runs at. The coupling blocks on the rear of the extra-10 have a range of movement that is affected by the rail angle. If you are starting at an angle different from factory specs you are losing some performance characteristics allowed by the blocks. Wait a minute, what am I saying, maybe you could install this suspension to a totally new set of holes and create an even better ride, but I doubt it. The extra-10 is the best riding and most adjustable suspension I've had. I started out with an xlt special with an extra-12. It had a great ride but it was a bit on the high side of the center of gravity. Don't get me wrong there either I could ride that sled all day and push it as hard into the corners as I wanted to without fail. But you were pretty tired by the end of the ride. When I went back to the extra-10, I waited til they came out with the p.p.s shock. That was the next biggest change that they made with this suspension since it's introduction in 1996. They didn't change that suspension til 99 and that change was the intro of the p.p.s. shock. I now ride my xc700 sp without bottoming out and have all the necessary adjustments to create a smooth ride either in the morning or by the end of the day. Anyway I'll stop babbling and wish you luck and please let me know how your project works out. I would be very interested in finding out your new hole dimensions.
If you need any tips for suspension removal and installation let me know, I can help, If there is one thing I've learned about getting a skid in and out it's to use all the patience you can muster. Take your time and don't get in a hurry. And also air tools help out ALOT!!
If you use the advice mentioned the only other thing you need is a good floor jack, a place to hang the back end of your sled and a buddy to help you is also extra nice. Good luck


I started laying out marks on the tunnel last night, this is what I found.

The front hole, from the orginal location on the XC-100, will move about an inch total distance and split between up and forward. Using the 11 1/2" dimension from the flat of the axel, and down 4 3/8" from the tunnel support. In this position there is still plenty of the steel support plate to use and I can just put the new hole.

The back hole is now set at 23 - 23 1/8" on a radius from the front hole and down 5 1/16" from the tunnel. I drilled out the rivets on the origional mount plate (steel piece) and moved it forward, (about 2.5") to look at it relative to the markings. It appears I can use the mount without modification. The origional hole used for top mount hole for the XC-100 will put the center of the mount for the xtra-10 about 5 1/8" from to the tunnel support. If I place it to maintain the 23" I don't think 1/16" of an inch hieght difference will be noticed.

What do you think? I think this will work.


Oh BTW...

I have the body work off and fluids drained so I've been working on the sled on it's side, makes things really easy to get at, so I don't thing installing will be too.. too.. difficult... I hopes...

If you are using 11-1/2 inches for the dimention on the front hole, I think you are headed in the right direction. Your old front hole must be in a different location than mine (thats where the moving front or back confusion is happening in my brain). Anyway by working with the sled on it's side it will be alot easier to remove and install the skid frame (suspension). However you wouldn't want to do it this way every time, as it would be a hassle to remove your fluids and bodywork everytime you want to pull your skid frame. Just remember to take the torsion springs and unload the tension by lifting the long leg off of the wheel and swinging that leg down towards the track. This will allow you to move the rear shaft around to get the bolts started. And also slide the rear axle all the way forward and snug up the bolts to hold it forward. This will help to get it into the track. Let me know how things go.

Even more on the topic.... (it never ends when working with an engineer... :)

Here's what I did last night...

I took my old XC-100 and laid it on the bench next to the XTRA-10. I then hooked up one of the springs on the XTRA-10 and compressed rear end of the suspension to achieve the 23" center to center distance, I left the front at full travel against the limit straps, that are adjusted to show 1 1/8" of thread past the nylock nut. I feel this is quite close to the installed position for a couple of reasons. First, the wear pattern on the spring where it mates with the rail bushing is matched. Secondly, the forward link stop block is just shy of making contact with the rear arm, and as you compress more fully it starts it's travel toward the back stop block.

Now I took all of the adjustment of the rear wheels to full forward (loosest track) and lined the two suspensions along a plane that was tangent to the rear boogey wheels.

Anyhow.. With them both laying there I found that indeed the front mount location on the xtra-10 was little forward of the XC-100. This semi re-enforced my measurements I took from the net and laid out on my tunnel, (no drills yet just markings). The measured locations indicated that I would be raising the suspension in the tunnel, but as of yet I don't see that on the bench comparison. I will be double checking sometime over the weekend, so I am not positive on height yet. But, another thing popped up and I started thinking about it...

The approach angle (or degree of curve that the front end of the rails produces) was higher for the XC-100 than the xtra-10. This could produce a problem if the xtra-10 is mounted too far forward in the sled, as the track would have to make a hard turn on the plastic wear blocks at the front of the rails. So as a last check before I drill... I am going to do a dry mount and check everything out. But, I need my new track before doing this, may be today or tomorrow.

I also have an idea for installing/removing the skid frame. I can take a couple of long (and fairly thick) tie wraps and use them to compress the suspension to the 23" center to center. These will hold the suspension compressed while I install, then once I have the bolts in I can then just cut them off and pull them out. For removal the reverse could be done, have someone sit on the sled, compress the supsension a little, tie it up, pull bolts.. and whalla, out it comes, I hopes

When I put an Xtra-10 in my 95 Indy 500, I got excessive wear on the hyfax near the front of the skid. However, the skid I bought only had four wheels showing on the outside of the suspension rails. There are two more you can buy for the front that push the track away from the hyfax at the wear point. I installed these this summer and am hoping they make a difference. If the skid you are installing has three bogies showing per side you will be all set.
Compressing the suspension before installing is definately a good idea. So is taking the torsion spring off the tensioner blocks. I would be interested to know how the track tension turns out when you have completed the installation, as I did not move my front mounting hole.

Man this is getting deep. It makes you think about all of the things that are happening underneath your rear end while you're on a sled. I have some insite or at least an opinion on the last posts. Accelerated hyfax wear would probably be caused by using the existing front mounting holes from the old xc-100 suspension. Here is why I think this way; the xc-100 had only about 8 inches of travel. the extra-10 has about 10. When you install this taller suspension into an older sled using the old holes particularly the front hole, you do a couple of things. 1. you raise the ride height. Polaris learned from the extra-12 that raising the ride height is not always a good thing (speaking from experience here). 2. You also change the approach angle of the track to the suspension. The track is on a steeper angle between the driveshaft and the slide rails and this is what is causing the wear on the front of the hyfax. Now if you add two inches of travel to a suspension and raise the mounting holes approx. one inch you only raise ride height one inch. The rest can be made up by different shock and spring combo's to provide the amount of sag when you sit on the sled which will bring the ride height back to the original height or close to it. As far as the rear and front scissors stop blocks,(commonly referred to as f.r.s.s. and r.r.s.s. in the polaris manual I think that the front stop should be touching the scissors when you are not on the machine and when you sit on it the scissors should by half way inbetween each of the stops. This will allow the suspension to move either direction and be prepared to let the scissors go forward or back to handle any situation. From that point you can turn the blocks to acheive other riding styles i.e. drag racing or deep powder riding. I think your limiter strap may be a little tight, not by much maybe a 1/4 inch or so. If you have a limiter strap on the rear scissors maybe it is a little to tight which would not allow it to fully extend and touch the f.r.s.s. And by uusing a strap to compress the suspension is a super good idea but for measuring purposes make sure you are just moving the torque arms and not compressing the rear shock Have you guys read anything about rising rate or falling rate suspensions. This complicates things even more. So anyway I'll quit babbling on and wait for your reply. Keep up the good work and I hope to get to my extra-10 installed this weekend providing we don't get to much snow. I'm starting to get the itch really bad as it has been snowing a couple of inches every day this week.

Sorry I haven't communicated in a little but I've not been able to get in the garage until last night... results are as follows... and I am still waiting on some parts.

Well I've ran into anouther challenge... my new 1" lug height track is just going to fit, I have about 3/8" - 1/2" clearance MAX, belt tension will have to be right on. I am putting 96 1.075" studs in it and need to put different tunnel protectors to avoid an interference (current protectors hang down about 3/4"). So tonight I continued the dis-assembly process and removed the seat/tank assembly so I can remove the old tunnel protectors and install new ones.

To put protectors back in I'm going to have to get inventive. The newer design track I have has hifax clips every third window and has two windows filled. On the filled windows there are lugs that stick up the full 1" height. I don't intend on installing the studs in a pattern that will put any in the line of the hifax so, my tunnel protectors will be located directly above the windows. Since my studs should protrude about a max .25 - .30" above the track lugs I will have to find/manufacture some protectors that are only .375+" tall. I have some nylon sheet at work that I may be able to cut into strips on a table saw and use, I hope. As most recommendations for a 96 stud patten do not have any installed on center line I may add a third protector directly on center in the tunnel also.

So tomorrow night I will drill out the old protectors I will finally be able to do my dry fit into the tunnel. I just got my Fox shocks back from being rebuilt and installed them into the suspension and compressed the suspension with heavy tie wraps to the 23" on center mounts. I noticed something else that tends me to believe this is the proper center to center distance. When compressing the rear of the suspension to achieve this distance was at relativily the same point were the bell crank on the forward side of the dampener rotated to a position that any further motion would result in compression of the dampener. I'm not positive but, this just seems to be "right" from an engineering perspective.

Oh I forgot I have volunteer stuff to do tomorrow so it will be at least Wednesday before I get in the garage again. My bogie wheels and studs may be there by then anyhow, and I can start checking my minimal clearance condition.

If I can get ahold of a digital camera I will start uploading some pictures of my now totally naked sled and the fits I work out.


There should be enough clearance for the 1" track. I have a 1-1/4 track on my 2000 XC700SP and don't have any clearance problems. I was going to put a track on it that I could have gotten a good deal on but it turned out I couldn't use it because of that very reason. It was a ski-doo track and had the taller lugs where your tunnel wear strips normally were. If I had tunnel wear strips I could have just removed them (running without studs). But on the Gen II chassis the tunnel protectors are also your coolers for your engine. I tried to think of a way to get that track to work because I had it in my possesion for about a month as I was reassembling the sled from a wreck. Without changing my suspension mounting holes (possibly compramising a great ride) or using smaller idler wheels on the top of the rear scissors or moving my coolers to the outside (pain in the ###). I even thought of grinding the notches into the new track( time consuming and smelly). I still couldn't get enough clearance. Fortunately the dealer that I had purchased the track from was willing to take it back and gave my a good price for the proper track with the cutouts for the coolers. 1600 miles later I am very happy that I had done it the way I did. Left the suspension in its original place and bought the right track. If it were a fan cooled sled I would do exactly the same thing you are doing. You will like the taller lug providing you have enough snow to keep the hyfax cool. You may want to think about an extra set of wheels for the suspension to take some of the pressure off the hyfax. Later

Thanks for the info....

It is tight for the track, but, should still fit.

I do have the design that has three sets of bogie wheels on the outside of the track.

Hey for those who are interested...

I did the dry fit last night, with the suspension compressed to 23.125 on centers.

I'm very close now... everything fit and the front holes as predicted are going to have to move forward about an inch, maybe a tad more for ease of removal and installation. I should still have plenty of adjustment. When I am pulling hard against the new track tensioning it up as much as possiable the front mounts land about 1" from the original holes.

When measureing out the xtra-10 and the xc-100 next to each other the front arm is the same length from the mount to the pivot on the skids, this is leading me to believe the new mount hole should be the same hieght as the old and to just move forward. And this was somewhat confermed during this dry fit, if I postioned the front mount hole at the same level the track is leaving the front of the skids about 2-4" shy of the ends. When positioned at the level of the "aggressive", lower setting that the xc-100 used the track has to make a slight turn at the front wear end on the skids. This seems to be adding up, the dry fit is definally a good idea before drilling.

The 1" Lug track under tension will be able to rotate, getting studs on is going to be tough. I started working out where to put protectors, and that will require some "customization" to the lugs if I put them directly above the windows. My plan is simple...

Install track without any studs mounted, ride when snow gets here... make sure that I'm not rubbing, and I can work out a good track tension setting. If this "gells" then start thinking about putting the studs in. I am fairly confident I can get it to work, my old track (I think stock) that was falling apart, (left about 4 nice holes in my tunnel were studs few off), had studs in that when measured from the inside of the track to tip should be about the same as the hieght my new ones will be. This difference is gained by the newer designed tracks are made of a thinner material through the section.

216 Posts
Just a note here, if anybody is interested in installing a 133.5 touring skid into a standard indy chassis I could also post that info as well. My next project sled after I finish the 94 classic upgrade to aan extra-10 is going to be a 97 xc600 chassis with a 133.5 touring chassis. Of course I have a 133.5 x 1.5 inch paddle to fit with the skid. I probably won't be working on it till the next summer as I'm still collecting parts for this sled. But I 've got the touring sled to get the dimensions from, so if the track will clear I'll have good numbers in a few days. Stay tuned.

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