Polaris Xtra-10 Rear Suspension: Improving the Xtra10 ride Xtra-10 installing a PPS shock, standard and XC skid differences Swap instructions

Improving the Xtra10 rideAs a trail rider, my concern isn't about track speed or how fast I can make it across a lake; I need a sled that is easy to steer, comfortable to ride and plenty of torque to pull from corner. I typically buy Polaris machines as they fit this style of riding very well. However, that doesn't mean that there is no room for improvement. When snowmobile manufactures choose the step that the snowmobile is sent from manufacturing with it is a compromise to satisfy the average rider. Sometimes just small tweaks in setting up your snowmobile will make a world of difference in how it will perform for you. Although Polaris sleds have great suspension, some are known to have a loose feeling at the track, commonly referred to as the "Polaris Shuffle". This is mostly found on snowmobiles with an XTRA 10 rear suspension, which was installed on quite a few snowmobiles from 1996-2001. Note: The procedure that is described below may not be possible on all snowmobiles with the XTRA-10 rear suspension. Earlier models may not have an upper mounting location on the front torque arm and snowmobiles with the remote reservoir will not fit when mounted to the upper location. Other limitations may exist so refer to the section "Other items worth mentioning" for more information. The Polaris shuffle generally occurs when you have a hard packed trail with a bit of loose snow on top of it. If you ride in an area with good snowfall, and a lot of snowmobile traffic, this can end up being a large part of your season. The Polaris shuffle feels like driving a rear wheel drive car on a snowy road. While you are steering in a particular direction, the back end will sway from side to side instead of going in a straight line. This is compounded greatly if you're sled front end is shifting side to side because it is running in the groves from other snowmobiles (trail darting). In many occasions this can cause a very unsafe feeling to a rider, as the sled never feels entirely set on the trail.

The Cause and SolutionI have always done my own sled maintenance. On two of my snowmobiles that had XTRA-10 suspensions I noticed that the section of hifax closest to the rear scissors is always worn out before the section closest to the rail tips. I noticed the same thing when helping friends with their snowmobiles as well.Rear hifax wears quicker than at the rail tipsclick for larger image

The following seems to be the explanation: The front shock was collapsing to easily on the X10 skids for trail riding forcing the weight of

the rider to be placed on the rear of the suspension instead of it being evenly dispersed along the track. This not only decreased the traction I was getting but forced the snowmobile to "wheelie" on the rear of the skid. This is a good thing if you are a powder rider, but not if you are a trail rider. To improve on this, three items need to be addressed: 1. Change the front shock/spring mounting position to the upper location on the front torque arm instead of the lower one. 2. The rear scissor stop needs to be moved to a tighter setting. 3. Adjust your rear springs to a higher setting.

The three areas we're concentrating onclick for larger image

Remove the rear suspension

Every year I remove the skid frame from all my snowmobiles. I find it is the only way to be confident that everything in your skidframe is in perfect shape for the winter to come. There are a variety of techniques to removing the skidframe, but I'm going to share the one that I have found to be the easiest. Loosen the 4 bolts that hold your skid frame in. This might be tricky because there is threadlocker on the bolts to hold them firmly in the snowmobile. As the bolts are threaded into a shaft that spins in the arms of the suspension, removing the bolts can be tricky. Once you loosen one bolt and then try to loosen the bolt on the other side of the shaft, the shaft might just spin inside of the skidframe. If this happens tighten the bolt you had just loosened and then loosen the other bolt. You might have to do this procedure back and forth a few times to get the bolts out of the tunnel. Once you have the 4 bolts out, swing the machine over onto its side. Note: Put something soft under the machine as to not scratch it. Swing the rear of the track perpendicular to the machine, pull the suspension back and the front of the suspension out of the tunnel. Then pull the skidframe out of the snowmobile. Once you have the skidframe out of the snowmobile, you need to move the shock from the lower to the upper mounting location. This is not as easy as it sounds as the shock is under tension while it is installed, and it won't simply slide past the front torque arm. There are a few techniques to move Change shock angle to the shock into the upper mounting location.steeper positionclick for larger image

If your sled has an adjustable front spring, take note of how much tension is on it. You can do this by either measuring from the bottom of the spring adjuster to the bottom of the shock, or by counting how many threads are visible from the adjuster down to the bottom of the shock. Spin the adjuster down all the way down to relieve the spring tension from it. If you find it hard to spin the adjuster down by hand, try using a strap wrench. A strap wrench will be able to wrap itself around the entire adjuster ensuring a firm grip on it. Remove the top bolt that holds the shock to the front torque arm. Remove the retainer clip from the spring and lift the spring off of the shock. Press the shock down enough to move the shock under swing arm.

If your sled does not have an adjuster on it undo the limiter straps that hold the front torque arm down. This will allow the torque arm to lift up and remove the pressure on the bolt holding the shock in. Lift the swing arm up out of the way and then stand the shock straight up and down. At this point you can remove the black cover from the front shock and check the condition of the shock. To remove the spring from the shock either use a spring compressor or use a pair of large channel lock pliers to compress the spring. Once the spring has been compressed the retainer ring can be removed so you can inspect the shock.

Front rear shock and limiter strapsclick for larger image

Push it up and down all the way through its travel to see if you hear squishing noises or if the shaft doesn't move up and down smoothly. If you heave either of these cases you need to have the shocks serviced. Fox Gas shocks can be disassembled and rebuilt by an authorized dealer. If you have the standard Ryde FX shock it will have to be replaced as the Ryde FX shocks used in the XTRA-10 skidframe cannot be serviced. Note: If the shock needs to be removed from the skid frame more time is required to disassemble part of the skid frame. The bolt that holds the shock on the lower mounting position is too long to remove with the idler wheels on either side of it. After making sure that your shock is in good shape, place the spring over the shock again and install the retainer ring. You should take the bolt out of the top of the rear shock and check its condition as well. Mount the shock in the upper mounting position with the black plastic shock protector installed over the shock. If you had a shock with the threaded adjuster be sure to put the adjuster back to the proper setting. If you had to take the limiter straps off, use a ratcheting strap to pull the torque arm down into place so the limiter strap can be fastened again.

Two mounting positions are available, above and below the front armclick for larger image

While you have the skidframe out of the snowmobile take some time to make sure that everything is in perfect shape. From time to time the bearings on the skid frame need to be replaced, so check over all of the carefully and replace the ones that are worn. Take time to grease all of the fittings and replace the hifax if they are worn out.

Install the rear suspensionAt this point your sled should still be sitting on its side. Swing the track out from the sled and put the rear of the skidframe into the track. As the inside of the track has the rubber nipples for the driveshaft to grip, you will need to work the track around all the wheels so it will clear them on the way down. Drop the front of the suspension into the track. Once you have the suspension inside the track move the front arm of the suspension into place. Put some threadlocker onto your bolts before installing them into the rear suspension (I use Blue Locktite). Put your first bolt into the front arm finger tight. Move the rear arm into position and the bolt in finger tight.

Note: Before installing the rear arm I lift the springs off of the mounting blocks on the side rails (be sure to do both sides) so it is easier to position the rear arm. This is not necessary but I find it makes the job a lot easier. Carefully flip the snowmobile onto the other side, move the arms into position and put the bolts in. Now you can put the snowmobile upright (connect the rear springs again if you opted to disconnect them) and torque the suspension mounting bolts to 35-40 ft lbs.Unhook the suspension springs for easier installationclick for larger image

By moving the front shock to the upper mounting location you will notice that the rear suspension will collapse slightly easier then before. This is happening because the front shock is now a stronger pivot. If you were to drive the snowmobile like this you would find that you would get excellent weight transfer when accelerating but cornering tends to be a bit more prone to lifting the inside ski. To combat this we move the rear spring Tighten the rear spring setting stiffer by one position and move the rear scissor stops one step blocks tighter (closer to the rear swing arm). This will return the snowmobile to the click for larger image same handling characteristics as before without trail darting. Other items worth mentioning:

If your Rear scissor stop was already at the tightest setting, move the rear swing arm mounting position in the slid rails back one position. This will also aid in limiting weight transfer. There are different springs available from your dealer for the rear suspension. If your springs were already on the stiffest setting, check with your dealer to see if stiffer springs are available.

Move the rear scissor stopsclick for larger image

Xtra-10 installing a PPS shock, standard and XC skid differences:Can You Put A PPS Shock In Your Xtra-10 Polaris?Executive Summary: Yes you can. Should you do it? Read on....

Background: Prior to 1999, Polaris Xtra-10 suspensions could be tuned for either slowspeeds and small bumps, or higher speeds and bigger bumps, but not both. Well, not very well, anyway. The skid uses torsion springs, which are strictly straight rate springs. So, you pick your rate and make your compromise. A softer spring gets you a softer ride but bottoms too easily. A firmer spring works better at speed, but rides harshly when you're just cruising. Help is available from tunable shocks, suspension mount settings, and coupling adjustments, but those darn torsion springs are still a compromise. Enter the Polaris Position Sensitive shock, used on the 1999 XC and XLT Special lines. By now, you've probably read about its bypass valve design, and seen the ads with the cutaway illustrations. The PPS is designed to overcome the compromises of earlier Xtra-10s. It allows the 99 XC to run the stiffer spring needed for big hits, and it provides appropriate damping for big hits with the stiff spring. However, on small hits, the shock is intentionally flabby, leaving most of the bump handling job to the spring. With little shock dampening in the "ride zone", the spring/shock combo is no longer too stiff, it's just right. And 99 XC riders will live happily ever after. So, you want to put a PPS on your pre-99 Xtra-10? So did I. I bought a used 1998 XC 700, a sled that is notorious for riding like a lumber wagon at low speeds. Before picking it up from the dealer, I had him install a PPS. It bolted right in; things looked great! However, I kept reading and hearing "It can't be done", "Things will break", etc. I decided to really dig into it, to compare my skid to the 99, and further, to see if other Xtra-10 versions could be fitted with the PPS.

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The first thing I did was pull my skid frame out of the sled for intense scrutiny. I cycled the suspension and found the PPS could hit as it slid underneath the front arm. However, I later realized it was not a valid test. I allowed too much movement by not having the torque arms mounted as in an installed situation. After I spaced the arms properly, there were no clearance problems. Hooray for our side!

Next, measuring tools in hand, I went out to my friendly local dealer, Bob Lissy at Lissy's Polaris in Wilmington, Illinois. With Bob's permission and tolerance, I sized up the skids. After making several sketches that included each and every mounting and component dimension that affects the PPS installation and functioning, I am confident in saying the following. The PPS can be mounted in 1998 XCs, as well as other 1997, 1998, and 1999 Xtra-10 short tracks. I did not have access to any long track or 1996 versions. However, others are reporting that 1996 short tracks are not a problem.

Here are some of the noteworthy items I found. The 98 XC has a skid version different from other 98s. Other 98s were apparently similar to 97 skids. These two versions also appear to be in use in 1999. The two skids differ as follows. The XC skid has three mounting hole locations for the lower rear scissors to the slide rail, whereas the "regular" skid has just one scissors mounting hole. The one hole on the regular skid is located where the front hole is on the XC version. The stock mounting on the XC skid is in the center hole, making it somewhat stiffer in initial spring rate. Also the two skids differ in the FRSS and RRSS block positions offered. The XC offers more choices. The remainder of the basic geometry is unchanged between the two versions. To test the PPS clearance in the regular style scissors mounting, I moved my scissors to the front hole, and cycled the suspension again. No clearance problems whatsoever. In fact, the tightest clearance occurs with the XC scissors set in the rear hole, and the FRSS click for larger image set at low-low. It may look like the shock is hitting the arm in the photo, but there is still about 3/16" clearance. And that's as close as it gets, using a scissors and FRSS combo that is not normally used, and is not even available on the non-XC skids. Some people have reported having to use washers to space the shock relay rods (thin rods that are just under the shock body) farther apart than stock, to clear the shock body. On the 98 XC, this was not an issue. On my 97 XCF, the rods do measure slightly closer together. Adding a washer on each relay rod attachment would not be any trouble. The 99s do not have washers and have the same shock rods as the earlier models. Manufacturing variances may explain why some suspensions will need to have washers installed. Just check your suspension in this area for clearance when installing the PPS. One interesting find is that in all measurements pertinent to the PPS fit and function, the 98 XC skid was identical to the 99 XC skid. Yes, identical. But there are differences, you say; you've read about them? Yes, there are. But they don't affect the PPS. Here are the differences and updates for 1999. According to an inside source, skid frame changes have been made in two areas: 1. More front arm travel, better planing and rolling resistance. A flatter-angled rail is used. The front arm is the same part as last year, but it is mounted in the top mounting hole in the tunnel bracket, which is 3/4" higher than the 98 center-hole mounting. The rail is then lowered back to the right place by using limiter straps that are 1" longer than in 98. The Indy Select shock is the same part for 98 and 99. We will cover spring rates later. None of this affects the PPS. 2. Moved the carrier wheels (up inside the tunnel on the rear arm) away from the edge of the track. Polaris moved the wheels inboard to address track durability issues. This required a different rear torque arm, new square-wire springs, and related spring mounting hardware. However, no geometry changes were made, therefore it's a nonissue regarding the PPS. The 99 XC torsion springs are the same rate as the old round ones on the 98. Now, should you consider installing a PPS? Why would you not want one? Well, consider some drawbacks. According to sources, the PPS is not a snocross racing shock. It is tuned for comfortable and aggressive trail riding, which is a neat enough trick in itself. Later on, there will be performance

kits to reduce the amount of bypass, which will make it more like a regular Fox. One interesting advantage it has is better heat dissipation due to the aluminum body and large oil capacity. Here's a tip: For best heat dissipation, remove the pretty body graphics wrap. The PPS is also not a drag racing/holeshot/big transfer shock. It requires tight coupling to work, and tight coupling is not desirable in drag racing, hill climbing, and many performance situations. If you do run a PPS not tightly coupled, you may not like the resulting quirky behavior. If you do run a PPS, emulate the stock settings: 1. FRSS in high hole, set on medium or high. 2. RRSS in high hole, set on low or medium. 3. Scissors mount in center hole. 4. Torsion springs at medium. Those settings assume an XC skid. What kind of performance can you expect if you put a PPS into a regular skid, especially one with softer springs? We don't know. The PPS is calibrated right now for the springs of the XC. For 98, those were .421 diameter round springs. If you put a PPS in a skid with .406 springs, it is reasonable to assume that the ride will be softer overall than an XC. Will you like it? Will it be too soft? You pays your money and you takes your chances.

Now let's talk springs and other things you can play with.Front track shock springs: The 99 XC SPs have a front track spring that is 190 lbs. straight rate along with its Fox shock. The 98 XCs and 99 XCs have a 200 lb. variable rate spring. Running the 190 lb. spring is reported to give a noticeably better ride, but this may be because of the change also to a Fox shock. The 200lb variable is there for the times when you hit that super big bump. The Xtra10 works well if you can lighten up that front track shock spring as much as possible while still avoiding bottoming. If you don't pound bumps at 40+mph then softening it from the 200lb variable will help the ride quality. The dealer has a listing of all the shock springs available, you might want to try and soften yours up if you don't pound the big bumps. The other thought is that you're putting the PPS in the back so to get all the benefits you might well want to put a Fox in the front of the rear suspension as well. IFS springs: The 98 XC has 75 lb. straight springs. The 99 XC has 100 lb. straight springs, and the 99 SPs have 74/120 variables. It was discovered that 98 riders were cranking up the 75 lb. springs so far to get the right bump handling that they were creating a nose-up attitude. Switching to the 99 100 lb. springs is recommended to cure this situation. Front torque arm: The arm is the same for 98 and 99, as previously mentioned, as is the Indy Select shock. Should you move your 98 arm up and use the longer 99 straps to let the rail back down? After all, you gain an inch of travel, and the upper holes are available (undrilled) in the mounting bracket. Well, sources say "Don't do it". Apparently, you will create "slight adverse track tension issues". It is not clear why it is an issue for 98s but not 99s, but that's the word. For those who do decide to move the front arm up, pay attention if you are using a Fox front arm shock. For 99, the Fox shock used on the SPs is 0.1" shorter than the previous versions. You can shorten an older Fox by replacing the bottom cap. While you are at it you can install the

multi-step nut that fits both size springs. If you don't shorten your Fox shock, you can bend or crack the torque arm, according to our sources. Don't let all this trivia obscure the main point. You can install a PPS in your earlier Xtra-10, and if you're a trail rider, you'll probably be glad you did.

Xtra-10: Swap step by stepDonor Sled: 2000 XC 700sp Recipient sled: 1994 XCR 440 The measurements I used came from a 96 XCR 440 that came factory with an XTRA 10. If youre unsure find a similar sled that came with an XTRA 10 and used those measurements. DONT USE AN XTRA 12 AS THEY ARE COMPLETELY DIFFERENT. You should be able to do this in an evening or two. You are going to need a big rivet gun, rivets or Stainless steel bolts and nylock nuts, drill, and other small common shop tools. The biggest thing here is to measure accurately and make sure your measurements are square on both sides of the tunnel. Always measure from the top of the tunnel and not the foot board as this differs from year to year. The following instructions are from my own swap using the above sleds. I have sent this to several others on this form and they have had success as well. To get the old plates off your best bet is to grind the rivets off from the inside of the tunnel as this wont mark the part you can see. Once you get the old mounts off your going to have to modify the rear mounting plate to get around your cooler (see #264 & 265). If your original skid is either an XC 100 or XC 101 then your front plate is probably in the right spot as these skids were the predecessor the XTRA 10. Your front plate should be between (12"-13" back from the center of the jack-shaft). You will then have to drill new hole in the front mounting hole up to the next hole in the plate.

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Note: Xtra-10 skid mounting diagram above is for a 97 Ultra SPX SE.

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The measurement you need are as follows: From center of Jack-shaft to center of front mounting hole - 12 1/2 " (if your off by 3/4" or less don't worry about it right now) and 4 1/4" down from the top of the tunnel (this is more important right now) From the center of front mounting hole to the center of the rear mounting hole 23" (this is the

important one) and 5 1/4 " from top of tunnel. Some people have told me that this varies from 22 - 23 depending on the sled.

Rivit the rear bracket on, put the new skid in, tighten the track as normal and your ready to hit the bumps. The measurement discrepancies that are within 1 inch can all be made up with the track tensioning adjustment. That should be it. The biggest mistake people make doing this swap is the distance between the front and back holes. You could take that xtra 10 skid and bolt it into the sled with out changing any holes and it would fit but it wouldnt work. The last few pictures are what the sled should look like once youre done. You might also want to find a set of spindles from a 97, 98 or 99 and swap them out. They are about 1 1/2 longer and will raise the front of the sled putting more weight back on the skid. This helped my darting problem. I also filled the old holes with rivets and bolts so it looks good.click for larger image

Finished results

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Take your time and good luck. The results will be worth it.

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