Xtra 10

I've put X-tra 10 rear suspensions in 2 of my SRVs. The suspensions I used were from a 1999 XCSP and a 2000 XCR 800. They are the same suspension. The only difference is the shocks: the XCSP came with a hydraulic front and a Fox position sensitive rear. The XCR 800 came with Fox shocks. I think other Polaris sleds used these suspensions, too. I think pre 1998 X-tra 10 suspensions were a bit different. I like the suspension with the regular Fox shocks better. Fox shocks are readily available for these on ebay. Before I installed the suspensions, I disassembled, sandblasted and painted all parts. I sent the Fox shocks to www.deycore.com for rebuilding. I replaced all bearings.

The center to center distance for the suspensions I used is 23 1/8". I used the rear mounting hole from the stock SRV. I needed to drill a new front mounting hole 23 1/8" in front of the rear hole. I drilled this hole 5 1/2" below the below the outside top edge of the tunneland it works well there.

I needed to reinforce the tunnel at this point. On one sled I used .063" thick 4130 Chromoly steel. On the other, I used .063" thick 7075 aluminum. I bought both Items at www.aircraftspruce.com. The 4130 chromoly is stronger, but it is more expensive and tougher to cut. To make the plates, I just traced the contour of the edge of the bulkhead. I made two plates per side. I riveted one plate along the edge of the bulkhead and then riveted the other on top, sandwiching the bulkhead and the first plate. I'll post a pic of this on the next post. If you use steel(or even aluminum), you should paint the plates before assembly to keep dissimilar metal corrosion from taking place. I used Dupont Tufcote. This is a thick automotive primer. If I didn't have that, I would use oil based Rust-Oleum metal paint.

For Rivets, I used steel Huck magnalok rivets in 3/16" diameter. These are available at www.rivetsplus.com or www.rivetsinstock.com. The part number you want is MGLP-R6-4. These rivets require a #10 drill bit. Don't use rivets from the hardware store. They aren't strong enough. The downside to the Huck Magnaloks is that you need a hydraulic rivet puller to pull them. Magnaloks will break mormal rivet guns. Harbor Freight makes a good pneumatic-hydraulic puller for $99: part 16680VGA. This is the one I use and it pulls the Magnaloks with no problem. Buy the $99 aircraft model, not the cheaper regular one(167-5VGA). The cheaper one isn't as strong. To insulate the steel rivets from the aluminum. I dipped the rivet tails in epoxy before I installed them.

The X-tra 10 needs to be narrowed before it can be mounted. If I remember correctly, I had to narrow them 7/8". I chopped 7/16" off of each end of each axle. To get the number, I just measured the length of the original SRV axles. You need to narrow the torque arms, axels and 2 retainer collars. I used an electric miter box fitted with a metal cutting blade.

There's really not much to fitting an x-tra 10. You just need to narrow it, reinforce the tunnel and put it in. You could use an earlier x-tra 10, but you will need to know the center to center mounting distance. Remember that you will need to narrow the suspension. Later suspensions with the extra dogleg on the rear torque arm can't be narrowed. I bought my suspensions from forum members on www.snowest.com. I think one was $240 and the other was $260. Deycore charges about $30 per shock for rebuilding. You can find bearings on Ebay for about $20 for 10. It took me awhile to post his because I knew I'd be typing for awhile. If you have any questions, just ask.

You can see the reinforcing plate in the corner of this pic. The plate is actually 2 plates, .063" thick, staggered and stacked.

I drilled out the locator plates from sround the original front mounting hole and riveted them in place around the new holes.

We've put somewhere around 500-800 miles on the all black sled so far. It'll do 85 on a groomed trail and still have throttle left to go. I suspect top speed in good conditions would be 90-95, although 65-70 is about as fast as I ever want to go. The track on that one has 1" lugs. (Camoplast #9793, about $265 at www.tracksusa.com). I think changing the suspension and track could change the requirements for the clutching. I'm running a Comet 108exp, A1 weights, Comet red spring with 1 engagement shim and the secondary in the B1 condition. This works very well on groomed trails. The sled has a little trouble(I'm really splitting hairs here) when you're breaking trail in 2+ feet of fresh powder. Most old sleds and a good number of not so old sleds would have a bit of trouble in these conditions.

The early SRVs (1983 and older, I think these all had the chunkier tunnel) used 116" tracks. The later SRVs used 121" tracks. I think you can fit a 121" track to an early SRV, but you need to swap out the suspension and possibly extend the tunnel. It's a bit more work. What I say below pertains to the newer SRVs.

Just about every short track(non-mountain) sled in the last 20 years uses the same dimension track. This dimension is 15"x121". 15"x121" is the standard size for a short track. The pitch of the track is 2.52". This is the basically the distance between the track clips or the distance between the driver's teeth along the circumference of the driver. Some of the newer Arctic Cat and Ski-Doo sleds use a 16" wide track with a 3.00" pitch. These are not compatible with the srv.

The size of the lug varies. The stock SRV track has 5/8" lugs. Fitting a track with larger lugs greatly improves the traction, acceleration, and handling of an SRV.

A track with 1.25" lugs is about the largest that will fit on an SRV. A 1.5" track will barely rub. Any 121"x15", 2.52" pitch track with les than 1.5" lugs will fit on an SRV. When you install the larger lug tracks, you may need to flex the paddles to fit the drivers in. This can be a bitch. a 1" lug track fits with no problem.

To answer your questions, The stock 121" SRV track will fit with the X-tra 10 rear suspension. The stock Polaris track from the donor sled will fit as long as the track's lugs are 1.25" or shorter. The ride quality is nicer and plusher with the X-tra 10 fitted. Your body takes less punishment. You can't really compare the SRV's ride to anXCSP or XCR's ride. They have different front suspensions and that makes a big difference. In addition to the improved ride, an x-tra 10 has better parts availability. Rebuildable Fox shocks are readily available for decent prices. The front shock on the SRV rear suspension is basically no longer available. As for a clearer write-up, I'm not sure how much clearer I can be. Lay on your back and look at your sled's suspension. Figure out how it works. When you pull it apart, you will see how it mounts in the tunnel. This is pretty straight forward. There's been a lot of good information posted in this forum over the last month. Read all of this season's posts and print out the good ones. If you're stuck, ask questions.

A Big thanks to NortherLPRob for Taking the time to write this up!