I picked up a couple of the factory made 2-wheel kits for our m-series sleds. The directions are a bit vague, but I figured I'd add a few ideas to the kit.
When I put the kit on my sled, I noticed that the instructions did not tell us what to do with the spacer sleeve that is on the stock setup. I chose to cut my spacer sleeve down to 4 3/8", and to put that between the rear wheels. I know, you don't have to do that, since the lugs on the inside of the track will keep the wheels in line, but I liked the idea of having them positively located, but more importantly, I liked being able to clamp the rear axle with the axle bolts. Without using this sleeve, the track tension is maintained only by the adjuster bolts. I'd bet the bolts will hold just fine, but the plastic guides that slide in the groove are kinda soft for that kind of force, so I liked the idea of the sideways clamp force you can have with the use of that spacer. I guess I should have taken pics to post, but I might do so now that it's done. Seems to work well.
When I put the kit on my sled, I noticed that the instructions did not tell us what to do with the spacer sleeve that is on the stock setup. I chose to cut my spacer sleeve down to 4 3/8", and to put that between the rear wheels. I know, you don't have to do that, since the lugs on the inside of the track will keep the wheels in line, but I liked the idea of having them positively located, but more importantly, I liked being able to clamp the rear axle with the axle bolts. Without using this sleeve, the track tension is maintained only by the adjuster bolts. I'd bet the bolts will hold just fine, but the plastic guides that slide in the groove are kinda soft for that kind of force, so I liked the idea of the sideways clamp force you can have with the use of that spacer. I guess I should have taken pics to post, but I might do so now that it's done. Seems to work well.