I have a 1979 John Deere Trailfire that I have been restoring and I’m trying to find out what the track tension should be adjusted to. I have just replaced the track and I’m not familiar with the correct procedure for adjusting the track to the proper tension for the optimum performance and track life. Any advise would help me out a lot.
The basic rule of logic would be a tension that works! Different sleds have different specs as to where to measure and how much weight pull and much slack should be measured. What we’re after is for the track to be tight enough to not ratchet under full throttle and /or derail with a side load applied (cornering) but not so tight that it increases the friction and rolling resistance to the point it is consuming your horsepower. Generally, we will run a track as loose as possible so it doesn’t ratchet. The old guide was if it ratchets, tighten the adjusters a couple turns. And when you’re at this point, if you lift the rear of the sled you will have some slack midspan on the track hanging from the rails. The longer the track, the more this droop usually is. Similar to a dirt bike chain, the actual tension varies through the arc of travel, and it ends up being looser than what you might suspect.
First, you must loosen the rear axle so it will move as you make changes to the tension adjusters (long bolts that change the position of the rear axle). Set both side evenly, checking alignment, so you have some slack hanging in the middle of the track and adjust as needed based on test driving it. If it ratchets at all as you accelerate, loosen the rear axle, crank on the adjusters to push the rear axle towards the rear of the rails (say, a full rotation), check alignment, and tension the rear axle. It’s easier to work your way up from ratcheting than to work down from being too tight.