I recently had the opportunity to pick up a used set of Grouser OTT steel bar tracks for my S650. They do not appear to be worn excessively and the price was pretty good compared with new. While having to adjust the length to properly fit the shorter wheelbase on the 650, I had to relocate a number bolts on each track. As I have no past experience with tracks, I have no idea what is considered excessive wear on the bolts and bushings and what is not. I can replace all the bolts and bushings but do not want to do that if it's not really needed at this time. My use of the tracks will be fairly light, intermittent duty in woods around my own property. I am concerned, however, about possibly breaking one or more bolts out in the woods caused by bolt wear. Below is a picture showing typical wear of the bolts that were relocated. I would like any opinion if this wear is considered bad enough to consider replacement with new before using the tracks. I almost don't think so but thought I would ask those who have experience with such tracks.
I've got 600 hrs on my set of grousers and don't believe the bolts are that worn. You have to be careful relocating the bolts to shorten tracks because they can can only be in certain positions and the Grouser website has an intall site that explains it. Maybe just keep a couple extra bolts and nuts with the machine and if something does happen at least you have some spares to get the machine out of the woods. If they continue to break, you may have to replace them. The only thing is that I haven't been able to find grade 8 carriage bolts and I have used grade 5 without any problems. These bolts I believe are a special type. Good luck.
You still have a good bit of life left on those bolts and bushings, how do the dog bones look? I have ran OTT's with a lot more wear in on the bolts and bushings, and I can't recall ever breaking one. Like fencefool said, keep a could extra bolts, nuts and washers around when you go to use them.
@fencefool: Thanks. I could find Gr 8 carriage bolts but they are threaded all the way down. When you take into account the reduced shear area at the root of the thread, the benefit of the increased strength is essentially eliminated. It may also be that the special Grouser bolts are hardened specifically for the purpose. Anyway, I've got some new spare Grouser bolts and bushings on order to keep on hand if needed. I downloaded the Grouser instructions and found that the previous owner had used the shortest possible hole arrangement in several locations, something that is NOT recommended as you rightly pointed out. When everything was considered, I was able to remove one track pad entirely and get a proper fit using the recommended holes. So now I have two spare pads and four spare dog bones . @CM1995: Thanks. The dog bones that I have disassembled look pretty good to me. There is no obvious elongation of holes. Here's what a typical one looks like: