A while back I acquired a spare rear wheel for my Sherco. The idea of keeping a competition tire fresh and sharp and then having a practice tire/wheel sounded great. Easy enough to throw in the van as a back up too. Well, the Sherco was sold and replaced with a TRS. I discovered that the Sherco wheel would fit the TRS with just a 1mm washer on both sides of the wheel. The most important thing is to get the brake disc to roll free between the brake pads. Now, I am playing with a Montesa and it makes me cry to think that expensive Michelin is going to wear out just practicing. So, on goes the Sherco wheel. This time I need a 3mm washer on the disc side and a 1mm washer on the sprocket side. Now I have a Montesa practice wheel. Just for fun, sized up the TRS wheel to fit the Montesa. I needed to use the TRS wheel spacer on the sprockets side plus 4mm of washers and the stock Montesa wheel spacer plus a 1mm washer on the disc side. You can get 1mm washers and 3mm washers and mix and match. Moral of the story is it is very likely most current trials wheels can be swapped with one another with the help of some washers - they all seem to have a 17mm axle . Sprockets, of course vary so they may have to be swapped but that isn't too hard. Besides saving my good tire, my spare has already saved the day on far away ride for a friend that that had a flat. Grabbed it out of the van, swapped sprockets, and off he went. Here are a few pics.