I have a Sole E 25 it worked fine for several years then the rollers kept coming off the t outside of the right track. I removed the track and the wheels and the tee shaped end with the brass bushings and switched them to the opposite side that never comes off. After switching the parts from side to side the right still came off the outside and the left stayed on. Since the different parts did not make any difference i knew buying new parts would not do any good. I saw that Sole made a replacement track for their single wheel machines that had a side on it to keep the roller from coming. They do not make a replacement for the double track so I make my own. I used a 1/2 thick by 2 ft. long by 4 in. high piece of white plastic I had laying around to use as a guide to keep the wheels on the track. I also used a 1/4 in. by 2ft. long by 1 5/8 wide piece of plywood to space it away so the rollers would clear the white plastic. I drilled 3 holes through the plastic and plywood them marked the black round steel tubes that support the aluminum tracks that the wheels ride on. Make sure and drill the steel a little smaller than the sheet metal screws so they will hold. I used 3- 1 1/4 sheet metal screws to anchor the plastic and plywood to the eliptical. I used plastic because it would be quieter and less friction than steel or plywood. I works great again.
