I'm 240 and tow a Burley Travois typically loaded to a total weight on the bike of around 300 lbs. I've had no spoke or axle problems, but since the trailer attaches to the seat post rather than the rear axle (like a Bob) in addition to some of the weight rolling on the trailer wheels, maybe my experience doesn't apply. I have 26" wheels with 2" wide Marathon Plus for cushioning (the rear tire was very difficult to put on!) The rear wheel ride on my bike is pretty harsh- if you have a chance to ride something similar to the bike you will use, do try it before considering the kit. The D-series rear wheel is pretty heavy and makes for an uncomfortable ride on my bike without modifications. I don't know if a Thudbuster seat post would help much or not.