I write articles for the local tri club's newsletter. Next month I plan to tackle indoor training options. I don't like to recommend a rear wheel mounted trainer without explaining my reservations to this particular choice.

As a disclaimer, I am in no way, shape, or form an engineer. My problem with rear wheel mounted trainers is the forces that the bike has to absorb. The way I see it bikes are engineered pretty well to do the job they were designed to do, i.e. transfer your available power into forward motion. The frame needs to be able to absorb some road shock without sacrificing too much rigidity. In any case, I don't think bikes are at all engineered to be fixed at the rear axle. I like to illustrate this to others by having them think about what a bike looks like from behind when a rider is standing and hammering up a hill. Lots of side to side motion right? If that rear wheel is fixed in a trainer those type of forces have to be absorbed by either the frame (mostly the rear triangle) and the trainer. I argue that over time this COULD cause fatigue and damage to the bike frame. My suspicion is that this type of trainer is also hard on the rear hub, but I would have a hard time backing that up.

I also say if you have a second bike that isn't your race bike go for it. I also don't think you will have any problems if you stay seated. Some of my friends like the Spinerval videos. I think if any damage is likely to occur it is from these hard sessions where you are out of the saddle hammering away.

Opinions? Testimonials? Real engineers to tell me to stay in the humanities where I belong?

Chris Sweet