Trainer modification

Trainers are nice tools.

For the consumer, they are a handy tool for staying in shape when going outdoors is not possible.

For the racer, they are a tool to help stay warmed up until just before the race starts.

In the shop, they are a tool to help with basic fitting of the rider to the bike and sort out numerous problems that may need to be seen with the rider on the bike.

Back in the day, all bikes had quick release skewers. Today, almost nothing in the performance category will. The problem here is that most trainers in existence are designed for QRs being on the bike.

Companies like The Robert Axle Project have worked to help with the needs of cyclist with after market axles that improve the interface between bicycle and trainer or trailer.

I purchased a TRA204 axle and a ‘Spacer 6mm flat’ from them to mount my bikes with 142mm or 148mm Paragon 12×1.5 dropouts to a trainer for a project I’m working on. The parts are nice enough. Look great, fit great. I’m sure they do the job well.

The problem isn’t solved yet. The trainer side of the equation.

I’ve done this modification for a few of my local fit studios. It’s been a thorn in their side and I’ve helped a bit to get them dialed in.

These ends are from an old  Minoura MAG850G tire drive trainer. The concept remains on any skewer mount unit. The key is that we want to mate a cone with a cone for the most solid and secure fit the system allows. In this case, a 14° taper to match the RAP axle.

These new ends will provide a very much improved connection to the trainer with far less load on the trainer arms.

For my CycleOps trainer, the fix was a little more tricky. I needed to drill a smaller hole. That’s not as easy as drilling a larger hole. Still, now that trainer is ready for another 10 or 20 years of use. I could have ordered there own Trainer TA, but I would rather keep to the RAP system.

While I was working with the CycleOps trainer, I decided to add a couple more holes to the adjustment system to help work with wider hubs that are in the modern era. The holed are 5/16″ diameter spaced at about 14.75mm and are 5/16-18 threaded on the through side.