Indoor training, part 5: Turbo trainer tweaks for a folding bike

Previously I wrote about how Bino, my 20″ folding bike, interacted with my Minoura LiveRide LR340 turbo trainer. Officially, with the Z-adapter installed, Minoura says it can support a bike with 24″ wheels, and this became apparent when the threaded shaft on the adjustment knob simply ran out of room to squeeze against Bino’s 20″ x 1.75″ Impac Streetpac tire.

Another issue I ran into was the much greater amount of rubber dust particles generated by the smaller wheels. Because the circumference of the 20″ x 1.75″ tire is smaller, it goes through more revolutions at a given road speed compared to Hyro’s 700C x 28 mm or 700C x 32 mm rubber…which directly translates to much faster wear. The rubber dust particles themselves fly out over a larger area because the wheel is suspended much higher off the floor, making cleanup a chore.

So, I had two issues that need resolution.

I took a page out of Steve’s playbook and fashioned an extension for the adjustment knob’s threaded shaft, in order for the resistance roller to get more pressure against Bino’s rear tire. Basically I took a large brass dome nut and slipped it over the end of the adjustment knob shaft. It didn’t matter to me that the threads between these parts were incompatible with each other – all I needed was to give it a bit more length.

With the dome nut stuck on the end, I got more consistent and more positive pressure on the rear tire, and I was even able to reinstall the large cone spring that should have been there in the first place. This also opens up the option of using narrower tires for turbo trainer duty instead of being stuck with the 1.75″ width option. Schwalbe’s full-slick Kojak at 20″ x 1.35″, in particular, is a good candidate, although I might need to swap to a bigger nut.

See all that gray inside the box? That is all rear tire dust.

Addressing the problem of rubber dust particles was even simpler. All that took was a large cardboard box. Every time I use the turbo trainer, I basically put the cardboard box as close to the rear wheel and resistance unit as possible, so it catches all the rubber that gets flung off. The box flaps rest on the rear fender so there’s no rubbing anywhere.

These two simple hacks solved my problems. They’re not going to do much about the accelerated actual tire wear, though – that’s just a fact of life when using a small-wheeled bicycle on a turbo trainer, I guess.