Indoor training, part 4: Bino on the turbo trainer

So far, everything I’ve written about indoor training has involved Hyro, my cyclocross bike with the 700C wheel size. However, one of the features that my Minoura LiveRide LR340 turbo trainer listed was its use with small wheeled bikes.

That got me curious: how would Bino, my 20″-wheeled folding bike, fare when mounted on it?

To mount Bino on the LR340, I needed to go back into the box and pull out the Z-shaped small wheel adapter, or “Z-adapter” for short. Along with it were a couple of hex-headed bolts with spring washers through them.

I would then have to remove the resistance unit from the round-headed bolts and rubber shim of the LR340’s frame. The Z-adapter will then be installed between the resistance unit and the rubber shim. The hex-head bolts go into the resistance unit, while the round-head bolts attach to the foot of the Z-adapter and the rubber shim.

Once the Z-adapter is in place, Bino has to switch to Minoura’s chrome steel QR skewer.

The rear wheel gets clamped into the LR340 frame, then the resistance unit has to be raised to the point where its roller sinks about 5 mm into the tire.

This…is where things got a bit problematic.

Bino’s rear tire is a 20″ x 1.75″ (47-406) Impac Streetpac. Even with this relatively generous width and inflated to a maximum 65 psi, the roller wasn’t compressing itself against the tire enough. I could barely feel any resistance. (This also means that mounting any 20″/406 mm tire narrower than 1.75″/47 mm will not work for indoor training purposes.)

The adjustment knob for the resistance unit was already at its limit.

My solution here was to disassemble the adjustment knob, remove the cone-shaped spring, then reassemble. That yielded just a little more travel for the knob to push into the tire better. Alternatively, you could thread the spring onto the other side of the adjustment knob so you don’t lose it.

The end result turned out pretty good. The Streetpac is treaded, but has a continuous center line of rubber, so it didn’t get as noisy as I thought, although more audible compared to Hyro on slicks. Unfortunately, if I wanted to use the LR340 with Hyro again, I’d have to take out the Z-adapter.

I clipped the remote resistance knob onto the handlepost, just under the handlebars. I could crank up the resistance to maximum with barely any slippage and tire hop on the resistance unit, as long as the rear tire is inflated to exactly its 65 psi limit.

The front riser block needed more height to level out, so I put an old book under it. Swap in the T780 pedals, clip in, and Bino is now an indoor trainer bike.

The resulting mess after every indoor training session using Bino.

You could say that the effort of cleaning this up after each turbo trainer session makes for some added light exercise!

The one disadvantage with using Bino on the LR340 was that it generated a lot more of the fine rubber dust particles that are a normal byproduct of a tire making contact with the ground. This is because Bino’s tire is mounted much higher up on the trainer compared to Hyro’s, and the smaller diameter 20″ x 1.75″ tire wears through its tread quicker, since there’s less of it going round per revolution compared to a 700C x 28 mm tire. All this equates to a slightly bigger mess after an indoor training session, but it’s not too hard to sweep clean.

Finally, to help track my progress and mileage on Bino even while riding indoors, I moved the Cat Eye Velo Wireless+ cyclocomputer and sensor setup from the handlebars and now-stationary front wheel to the rear wheel and the non-drive side chainstay.

Ideally, I’d have a more sophisticated cyclocomputer that would measure both wheel speed and pedaling cadence from one sensor mounted on the same chainstay. However, I think it’s an expense that would be better put into other components or apparel, and I have yet to see one that offers backlighting functionality. So far, this jerry-rigged setup makes efficient use of my existing hardware, and mounting all of it close to the rear dropout means no heel strike on training sessions. I do have to clean off the fine dusting of rubber particles it gets, though.

Despite the challenges, Bino makes sense as an indoor training bike, leaving Hyro to all-weather riding duty. To give Bino a bit more commitment to this role, I’m thinking of eventually getting a second-hand set of SPD pedals to eliminate the pedal-swapping I currently need.

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