With rain in the forecast this weekend, and only a couple of weekends left before the Tour de Tohoku, I brought Kuroko up into the Workshop in the Sky for some timely maintenance.

I had two areas of concern: a slow leak in the front tire, and a clicking noise that only occurs while pedaling in gear 7 (counting from the largest cog) on the rear.

Easily sorted — perhaps

The front tire is tubeless, and it’s been slightly more than a year since I did anything more with it than replacing the valve. Obviously, it’s overdue for a sealant top-up. I simply unscrewed the Clik valve (they go on and off by hand, unlike Presta valves) and let the air out. I already had about 80ml of sealant measured out in a small bottle, so I squeezed that in through the valve body and put the valve back in. That done, the tire pumped up easily, with just a few drops of sealant spritzing out from the bead / rim interface adjacent to the valve.

I gave the tire some spins to distribute the sealant and considered the job done. Of course I’ll check the pressure again tomorrow to make sure it’s holding.

Gear 7

(Wondering now if I should trademark that as a designer label.)

This gear has been making a very constant clicking noise for some time now, but usually only noticeable when I’m riding next to something like a guard rail or high curb (and it’s not being drowned out by traffic noise). It sounds like the chain is not quite aligning with the teeth. It’s a puzzle because there’s no such noise on any of the other cogs. I had a few theories I wanted to check:

• Forgotten or incorrect spacer between the cogs
• Bent, worn or damaged teeth
• I’d somehow got the cog on the freehub in the wrong direction

The last really shouldn’t be possible as the cogs are keyed to the freehub such that they’ll only go on one way. But it’s a DT Swiss hub, not a Shimano, so maybe it’s possible? (Although DT Swiss are known for their quality.)

It looked from visual inspection there might be a bit of extra space between the sixth and seventh cogs. But when I removed the cogs I saw that this spacer is built into the 4-6 assembly. (The largest six cogs are grouped in two preassembled spiders with three cogs each.) The remaining spacers were all the same width as far as I could see. (Didn’t bother with the vernier.)

I cleaned the cogs with some degreaser and inspected the culprit closely. I didn’t see any obvious signs of warping, wear or damage. With a mental shrug, I reassembled the cassette and tightened it.

With the wheel back in the bike, I cleaned the chain and then gave the bike a rather cursory washing. I used the Hudson sprayer for this, which I got as a replacement for the Kärcher that had fallen apart. I was expecting a bit more pressure from the Hudson — similar to the Kärcher — but it was sufficient to rinse off the bike given some persistence. And it was much quieter.

After rinsing off the bike, I put it back in the stand to dry the chain, first with paper towels and then an air sprayer. The final job was to lube the chain, wipe off the excess, and check the adjustment.

And … it was exactly the same as before. Shifting was fine, and there was no jumping out of gear. Just that annoying ticking noise. And try as I might, I couldn’t see it happening — couldn’t see the chain hesitating before dropping between the teeth, for example. I tested the chain for wear and it has very little, as expected. It’s only recently been replaced.

Finally I gave the derailleur a fine adjustment, following the Better Shifting guide. And that seems to have worked, at least partly. I can still hear a bit of the clicking, but it’s much less than before.

I’m not sure how much comes through on the video — I probably should have recorded before the maintenance as well, for a comparison.

In any case, that’s good enough to be getting on with, at least until the next chain replacement. And meanwhile the bike should be ready for the upcoming ride (assuming the front tire is holding air now).