Tightening the chainring

Learning experience

Last weekend, on my first ride on Kuroko in several weeks, the bell failed. Apart from being a violation of the law, this can be a fairly big safety issue when riding on mixed-use paths with pedestrians and other cyclists.

I also noticed a rattling noise. It would happen in time with my pedaling, and the bike was silent when coasting (apart from the freehub ratchet, of course). During a rest stop I checked for anything that might be loose, including the water bottle cage. And I grabbed each crankarm in turn and gave them a tug. I didn’t notice any play.

As the day progressed, the rattling noise just got more constant, and I became convinced it was time to have a look at the bottom bracket. I’ve had this one just a couple of years and have put less than 4,000km on it. As Fearless Leader Joe noted, it should last much, much longer than that. On the other hand, it’s already lasted longer than any of the bottom brackets I had with the ill-stared FSA crankset.

Dumb bell

The bell has been on Kuroko since she was new. I have no idea why it chose this moment to take an oath of silence. It seems like the spring for the thumb release is broken. It just took a moment with a hex wrench to remove the bell, but it took a bit more time with degreaser and a thumbnail to remove the residue left on the handlebar.

As always with gear swaps, I have to do a weight comparison. I fully expected the new bell to weigh more, so it was a pleasant surprise to see it come in at 2g less. (Yes, I fully appreciate the fact that either bell weighs just a fraction of a full water bottle, or even the spare inner tube in the saddlebag.)

Most of the time for this bit of maintenance involved searching on the floor for the screw and clamp for the new bell after I dropped them. After that it was just a few seconds to tighten it all up and give it a few experimental rings.

Knog on

The bell is a Knog Oi Luxe. I previously purchased one for the Halfakid. They’re a bit pricey, but I love the sound.

Monkey with a wrench

Next up was the inspection and adjustment of the bottom bracket. I’d found a note on the manufacturer’s site that the non-drive-side crank could rattle if it wasn’t tightened properly (the washers on the clamping bolts can rattle), so I made a mental note to have a look at that.

The first order of business was to make sure I had all my tools ready for the job. A special tool for the preload nut, and another for the chainring bolts. A torque wrench and hex wrench, both 5mm, for the crank bolts. I had the bearing press on standby in case it was necessary. Of course, I overlooked the fact the chainring bolts were Torx, and so I had to go back to the toolbox for that when the time came.

I had no difficulty removing the crankset. With that out of the way, I inspected the bottom bracket, and I spun the bearings on both sides with my fingers. There was no sign of play or roughness.

I took some time to check the chainring bolts. They were fine on the smaller chainring, but some of those on the larger chainring were a bit loose. This is the one I replaced when the crankset was new. It was the work of a moment to tighten them all up again.

That done, I decided to give the crankset a good scrubbing before putting it back on the bike. There was a lot of grunge built up on the chainrings, and it took more than a bit of scrubbing to remove it all.

When the chainrings were sparkling again, I set about to put the crankset back in the bottom bracket. That’s when I made a shocking discovery. What was this little thread sticking out from the bearing? It only took a moment’s inspection to confirm my worst fears: the bearing seal was coming out. I gave the bearing cap a couple of tugs, thinking I could get it off and stuff the seal back in place, but I knew even as I did it that it was a vain attempt. The people who manufacture these things for a living can probably get the seals back in, but for us mere mortals the only likelihood is doing more harm than good.

That’s where experience comes from

Reluctantly, I tugged the seal out and discarded it. I had a look at the opposite side and discovered the same thing: the seal was sticking out. It followed its mate into the rubbish heap.

I’ve had a look at the photos above and there’s no sign of the seal in the picture I took immediately after removing the crankset. It’s pretty clear that I disturbed the seals when I was mashing the bearings about with my fingers, trying to feel for play or wear. Heavy sigh.

The good news is the bottom bracket was fine after nearly 4,000km. It’s probably good for many more, but with the seals gone now it will be at the mercy of the elements, and the bearings will no doubt fail in time from the incursion of water and road grit. For the moment I’ve put the crankset back in, tightened it properly, and given it some test spins. It’s fine.

That rattle

While I was putting the crankset back in, I nudged the water bottle cage — the one hanging below the down tube, near the crankset. It was loose. I quickly tightened it up again and all is shipshape.

I could have chosen to preserve my pride and not admit any of the above tomfoolery, but in the end I decided the comedic relief was more important it would be a good object lesson.

Ridin’ dirty

Kuroko has splashed through more than a few puddles over the past month. It had been my intention to give her a bath after the maintenance, but I decided to hold off for the moment in light of the missing BB seals.

Parting gift

Fearless Leader Joe has been putting in the kilometers without cease, and it’s time for a cassette replacement for his Jamis. Unfortunately, he needs a popular model that’s out of stock just about everywhere, with no estimate given of when it might be available.

I have the same range, 11-32T, in my spares, although it’s 105, which is one step down from the Ultegra he’s got on the Jamis. Apart from a few material choices (and hence a few dozen grams), there’s no real difference, though. After all the maintenance on Kuroko was done, I dug this cassette out of the toolbox and cleaned it up so I can send it to FLJ. This is a cassette I had on Kuroko for probably less than 1,000km before swapping it (and the derailleur for good measure) for an 11-34T cassette.

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2 responses to “Learning experience”

  1. […] yesterday’s learning experience, I was confident that Kuroko was up for a nice, long ride. The only question was whether I wanted […]

  2. […] know if Kuroko’s frame has space for it until I remove the bottom bracket (already slated for replacement). The alternative is an external model which pairs nicely with the external battery solution, but […]

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