A customer brought in a Racing Zero for service.
Since this customer is a regular, I asked them,
"Have I inspected this bike before?"
and they said, "Probably not."
I also think I probably hadn't. The whole bike was dropped off with a request to fix brake noise and vibration issues. The cause turned out to be about half wheel and half brake, which I ultimately resolved (probably).
Both front and rear hubs had play, particularly severe on the rear wheel. This made me even more convinced I'd never inspected this bike before. Both wheels had a slight wobble, and the rear wheel was significantly off-center.
The rear hub rotation was extremely rough, so I disassembled it and found pitting on the ball race on the non-freehub side.
↑There are three ceramic ball bearings. Going clockwise from the top: top is new, bottom right is freehub side, bottom left is non-freehub side.
The difference in shine on the new one is immediately obvious, but the non-freehub side is slightly duller compared to the freehub side.
What really shocked me was the ball race on the axle side.
↑This area is clean,
↑but there was severe pitting across a little more than half the circumference.
"The theory that the old black ball race wears easily (even against steel balls), and with USB it's against even harder ceramic balls so it has an even shorter lifespan, which is why they switched to the new silver ball race—but I shouldn't loudly insist on this or the thought police will come for me."
I replaced the hub-side ball race on the non-freehub side only.
As for the axle-side ball race, the split centering washer wasn't gripping properly and had movement marks on it. It seems this is what happens when you keep using a hub with play.
I noticed the valve on the rear rim was tilted, and it turned out the valve hole bush for 2WAY-FIT (product name: 2WF valve bush) was missing.
Interestingly, this bush has a peculiar characteristic:
↑After installation, if you push it in from the reverse side against the valve, it goes through smoothly
↑If you thread the bush alone onto the valve, it goes through smoothly
but when inserting from the outer side, it doesn't pass through easily. Similar symptoms occur with Red Wind and Bullet, which use bushes with the same shape but different part numbers.
While the intermediate valve's outer diameter being slightly larger than the valve diameter is part of the issue, since the bush alone passes through smoothly, it should basically fit. In this case, removing the intermediate valve would make it easier to fit, but it's definitely difficult with the original valve diameter.
Tubeless valves always have threads for attaching a nut, and with threads the outer diameter is thinner, so it passes through quite smoothly.
This tube has an extended valve because the customer has a separate deep rim wheel and this tube serves as a spare for that wheel.
Since this customer is a regular, I asked them,
"Have I inspected this bike before?"
and they said, "Probably not."
I also think I probably hadn't. The whole bike was dropped off with a request to fix brake noise and vibration issues. The cause turned out to be about half wheel and half brake, which I ultimately resolved (probably).
Both front and rear hubs had play, particularly severe on the rear wheel. This made me even more convinced I'd never inspected this bike before. Both wheels had a slight wobble, and the rear wheel was significantly off-center.
The rear hub rotation was extremely rough, so I disassembled it and found pitting on the ball race on the non-freehub side.
↑There are three ceramic ball bearings. Going clockwise from the top: top is new, bottom right is freehub side, bottom left is non-freehub side.
The difference in shine on the new one is immediately obvious, but the non-freehub side is slightly duller compared to the freehub side.
What really shocked me was the ball race on the axle side.
↑This area is clean,
↑but there was severe pitting across a little more than half the circumference.
I replaced the hub-side ball race on the non-freehub side only.
As for the axle-side ball race, the split centering washer wasn't gripping properly and had movement marks on it. It seems this is what happens when you keep using a hub with play.
I noticed the valve on the rear rim was tilted, and it turned out the valve hole bush for 2WAY-FIT (product name: 2WF valve bush) was missing.
Interestingly, this bush has a peculiar characteristic:
↑After installation, if you push it in from the reverse side against the valve, it goes through smoothly
↑If you thread the bush alone onto the valve, it goes through smoothly
but when inserting from the outer side, it doesn't pass through easily. Similar symptoms occur with Red Wind and Bullet, which use bushes with the same shape but different part numbers.
While the intermediate valve's outer diameter being slightly larger than the valve diameter is part of the issue, since the bush alone passes through smoothly, it should basically fit. In this case, removing the intermediate valve would make it easier to fit, but it's definitely difficult with the original valve diameter.
Tubeless valves always have threads for attaching a nut, and with threads the outer diameter is thinner, so it passes through quite smoothly.
This tube has an extended valve because the customer has a separate deep rim wheel and this tube serves as a spare for that wheel.