20080910 Bicycle Maintenance

September 10th, 2008 by scott and becky

This post isn’t very exciting unless you’re fascinated by bike parts. I’m mostly posting this for reference.

We had a number of packages delivered to us in Fredericton, including one from Rohloff which contained two new 17-tooth rear sprockets and a tool to change sprockets. This and the 6 chains we ordered through Radical Edge (a bike shop in town) allowed us to correct our chain stretch problems. Unfortunately, when Scott compared the old sprockets to the new, he discovered the old ones were 15 tooth. If we did a direct replacement, it would mess up the gear ratio (currently 36/15 – 2.4), but fortunately we had a couple of 40-tooth front sprockets in the resupply gear Mom & Dad Drennan brought. That brought the gear ratio back to 40/17 = 2.35 – quite acceptable.

The new chains and sprockets are much smoother, and hopefully the combination of better chains (SRAM 870 instead of 830) and larger sprockets will allow this chain to last longer than the last one.

Our odometers are only reading 4200 km, and an oil change isn’t due until 5000, but we had the kits (and didn’t want to carry them), so decided to change the oil now. We’re glad we did, the hubs seem to be running much more smoothly. We have read elsewhere that as the hubs age they get smoother – hopefully this is the start of that process.

We also tested out the emergency rear shock replacement Scott’s Dad built for us. It’s a bar of aluminum with two holes for bushings, and four bushings made of Ultra-high molecular weight polyethelyne. The dimensions are designed to match the existing rear shock, but it’s rigid, so doesn’t do much to soak up energy over bumps. The important point is that It is much lighter than a spare shock, so we can carry it without too much trouble. Thanks Dad!

3 Responses to “20080910 Bicycle Maintenance”

  1. Kevin Smith Says:

    Any opinions on oil vs. grease for hubs? I’ve only seen grease in the hubs I’ve overhauled, and that’s what I’ve replaced it with.

  2. becky Says:

    Hi Kevin,

    We don’t really have an opinion. Our hubs are special, in that they are the Roloff 14-speed hubs (no derailers). The only user maintenance on our hubs is a regular oil change (the oil change kits are purchased directly from Roloff). We don’t have any recommendations for a standard bicycle hub, sorry.

    Cheers,
    Becky

  3. scott Says:

    Hi Kevin,

    For a standard hub, I’ve never used anything but grease, and I doubt oil would have enough viscosity to stay for any length of time. The Rohloff hubs are fully sealed, so the oil stays in the hub and flows through the planetary gears as the hub rotates. There’s a neat video of the hub on youtube if you’re interested.

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