Saturday, April 14, 2007

Refurb complete!

Not that I had any doubt of my mechanical prowress. I've rebuilt engines, replaced clutches and swapped transmissions. I have also worked on delicate things like wind-up clocks and watches. One of my biggest website projects is chock-full of instructional walk-throughs for car maintenance, performance tips, and other stuff like that.

A bicycle is just another machine to me. It's a different kind of machine than I'm used to tinkering with, but a machine all the same. I have an interesting thing about machines of almost any type. I always appreciate them more once I've fixed something that's broken, or have taken it apart for no other reason than to see how it ticks. There's not much to take apart on a bicycle. You can see pretty much everything without so much as taking an allen wrench to it.

With the second failure of my bottom bracket, I decided it was time to break out the tools and figure out what was up. Getting the crank bolts off was simple enough, but having never really done this before, I quickly found out that I needed a device that screws into the cranks and presses the spindle out. I have tons of similar devices for yanking pullies and whatnot off of engines, but nothing for this task. A quick check on Sheldon Brown's site showed that I needed a crank puller. Fair enough. Off to the bike shop, but without the bike this time. I got my crank puller.

While I was out, I went ahead and splurged for some bearing grease. Given the fact that water had gunked up my bottom bracket twice now (and that I have no idea what's the proper grease to use) I picked up some trailer axle grease made for boat trailers. It's supposed to be great for applications where water can gunk up bearing surfaces.

I found that the bearing cage nearest the chainrings was totally destroyed. My guess is that the water and sludge got in there and diminished the lubricating properties of whatever grease was left in there. The carnage happened very soon after I'd hammered it downhill at about 35 MPH right before I got home.

Off to the bike shop again for some new bearings!

I polished up the bearing races on the spindle and cups before packing the bearings with the new swanky axle grease. I adjusted the bottom bracket until it felt right and tightened the lockring. Next, I bolted the cranks back on, and she spun like new!

While I had the bike inverted and before cleaning my greasy hands, I also re-packed my front hub with the same axle grease I threw into the bottom bracket. It has been a little rough feeling for the past few weeks, but after checking out the bearing races, there wasn't anything wrong that a little cleaning and some fresh grease couldn't fix.

In closing, I recommend that anyone who relies on their bike for basic transportation get familiarized with common problems, and invest some time and money into learning to fix them. After all, flat tires and the occasional loose bolt aren't the only problems that plague commuters and utility cyclists.

A bike might seem a little bit complicated for some people to just dive right in, but believe me that it's really simple and that many common problems can be fixed in your own home. You might also find out that buying the parts and tools to fix one problem costs the same or even less than having the shop do it. Then, you not only have the tools to fix the same problem in the future, but the knowledge and the confidence that you've done it before.

Here are some handy links to excellent resources for fixing your bike up properly:

Sheldon Brown's articles about bicycle repair
Park Tool Repair Documents

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