Wednesday, April 11, 2012

On the road again

My 12-year old son has been riding a pretty cheap, 20" bicycle for a few years now.  It works, but it's not fancy.  He's dreamed of having a suspension bike, but chooses to spend his money elsewhere.  Last week, I was out at my parents' farm, and saw my little brother's old Mongoose full-suspension mountain bike sitting beside the barn with other discarded bikes, where it had sat in the rain for at least a couple years.  Dad was going to take the lot to be recycled, but asked me if knew anybody who'd want the Mongoose.  I almost didn't let him finish his sentence before I loaded it into my truck & brought it home for my son.

Under a tree in 2010
Of course, any 7-8 year old bike that's been sitting in the elements for that long isn't going to be showroom new.  The chrome handlebars had some surface rust and both tires were completely flat, but it looked serviceable.  I figured this would be a great opportunity to teach my son Micah a few repair skills, spend time together with him, and get him a nice bike at the same time.  I was right.

After hosing off all the dirt & spider webs, our first job was to repair the flat tires.  I showed Micah how to remove the tires using a special tool and then fill the tube & dunk it in a sink full of water to find leaks.  One tire had two, which we patched.  The other tire didn't seem to have any leaks, but did seem to contain some slime from a previous repair attempt.  Both are still holding air a week later.

Next, we cleaned & lubed the chain.  I'm an accomplished automechanic, but I know very little about bicycle repair and don't have any of those specialized tools (except for the tire removal spoon).  The two of us cleaned the chain & sprockets together using brake cleaner and two old toothbrushes.  Once done, we lubed it up with WD-40.  I'm sure all of you cycling nuts out there are cringing, but it's what I had on hand, and it gets the job done.

The brake pads were also misadjusted and had to be realigned before the wheels would spin freely.

I lowered the seat post as far as it would go, and after a quick lesson on how to shift gears (this is Micah's first geared bike), he set off around the block to show the neighbors.  He came back a while later walking his bike and limping.

It turns out the gear shifters weren't adjusted right, and putting the rear shifter into 7th gear actually overshot 7th and pushed the chain right off the sprockets, jamming it between the sprocket and frame, freezing up the pedals, and sending Micah over the handlebars.

Micah nursed his wounds while I adjusted the gears alone.  I'm not sure if I did it right, but I loosened the nut that holds cables in place, then tweaked the cable length until the derailers were lined up right with the gears.  That doesn't feel like the right way to do something like this, but again, it got the job done.

The next day, he walked the bike home again, this time with the entire front crank bracket assembly wobbling loose.  It wasn't like that when we brought it home, so I can only assume that the sudden use after years of neglect caused the various nuts to work their way free.  Further inspection revealed that the nut that holds one of the cranks onto the shaft was completely missing.  Photos indicated that it was there when we brought the bike home, so it must have fallen out during the bike's maiden voyage.

After consulting a couple cycling friends, I bought a crank puller (ParkTool CCP-22) at a local bike shop.  Micah & I removed one crank with the tool, but the other one just fell off in my hand when I grabbed it.  We found nearly every threaded fitting to be loose.

Since we were in there already, we tore the entire bottom bracket apart, cleaned & repacked the bearings, and reassembled it all.  Like all first-timers, Micah was resistant to grabbing wheel bearing grease with his fingers to manually re-pack the bearings, but he got over it & enjoyed the experience.

I lacked a few of the special bike tools that would have made the process easier, but was able to make do with various other tools from my automotive collection, including a large crescent wrench and a large pipe wrench.  It would have been nice to have some way to get a torque wrench onto the bearing cups that enclose the bottom bracket, but I've installed enough wheel bearings that I was able to do a decent job just by the feel of the pipe wrench.  We'll see how well it holds up over time.  I'm glad I bought that crank puller, though, because I'm not sure I'd have been able to pull the cranks with any of my existing tools.

With the missing nut replaced ($1 from the spare parts box at a local bike shop), Micah is back on the road with his new bike... for now.  Of course, the best thing about this experience was that I got to spend quality time with my son and that he learned some new handy-skills that will benefit him the rest of his life.

I decided not go into too much detail here on how I did what I did, because I was really just winging it and may have done a number of things that really aren't recommended.  If you're anal about this sort of thing, there are surely countless sources of accurate instructions online.  For starters, ParkTool (makers of many cycling tools) has a lot of good educational videos on their web site.

If you've got any questions, comments, corrections, or criticisms, feel free to speak up in the comments section below.  I love hearing from my readers.

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