23 March 2009

Learning about Bicycles

It's been a while since I've spent a 36°F night out in the garage working on bikes until I can't feel my fingers. Today my dad brought over two 20" kid bikes that he aquired while helping someone move, so I had an excuse to do some wrenching in the cold. We've done this a few times before where he finds the needy bikes, I fix 'em up, and then we place them in a good home. The problem is that some bikes are worth working on and others are not.

Yes, the fork of the blue one was backwards. Both also had bent brake calipers and other borken bits here and there. I took the broken stuff off, then adjusted seats and bars, aired the tires (all were good, I was shocked), and flipped them over to inspect the tranny.

The orange one was fine, though the hub needed adjustment. I'm sure someone thought the front hand brake was a good idea, but I doubt that it ever helped to stop the bike any faster. I ditched it since the coaster brake worked ok. My first BMX bike only had a coaster brake and I remember it stopping on a dime (though it likely did not.) On to the blue bike.

The blue bike was problematic. When coasting, there was a horrendous high pitched grinding noise that seemed to come from inside of the hub. I thought maybe it just needed the outter cone adjusted, but that was not the case. So, I just took it apart completely. Why not?

I've never taken a coaster brake hub apart before, so it took a while to figure out. Late in the game, I remembered reading somewhere that you should use a bench vise to hold the wheel on one side. Bingo. I cleaned everything up and tried to understand it's workings. I reassembled it twice, wrongly thinking I had found and solved the problem. I finally deduced that the spring which controls the un-braking mechnism needed to be reshaped a bit and heavily greased. I'm glad I bought those cone wrenches ages ago when they were on sale.

With the bike returned to it's upright and fully locked position, I returned to the house for a cup of tea and some cookies.


melanie said...

And stuff like this is why you're smarter than me.

Mum said...

You are such a good man! Hope these bikes went to make some kids very happy.