Wednesday, August 25, 2010

Unless you look...

I've been using my Schwinn Sports Tourer about once a week all summer. I take it out with Ava on the trailer bike, to the grocery store for light shopping runs, over to the lake for kayaking trips, and it even went to Staples for a school supply run last week. That's not a lot of use -- less than 300 miles -- but it's regular use. The bike has felt and sounded just fine, from the saddle. Other than keeping the chain lubed and wiping the wheels down to clean off the aluminum dust after a wet ride, I haven't seen cause to do anything to it.

On Monday, though, I had my last class at Broadway Bicycle School, and brought the Schwinn into town for its turn in the work stand. The topic for Monday's class was to look at the front derailleur. Though none of my front derailleurs was giving me any problems, I do struggle with setting them up right the first time during a build. I usually get the angle a bit wrong, and have to tweak that, but sometimes I also end up with a chain that overshifts and drops off the big ring, to the outside, at the least opportune time. Easy fixes, but things I should be able to avoid by setting it up right in the first place. So I was looking forward to learning tricks from Dave, our instructor.

I wasn't disappointed. I learned that I typically set my front derailleurs too high above the outer chainring (just 2-3mm). I learned the proper angle for a front derailleur (outer plate parallel to the chain while in the outer position), and that setting this always a guessing game because you can't adjust it while it's in that position. And as an unexpected bonus, I saw a real cable housing cutter in action, making quick work of derailleur housing (which has linear wire strands under the casing, rather than a helical coil of flat wire). I tend not to use this stuff because it's so hard to cut with the tools I have, but it's not ideal to use the other stuff with indexed shifters, and I should get one of those cutters at some point.

On the work stand, I saw that my front derailleur was on the verge of overshifting the chain off the large ring, that there was a little slop in the derailleur cable, and that my derailleur was a little high, relative to the recommended position. The first was probably caused by having my cranks snugged down a bit in Siena -- I don't think I ever re-adjusted the derailleur's limit screws to match the cranks' slight shift inboard. The second was either because I didn't take all the slack out the first time, or because the housing settled a bit or cable streched. And the third was just me not knowing any better. All good to catch.

But as I poked around, a couple of other things popped up, completely unexpected. For starters, I was able to hear a lot more noise coming from the rear derailleur on the work stand than out on the road. In top gear, the derailleur was on the verge of noisily overshifting the chain off the cluster altogether, and in low gear, the jockey wheel was riding right on the sprocket, which was particularly rumbly when pedaling backwards. Both were easy to adjust away, but had been missed because I hadn't checked for problems in a while -- even though I'd made major changes to the bike (like a new wheelset after my May crash).

More seriously, though, I discovered that the rear wheel was a little out of true, and that the cause was a broken spoke. These wheels have maybe 500 miles on them, and have never been abused, so this was pretty surprising - I haven't broken a spoke in over 15 years! These are factory-made wheels, but they're not assembled from junk, by any means. The rims are Sun CR18's which are a strong touring/commuting rim. The hubs are Quanta parts with cartridge bearings -- perfectly decent hubs. And the spokes are straight-gauge DT Swiss, which are good spokes used by wheel builders everywhere. The spoke broke at the bend down at the flange, so maybe it had been weakened during forming, or maybe it had been overtensioned by the lacing machine -- who knows. I just hope I don't end up breaking spokes all over the place with these wheels.

Dave suggested we replace the spoke in class, since I was there and otherwise done with my tasks for the evening. So I took the wheel off the bike, removed the tire and tube and unscrewed the spoke from its nipple. Then I tried to remove the freewheel from the hub, but it wouldn't budge. Dave tried, too. Then we double-teamed the wheel and still couldn't unscrew it. I had the same problem with this freewheel on the previous wheelset as well, but the bike shop guys had been able to get it off for me. I'll hit it with some penetrating oil and give it another shot, but in the mean time left it in place, and just curled the spoke past the big sprocket. That proved painless enough, since the spoke was on the left side, not the drive side. Once the spoke was screwed into the nipple, I put the rim on the truing stand and straightened it out.

None of these issues were hard to address (though I'm glad I found the broken spoke in the setting I did). And none of them would really be surprising tweaks to have to make sometime after a build has been completed and things have settled in. What they really reinforced for me, though, is how important it is to give your bike a deliberate inspection every once in a while -- even just once per season -- to make sure everything is adjusted properly. I've never really believed in a regular tune up, thinking that the bike would tell me during normal use if something was wrong. Finding these problems really showed me that unless you get the bike into a stand and look, you may not notice problems that could leave you sitting by the side of the road, waiting for a lift home.

All for now,


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