Monday, October 08, 2012

Cog farming and toolmaking

Late last winter when I converted the mountain bike for commuting I made a note to put some higher gears on it. I'd built it originally for technical riding and then never used it for that. So I slapped on some bigger chain rings. The result was better but not good enough. Then I remembered I'd put a 7-speed 13-30 cassette on the bike.

The steps in a 7-speed 13-30 are 13-15-17-20-23-26-30. Annoyingly, if you go to a stock 8-speed, all you can get is an 11-30. I don't need a stinkin' 11.

The shifters, transferred with all the other parts from my 1991 Stumpjumper when I switched to the Gary Fisher frame, are 7-speed Deore DX thumb shifters. Like most top-mount shifters, they have a friction option. I'd just never taken advantage of it. In friction I can shift whatever rear gears I want to stuff in there.
 The Cog Farm

When I got to work on Wednesday I went to our cog farm to look for a 19 and a 21. I ground the heads of the rivets off the back of the 13-30 so I could take the cluster apart and inserted the 19 and 21 in place of the 20. Now it's an 8-speed: 13-15-17-19-21-23-26-30. The jumps are only two teeth for five shifts, then three and four. So far, at the low low end I haven't been bothered by those intervals. Cruising the path, the mid-section of the cassette offers nice close options for minor changes of grade, surface or wind.

The 24-34-46 chain rings might need a little fine tuning. Maybe the 44 will be fine. I spend almost no time in the 46-13.

During the early weeks of my path commute I run into a lot of other users. As the evening comes earlier, the chill bites harder and the pretty leaves fall away, fewer and fewer people will feel like taking a walk out there. For now I have to be ready for delays and obstacles.

This truck was plugged into the path at Bryant Road on Wednesday morning. Beyond Bryant the trail needs work because of a washout.

Closer to town, where the path goes on the causeways with pretty views of the water, people walk in clumps. A lot of people use the path as a dog-walking area, too. Most of them clean up after the pooch, but not all of them.
This dog-walker with stroller lined up with an oncoming rider for the perfect blockade. Slow down, smile, act like it doesn't matter. It doesn't, really.


On beautiful days in foliage season we might do a few emergency room repairs for visiting riders who have an unexpected mechanical problem. A big guy asked if we had batteries for Powertap hubs.

"What size are they?" I asked.

He looked at me like I was a pathetic yokel.

"They're for Powertap," he said, looking slightly pained. Then he got an Important Call on his groovy earpiece telephone and gave me the time I needed to jump on the Internet and find out that the hub takes two SR44 button batteries and the computer head takes the ubiquitous 2032. No problem.

"Do you have the Powertap hub tool?" he asked.

I looked at the hub. It had two little wrench flats that looked like a headset spanner would fit. I grunted and took the wheel in the back shop. Of course the fashionably curvaceous hub cap rejected the plebeian wrench. A quick look on line showed me how weird-looking the official tool is. The customer commented that it doesn't work very well.

The service instructions also noted that the O-ring seal of the hub cap makes it resist turning but that the cap is regular right-hand thread with no tricky spring catches or other booby traps. I gave it a surreptitious twist with the full strength of my tire-changing fingers. It seemed to give way slightly, but at a cost that spoke to me of future crippling arthritis. But maybe this miracle of modern technology was no more forbidding than a new jar of pickles.
The Cafiend Powertap cap removal tool

I wrapped an old inner tube around the cap to protect it and muckled on with some big honkin' water pump pliers. The cap came off without a problem.

The customer was actually a nice enough guy. He never did get the hub to communicate with the computer he was using. He'd substituted a Garmin wrist unit for the Cycle Ops computer head. He went on his way to wrangle with recalibrating it after his ride.

The evening was beautiful so I rode beyond my car at the outer end of the commute, up a dirt road I had explored once before. It has a Class VI section (no longer maintained) that follows a very nice grade to Stoddard Road. I was thinking it might add a bit to the ride and shorten the drive for my park-and-ride commutes, but the Class VI is very overgrown. If I had a problem in there, particularly riding alone in the dark, it might inconvenience my wife.

Before the junction with the abandoned part there's a nice wetland.
On this mild fall evening the mist was forming in the center of it, precursor to the morning fog that is a trademark of New England in the autumn. Late-season mosquitoes harassed me.

The overgrown section apparently channeled some runoff during Hurricane Irene last summer. Our area saw none of the damage that hit Vermont and many other states, but we did get some heavy rains along with plenty of other downpours over the past year. The trail surface was rockier and slipperier by far than when I went through on the Cross Check with its fairly smooth 700X32 tires. In gathering darkness I only went a few yards in before returning to the maintained dirt road. It's worth future exploration and some minor clearance at some point.

No comments: