Driveshaft Disassembly

Today I finished stripping my Crosstown 7 in order to replace the broken frame. That involved removing the driveshaft assembly, cleaning it out, and re-greasing it. The bottom bracket came out by loosening the three screws on the left-hand side. Here's what the inside looks like. Somehow, dirt managed to get in there, but I don't think that had any consequence on performance, since the whole front crank case is sealed.

Here's what the front crank-case assembly looks like fresh from the bottom bracket.

Loosening the three screws on the other side allowed me to open the case and remove the gears for cleaning. Initially, the inside of the crank-case was full of grease, which I removed with clean rags.

I noticed that the gear ratio was 11:27. Because 27 and 11 are both prime, each tooth on the shaft eventually interacts with each tooth on the bevel gear, and no wear pattern develops. After cleaning everything up, I closed it up again and shot it full of fresh Teflon grease.

Here's what the rear end of the drive shaft looks like. This is where the 7-speed internal hub connects. The hub is similar to the chain driven version except for the bevel gear in place of the chain cog.

The next step is to receive the new frame and reassemble. I'm expecting the frame on Wednesday, so I'll post photos of the reassembly process then.

Stripping the Frame

As I said I would, I started to take apart my Crosstown 7 in preparation for replacing my broken frame. So far, this job has been about what I expected, with no surprises. I started by removing the bike rack, seat post clamp, and rear fender, which all came apart as an assembly. Then I removed the brakes.

Then I removed the front brakes and unhooked the shifter cable, which allowed me to remove the handlebar, with everything still attached. At this point, my neighbor Emily saw me over the fence and offered me the use of her husband Jeff's work stand. I accepted, and boy what a difference that made. That enabled me to remove the kickstand and take off the cranks. Fortunately, I had a crank extraction tool from a previous project. Without a crank extractor, that task is near impossible and guaranteed to mess up your bike.


One interesting thing to note here is that when you add grease to the crank, it eventually comes out through the bearing on the right side near the crank arm seal, which makes it kind of messy since this spot is tough to clean with a rag with the crank arm still installed. In the photo below you see a year and a half worth of grease accumulation. The color of this grease when clean is light brown, almost white. A couple of times I had added shots of the green marine grease that I use for my water-brake dynamometer at school. I plan to open this up and clean it out thoroughly and re-grease with the white teflon grease supplied by Dynamic.

In a way I'm glad for the opportunity to get inside my bike and see how it all goes together, although this process is time consuming and no so convenient. I'll take the challenge to learn a little about bike repair rather than complain. Here's how I left things when it got too cold and dark to keep going tonight. (My workspace is the back patio. I miss my garage workshop.)

Frame Update

Micro-post here: as promised, Dynamic shipped my frame yesterday. This morning I got the shipping notification from UPS. It should arrive next Wednesday. I hope to start posting disassembly photos this weekend.

Video: US Airways Flight 1549 Lands in the Hudson

The story of the landing of Flight 1549 in the Hudson River has been really powerful for me. The pilot of that flight, Chesley Sullenberger,  is my kind of hero. I'm thankful that neither a single death nor any major injuries occurred as a result of the landing, and the passengers tell a consistent tale of a calm, collected, women-and-children-first evacuation. That happened as a direct result of his cool head, his quick thinking, and a little bit of divine intervention. It could so easily have been otherwise.

At the time of the rescue, there were helicopters with video cameras all over the scene, and the rescue was pretty well documented. So why am I blogging about it now? Well, I knew it would only be a matter of time before a video of the landing surfaced, and I wanted to have something constructive to offer to my readers instead of another rehash of the events.

Here it is, courtesy of the U.S. Coast Guard, unedited, and no sound track. The splashdown occurs at 2:02, and if you stick around for a couple of minutes, you can see people emerge, fall off the wing, get pulled back up onto the wing by other passengers, and eventually get picked up by the ferries.

Commuter Tires

Yesterday, I dusted off my wife's Raleigh hybrid bike to ride it in to work since my regular commuter has a broken frame. I enjoyed the change of feel and posture on the ride in and was starting to think this might not be so bad after all. Then on the ride home that all changed. After picking up Ian at his Tae Kwon Do class and attaching the tagalong trailer, we started our 3-mile ride home. Not far into the ride, we got a flat.

Of course, I had not switched my seat bag and tool kit over to the Raleigh, so we were stuck (literally) out in the cold. Fortunately, our route lies close to the bus route, so we walked a block over to the bus stop. Fortunately, the bus is on a 20-min frequency, and was supposed to have been made more frequent by the addition of several evening buses. Unfortunately, that is just a wild dream, and we waited for more than 45 minutes with no bus until my dear sweet wife finally came and picked us up. At least we got to have some father-son heart to heart time.

Three things went wrong. (1) I switched to a bike that did not have Kevlar tires. My regular bike has Kevlar tires, and in a year and a half of riding with them, I have gotten exactly one flat. On the first day with these other cheap tires, I'm dead on the roadside. (2) I did not pack the tool kit, which would have allowed me to make a roadside repair. I've gotten out of the mindset of needing it because I almost never do. (3) I had faith in the public transportation system. In principle, I'm a big believer in public transit, but Austin's Capital Metro has just not got it together with the P.M. buses. Nearly every time I've tried to take one in the afternoon or evening, I end up with a long (40-45 minute) wait.

Moral of the story. Be prepared!

The downside of aluminum frames

It's time for an update on my Crosstown 7 (see all the articles here). This is a shaft-driven bike from Dynamic Bicycles, most similar to the currently available Crossroad 8. A couple of weeks ago, I noticed that the bottom bracket was starting to move side to side more than usual, and I thought that was probably not a good sign and that it would suffer a fatigue failure. Well, today, as I was riding home, I noticed the frame get loose and start to creak. When I stopped to look it over, I noticed a nice big ugly crack where the seat tube meets the bottom bracket. That's not supposed to happen. Unfortunately it's an inevitable consequence of aluminum butt-welded frames, and I think that the design of the bottom bracket on this shaft driven bike may have amplified the stress or strain in that area. Since purchasing the bike in August 2007, I have put 5900 km (3670 miles) on the bike. It's the 22" frame, and I'm a heavy guy (~215 lbs) and carry a heavy (~15 lb) back pack on the book rack, and I tend to have more of a stoking rather than a spinning pedal style, so it's safe to say that I'm a heavy user, but not unusually so.

When I got home today, the first thing I did was to locate my warranty and confirm that there is a lifetime guarantee on the frame. I called up Dynamic and told them what happened, and I was very pleased to hear and immediate "Man, I'm so sorry that happened to you. We'll get a new frame shipped out to you right away." We went over the details of what I need, including agreeing to how much I would need to put together, and was I able to do the things, and did I have the right tools, etc. The attitude I got was 'what can we do to make this right for you as quickly as possible?' and I have to say that I appreciated that. I've had some very poor customer service experiences before, but not with Dynamic. Others have complained about them, but it's just not been my experience, I've always found them to be friendly and helpful.

I'll post again when the new frame arrives, and maybe I'll document the repairs that are necessary.

In the mean time, keep on biking, and click on over to support my friend Margo in her New Year's resolution to start biking to work again. Leave supportive comments, and ask her to blog about the very funny story of when we rode home together one time...

How is a Man Like a Peach Tree?

I recently read about peach trees that they need a certain amount of cooling in order to be productive. That is, if they don't spend a minimum number of days below a certain temperature, then their fruiting is limited. I wonder whether there could be a hormonal or other chemical basis for a similar response in humans...

This morning, for example, I awoke to a dreary drizzly day, with temps in the 40's F. I experienced a brief struggle between the desire to ride in on my bike and to ride to the bus stop and enjoy reading a book on a nice warm dry ride. I was starting to express this to my wife and had got as far as saying that I was thinking of riding to the bus stop when she interrupted (innocently, I'm sure) to say what a great idea that was. I had, after all, mentioned more than one how drizzly and cold it was outside.

Then the oddest thing happened, at the top of my street, where I turn left for the bus stop and right to ride all the way in, the whole struggle came back to life and the desire to ride through the invigorating weather bubbled up inside, and before I knew any better, I was accelerating down Daugherty, to the right. I arrived at school slightly damp, but quite recharged. It's as if I need to be cold in the winter. If I don't get chilled down enough days, then the endless heat of summer becomes oppressive and unbearable.

Does that make any sense? Am I completely crazy? Is there possibly any physiological basis for this?

And just in case anyone's paying attention, I've put about 5700km on the Dynamic Crosstown 7 now. It's still doing well with no major problems. The shifter has lost a little precision, and I have a little trouble downshifting into 1st. I don't know whether the indexes in the shifter are wearing out a little or maybe the shifter cable is dirty. I just can't get it quite right with the adjuster barrel. At some point it will become irritating enough for me to take it all apart and clean it out, but for now it's not that big a deal.

Also, I think it's always done this, but the other day I noticed that the bottom bracket does deflect quite a bit to the left on a right-side down stroke. Not so with the left-side. Hmmm. No problems yet, but I wonder whether this will turn into a fatigue failure at some point.