Railbike progress
Sep. 17th, 2009 09:55 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
alessandro_bardThe last few days have been trying. I've been down a few side paths, but now I'm back on track (so to speak).
First was a serious structural failure. It happened at low speed - the bike rear tire and its guide wheel wound up splitting over the rail, which led to some bends where they shouldn't have been - and reinforced to me that the whole shebang needs a lot more structural stability. So, after much more puzzling, cutting, and welding, it's surprisingly solid now.
A distraction was the potential to have to cross a grade crossing at the event. I figured the guide wheels wouldn't fit, so I spent a day working out a separate flange system (based on circular saw masonry discs with saw blade backings). It looked wickedly cool, but turned out to both track poorly and have a lot of drag. Plus, it was really noisy.
Then I went and measured an actual grade crossing built to modern standards, which is what I'm expecting at the event. Turns out the guide wheels will indeed fit, so I was back to wheels! Now, with the improved structure, the whole guide wheel system works considerably better. A few more mods to the wheel location parts and I should be ready to deal with any variation in gauge and rail width.
Then I need to get my bike to a shop. The shifter for the front derailleur won't stay in place, and wants to keep dropping to granny gear. With enough attempts, it will stay on the middle gear, but it won't go to high gear - and I'm going to need high gear! Due to my lack of stature, my bike has 24" wheels, not 27", so I need all the mechanical advantage I can get.
Another run tomorrow morning!
First was a serious structural failure. It happened at low speed - the bike rear tire and its guide wheel wound up splitting over the rail, which led to some bends where they shouldn't have been - and reinforced to me that the whole shebang needs a lot more structural stability. So, after much more puzzling, cutting, and welding, it's surprisingly solid now.
A distraction was the potential to have to cross a grade crossing at the event. I figured the guide wheels wouldn't fit, so I spent a day working out a separate flange system (based on circular saw masonry discs with saw blade backings). It looked wickedly cool, but turned out to both track poorly and have a lot of drag. Plus, it was really noisy.
Then I went and measured an actual grade crossing built to modern standards, which is what I'm expecting at the event. Turns out the guide wheels will indeed fit, so I was back to wheels! Now, with the improved structure, the whole guide wheel system works considerably better. A few more mods to the wheel location parts and I should be ready to deal with any variation in gauge and rail width.
Then I need to get my bike to a shop. The shifter for the front derailleur won't stay in place, and wants to keep dropping to granny gear. With enough attempts, it will stay on the middle gear, but it won't go to high gear - and I'm going to need high gear! Due to my lack of stature, my bike has 24" wheels, not 27", so I need all the mechanical advantage I can get.
Another run tomorrow morning!
