Monday, August 30, 2010

Trike Frame Pictures

Finally - pictures of the trike frame. Construction is going pretty fast so far. I'm using bottom brackets for the king pins. I ordered the shells from Nova Cycle Supply, and got the bottom bracket parts from Jenson USA. I'm a little concerned that the cheap bottom brackets might not hold up well to the pounding they will take by being loaded vertically, but by using cheap standardized parts, I can test the concept for under $40. Then if the design seems to work I can upgrade to better quality parts when these wear out. If, in practice, my idea just totally stinks, I can always cut the bottom bracket shells off and redesign the steering knuckles from the beginning. The axle will mount to a (still to be designed) T bracket that will fit onto the lower square taper of the bottom brackets. The handlebars will fit onto the top taper. Simple, modular, easy to modify and easy to repair.

This is my son's trike. He's currently 9 but will top out at around 6' and easily hit 200#, according to the pediatrician. The trike needs to be very adjustable so he will be able to ride it for years (like to college because his poor dad isn't going to buy him a car).



Tuesday, August 24, 2010

Handlebar Mod

Well, I survived a day at the Recumbent Retreat. My buddy Mike and I went. He's the one who got me interested in recumbents and velomobiles in the first place. We picked up a flyer at the Human Power Vehicle Challenge at PIR in May, and I knew we had to go, and I'm so glad we did. We rode 46 miles by the time the day was finished. That's 2.5 times farther than I have ever ridden before. It's pretty paltry in comparison with seasoned cyclists, and downright anemic for most recumbent riders, but pretty darn good for me. The bike held up great, and I have to admit I was proud of the looks it got.

I'd been thinking about narrowing my handlebars for a log time. When I ride the I-5 bridge this summer (across the Columbia River) it was tense. My knuckles were only a couple inches from whacking the beams on one side, or the railing in the other. It made for a very slow commute, and after connecting with an electrical box sticking out, I decided I would never ride that path again.

The more I ride the bike, the faster my top speed gets. The faster I go, the more I crave it. So far, my top is 43mph down a very long steep hill. So, whether the decision to chop the handlebars is driven by scraped knuckles or adreneline, I did the dirty deed today. They measured 30" wide before, now they are 27". I removed the bars, then screwed wood blocks to my work table to make a jig. After cutting the tubes on each side, I overlapped them slightly and welded them in place. Following paint and reinstallation I did a quick test ride and I'm very happy with the result. The grips are at the same height as before, just inboard 1.5" on each side. The top pic shows before, middle shows after, bottom shows where I chopped the bars and fillet welded them back together.

Oh, by the way - I've discovered that I weld much better if I wear my reading glasses inside my hood. Duh - old age.


Wednesday, August 11, 2010


Here are pics of the completed V-Brake mod to my recumbent. They work great! I love them on the back. If they work half this well in the rain, I'm set for winter. The V-Brakes remind me of power brakes in a car - not much lever feedback, but solid stopping power.

I picked up these levers at a garage sale - someone had done quite a bit of upgrading, and I bought a bag of used parts for $5. In the bag were these levers (Shimano Deore XT), a bottom bracket, bar end levers (which I might use on the trike I'm building) and some small hardware.

I cut the studs off a donor bike hanging in the garage, cleaned them up a bit on the grinder, then held them in place with magnets while I measured the distance between them. Then I drilled two holes in a block of oak flooring exactly that distance apart, and inserted the studs into it. I clamped the block of wood in place so the studs were held snuggly where I wanted them, and tacked them on. I pried the wood block off, then finished welding and painting them. I stopped by Bad Monkey to pickup new brake pads, a noodle (which was missing) and got a cool sticker. I found metric cap screws to hold the levers on at the hardware store.

Now, to find an even bigger hill.......


New Brakes

Hmmm..... After riding my completed bike for a while, I realize my brakes really stink. The rear bake is totally ineffective, and the front brake just melts, giving me about 3 or 4 good rides before I need to peel the rubber off the rim.

I found some V-brakes in the parts box, and I'm in the process of installing those. I welded the bosses on tonight. I'm missing the noodle and the screw that holds the lever onto the boss, so that's on tomorrow's list. It should be a huge improvement. If not, I need to look for a disc brake to put on the back. I hit 43 mph on a down hill the other day, and was quite lucky to have a green light at the bottom of the hill.

Other changes due to learning as I go - the head light set up I had was too flimsy and worked loose. I'll need to build a sturdier mount for that. I removed the chain ring disc - it was rubbing the derailleur. My front derailleur is a bit flimsy making downshifting under a load difficult, so maybe this winter I'll build it up, also extend the cage a bit.

I've started building a tadpole trike for my son. I bought 2" tubing for the frame, and 1" tubing for the seat. The seat tubing seems like overkill, but I want it to add strength and stiffness, as it will be suspended, structurally speaking, between the rear triangle and the front legs that go out to the front wheels. Right now the bike is in a jig, and partially welded. The rear triangle needs to go on, as well as the cross arms and turning tubes. I'll toss up a picture when I get some good visual progress.