Ironic as it may seem, after all these years, this is my first electric bicycle. Blazing Saddles, the largest bike rental company in San Francisco recently got some new A2B Metros, and by doing some consulting work for the owner, I was able to trade for a non-functioning old one that was in the 'junk' pile.
One of the first issues I dealt with was the rear shock. The stock unit had virtually NO damping, so if you hit a good bump, especially on a corner, the rear wheel would bounce and skip over to the side. In my junk box, I had an old shock that was a much nicer one, but had a spring rate of 650 lb/in versus the 1500 lb/in for the A2B. I tried swapping the springs, but the A2B spring was a little longer and impossible to install, well, at least easily... Eventually, I compressed the spring using my bench vice and wrapped it up with many strands of nylon cord while compressed. This allowed just enough clearance to install on the new shock. Once installed, I snipped the cords and 'boing' it returned to original length. New shock has adjustable compression and rebound damping. Very nice. Much improved handling on bumpy surfaces now. Looks cool too. Don't ask me where the shock came from or how to get one. It was traded many years ago and saw service on my Vego scooter.
Another thing missing from the bike was a rear view mirror. I see they show one in the manual, but mine was missing. The levers have a 8mm threaded hole for a mirror, so I found one for $14 at the local motorcycle parts store. It's made by BikeMaster and seems to work well. Not too flimsy, not too heavy, and the big 4" round gives a decent rear view.
Another well known design flaw is the steering geometry. I think what it really needs is slightly more rake angle, but cutting the frame and welding it back is not something I'm about to do. What I came up with is a workaround for that. The basic idea is to flip the top half of the fork around backward so the front wheel has more trail. The stock configuration looks like this
After flipping the fork around, it looks like this:
In order to do this, I had to separate the fork sliders from the stanchions. The top cap of the fork tubes have a 29mm hex head
I was thinking these things might be installed with Loctite and really take a lot of torque to get off. I found a 29mm socket at Sears, and spent some quality time with my bench grinder thinning out the wall enough to fit into the recess on the top of the fork.
Grinding it down took a while, but it fits nicely. I used a piece of wood to block the forks from turning when I unscrewed the caps.
When I went to unscrew the caps, I was almost disappointed in how easy they came out. I think you could get them out with a big needle nose pliers. Once the caps were off, I removed the springs and then the two lock nuts on the bottom of the fork sliders. Then, you need a really long 6mm Allen wrench to loosen the bolts. I used a 6mm Allen socket bit and a long wrench extension. These came out relatively easily as well.
Once those are off, the sliders can come off (you need to disconnect the brake cable first).
Once those are off, you then loosen the steering head clamp, spin the fork around backwards, and put everything back in reverse order. This is a good time to clean and re-lube everything inside the fork. I found quite a bit of water inside one leg, but it didn't seem to hurt anything. These are really top quality forks from looking at the insides. One thing they don't mention in the manual is the preload adjusters. Maybe they assume everybody know how they work. Anyway for the dummies out there (like me), if you turn the adjusters clockwise, it increases the tension on the springs. Be sure to turn both sides an equal amount. Here's how the adjusters look:
Well, after a quick test ride, I can tell this really helps a lot. Before, it was difficult if not impossible to ride with one hand at 20 mph. Now, it's much more stable at speed and pulling a high-G corner doesn't scare the crap out of me anymore. Downside of the mod is the tire is now about 2cm closer to your toes and could possible make contact when maneuvering at low speed. I think it's well worth it. This will be important later on when I get to the speed mods
Edit: after more test riding, I can say this mod absolutely fixes the handling issues. I have not had any problem with the tire hitting my toes. Handling is still nimble but now very stable and easy to take tight corners with. I think 30mph should be no problem now.
Next on the list is some lighting. I had a cheap blinking rear LED light that had the batteries leak inside and corroded the battery contacts. It was made to run on two alkaline batteries (3V). I tossed the batteries and battery contacts and soldered wires to the board and brought them out to a dc-dc converter. The converter is really a wall wart AC power cube for a Nintendo game. Output 5v. This thing is amazing. I start getting output at 12v and get full output around 24v. It's good up to rectified 240VAC (around 300VDC). Feeding 5V into the 3V LED blinker made it nice and bright, but it ran a bit hot. I placed a regular diode in series with the 5V to knock it down to 4.3V. This made it run a lot cooler but still really bright. I took it apart and removed the AC prongs and soldered wires on for the input.
One hitch is the blinky light has a pushbutton to turn off and change blinking modes. I don't want to have to press the button every time I want it on. I want it to come on as soon as power is applied. I removed the push button and soldered a 1uF capacitor across the switch contacts. This did the trick nicely and it automatically goes into the first mode when power is applied. If I 'flash' the power off/on, I can make it change modes. The little Nintendo adapter is small enough to fit inside the rear frame of the rack.
For the headlight, I found a super cheap "9W" LED headlight on eBay for $15 shipped. This is one of those "DIY" versions that is not really rain proof or particularly well built. The built in dc-dc converter is rated for 12v - 85v and is easily removed by unscrewing the rear bracket.
The dc-dc unit is not water proof or sealed. This looks easy enough to fix. Out in the garage I had some old marine epoxy, probably 20 years old in a can. Still hardens with some fresh hardener.
I pulled out the dc-dc unit and pried off the cheezy plastic cover over the box. I held it in the vise and poured in enough epoxy to completely submerge the circuit board. Afterward, I regretted not replacing the wires, but I can always splice them to the final wiring.
With the dc-dc potted, I think the rest of it can survive a bit of rain or washing. The lens assembly comes apart by unscrewing the ring on the front.
While apart, I added some heat transfer compound between the finned part of the heat sink and the plate holding the LEDs.
Since the heat sink was off, I decided to spray paint it flat black mainly for cosmetic reasons, but the aluminum was bare and would oxidize eventually if not coated. It's a bit tricky to get everything back together and you need to avoid leaving finger prints on the optics.
It runs noticeably cooler with the heat sink compound. Although advertised as a 9W light, it measures closer to 5W input when tested. Still, it seems bright enough for my purposes. I might get another one later and make a dual setup. It's not installed yet pending some wiring work.
Finally got time to install the headlight... more wire stuffing and into the hairball again. I mounted it on the right side handlebar and installed a waterproof push-on/push-off switch that activated both headlight and tail light. I used a 3 conductor cable to feed switched power back to the tail light.
The tail end of the frame used to have some kind of plastic cap and a lock for the 2nd battery. These were gone when I got the bike, so I mounted the tail light to cover the hole:
I had to drill a small hole in the frame to route the wire for the light.
Since I frequently use the bike for short runs to the local grocery store, I scored a used rear A2B pannier frame. The frame is surprisingly light weight but seems sturdy enough. I combined this with an old Wald folding basket I had lying around. The basket folds flat when not in use and doesn't rattle too badly.
When I need to carry cargo, it just takes a second to fold the basket out and it can carry a standard sized paper grocery bag or probably two 6-packs of beer. I could get a second one, but I'm reserving the other side of the rack for a secondary battery.
Really not too bad off, but flat tire, sheared off bolts stuck in the holes, assorted dents and scratches, corrosion and a totally messed up rear brake. Amazingly, the battery still seems to have decent capacity, so I've been riding around with it to at least experience the stock bike setup.
Overall, I'm very impressed with the quality of this bike and the $3k original price tag is not really outrageous for what you get. So this thread will be sort of a build log as I transform the A2B into something even better.