Danimal, Any rough idea when you will have these in production? And do you have a finalized design yet?
Also, will you offer them without the swing arm? Or build a custom swing arm? The wheel I have in mind won't fit a standard swing arm
We are shooting to be production ready by Jan. - Feb 2012, pending field testing. This means we plan to start building them as they are ordered around this time.
Have you investigated shipping costs yet?
We will be using UPS to ship, you can get an estimate from their shipping calculator, coming from zip 90278. The package will be approximately 35 lbs, that is a liberal estimation.
1) Please explain why you switched from light weight carbon fiber composite to heavy Crmoly?
2) Did the carbon fiber prototype have any issues in the design, construction, or durability in field testing?
3) What is the total weight difference between these two bikes when using same weight components & parts using Crmoly vs Carbon Fiber?
1) The main reasons we switched from Carbon Fiber to Chromoly, as mentioned by Alan B are cost and labor. Expensive material, expensive and time consuming to manufacture. Lots of one off parts. Harder to repair. More complicated to scale up production. Relative to working with steel, it's just kind of a PITA in my opinion. We see the DIY market wanting something cheaper, and easier to customize (weld on) even if it is at the expense of weight.
2) Issues in the design, not really except a clearance issue with the rear tire / rear shock that luckily was an easy fix. The construction went smoothly, albeit time consuming and messy. As for durability in testing, There was minor surface cracking around one of the swingarm pivot mounts in the frame, but it is still strong and structurally sound, nothing that would make me hold back on anything for fear that it would break. The carbon fiber is very strong, but one good tumble into some rocks could destroy the frame, and it wouldn't be easy to repair. The geometry has been revised, to give more leg extension for pedaling, a lower seat height, and a more slack head tube angle. We destroyed some rims jumping out of a 6 set of stairs, went through a one way bearing from the older generation BMC motors, broke off the derailer. Those are the only issues we have had with the bike so far, and it has taken some beatings, including tumbling down a steep hill for about 100 feet (luckily I didn't go with it haha). One of the dropouts in the aluminum swingarm are getting a little thrashed, since after welding the derailer mount back on the aluminum is back to soft 'O' condition in that area from the heat of welding and not re-heat treating.
3) The total weight of the CF frame was 9.0lbs, and the swingarm was around 3lbs I think so about 14lbs alltogether. The Chromoly frame is expected to be around 16-20lbs with the swingarm. However it is designed to use mountain bike suspension, which all together is about 18lbs lighter than the heavy motorcycle suspension used before. The Carbon Fiber Prototype was 90lbs with a 72V, 10A*hr battery, and BMC motor. Using the same battery / motor in the new model would end up around (90 + 7 - 18)lbs = ~79 lbs, but since we are using more batteries in this test model it will probably end up around 90lbs.
We are getting very close to building this first frame out of the new jig, we hope to have some pictures of a physical frame for you guys soon here..
