First I want to thank Oatnut for his gracious loan of his photos or I wouldn't have any before shots. Coincidentally he is selling the same type of bike I started with in this thread.
http://www.endless-sphere.com/forums/viewtopic.php?f=9&t=10575
This is not my first post exactly but for the sake of argument I consider it my first "official" post. I want to thank all of you for being here I was very impressed after a few days of reading through the posts to see the level of professional content and wide range of experiences being shared. I feel like I have finally come in from the cold and found a place where I belong.
The Tidal Force S-750 that I started with came in a box looking pretty much like this when I bought it on Ebay. I really had no idea of what a tremendous score I had pulled off until I opened the box and got to work. I was just glad to get my hands on a quality aluminum frame at a good price when I made the initial purchase.
The model I got was the rare complete set except for wheels and included everything you see on Oatnut's list except the SRAM but mine had the front forks, which I do use. I began by setting up as a standard frame with all the components but I quickly found i wanted higher performance specs than came with it so that I could push for speed on a full road setup. I wanted to keep some low end gearing for climbing because I needed to have the ability to climb with no battery in the hills where I live.
On this note one problem I have experienced is breaking chains with no e-assist and climbing steep inclines. This was when I still had the SLA 12 AHr pack but the new 20 AHr Duct tape special isn't that much lighter that I think this won't occur again. I am starting to put master links in the tool kit for the road repair because just reinserting the pin with a chain tool doesn't seem to be good enough. I am open to some good suggestions on better quality (maybe titanium) chains that can handle the stresses but still be lightweight and narrow gauge.
Anyway I decided to pull off the 48t/38t/28t Suntour crankset and replace it with a lighter weight aluminum and serviceable PC-1057 crank with a 55/40/30 configuration and 175 mm crank arms and caged pedals for safer, higher performance speed running. I also use a threaded type freewheel cassette that reduces the number of gears from 7 to 5 ( 11, 15, 20, 26, 30) so I could mount it on a rear, geared hub motor. This provides a 5:1 high end ratio that takes advantage of the sustainability of ebikes at cruise speed and a 1:1 low end ratio that can climb up hills with a loaded bike and no battery assist and get home. I also replaced the wonderful but larger and heavier than I now needed Shimano Acer set that came with the kit, with a Deore LX front and rear derailleur set.
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The rear 26 inch wheel is a geared, internally freewheeled, brushed motor made for 24v Schwinns and I believe was rated 250 watts; though it seems to be much more powerful than that. I am running it at 36 volts on a shared 35 amp/100 amp peak controller that I adapted from scooter tech. More on that later but this configuration runs very cool and I do not experience any problems at this voltage and I suspect I could push it to 48 volts with the same positive result. I found in a series of earlier experiments that it is pointless to use the closer gearing more common on standard bicycles because having an ebike is in many ways is like riding a tandem and the power/performance ratio with respect to torque and speed allows much greater efficiency and performance under most conditions with a significantly wider gear ratio. This is an aspect that I design for and take advantage of whenever I can because the resulting performance curve is significantly wider and higher.
Another mod I see is pretty common here that I also employed is the use of heavier gauge #10 threaded wire. I adapted a high flex all weather household type 10-4 and built a trunk line out of it to go from the battery in back to the controller in front and then back to the rear wheel from the controller. I was able to install this inside the frame's pre-made ports for this purpose. One thing I would love to set pinned up front that many here take for granted might be a discussion on connectors and posts. Quality, types and sources. I have seen a few of you use the connectors out of heavy duty computer UPS's and recently I found out about them and was thinking of adapting them too but I for the time being have been just bolting wire sets together to save time, ensure minimal resistance and maintain serviceability. It is a little clunky at times and I have to be careful about wrapping them but I do not have wire disconnects, terminal corrosion and breaks anymore. I consider it an example of field KISS. I would like to adapt threaded insulted poles to this purpose from the auto industry so I can handle multiple circuits and use some fusible links. I put a 100 fusible link on the battery as insurance and I use a 12 - 65 volt DC, 40 amp circuit marine breaker switch as a master switch to protect the controller.
Another mod I made to the Schwinn hub was to take advantage of the standard rear disk brake mounts that are on the S-750 frame and install a 3rd brake in the system. I found in the earlier prototypes that combining hills, high velocity, and higher mass ebikes with standard brakes is an invitation to accidents. The stopping distances were far too long and the heat and wear generated to great to rely on just the cantilever or V-Brakes no matter how good the Tektros that came with the bike are and they are great. So the 3rd brake on the rear makes a very big difference and what I did was put both Tektros on one handle and the disk on the other.
In addition to the other mods I decided to use old fashioned 10 speed aluminum drop down bars instead of the really great TruAtiv bars that came with the kit so I could lower my wind profile more and I added a bell, halogen light, led flashers, a wireless computer, white reflector, bar-end shifters, and a thumb throttle. The set up is a little tight and not for 'easy riders'
but it works great even though it is only for serious bikers not the uninitiated. There is a lot of wrist strain from all the stretching and even with keeping the front shocks I notice shock strain on long distance rides too. I also always use Bell bike gloves when I ride.
BTW the fairing that I adapted for the front wheel is adapted off an electric scooter that I cut in half and I use it not only for a fender but to hide the electronics and mount the controller in the optimal airstream above the front wheel. The deck also serves very well for my switches, which include a master, a controller, and an on/off for the rear wheel and places the controller in an optimal cooling location just above the front fork. I also have a 3 position switch I will be using for solar powered turn signals when I get past the next phase of mounting a hybrid generator on the rear deck. There is a red flasher/reflector built into the Bell seat too.
That is the reason I built the funny looking plywood rear deck over large, not because I needed a rear spoiler. :lol:
You can also see in that picture how I adapted a power plate off a computer power supply to be the charging plug for the LifePO battery and also why I want to do surgery on the duct tape special. For now I am just putting the battery in this mounting for testing purposes but I hope to divide it up as I have seen done here and put it below the deck in a pannier configuration. In that shot you can see where I installed the 100 amp safety fuse for the battery and also the hybrid street tire I chose that has a very efficient road tread but is still pretty good in gravel and softer surfaces.
Originally I had the old steel rack that came with the Wilderness BD-36 front hub kit that makes this a dual motor bike but I found that rack tore itself up with the SLA load. So I am trying to both lighten and strengthen the new rack while reducing the weight on it. Anyway here is the final product that is obviously still going through trials and is meant to eventually have a small fueled generator mounted in back (along with addition load support bars and traffic lighting) to provide an unlimited range.
I live in some serious hills and the rear motor is switchable allowing me to sustain cruise speed (over 20 MPH) at climb under most road conditions though I eventually want it to have a sensor switch that turns it on and off based on tire rotation speed. My top speed so far was 72 plus MPH in a downhill. I have a pair of RoxShoxs I could switch too if that would be better but I found I tore apart a set of steel fixed forks on the first prototype anyway.
I should mention that I have heard about the issue of mounting a hub motor on the front shock forks and I will start looking into it more closely. I have a friend who has a brushless pedal start hub motor mounted on the same forks (same model) but we haven't observed a lot of wear on them yet and he has hundreds of miles on Florida pavement but I am going to start looking more closely. I guess a lot of the issue is how much it torques relative to load and the way I have set it up is meant to reduce that and distribute a lot of the torque to the rear wheel. But if this is a time bomb then we should address it before it blows and I am open to alternative shocking forks for this task but at the speeds I have been running I need to have a suspension up front to prevent steering loss and shock to my wrists and arms.
I can't tell you all enough how glad I am to find this community thanks to VRdublove who invited me and to finally join a group that shares the same goals I do. I look forward to a long relationship of idea sharing and who knows, if any of you are in the NYC regional area maybe we can collaborate even closer. Safe roads to you all.
