This is exactly what I had in mind!tangentdave wrote: ↑Jul 02 2018 2:15pm
This drive is easily removed from the frame in only a few minutes, turning the bike into a 34lb enduro beast. A custom mounting bracket matches the lines of the frame and shows no flex under a full 8kW load. The freewheel crankset can remain in place or is quickly swapped with a standard crank arm for another 1lb of weight savings. The CA remains tucked behind the handlebars, the Domino is exchanged for a normal lock-on grip.
Why a removable motor unit? So I can race Cascadia enduro events one weekend, plug the motor in, race Lost Sierra the next, pull the motor and ride the Downieville DH course same day. This bike is capable of competing in absolutely punishing Enduro World Series events and hang with the motos in OHV areas. One bike, any trail.
Interesting question. Dave stated it should take about 10ml. Initially I filled until I couldn't get any more water in with the bike sitting level. Probably around 10-12 ml. I then flipped the bike upside down for some work and when I placed it back down I checked the water level and found it could take an additional few ml. Maybe 5ml more. So far I haven't ridden the bike hard enough to get the water to boiling temperature, only peaked at 55C. I am thinking though that I will probably add glycol to it at some point so it doesn't freeze if I leave the bike in the garage over the winter.
The math above doesn't quite seem to add up.tangentdave wrote: ↑Jul 02 2018 2:15pm
Drive unit weight: 7.5lbs
Dimensions: 100mm diameter, 120mm length
Engine: Neutronics 3215, 225kV
Controller: Castle Talon 120, custom mount/heatsink, QS-8 main battery connect
Performance (calculated w/ 120A phase):
135ft-lbs crankset torque
48t cog: 216ft-lbs wheel torque, 21mph
42t cog: 189ft-lbs wheel torque, 24mph
32t cog: 144ft-lbs wheel torque, 31mph (straight chainline)
24t cog: 108ft-lbs wheel torque, 41mph
18t cog: 81ft-lbs wheel torque, 56mph
Thanks, I'm hoping it makes a nice ebike since I don't have much actual downhill in El Paso. I fiddled with the graph, added MPH for myself. I'd like for someone to take some actual numbers to see what percent difference losses in motor efficiency take place. We have already seen the drive capable of high speeds. In the future I would like to add some output wattage at X speed. Only good for estimation since anything other than level ground will change those numbers.cr0m08 wrote: ↑Jul 19 2018 9:15pmWhilst on gearing, I did an excel calc for gearing with the tangent kits I have (screenshot and excel attached). The formulas can easily be changed to suit others if wanted (description of formula at top). I know its not much, but thought some of the newer guys may like it. Of course its only calculated and doesn't consider loading or drag. The motor revs or RPM calculation is based on 12S LiPo at 50% charge, either a 3turn 3220 or 7turn 3210 so just change the figures in the formula to suit others. Hope it helps someone.
That GT Fury is one nice looking rig and should be a hoot with a Tangent! Post updates
The drive actually runs up to a cadence of almost 400 (with 20t motor FW, 32t at crank). Pedaling has little effect with any throttle amount over about 10%. A higher motor cadence keeps the driveline stresses tolerable, and besides, you don't need to use the full RPM but it's nice to have it when you're motorbiking. When you wanna ebike, just restrain the throttle input or create a custom profile in the CA.pedal cadence of over 300 I wasn't sure if it had a place since we cant pedal that fast anyways