I am happy to say that the Flux eBike prototype survived the first trial run on my usual trail. The trial run is documented on my Strava account here.
I also made a short video of a trail run that I did on my carbon fiber Flux bike a couple of months back that you can see below for some added perspective on where I took the Flux eBike prototype for live testing.
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If you do not have the time for the video or the somewhat crushed and blurry quality proves too much (play it on HD, but do not expand to full screen) the trail is steep, extremely rocky, with boulders, step-ups (and step-downs) of up to 50cm and can be fast on a right bike – any Flux hardtail for example.
The battery lasted well, but since this was my first run I decided to be a bit more conservative so I ran on the “ECO” mode for the 9km approach to the trailhead and it proved ample for combating the head wind. However, the eBike completely annihilated the climbs. For the climbs I had it set on “SPO” (sport) mode thus unleashing the full 400W/40Nm of power and torque assist for the first part of the climb, but half way up I noticed that the battery level was dropping so I cut the assist back to “ECO”. At the full assist, “SPO”setting, it was surreal. I was climbing so fast that several turns and changes in terrain caught me unawares, they simply came too quickly. A passer by asked me if I was running on petrol, I was climbing that fast. “ECO” mode was slower but still faster than the best times I achieved on a non-eBike Flux Alloy 29er.
Rocks, vibrations and terrain did not upset the bike’s balance in the slightest and overall there was nothing at all to sap confidence or trigger the “take it easy” feeling. In fact the only undesirable thing that happened while climbing was due to a city bike grade crankset which is all we had on hand when we were building the prototype. It would drop the chain when I attempted to hammer up some particularly steep sections. We are getting a hopefully superior FSA crankset next week.
Even with the dropped chain and several forced downshifts due to the already mentioned awful crankset, and my fear of running out of battery and thus cutting the power assist by 2/3, I smashed my previous KOM by 6 minutes 30 seconds!
Coming back down was not as pleasant as with the non eBike version, but I will reserve judgement until I can run the eBike with the same or similar tire setup that I use for my other Flux(es). See, I was a bit paranoid about getting a pinch flat on the mountain due to the extra weight of the eBike parts, most of which are due to the rear hub motor, so I ran the tire at 60 PSI. This is way too much and I normally run with WTB Nano 2.1 TCS at 30 PSI with no issues (I am 93kg so 30 PSI on the rear is fine thanks 🙂
Returning back to base was done on the full power “SPO” mode. By then I realized that I had more than ample battery power left so I went flat out. It is hard to describe what 400W and in particular the instantly available 40Nm of torque feel like when riding on a flat road. Hand of God comes to mind. The feeling is intoxicating. Overtaking the petrol powered traffic is exhilarating Hitting the (programmable) 40 km/h power assist limiter was unwelcome, but provided repeat opportunities to accelerate back up to 40 km/h and experience that huge but progressive and gentle shove forward.
Overall this first test was a remarkable success. With some deliberate component changes and upgrades the Flux eBike will be a truly formidable and thoroughly enjoyable bike to use on and, in particular off road.
Prototype Flux eBike specs:
Frame: custom Flux Alloy 29er frame size L
Wheels: Custom built
Tires: Maxxis Ikon
Fork: Magura TS8 R 29″ 15mm axle
Stem: Truvativ Stylo T20
Handlebars: Truvativ Stylo T20
Seatpost: Truvativ Stylo T20
Saddle: Prologo Kappa
Grips: Syntace Moto
Shifters: Shimano XT
Brakes: Tektro Auriga with regenerative braking switch 180mm/160mm
FD: Shimano SLX direct mount
RD: Shimano XT
Crankset: Driveline X5
eBike components: GreenTrans custom 400W/40Nm with Lithium battery pack
Total weight: 21kg