I had the privilege to get another cyclist to test out a front wheel build, running a "vanilla" front wheel drive 24v 500w 26" conversion kit
Mr Tester Cyclist (from now on called MTC) does a 60km round-trip commute, from the foothills of the dandenong ranges to Melbourne on a high-midrange 700c based, road oriented bicycle, using flat bars with barends, 9 speed freewheel and 53 tooth chainring.
I want MTC to test one of my builds. “real cyclist” input is something I have not had and dearly want.
By real cyclist, I mean someone who is competent, confident and a long term regular user of a bicycle (human powered only) for both fitness and transport.
Someone who can assess whether a bicycle is rideable over the longer term, and whether a bicycle fitted with one of my kits adds ANY advantages or positives over a human + bicycle.
Meeting the challenge:
First up I personally know that e-bikes make a positive difference to my riding experience. Particularly from the perspective of being an office worker doing a daily commute, and carrying a few injuries from a hyperactive and risk-taking past
My reality tells me that the reason I am happy to do a daily commute of 30km round trip by bicycle is because that bicycle is electrified.
I have done the same commute tens of times by human powered bicycle alone, and I have done the commute hundreds of times on various electric bikes.
So yeah, I KNOW a motor is a good thing, and I also know that with MTC the last 5 or so kms, going home, and entering the hills, are killer, and motor assist here would be pretty bloody good.
To me this meant that the challenge could be boiled down to a simple requirement set. Build a road oriented electric bike that has a powered range of 30km over varied terrain when coupled with consistent human power.
Based on MTC’s commuter bicycle’s gear set, a 53 tooth chain ring and lowest tooth count of 11 on a 9 speed rear free-wheel, means MTC can probably do 40km/hr on the flat, and probably cruise at 35 km/h.
I tried to acheive a 30km/h cruising speed on a vanilla kit build based on an entry level mountain bike, but pedalspeed was really too high for a standard gearset… a lot of energy seemed to go in just turning my legs around trying to keep the bike up to the speed of the motor. Range OK… at least 25 km on varied terrain, with no peddling, but that was at the limit.
My conversion kit wheels come laced in 26″ frames, and this currently limits me in that the electric drive wheel can only be 26″.
A Front wheel build with a 700c, human powered only rear end gave me closer to what I needed for MTC to test a return commute.
the Pocket Rocket morphed from a human powered frankencycle (multiple bikes sourced for parts to build one complete bike) to a road-oriented Front Wheel Electric Drive, rear wheel Human Drive.
In its final iteration, powered by a Ping 24v 10ah battery, I could comfortably ride the Rocket on a 30km commute, the setup was comfortable enough to do it consistently. though a few potential problems were apparent, I’d ridden the rocket a few hundred kilometres without more than the usual fear, rage and unbridled enthusiasm that such activities can induce..
The frame was a 26″ frame, with a 700c fitted to the back. retrofitted forks, To level out the front, and provide suspension (Must be considered for front wheel builds) raised the complete frame by at least a couple of centimeteres, making the bike pretty “tall” IE the pedals far off the ground. That coupled with the smaller fram meant distance between handlebars and seat post was not optimum for my or MTC’s 6ft frames, adequate but not optimum.
The motor and controller, at 24volts, ends up with a max speed at around 27-30km/hr. This is a bit slow for someone who can cruise at 35.
Everything else though had me beleiving that the boiled down challenge of creating a road oriented bike that would provide electric assistance for 30 km had been met.
A few things came together well in terms of battery placement.
A front wheel build meant that the majority of extra weight from the bike to e-bike conversion was in the front. this meant that putting the battery at the back provided a balancing solution.
in my endless search for batteries, battery chargers and battery enclosures, i had managed to come up with the combination of a ping battery and 6A charger that comes with it, a robust and ok looking purpose built for bicycles rack bag and a light weight yet robust rear rack with mudguard capabilities.
Ultimately a mountable, demountable and easily carriable “battery Bag”, with everything you need to plug into the nearest mains and charge the battery. No degree in chemistry or engineering required for use or construction
Met MTC in the carpark of my old work building… gave him the info on how to charge the batteries, and ran away suffering from separation anxiety over the Pocket Rocket…
A few hours later and i get a text.. Mr Test Cyclist is home, and both the bike and he were still powering in the last few hills home (W00t).
Later MTC let me know that the battery had recharged in 45 minutes, meaning he’d used less than half of it’s capacity.
Next afternoon, I met up with MTC in the same carpark, and we went over the ride.
It was OK, the bike had got him through a complete commute.
The bike was definitely heavy, and did not power up to MTC’s cruising speed of 30+, meaning he had to haul the bike’s extra weight at these speeds.
The set up was too cramped, for himself MTC needed the bars further forward and possibly out more (note on his bike he had wider flat bars than on the Rocket).
MTC was looking forward to a better iteration..
Now, I wont lie, if MTC had come at me with a fist full of dollars and said “I need one, sell it to me” I would have been satisfied
But bearing in mind all of the drawbacks of the bicycle components behind the build, Ultimately I am pretty freakin pleased with how this particular build, the pocket rocket, kinda sorta coulda met the challenge.
Wheel Size and the complications arising from it need to be sorted when dealing with human powered 30km/h + speeds on 700c bicycles.
Interestingly enough I have just pulled apart a different style of hub motor, a geared unit, which I sourced from a secondhand commercial build… and it is laced into a 700c rim, weighs about half or less than the wheels in my kit, and I reckon would take up to 1000 watts, with a bit of care.
Also have a cheap complete 700c based bike… looks like another test build coming up, and then I unearth my uber awesome butted steel frame racer resto I am doing, pop the hub into that…. Second iteration of the rocket somewhere in the visible future, methinks.
What I do with the rocket now is a tough one... maybe a museam piece in 50 years...