Well, this is more like broomstick number four, but it's hard to give an exact count. Needless to say there were many that came before this. So, what is a broomstick and how does is relate to e-vehicles? Presumably at some point you've seen a witch riding a broom. This is the same thing except the witch is on skis, the broomstick has a big motor, and there is a handlebar to hold onto. So, some upgrades over the traditional witches broom, but the mechanics of riding the thing are the same.
The idea was born a couple years back while using a power-broom attachment on a weedwhacker. Turn that thing around, straddle it with some skis and you've got yourself a seriously good time. Sadly, the power-broom never realized it's full transportation potential, as around the same time I got my first ebike. From then on everything seemed like it could, or should, have an electric motor. (e-shoes, e-stroller, e-pulk, e-wheelbarrow, etc...) I imagine the majority of people on this site have experienced a similar e-enlightenment at some point or another. Anyway, the broomstick was electrified and it's been a wild ride since.
Like I mentioned, there have been a few iterations. The most recent and well used ones have been built around ~2kW hub motors laced to 20" rims. 20" rims seemed a good balance of minimizing wheel diameter for torque/overheating reasons and still being large enough to fit a decent sized hub motor. On top of that there is a good selection of 20" fat bike tires that in normal times are readily available (A little harder during a pandemic).
The first serious broomstick used a Gmac, phaserunner, and three Milwaukee M18 12.0 batteries. The broomstick part of it was an old carbon fiber oar shaft. This setup opened my eyes to the potential but had its limitations. In order to get traction in certain snow conditions (chopped up new snow) I would wrap a snow machine track around the tire, which worked great, but had the adverse effect of causing the motor to overheat. From what I can tell, geared hub motors are hard to cool without filling with ATF or some similar such thing. I didn't really want to go that route, and without the track on, overheating is a non-issue (groomed trail/crust conditions). Also the oar shaft, being tapered, was really hard to clamp to without crushing. Occasionally the shaft would rotate within the bike stem, which would cause the broomstick wheel to shoot out sideways and take out your legs. While this provided a little added excitement it wasn't exactly ideal. Eventually the oar shaft was replaced with some 80/20 extrusion (torsionally flimsy though easy to attach to). And finally, the continuous draw from this thing (often 1800-2000W) was just too much for the batteries and they took a bit of a lifecycle hit (However they do have a 3 year warrantee, which is hard to match with any ebike battery).
The original GMAC version -
So ideally I needed better traction, less overheating, more battery, and a stiffer broomstick. I settled on a DD45 because Justin from Grin suggested it would be hard to overheat with the max phase current a phaserunner is capable of (Still possible, but without statorade and in certain low RPM high torque applications. Haven't gotten over 60C with statorade). Traction wise, the snow machine track is the best I have, though will still bog down in deep new snow. The M18 batteries were switched out for parallel 14s5p 30q EM3EV batteries (essentially a 14s10p battery), which seem to handle 50Amps continuous without too much trouble. And the 80/20 was replaced with an aluminium tube with an ID to match fork steerers (1 1/8") and OD to match an odd stem standard (1 1/4"). The result is a lot stiffer and simpler than previous generations. On top of this I added a little extra rake to the fork, which improves the overall handling. It could be better, but it's a pretty mean machine as is.
Upgraded DD45 Version -
With the studded ice tire -
Adding some rake to the forks. I just used a 1" EMT bender and they came out pretty well. Not sure what the sunscreen is doing there.
Here's a look at the DD45 version riding some singletrack
[youtube]x4ruIxY7i1U[/youtube]
And a view from the side
[youtube]zDZreKX2fcg[/youtube]
Some Spring time broomsticking from last year-
[youtube]wEWWz7TvwNs[/youtube]
So far I've used it with a studded track and hockey skates, a normal tire and nordic skis, and tracked with touring skis. At this point I've pretty much given up on the nordic skis as there is enough power that it gets pretty hairy. Still need to solve the traction issue in deeper snow and ideally work out a geared version. I have a 3 spd hub and cyc x1 pro that I would like to combine into a more burly broomstick but am having trouble finding the time.
Not sure what I was trying to do here, Re-invent the bicycle with 80/20?
Too much fun-
The idea was born a couple years back while using a power-broom attachment on a weedwhacker. Turn that thing around, straddle it with some skis and you've got yourself a seriously good time. Sadly, the power-broom never realized it's full transportation potential, as around the same time I got my first ebike. From then on everything seemed like it could, or should, have an electric motor. (e-shoes, e-stroller, e-pulk, e-wheelbarrow, etc...) I imagine the majority of people on this site have experienced a similar e-enlightenment at some point or another. Anyway, the broomstick was electrified and it's been a wild ride since.
Like I mentioned, there have been a few iterations. The most recent and well used ones have been built around ~2kW hub motors laced to 20" rims. 20" rims seemed a good balance of minimizing wheel diameter for torque/overheating reasons and still being large enough to fit a decent sized hub motor. On top of that there is a good selection of 20" fat bike tires that in normal times are readily available (A little harder during a pandemic).
The first serious broomstick used a Gmac, phaserunner, and three Milwaukee M18 12.0 batteries. The broomstick part of it was an old carbon fiber oar shaft. This setup opened my eyes to the potential but had its limitations. In order to get traction in certain snow conditions (chopped up new snow) I would wrap a snow machine track around the tire, which worked great, but had the adverse effect of causing the motor to overheat. From what I can tell, geared hub motors are hard to cool without filling with ATF or some similar such thing. I didn't really want to go that route, and without the track on, overheating is a non-issue (groomed trail/crust conditions). Also the oar shaft, being tapered, was really hard to clamp to without crushing. Occasionally the shaft would rotate within the bike stem, which would cause the broomstick wheel to shoot out sideways and take out your legs. While this provided a little added excitement it wasn't exactly ideal. Eventually the oar shaft was replaced with some 80/20 extrusion (torsionally flimsy though easy to attach to). And finally, the continuous draw from this thing (often 1800-2000W) was just too much for the batteries and they took a bit of a lifecycle hit (However they do have a 3 year warrantee, which is hard to match with any ebike battery).
The original GMAC version -
So ideally I needed better traction, less overheating, more battery, and a stiffer broomstick. I settled on a DD45 because Justin from Grin suggested it would be hard to overheat with the max phase current a phaserunner is capable of (Still possible, but without statorade and in certain low RPM high torque applications. Haven't gotten over 60C with statorade). Traction wise, the snow machine track is the best I have, though will still bog down in deep new snow. The M18 batteries were switched out for parallel 14s5p 30q EM3EV batteries (essentially a 14s10p battery), which seem to handle 50Amps continuous without too much trouble. And the 80/20 was replaced with an aluminium tube with an ID to match fork steerers (1 1/8") and OD to match an odd stem standard (1 1/4"). The result is a lot stiffer and simpler than previous generations. On top of this I added a little extra rake to the fork, which improves the overall handling. It could be better, but it's a pretty mean machine as is.
Upgraded DD45 Version -
With the studded ice tire -
Adding some rake to the forks. I just used a 1" EMT bender and they came out pretty well. Not sure what the sunscreen is doing there.
Here's a look at the DD45 version riding some singletrack
[youtube]x4ruIxY7i1U[/youtube]
And a view from the side
[youtube]zDZreKX2fcg[/youtube]
Some Spring time broomsticking from last year-
[youtube]wEWWz7TvwNs[/youtube]
So far I've used it with a studded track and hockey skates, a normal tire and nordic skis, and tracked with touring skis. At this point I've pretty much given up on the nordic skis as there is enough power that it gets pretty hairy. Still need to solve the traction issue in deeper snow and ideally work out a geared version. I have a 3 spd hub and cyc x1 pro that I would like to combine into a more burly broomstick but am having trouble finding the time.
Not sure what I was trying to do here, Re-invent the bicycle with 80/20?
Too much fun-
