Step 1 was choosing the base bike to use, growing up riding BMX there was no other choice, but 20" wheels are pretty small for going longer distances, and getting motors and batteries to fit on extremely slim frames would be challenging. Luckily there are some great 'big' BMX bikes available now like the Verde Modus and the Kink Drifter. There was limited availability on the Drifter so I ended up ordering a Modus from Albe's BMX.
Step 2 was choosing the motor. Every hub motor on the market is designed for wider mountain bike/ road bike dropouts at around 130mm, compared to the 110mm on the Modus (and any other BMX frame). I actually have a custom Standard 125R with a stretched back end to fit normal hub motors but I'll leave that for another post. Since hub-motors won't fit I went with a mid-drive and chose the Shimano E7000 due to its narrower Q-factor and decent reviews.
Luckily I found the motor mount from TI Cycles in Portland which simplified things greatly. Now don't get me wrong, I can weld, but cutting the frame and fixturing up the mount was not really something I wanted to attempt. Luckily my wife's company was running an event where their model shop would do work for donations to a charity, so we got the frame cut, welded, and painted for a good price and a great cause.
My original plan was to use my own 36V battery instead of the Shimano STEPS version because it seemed overpriced, but after getting the motor I realized that the Shimano drive requires CAN status messages from the battery to operate so I had to go with the Shimano version. I got a great deal on the parts from JJ at West Michigan Bike and started assembling.
Mounting the battery to the frame consisted of drilling directly through and using black oxide button head hex drive screws to secure the battery mounting brackets. The lock for the top battery mount was on backorder so my initial testing was done with electrical tape securing the top of the battery to the frame. And brakeless of course in true BMX fashion.
The initial testing went great but the 20mph cutoff that's built into the E7000 drive is heart-breaking. As soon as you start getting up to a great cruising speed the motor just cuts out and your left wondering WHY?!?! I'm pretty sure this can be modded to get up to 28mph but I haven't done this yet.
I'm a bit of a purist and know that electric BMX bikes don't belong on the track or at the skatepark, but they are awesome for going longer distances and cruising around the neighborhood. I wanted to get some professional shots of the bike and so I found Rob Sackyta who did an amazing job on super short notice. I really didn't want to shoot at the skatepark (for the reason above) but Rob insisted and the shots came out great.
So that's it, prototype v0.01 is complete.
I had initially thought about doing a crowdfunding campaign to sell these but the Shimano system is crazy expensive and, to me, a $3k electric bike just doesn't really make sense (you can buy a cheap car for that). Now it's time for prototype v0.02, for this I'm going to design and build my own hub-motor that should be quite a bit lighter (and cheaper) than the Shimano system.
If you have a second, check out the project (and vote) at 5x5night. Judging is partly based on online votes so help me win this thing and get v0.02 made ASAP!
Post below and let me know what you think...
Step 2 was choosing the motor. Every hub motor on the market is designed for wider mountain bike/ road bike dropouts at around 130mm, compared to the 110mm on the Modus (and any other BMX frame). I actually have a custom Standard 125R with a stretched back end to fit normal hub motors but I'll leave that for another post. Since hub-motors won't fit I went with a mid-drive and chose the Shimano E7000 due to its narrower Q-factor and decent reviews.
Luckily I found the motor mount from TI Cycles in Portland which simplified things greatly. Now don't get me wrong, I can weld, but cutting the frame and fixturing up the mount was not really something I wanted to attempt. Luckily my wife's company was running an event where their model shop would do work for donations to a charity, so we got the frame cut, welded, and painted for a good price and a great cause.
My original plan was to use my own 36V battery instead of the Shimano STEPS version because it seemed overpriced, but after getting the motor I realized that the Shimano drive requires CAN status messages from the battery to operate so I had to go with the Shimano version. I got a great deal on the parts from JJ at West Michigan Bike and started assembling.
Mounting the battery to the frame consisted of drilling directly through and using black oxide button head hex drive screws to secure the battery mounting brackets. The lock for the top battery mount was on backorder so my initial testing was done with electrical tape securing the top of the battery to the frame. And brakeless of course in true BMX fashion.
The initial testing went great but the 20mph cutoff that's built into the E7000 drive is heart-breaking. As soon as you start getting up to a great cruising speed the motor just cuts out and your left wondering WHY?!?! I'm pretty sure this can be modded to get up to 28mph but I haven't done this yet.
I'm a bit of a purist and know that electric BMX bikes don't belong on the track or at the skatepark, but they are awesome for going longer distances and cruising around the neighborhood. I wanted to get some professional shots of the bike and so I found Rob Sackyta who did an amazing job on super short notice. I really didn't want to shoot at the skatepark (for the reason above) but Rob insisted and the shots came out great.
So that's it, prototype v0.01 is complete.
I had initially thought about doing a crowdfunding campaign to sell these but the Shimano system is crazy expensive and, to me, a $3k electric bike just doesn't really make sense (you can buy a cheap car for that). Now it's time for prototype v0.02, for this I'm going to design and build my own hub-motor that should be quite a bit lighter (and cheaper) than the Shimano system.
If you have a second, check out the project (and vote) at 5x5night. Judging is partly based on online votes so help me win this thing and get v0.02 made ASAP!
Post below and let me know what you think...
E-bikes are fine at skateparks. One advantage is the ability to ride easily for long distances then get to the skatepark enjoy your time there and then still be able to ride back home. It's not cheating it's not inappropriate it's just progress get used to it. Don't be an elitist, cause after 'they' ban my type of bike, yours IS next.
ReplyDeleteThose are good points Scott, I definitely don't think they should be banned, was just stating my personal opinion. Actually, as the technology improves and ebikes get lighter this becomes more practical.
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