sn0wchyld
100 kW
Thought I'd start a new topic to document a project I've been working on quietly on and off for a few years now... a custom frame for a mid-drive ebike. Its been through many iterations while i've tought myself how to use CAD software, some basics on bike geometry and what hardware I wanted to utilize in the build.
Heres some of the early designs, which are almost embarrassing to show now . These are before i got my hands on a CNC router...
2012
2013 - 2015
Bought a cnc router, so the design changed as a result - this is the latest version form mid last year
2016
Larger pic
I actually prefer the look of the 2015 version, it looks cleaner and leaner, but I built it with little thought to the actual practicality of building it, and how it would perform, hence the redesign. the 2016 has far more thought given to making sure everything fits with ample room, and that its all 90% buildable with tools and skills i have right now. Most of the designs were built with John's mini monster in mind, though the Revolt RV120pro and 160s have been considered too, as well as a few others.
the current version has been made with a few criteria in mind:
Predominantly, or entirely weld-less frame
This is mainly to facilitate changes i'll probably want to make after riding it, as many parts will be transferable to a new frame, and making small tweaks to geometry wont require construction of an entirely new frame. I'll probably make a welded frame once I have some welding skills and have buit a frame or two to come to a design im happy with.
2 speed drive for both pedals and motor
I like 2 styles of riding - slow, technical trials like riding and also flying down trails. a 2 speed means I can crawl up steep terain with silly ammounts of torque, without ever stressing the controller or motor, while still enabling a good top speed.
I'll be building a 2 speed single engagement dog box for this:
From left to right is 1st speed (with freewheel), 2nd speed (both going to the rear wheel), the dog drive, the freewheel sprocket from the pedals, and the motors 1st stage sprocket.
The pedals and the motor come to a single drive shaft, that also serves as the axle for the swingarm. This will hopefully eliminate much of the pedal jack and chain growth that a high pivot swingarm would normally suffer from. 1st should get me to about 30km'h, with 2nd giving somewhere round 70.
high pivot swingarm
I've never actually ridden one, but a rearward traveling suspension ark really appeals, compared to the relative 'bang' you get with traditional geometries on square bumps. It also makes chain routing relatively easy vs a pivot point centered near the BB.
Capacity for 20s 15ah or more - based on the 4s hardcases I have plenty of right now. I'm simultaneously making sure it'll fit about 20s20ah worth of 18650's too.
Capacity for controller inside the frame, heat-bridged to the side covers.
I'll be using a MAXe (gen1) so it's ideally suited to this with its flat body.
Capacity for johns mini monster motor.
I've had it for about 4 years now! time it got used, and it looks to have the power density im after. I'll probably end up modifying it pretty extensively with an aim of getting a solid heat path to the frame of the bike to aid cooling.
'stealthy'
One thing i dont like about the stealth's, the vectors etc is the blob of triangle that (to me atleast) stands out as a ebike frame. I want to keep this thing as slim as realistically possible in profile, with as little hardware as possible visible. So everything (motor, controller, batteries, HUD etc) will be inside the frame. Also makes the bike a bit safer too as a bonus.
Not too heavy
The goal is a total weight under 45kg. Probably a bit ambitious without a welded frame or huge time spent with optimization software/simulations (which i cant afford atm). Frame thus far is shaping up to be in the 7-8kg range, which im pretty happy with given my old norko is around 5kg Should result in a empty rolling frame of about 25kg (norko was about 19kg before electrifying). With a 10kg motor, 7.5kg battery and a 1.5kg controller 1.5kg 2 speed, 45kg doesn't seem impossible, and sub 50kg should be pretty easy.
Capacity for 21" moto wheels.
This would likely take it beyond the 45-50kg mark but I'd like it as an option, since moto wheels provide so much more durability and grip. I've got some rather nice 21'' rims and tyres waiting, but i might save it for use with a lighter motor to help even things out (possibly a revolt 160s)
Bombproof
My biggest beef with all my builds to date is their lack of durability. I've been breaking spokes, overheating, or having some other issue that's meant ive never really been able to rely on my bikes, as such i've always babied them to some extent. Hence why im over building many aspects of this frame (its mostly cnc'd ally, ranging between 6 and 15mm thick). Its also why I plan to have the motor and controller 'heat sinked' to the frame - with the idea that overheating will be all but impossible even when crawling up steep hills all day.
The frame geometry is loosely based on my norko, which i quite like the feel of. The main changes (other than the swingarm) are a extended wheel base (1.3m, up from 1.2ish) and a slightly lower BB (about 25mm). Shock compression ratio remains approximately the same, with a slight rise through the range of travel, that should be around 8.5'' in total.
if this one works out ok I'll probably build a 2nd bike to be much lighter as a little tear around, but this current one is one that I'd like to both commute on and tear around on.
TLDR:
its a custom, heavily built frame with a goal of having a dual purpose (thrash and commute) ebike that'll never quit and (hopefully) rarely break down. 2 speeds, 10-12kw, 20s15ah 40-50kg.
Love to hear any feedback or ideas. Cheers all.
Heres some of the early designs, which are almost embarrassing to show now . These are before i got my hands on a CNC router...
2012
2013 - 2015
Bought a cnc router, so the design changed as a result - this is the latest version form mid last year
2016
Larger pic
I actually prefer the look of the 2015 version, it looks cleaner and leaner, but I built it with little thought to the actual practicality of building it, and how it would perform, hence the redesign. the 2016 has far more thought given to making sure everything fits with ample room, and that its all 90% buildable with tools and skills i have right now. Most of the designs were built with John's mini monster in mind, though the Revolt RV120pro and 160s have been considered too, as well as a few others.
the current version has been made with a few criteria in mind:
Predominantly, or entirely weld-less frame
This is mainly to facilitate changes i'll probably want to make after riding it, as many parts will be transferable to a new frame, and making small tweaks to geometry wont require construction of an entirely new frame. I'll probably make a welded frame once I have some welding skills and have buit a frame or two to come to a design im happy with.
2 speed drive for both pedals and motor
I like 2 styles of riding - slow, technical trials like riding and also flying down trails. a 2 speed means I can crawl up steep terain with silly ammounts of torque, without ever stressing the controller or motor, while still enabling a good top speed.
I'll be building a 2 speed single engagement dog box for this:
From left to right is 1st speed (with freewheel), 2nd speed (both going to the rear wheel), the dog drive, the freewheel sprocket from the pedals, and the motors 1st stage sprocket.
The pedals and the motor come to a single drive shaft, that also serves as the axle for the swingarm. This will hopefully eliminate much of the pedal jack and chain growth that a high pivot swingarm would normally suffer from. 1st should get me to about 30km'h, with 2nd giving somewhere round 70.
high pivot swingarm
I've never actually ridden one, but a rearward traveling suspension ark really appeals, compared to the relative 'bang' you get with traditional geometries on square bumps. It also makes chain routing relatively easy vs a pivot point centered near the BB.
Capacity for 20s 15ah or more - based on the 4s hardcases I have plenty of right now. I'm simultaneously making sure it'll fit about 20s20ah worth of 18650's too.
Capacity for controller inside the frame, heat-bridged to the side covers.
I'll be using a MAXe (gen1) so it's ideally suited to this with its flat body.
Capacity for johns mini monster motor.
I've had it for about 4 years now! time it got used, and it looks to have the power density im after. I'll probably end up modifying it pretty extensively with an aim of getting a solid heat path to the frame of the bike to aid cooling.
'stealthy'
One thing i dont like about the stealth's, the vectors etc is the blob of triangle that (to me atleast) stands out as a ebike frame. I want to keep this thing as slim as realistically possible in profile, with as little hardware as possible visible. So everything (motor, controller, batteries, HUD etc) will be inside the frame. Also makes the bike a bit safer too as a bonus.
Not too heavy
The goal is a total weight under 45kg. Probably a bit ambitious without a welded frame or huge time spent with optimization software/simulations (which i cant afford atm). Frame thus far is shaping up to be in the 7-8kg range, which im pretty happy with given my old norko is around 5kg Should result in a empty rolling frame of about 25kg (norko was about 19kg before electrifying). With a 10kg motor, 7.5kg battery and a 1.5kg controller 1.5kg 2 speed, 45kg doesn't seem impossible, and sub 50kg should be pretty easy.
Capacity for 21" moto wheels.
This would likely take it beyond the 45-50kg mark but I'd like it as an option, since moto wheels provide so much more durability and grip. I've got some rather nice 21'' rims and tyres waiting, but i might save it for use with a lighter motor to help even things out (possibly a revolt 160s)
Bombproof
My biggest beef with all my builds to date is their lack of durability. I've been breaking spokes, overheating, or having some other issue that's meant ive never really been able to rely on my bikes, as such i've always babied them to some extent. Hence why im over building many aspects of this frame (its mostly cnc'd ally, ranging between 6 and 15mm thick). Its also why I plan to have the motor and controller 'heat sinked' to the frame - with the idea that overheating will be all but impossible even when crawling up steep hills all day.
The frame geometry is loosely based on my norko, which i quite like the feel of. The main changes (other than the swingarm) are a extended wheel base (1.3m, up from 1.2ish) and a slightly lower BB (about 25mm). Shock compression ratio remains approximately the same, with a slight rise through the range of travel, that should be around 8.5'' in total.
if this one works out ok I'll probably build a 2nd bike to be much lighter as a little tear around, but this current one is one that I'd like to both commute on and tear around on.
TLDR:
its a custom, heavily built frame with a goal of having a dual purpose (thrash and commute) ebike that'll never quit and (hopefully) rarely break down. 2 speeds, 10-12kw, 20s15ah 40-50kg.
Love to hear any feedback or ideas. Cheers all.