Building An E-Bmx, Design Ideas?

[gwhy]

yes I can see that it wil be slow and running on 24v.. why dont you try 48v, your controller may be ok with it, but the gearing may be way to high of on 48v so the motor will get even hotter..

[gudah]

Just tried running it with no load, bikecomputer says:

45 km/h @ 3230/395 rpm(Motor/wheel)....no wonder it´s a bit weak.

Best guess is that it needs 36-48V and a gearing to top max 20 Km/h(with load on).

Feels difficult to find a rear sprocket that will do the job, i´ve only found 11/90 T sofar.

For now, I maxed the tyres with 4.5 bars to help a little.

Will let the kids try it some day when snow is gone.

...Or just add a 48V/1200W OSET-motor and reduce the gearng by 20% to give it the same

performance as our OSET 20".

...Or buy a bike conversion kit with a 24" 48V1000W wheel but i don´t have the same good

experience with those BLDC motors as the good old fashionned brushed ones when it comes to

initial "hit", probably jus a setting in the controllers of the few ones i´ve tried on div. bicycles.

[sveson]

Snyggt jobbat! (Yes I am also Swedish).

Seems like a fun project. Not much power you say, but how is it to ride concerning geometrics, weight, suspension etc?

I am also curious about your boys Oset 16 with 20 wheels, do you have any pictures of that one?

[gudah]

Tack/Thanks Sveson.

Sofar it feels ok but i am not a trials rider, just freeriding and enjoying the silence and lightwieght

of these bikes, the rear shock has to be replaced with something a bit stiffer since it is taken from an old twinshock moped and a bit to soft.

My guess is that it weighs in at approx. 30kg´s so you could perhaps add a bigger motor and Lipo´s and still end up at approx 30 Kg´s.

Trivia:

Pricing is a strange thing..my neighbour bought a complete Ebike with 48V 1000W 20 Ah Lithium(Samsung-cells) from Conhismotor in China

at approx 1100 Euros and i almost felt like buying one to thrash for parts(Battery, BMS, charger and motor) and keep the rest as a standard bicycle.

It was 26" so i´d have to relace the hubmotor to a 24" rim but still it´s a fair pricing(the darn thing does 54 Km/H and pulls wheelies if you want it to).

For our standard 2012 OSET 20" I have a extra 48 V/7,2 Ah "Strap-on" SLA pack to extend the range

for up to approx 45 minutes of fun trailriding in a small forest and for my 74 kg´s bodyweight the extra weight of the batteries on the bike doesn´t matter

as the entire bike is still under 40 Kg´s in total(The extra 7,2 Ah in addition to the standard 10 also gives a bit more of punch when you hit the throttle).

This is why I made the "24" frame so it can house big batteries but right now I want to await the result/specs and of course pricing of the OSET 24" Concept before I decide how and if to proceed more on this one(Better to save the money for a new bike perhaps).

After all this build cost perhaps 50EUR so I havent really spent anything(Beer excluded;-) on it yet.

In my experience, you can build a pretty cool bike yourself but it is difficult to match something factory-designed.

Small improvments and adaptations you can do even better now and then, but an entire bike is tough as it´s all

about making good compromises to achieve an affordable (and desireable) end result.

Oh..and finally, i came across a new old BMX-frame..so perhaps next winter...a new project.

[gudah]

As requested by Sveson:

Homemade 20" OSET Lite, "Youtube-spec"

Standard OSET 16" frame.

Rear swing extended by 50 mm´s

24" front fork installed.

180 mm front disc.

Wider steerer(Same as oset 20").

Hydraulic brake converted.

Controls in accessible area.

[mikerenief]

Good job!!