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Another 2-speed dogbox

Posted: Jul 28 2017 1:18pm
by vax
Hi all
I posted this to ES facebook page, but I guess its better to put it here also.
I'm building my hybrid bike and one idea was to use 2-speed gearbox.
Initially I wanted to use Babetta automatic gearbox, but the guy whom I was gonna buy it, acted like a fool and ruined my plans.
So, next candidate was Riga V-501 engine which is really massproduced and easy to to get here.
It hasreally simple hand(cable) operated gearbox and gear ratios quite ok for electric motor.
So, I'm gonna use only internals and design custom casing for it, which eventually will be stressed member on my bikes rear swingarm.
I'm using Alien Power CA80 motor.
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Re: Another 2-speed dogbox

Posted: Jul 28 2017 2:14pm
by SlowCo
Looks great. But why not use a bigger motor/controller/battery combination for the same weight?

Re: Another 2-speed dogbox

Posted: Jul 29 2017 8:51am
by spinningmagnets
Both approaches have their merits, and also a useful application. Lets suppose you have a user-profile where you want to ride fast on roads from your home up to your favorite trail, using a lower voltage battery like 48V/52V. Easily done using off the shelf components. Then, when you arrive at your favorite trails, they are steep in many sections. Since you might have 4,000W of power, you decide you don't want to run it through a 7-speed bicycle drivetrain, but...you still want a lower gear for the off-road trails?

A high-powered 2-speed is not for everyone, but I like the idea, and I would also like to see a cost-effective version. I can make a custom aluminum housing, but I am curious where to get the guts for the 2-speed, rather than make my own (like Thud's)

Re: Another 2-speed dogbox

Posted: Jul 30 2017 8:07am
by Byte
spinningmagnets wrote:A high-powered 2-speed is not for everyone, but I like the idea, and I would also like to see a cost-effective version. I can make a custom aluminum housing, but I am curious where to get the guts for the 2-speed, rather than make my own (like Thud's)
I also like the idea of a 2-speed dogbox a lot. Making a housing and a shaft is not that big of a deal, but making custom gears costs a lot of money. I would also be interested in a supplier who sells stuff like this. Something like sdp-si.com, but they only sell regular spur gears.

Does anybody know a supplier for this :?:

Re: Another 2-speed dogbox

Posted: Jul 30 2017 8:17am
by vax
Well, I'm using standard moped gearbox.
The whole gear set cost me 30€ and I can get more in large quantities if needed.
The model is Delta RMR-24. There was box full of gearbox parts at local motorcycle shop.

Re: Another 2-speed dogbox

Posted: Jan 04 2018 11:23am
by vax
Just made some progress designing it. I have CNC mill, but it has only 110mm of Z travel, so I cannot do very high parts. This design takes it into notice. I have an idea of cable-operated gear change - normal MTB brake lever on handlebar. The gears are spring loaded to 2-nd, but if you pull the handle, 1-st pops in for better acceleration.
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Re: Another 2-speed dogbox

Posted: Jan 04 2018 11:54am
by Thud
That's some lovely modeling.

free advice:
You may want to add some "cush" to your design to help absorb the load spikes to the system.
Are you thinking of a grease packed primary reduction?

small gears are great for light loads, but do the math when scaling them to bicycle/light moped applications.
proper hardening & tempering will be critical for success.(as modeled)

love the compactness of the design.
good luck & keep going!
T

Re: Another 2-speed dogbox

Posted: Jan 04 2018 4:49pm
by vax
It's gonna have traditional oil sump shared for primary transmission and gears.
There's adaptor flange between motor and primary drive casing, with oil seal and additional bearing, so if you would want to use different motor, you would need just different flange.

As stated before, I'm using gears from moped engine, just making different enclosure for them.

Re: Another 2-speed dogbox

Posted: Jan 04 2018 8:43pm
by MrDude_1
doesnt the moped wheel mounting contain the cush drive?