E-bike version 1.0 complete

[dirty_d]

Well i finished making by bike, kinda, it works but it looks more like a pile of wires taped to a bike with batteries unsecured in a basket zip-tied to the handlebars. that will get fixed up soon enough though. i only had one problem if i tried to accelerate to fast i heard this nasty clanking sound, i thought it was the sprockets on the jackshaft slipping, they are on a 3/8'' D-shaft with only 2 small set screws holding each. i took them off and there was no sign of slippage so i figured out then that it was the chain going from the jackshaft to the wheel so i tightened it up, it helped a little but it still slips, i noticed when pulling on the chain that it actually flexes the 3/8'' shaft so it must be flexing just enough while under hard acceleration to slip. i wanted to go with a bigger shaft at first but didnt have anything to drill out holes big enough for the bearings for it to fit in. im not sure what im gonna do to fix this yet.

 

[fechter]

How about a picture

Increasing the angle of wrap will help slippage, bigger sprockets will too.

 

[dirty_d]

Ill take a picture when i get home from work today.

 

[safe]

This thread should be in the "Photos & Videos" area.

(Fechter could you move it?)

 

[safe]

...i noticed when pulling on the chain that it actually flexes the 3/8'' shaft so it must be flexing just enough while under hard acceleration to slip. i wanted to go with a bigger shaft at first but didnt have anything to drill out holes big enough for the bearings for it to fit in. im not sure what im gonna do to fix this yet.

Welcome to "Transaxle Hell ". (or in your case "Jackshaft Hell ")

Try taking my advice now at the beginning before you get into rebuilding everything (I'm up to Version 5.0 on mine) drop the Jackshaft/Transaxle COMPLETELY and replace your gearing so that it runs direct drive from motor to rear wheel. Either go:

#25 (scooter chain) - 11 / 90

http://www.electricscooterparts.com/sprockets.html

or #35 (go cart chain) - 14 / 114

http://www.gokartnminibikeparts.com/split_racing_sprockets.htm

Save yourself from a world of pain...

 

[fechter]

This thread should be in the "Photos & Videos" area.

(Fechter could you move it?)

I don't see any photos or videos yet. He's trying to solve a particular problem with the gearing, so I think this category is appropriate.

 

[dirty_d]

here are the pictures

 

[safe]

All you need to do is buy the go kart sprocket (114 tooth) and drill a few holes in the rear sprocket you already have and then bolt it over the top of it. Change the front sprocket to a 14 tooth and then get a #35 chain which is stronger anyway.

Simple

You'll also have to live with the idea of the motor hanging off of the side a little more than you have it now in order to get the alignment right.

 

[dirty_d]

and create a whole new motor mount assembly to move the motor over about 3 inches over the rear sprocket. but anyway whats the usual riding distance for a 48v system with 12Ah batteries going 25 mph on flatish roads no pedaling, not exact just a guess since its different for every bike and rider.

 

[knoxie]

Hi

Brilliant! like a mini version of safes super machine! nice

Now it would be really easy to whack in a nexus 8 speed internally geared hub and have 8 speeds to power that through! these hubs are cheap and available.

I am going to do something similar with one of my motors except I dont need the top reduction as my motors have a gearbox adaptor, I am looking to bolt it all on the right hand side and drive the hub direct, ala Randys early designs.

Great rig let us know how it runs!

Knoxie

 

[geoff57]

Hi all
dirty_d I don't see a drive train for the manual drive have you got rid of it?

Knoxie I am also going to have a go at putting a hub motor in line (between) the motor and the wheel on the KMX still in the theoretical, have been looking at the best type of hub to use and have gone for a sturmey archer 8 speed with disk brake mounts, the only hub with disk brake mounts <£200($400) the disk mounts are ideal to attach a sprocket to. As far as I know most hub gears would have to spin to work this could cause a problem.
By the way the shimano and most hub gears have a middle gear as direct drive(1:1) the sturmey has gear 1 as direct and 8 as 305%.

 

[knoxie]

Hi Geoff

Yes its a good idea, I like the Nexus coz its cheap, it hasnt got a mega spread but it spans 302% not bad, nowhere near high end hubs like the rolhoff but then its a lot cheaper. Gear five being 1:1, they span as follows.

1 - 0.52
2 - 0.64
3 - 0.74
4 - 0.85
5 - 1
6 - 1.22
7 - 1.419
8 - 1.615

I am going to lay some drawings up on the CAD and see how it looks, the only issue I have is whether I can get 2 sprockets on the drive side of the hub gear, looking at the drawing its a bit tight, the other option I have is running a fixed gear putting the drive on the other side and driving a reverse BMX free-wheel off the disc brake mount, this wouldn't be too bad, it would be better if I can get them both on the drive side.

Electricscooterparts do some free wheeling adaptors so it should be easy enough to cobble stuff on to it, just need to make a secure frame mount to hold the motor, I may have to use a steel bike and weld the bracets on like the currie Izip bikes, but on the opposite side.

Cheers

P

 

[safe]

I like the Nexus coz its cheap

The Sturmey Archer is the least expensive at $122:

http://aebike.com/page.cfm?action=details&PageID=30&SKU=HU2206

...and you get the disc brake mount too. By the time you buy ther Nexus and the shifter (separately most of the time) and their custom brake attachment you are up to $200+. However, if you can live without any brakes in the rear (or are okay with caliper brakes or a coaster brake) then there's this Nexus at $130:

http://www.bikepartsusa.com/product_info.asp?f_c=hub&cp=11&p=01%2D157679

 

[safe]

...whats the usual riding distance for a 48v system with 12Ah batteries

If I plug the numbers into the spreadsheet I get this for such a bike. Note that this is assuming flat land and it includes things like wind resistance losses and a bunch of other stuff. It's also assuming a 13/114 gear ratio, so to get more precise I need to know the number of teeth on all your sprockets. I'm also assuming a 40 amp controller.

 

[geoff57]

Hi all
Safe as far as I know the nexus does not have a disk brake version, shimanos new disk brake mount add on is not for the hub gear range, from what I've been told. but personally I prefere the sturmey anyway.

 

[Beagle123]

Hi all:

I use a Shimano Nexus 7 speed Hub myself, and I wouldn't reccomend it because I've had several problems setting it up. First the cheaply built roller brake didn't fit. I took it apart to fix it which ruined it, and had to buy another. Then the cheap PLASTIC thing that shifts the gears on the hub broke, and I had to replace it. It took a month and $300 to get everything right.

I'd try this one:

http://www.bikemannetwork.com/biking/p/COMPHUINT/HU2542

it has a bigger gear span (303%) and it touts durability. Also, it has a built in drum brake. That should work great.

 

[safe]

Safe as far as I know the nexus does not have a disk brake version, shimanos new disk brake mount add on is not for the hub gear range, from what I've been told. but personally I prefere the sturmey anyway.

Yeah, I don't think that the Nexus comes with anything but their "weird" proprietary band brake. I bought the Sturmer Archer and think it will turn out to be a really fine hub, but in order to use it you need to have enough of a gear ratio reduction to make it fit the range of speeds required. Fortunately if you take the Unite MY1020Z3 with it's geardown built in you get the perfect gearing range and can use some pretty normal bicycle components to do it. You can get by with an 18 tooth front sprocket and a 44 tooth rear sprocket... which means you build a "spider" mounting bracket on the rear so that you can mount different sprockets easily. Lot's of gearing choices at a low price because BMX front sprockets can be used.

But the cool thing about the Nexus is that you can run it without a gear reduction... you can go direct drive from motor to the rear hub if you use the go cart sprockets and go 13 / 114... 8)

 

[safe]

I use a Shimano Nexus 7 speed Hub myself, and I wouldn't reccomend it because I've had several problems setting it up.

The (new) Sturmey Archer hub is built really well. The new shifter location is made so that it pivots outside the axle rather than through the insides. This change in the design should have been done years ago because it makes the hub much stronger. (expect to see more of this)

I'd suggest going with the Sturmer Archer... it's "high tech" compared to all the old stuff that seems to have been invented in about the 1890's... :lol:

It's probably the most "beefy" hub I've ever seen...

http://www.sturmey-archer.com/hubs_8spd_XRK8.php

 

[Beagle123]

Fortunately if you take the Unite MY1020Z3 with it's geardown built in you get the perfect gearing range and can use some pretty normal bicycle components to do it. You can get by with an 18 tooth front sprocket and a 44 tooth rear sprocket... which means you build a "spider" mounting bracket on the rear so that you can mount different sprockets easily. Lot's of gearing choices at a low price because BMX front sprockets can be used.

But the cool thing about the Nexus is that you can run it without a gear reduction... you can go direct drive from motor to the rear hub if you use the go cart sprockets and go 13 / 114...

If you're planning on using a gear hub, I'd look at the way I did it on my bike-- I used the Unite 36v 750watt gear motor (I beleive its the one safe is referring to.) I welded a 18 tooth bicycle sprocket to the stock 11 tooth sprocket that came with the motor. The stock sprocket fit 420 chain. Since the gearmotor has a built in 6.66:1 gear reduction, it spins at about 500 max rpms. This is a good speed for attaching a chain directly to the hub without having to deal with a jackshaft etc.

In the end, you have a very neat setup-- a 18 tooth sprocket on the front, a 23 tooth sprocket on the back, and a nice looking, reliable connection from the motor to the hub.

Also, you have an option to change the back sprocket to fit your gearing needs because you can buy stock sprockets from 16-23 teeth.

Safe, what is a spider mounting barcket? What do you mean BMX front sprockets can be used? You mean BMX sprockets can be used to attach to the motor end?

Also, I read that when you run an electric motor to a wheel using a big gear ratio like you suggest, there is a lot of chain noise. The guy I got this from used a rubber belt to a jackshaft, then a chain to the wheel to eliminate the noise. I beleive he had a normal 3000rpm motor.

 

[safe]

In the end, you have a very neat setup-- a 18 tooth sprocket on the front, a 23 tooth sprocket on the back, and a nice looking, reliable connection from the motor to the hub.

Also, you have an option to change the back sprocket to fit your gearing needs because you can buy stock sprockets from 16-23 teeth.

Safe, what is a spider mounting barcket? What do you mean BMX front sprockets can be used? You mean BMX sprockets can be used to attach to the motor end?

I was going to overvolt my MY1020Z3 to 48 volts. You can overvolt pretty easily without too much worry, but when you overamp (raise the current limit) you have to worry about heat. I would be using a 48 volt controller so that side is stronger than needed. The bottom line is that for my setup the extra voltage means the rpms are higher. This means I need to lower the gearing to compensate. So in the stock setup you're right that all you need is something like 16-23 on the rear.

As for what a "spider" is... you know how on a front sproket on a BMX bike they have this mounting bracket for the sprocket? That's called a "spider". (because it looks like a "spider") The idea I had was to weld the spider onto my rear Sturmey Archer 25 tooth default rear sprocket and then use BMX front sprockets on the rear. So with numbers like 44 teeth you get the right gear ratio for what I have in mind. (other ideas involve using 114 tooth go cart chains on the rear... generally the rear sprocket needs to be bigger than the front) You also get much better efficiency with more teeth up to a point. Using 11 teeth on a front sprocket (like with my #25 chain) is a waste.

My #25 scooter chain makes a good amount of noise, but it's kind of cool sounding... when I rev through the gears it sounds like a very bizarre quiet, yet high pitched squeal.

Eeeeeeeee, Eeeeeeeee, Eeeeeeeee...

People can definitely hear me coming...