Building a compact cargo bike

General Discussion about electric bicycles.

Re: Building a compact cargo bike

Postby IdleMind » Sat Jan 30, 2016 11:14 am

Craiggor---That's exactly where this idea came from, the old BMW motorcycles.
User avatar
IdleMind
100 W
100 W
 
Posts: 100
Joined: Mon Dec 02, 2013 6:17 pm
Location: SE Wisconsin

Re: Building a compact cargo bike

Postby craiggor » Sat Jan 30, 2016 11:20 am

I had a photo of a BMW but it was to big to post.
craiggor
100 W
100 W
 
Posts: 118
Joined: Fri Jan 30, 2015 2:05 pm
Location: Bury,U.K.

Re: Building a compact cargo bike

Postby macribs » Sat Jan 30, 2016 11:26 am

craiggor wrote:I had a photo of a BMW but it was to big to post.


www.imgur.com

Upload you pic, change the image size click save and copy paste the bb code into the post here. Found on the right side of the screen.
User avatar
macribs
100 MW
100 MW
 
Posts: 2727
Joined: Tue Jul 22, 2014 5:59 pm

Re: Building a compact cargo bike

Postby craiggor » Sat Jan 30, 2016 11:43 am

I only have a tablet.I use the app tapatalk,most pics post just have trouble with a few.
craiggor
100 W
100 W
 
Posts: 118
Joined: Fri Jan 30, 2015 2:05 pm
Location: Bury,U.K.

Re: Building a compact cargo bike

Postby craiggor » Sat Jan 30, 2016 12:20 pm

uploadfromtaptalk1454174376932.jpg
uploadfromtaptalk1454174376932.jpg (96.03 KiB) Viewed 572 times
Rubber bands??
craiggor
100 W
100 W
 
Posts: 118
Joined: Fri Jan 30, 2015 2:05 pm
Location: Bury,U.K.

Re: Building a compact cargo bike

Postby IdleMind » Mon Feb 01, 2016 8:59 am

Here's how I tack welded the frame tubes. I made a drawing of the frame on a piece of 3/4" plywood, then screwed on straight boards to clamp the tubes against. Bored holes in the plywood in 3 places for the hubs. I used round & half round files to fit up and weld the tubes one at a time. Now I need to complete the welding.
Image
User avatar
IdleMind
100 W
100 W
 
Posts: 100
Joined: Mon Dec 02, 2013 6:17 pm
Location: SE Wisconsin

Re: Building a compact cargo bike

Postby dogman dan » Tue Feb 02, 2016 9:48 am

One nice thing about your design, a lot of it will lay flat on the jig. Should come out nice and straight.

Wish I welded as good as some of you do. :roll:
For those that still don't know, I work online, for E-bikekit.com

Frankenbike longtail
http://endless-sphere.com/forums/viewto ... cing+betty.

bolt on longtail viewtopic.php?f=6&t=74584

The mixte long tail. viewtopic.php?f=6&t=74384

Beach cruiser converted to long tail. viewtopic.php?f=6&t=67049&p=1045572&hilit=Longtail+beach+cruiser#p1045572
User avatar
dogman dan
100 GW
100 GW
 
Posts: 33516
Joined: Sat May 17, 2008 12:53 pm
Location: Las Cruces New Mexico USA

Re: Building a compact cargo bike

Postby IdleMind » Wed Feb 03, 2016 6:10 pm

I finished welding the frame, then assembled it with the swing arm and rear springs. I had been working on the spring assemblies prior to starting the frame so I just had to make some adjustments. The springs are swing springs that I got at a hardware store, they should work well here.

Image
User avatar
IdleMind
100 W
100 W
 
Posts: 100
Joined: Mon Dec 02, 2013 6:17 pm
Location: SE Wisconsin

Re: Building a compact cargo bike

Postby Wheazel » Thu Feb 04, 2016 5:46 am

Looking good! Following this with amusement :)
User avatar
Wheazel
10 kW
10 kW
 
Posts: 929
Joined: Tue Nov 02, 2010 2:30 pm
Location: Sundsvall, Sweden

Re: Building a compact cargo bike

Postby IdleMind » Fri Feb 05, 2016 2:46 pm

More photos for your amusement. This is how I fixtured the fork & front swing arm for welding. It takes a lot of time to make those little parts with a hack saw and files.
Image
Image
User avatar
IdleMind
100 W
100 W
 
Posts: 100
Joined: Mon Dec 02, 2013 6:17 pm
Location: SE Wisconsin

Re: Building a compact cargo bike

Postby Lurkin » Fri Feb 05, 2016 3:58 pm

Just curious - will you be producing more than one?
Lurkin
100 kW
100 kW
 
Posts: 1434
Joined: Sun Jan 18, 2015 4:31 pm
Location: Melbourne, VIC, AUS

Re: Building a compact cargo bike

Postby IdleMind » Fri Feb 05, 2016 4:09 pm

If I ever build another bike it will be because I have a whole new concept to try. I have wood working tools so it's easy for me to make a one time fixture for welding.
User avatar
IdleMind
100 W
100 W
 
Posts: 100
Joined: Mon Dec 02, 2013 6:17 pm
Location: SE Wisconsin

Re: Building a compact cargo bike

Postby Wheazel » Sat Feb 06, 2016 8:02 am

A hacksaw and files? Oh my. I would wholeheartedly recommend an anglegrinder.
It is an inexpensive tool that saves alot of time for various types of cutting/grinding.
You can even do very rough and fast sanding of wood with a flapdisc, if you need more buying reasons :)
Also makes basic fishmouth cutting easy.

https://www.youtube.com/watch?v=cj7IYqiv1ZY
User avatar
Wheazel
10 kW
10 kW
 
Posts: 929
Joined: Tue Nov 02, 2010 2:30 pm
Location: Sundsvall, Sweden

Re: Building a compact cargo bike

Postby Lurkin » Sat Feb 06, 2016 4:06 pm

IdleMind wrote:If I ever build another bike it will be because I have a whole new concept to try. I have wood working tools so it's easy for me to make a one time fixture for welding.


Thats a shame, I think you could sell this frame. It's a really neat concept! 8)
Lurkin
100 kW
100 kW
 
Posts: 1434
Joined: Sun Jan 18, 2015 4:31 pm
Location: Melbourne, VIC, AUS

Re: Building a compact cargo bike

Postby IdleMind » Sat Feb 06, 2016 6:24 pm

Wheazel-- I watched the video that you linked and can see that's an excellent technique. I do have an angle grinder, but for me hand work is also a good way. The main tubes are 1.25" dia by .035 wall 4130, very thin walls and easy to file. The radius of the file I used for fishmouthing made a perfect match. The drop outs and clevis tabs took more effort than fishmouthing the tubes.

Here's how the front suspension is looking. I am now working on adapting an old derailleur to work as a chain tensioner.
Image
User avatar
IdleMind
100 W
100 W
 
Posts: 100
Joined: Mon Dec 02, 2013 6:17 pm
Location: SE Wisconsin

Re: Building a compact cargo bike

Postby IdleMind » Tue Feb 09, 2016 4:23 pm

I managed to get part of an old derailleur mounted to serve as a chain tensioner. This will account for changes due to swing arm movements. I aligned it to minimize excess chain slack because I plan to use a 3 spd hub with coaster brake. As shown it only takes about 10 deg of back pedal to take the slack out of the chain, so it should work. I am concerned that the tensioner won't be strong enough to stand on the pedal in the back direction. I will give that a good test when I get the wheel installed. It will also have a front disc brake.

The photo shows the battery pack from my recumbent. I will be able to use this battery, but might eventually make a slightly narrower pack just for this bike.

Now that I got something real to look at I am rethinking ways to do the rear rack. I may be stuck for a few days while making some trial parts.
Image
User avatar
IdleMind
100 W
100 W
 
Posts: 100
Joined: Mon Dec 02, 2013 6:17 pm
Location: SE Wisconsin

Re: Building a compact cargo bike

Postby macribs » Tue Feb 09, 2016 5:40 pm

What if you dropped the battery one bar down and tilt it on its side?
Chain still in the way, or will it clear?
Last edited by macribs on Tue Feb 09, 2016 5:41 pm, edited 1 time in total. View post history.
User avatar
macribs
100 MW
100 MW
 
Posts: 2727
Joined: Tue Jul 22, 2014 5:59 pm

Re: Building a compact cargo bike

Postby IdleMind » Tue Feb 09, 2016 6:15 pm

The battery pack in the photo is about 6.5 inch wide so it causes a small problem. If you notice in the photo, I removed a handle and the front latch from the battery box because the heal of my shoe can catch as I pedal. Removing that latch might be a good enough fix. I won't know until I can actually get it out for a ride and that's not happening for awhile.
User avatar
IdleMind
100 W
100 W
 
Posts: 100
Joined: Mon Dec 02, 2013 6:17 pm
Location: SE Wisconsin

Re: Building a compact cargo bike

Postby macribs » Tue Feb 09, 2016 8:01 pm

Seems a bit of a shame to waste all the nice real estate in the triangle. But it is long wheel base so probably will ride well even if you don't use triangle.

Can I ask, what made you choose that particular fork? Never seen one of those before. Have you ridden bikes with forks like that before? Wonder how it handles? Sure will be a cool looking bike, looking forward to see it completed. It will stand out.
Last edited by macribs on Tue Feb 09, 2016 8:03 pm, edited 1 time in total. View post history.
User avatar
macribs
100 MW
100 MW
 
Posts: 2727
Joined: Tue Jul 22, 2014 5:59 pm

Re: Building a compact cargo bike

Postby IdleMind » Wed Feb 10, 2016 6:41 pm

The recumbent bike in my avatar has has a similar front suspension and it works great. Because there is no sliding action the friction is very low which helps the suspension respond to bumps.

I also wanted to use a spring that I had.I made those 2 red springs by cutting one long spring in half and closing and grinding the cut ends. Each spring has 13.5 coils, a wire diameter of .170" and a coil diameter of .970". From that I can calculate that each spring has a rate of 97 lbs per inch. So it takes 97 pounds to compress the spring one inch. I also designed the fork so the ratio of the leverage from the wheel to the pivot point versus the leverage from the spring to the pivot point is 1.3:1. From this I can calculate that it takes about 115 pounds to displace the wheel one inch. I estimate that the static weight on the front wheel is about 90 pounds. That's the condensed story, I actually built up a spread sheet to try many combinations.

This might be more info than you wanted, but for me that's part of what makes building a bike interesting
User avatar
IdleMind
100 W
100 W
 
Posts: 100
Joined: Mon Dec 02, 2013 6:17 pm
Location: SE Wisconsin

Re: Building a compact cargo bike

Postby Chalo » Wed Feb 10, 2016 7:48 pm

macribs wrote:Seems a bit of a shame to waste all the nice real estate in the triangle.


Pedaling isn't wasting it. I know if I put a 12oz can in a frame bag up near the seat post, my knees touch it when I pedal. If I used a battery case as wide as a suitcase there like some of y'all do, I might as well take the pedals off for all the good they'd do me.

The front triangles of my bikes are mostly gigantic, so I could trade thickness for area and still get quite a lot of battery in there. But keeping that room for my own operations is hardly a waste. Pedal cyclists could use the front triangle for luggage, but almost none do.
Last edited by Chalo on Wed Feb 10, 2016 7:49 pm, edited 1 time in total. View post history.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.
User avatar
Chalo
100 GW
100 GW
 
Posts: 5332
Joined: Wed Apr 29, 2009 11:29 pm
Location: Austin, Texas

Re: Building a compact cargo bike

Postby macribs » Wed Feb 10, 2016 8:20 pm

@Idleman not at all too much info. In fact I spend time here on this forum to learn from others. There are so many great fabricators, exciting designs and clever solutions in here so it is a joy to read. I have yet to lean enough to make my own frame and suspension but I would like to one day make my own bob cruiser and I can really picture such a bike with an unconventional fork so it really stands out.

Looking forward to see your build completed, a bike like this will be a prefect everyday bike to avoid using car as much as possible.
User avatar
macribs
100 MW
100 MW
 
Posts: 2727
Joined: Tue Jul 22, 2014 5:59 pm

Re: Building a compact cargo bike

Postby IdleMind » Thu Feb 11, 2016 7:58 am

I forgot to mention one more really important reason for making the fork the way I did. I like front wheel drive because it allows the use of any rear bike hub. I sized and built this fork to handle the forces encountered with a front motor. On my recumbent, I use a Sturmey Archer drum brake /cassette rear hub. With rear weight bias I mostly use the rear brake and this is a good one.

On this cargo bike I intend to use a 3 speed / coaster brake rear hub because I will be using it in winter as well as summer. With heavy mittens I wanted to have few hand controls. It will also have a front disc brake which will be the main brake in the nicer weather.

And I do like small motors that help but never eliminate pedaling.
User avatar
IdleMind
100 W
100 W
 
Posts: 100
Joined: Mon Dec 02, 2013 6:17 pm
Location: SE Wisconsin

Re: Building a compact cargo bike

Postby IdleMind » Mon Feb 15, 2016 4:01 pm

When I started this thread I asked for suggestions and got some good ones and made some changes. But, there was one aspect of the change that I never liked. In the original design the rear rack also served as a primary structure from the seat down to the rear axle. After moving the battery there was no longer a direct load path from seat/top tube junction to the rear axle. So here's a current photo. I added a tube within the main triangle to improve the frames structure. Maybe it was not needed, but it's a homemade bike and I'd rather be too strong than too light.

Since the rack is no longer needed for structure I made it from cheap electrical conduit. I spun the pieces of conduit in the lathe and sanded off the plating before welding.

I am stalled right now because the rear hub and front hub motor I will be using are on another bike I will be using for the next 4 to 6 weeks. So I will start working on a new battery box.


Image
User avatar
IdleMind
100 W
100 W
 
Posts: 100
Joined: Mon Dec 02, 2013 6:17 pm
Location: SE Wisconsin

Re: Building a compact cargo bike

Postby Chalo » Mon Feb 15, 2016 4:05 pm

Your frame still lacks bracing behind the seat tube. Maybe the tubes have enough beef to be loaded as beams, but that's less than ideal in any case
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.
User avatar
Chalo
100 GW
100 GW
 
Posts: 5332
Joined: Wed Apr 29, 2009 11:29 pm
Location: Austin, Texas

PreviousNext

Return to E-Bike General Discussion

Who is online

Users browsing this forum: andyjk, ClintBX, docnjoj, marcocolo, Rassy, Swe and 18 guests