A new DIY cargo bike on the cheap.

mlavis
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A new DIY cargo bike on the cheap.

Postby mlavis » Tue Jan 10, 2017 2:23 am

Hi everyone,
Living overseas as my partner is on a work contract for the next while and I find myself with some time on my hands. Always been interested in living a less car-centric lifestyle, and love riding bikes... so it wasn't long before I started looking at Cargo bikes, Particularly the 2 wheel bakefits/long john style ones. No kids yet but potentially in the future, and based in Canberra so have lots of great infrastructure to make bike riding a feasible alternative to car use.

Issue is that they are damn expensive in Australia, and non existent in Laos! The few that I have seen/ridden in Oz depart so far from regular bike riding experience (mainly weird geometry) that they are actually not enjoyable machines to use. I can't remember the model of the one I borrowed from my brother's neighbor in Newcastle but the super low bottom bracket made pedal strikes a significant issue when turning on a street with a gentle camber and the steering just seemed 'off'.

The goal at the outset of this project was to make an affordable 2 wheel cargo bike using limited resources that both I and my partner can ride (she is a shorty at 155cm or so), maintain fun bike riding geometry, space for 2/3 kids if needed, wide tyre capability for gravel/dirt touring/commuting, Hydro Disc brakes, Sturdy kickstand, bi-partable (for on car/international air travel) while maintaining a sensible weight. Also in the scheme of things is the option of mounting a mid drive electric conversion kit (the Bafang 8fun 750W mid-drive unit is the leading contender).

Options for donor bikes were limited in town, but stumbled on a small size mid 90s Trek Mountian Trek 850 for $80. Full rigid with 4130 Cromo tubing. Good standover height for my partner. I have to admit I have a soft spot for this model of bike (I rode a medium sized one across Asia for 13,000km in 9 months a few years ago.
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Donor bike sorted I had to find new steel to make the rest of the machine! No Cromo available here...no cold drawn tubing... had to settle for regular seam welded construction steel 1.6/2.0mm wall thickness or the project would never get off the ground.

Design wise I was taking inspiration from Bullit bikes, CETMA cargo bikes, Metrofeits, and kind of synthesized the elements I liked. I liked the Cetma bi-partable couplers and vertical steerer tubes that maximized cargo space. However because I needed this to be a simple frame build, my cargo frame design varied a bit from the regular manufacturers. My central cargo pole is the main load bearing element, and the cargo bay is just for stabilizing the load. So my main cargo boom is chunky, with the rest being lighter 22mm gal steel tubing. Both the Bulit and the CETMA use smaller gauge tubing but make the cargo hold a structural element of the front end of the bike.

I wanted to preserve the trad MTB handing so took some good measurements of the bike before working on it. I made a Jig out of left over 18mm ply and make spacers that would hold the bike and maintain the rear axle-BB drop/ seat tube angle. After stripping all the paint off it was time to get cutting. First to go was the headtube, then downtube. Cargo boom was shaped to fit the bottom bracket, seat tube junction, then top tube mitered to fit new vertical steerer. Steerer punched through cargo boom.
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Things ground to a halt as I couldn't find a 20" BMX style bike to use for the front end. Luckily my parents decided to come visit at Christmas so used them as parts mules to bring over a cheap BMX fork, rim, Hydro brakes and a few other goodies. Pretty soon the front end was all mitered up and ready for welding.


After all the work getting to this point I was pretty nervous about the welding step. Most of the welding I have seen here has been pretty gnarly stick welding done by kids in flip flops with no eye protection. Luckily I found a Vietnamese run place that has a few tig machines that make fancy stainless steel gates for the nuvo-riche of Vientiane. It took a while for them to warm to the idea of doing such a small project but they eventually got on board.
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I made disc brake tabs out of some 4mm plate steel and made a rear brace to help spread braking load across the chain stays and seat stays. The front fork is a beefy bmx one so no extra re-enforcement was used for the disc brakes.
Turns out the trickiest part of the whole build was getting the Geometry right for the steerer rod, and figuring out the kickstand.
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Bike is currently completely functional with 3x7 gearing, 2x shimano Hydro disc brakes, and flat cargo bed. Last things to do are to hack the frame in two and install my bi-partable couplers, weld on some steel tabs for ocky straps/kayak straps. Actually have some very nice instrument case/pelican case latches I picked up in Thailand for cheap that will make the carbo box easily/quickly removable. That is one innovation I think I am bringing to the current crop of machines which i'm pretty excited about (actually an intersection of two of my hobbies- Bikes and Sound Systems!).
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Next step is quick release cargo box using the aforementioned Music case straps, welding on the bipartable couplers and then cleaning it all up for a nice coat of paint! Currently liking the idea of a really dark Jaguar green with subtle gold fleck- like you see on some guitars... :)

Hope you like it! Actually not that hard to do if you have a little time on your hands. Could be easily done using 2nd hand parts in Australia. You can get a pretty good result and not have to fork out the 4k for one of the brand name ones.
Last edited by find_bruce on Wed Nov 22, 2017 7:56 pm, edited 1 time in total.
Reason: Restore photo links

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Mulger bill
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Re: A new DIY cargo bike on the cheap.

Postby Mulger bill » Tue Jan 10, 2017 8:06 pm

Nice work! 8)
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koshari
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Re: A new DIY cargo bike on the cheap.

Postby koshari » Tue Jan 10, 2017 9:27 pm

good job, how does the steering linkage couple to the front fork?
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find_bruce
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Re: A new DIY cargo bike on the cheap.

Postby find_bruce » Tue Jan 10, 2017 9:50 pm

That is going to look brilliant once you have painted it. Your centre stand looks like a better arrangement than most commercially available & I like that you have used your musical interests in making a flute for the steerer :wink:

What are you going to use for the "bi-partable couplers" ?

mlavis
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Re: A new DIY cargo bike on the cheap.

Postby mlavis » Wed Jan 11, 2017 2:01 am

(AT) Koshari- the steerer is extended to run the whole length of the head tube. There is a steel plate welded to the bottom of the steerer (pic no. 5). A steering rod is attached to that plate which acts as a crank arm. When you turn the handlebars, the crank arm also turns, pushing a rod which reaches up and around the front wheel- attaching to the fork leg. The steering rod has to have a dog leg bent into the front of it (which allows for clearance of the front wheel when the bike is in a hard left steering lock). The steering rod attaches to a tab welded on the front fork using a heim joint bearing. This is a pretty standard config for cargo bikes so you could look up images for either Bullit or CETMA cargo bikes and see something similar. Some European ones use nifty cable/chain actuated mechanisms, bit that was going to be too tricky for me to fabricate.

@find_bruce- thanks for the kind words. Yes i got a bit weight weenie on my bike while i was waiting for my 20" parts to arrive- not sure how much of a difference it made in the end but at least i felt like I was being productive at the time! My very high tech 'bipartable couplers' are just 4x 4mm steel plates drilled out for some high tensile SS bolts. They will be welded on to the top tube and cargo tube just on the rider side of the steerer tube. Going to use those nice little bullet head allen head nuts traditionally used for holding brake pads in place with some stainless steel bolts to hold it all together.

koshari
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Re: A new DIY cargo bike on the cheap.

Postby koshari » Wed Jan 11, 2017 7:51 am

mlavis wrote:(AT) Koshari- the steerer is extended to run the whole length of the head tube. There is a steel plate welded to the bottom of the steerer (pic no. 5). A steering rod is attached to that plate which acts as a crank arm. When you turn the handlebars, the crank arm also turns, pushing a rod which reaches up and around the front wheel- attaching to the fork leg. The steering rod has to have a dog leg bent into the front of it (which allows for clearance of the front wheel when the bike is in a hard left steering lock). The steering rod attaches to a tab welded on the front fork using a heim joint bearing. This is a pretty standard config for cargo bikes so you could look up images for either Bullit or CETMA cargo bikes and see something similar. Some European ones use nifty cable/chain actuated mechanisms, bit that was going to be too tricky for me to fabricate.


Ahh thanks, nice description.
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P!N20
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Re: A new DIY cargo bike on the cheap.

Postby P!N20 » Wed Jan 11, 2017 9:55 am

This is awesome. Can you make me one?

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bychosis
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Re: A new DIY cargo bike on the cheap.

Postby bychosis » Wed Jan 11, 2017 11:57 am

Great to see some creative works. Looks a treat.

One question: How well is your stand going to work on uneven surfaces? eg if there is a bump in the middle.
bychosis (bahy-koh-sis): A mental disorder of delusions indicating impaired contact with a reality of no bicycles.

mlavis
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Re: A new DIY cargo bike on the cheap.

Postby mlavis » Wed Jan 11, 2017 1:03 pm

@Bichosis- In the images it does look like the cross bar which attaches the two kickstand legs is welded right at the bottom of them- but it is actually 15mm short of the bottom. Now that I have some protective rubber feet on there it is more like 20mm. That seems to be enough clearance to prevent there being any issues with using the stand on uneven ground so far. I'll have to spend some more time with it all fully loaded up to make sure i'm happy with it in all sorts of parked situations. (I figure I should be able to transport about 6 cases of Beer Lao on it :P )

@PIN20- Completing this project in Laos has been a bit of a labor of love. Things that are dead simple in Oz become huge ordeals to figure out over here- so it's unlikely i'd be selling bikes any time soon. That being said, once I do return to Australia I am tossing up the idea of taking a TIG course so I could make these up in my spare time and sell them to friends and family (who all seem to be having kids at the moment!). I'd probably try to keep a high recycled bicycle content in them to keep every bike original and to keep costs down. Anyway- long time away but if the economics of unit value-VS value of my minimal spare time works out you may seem them out on the streets of Canberra in the future.

Today's job is to start work on the Cargo box V1. Features will include small storage area with elastic netting on rear of box for regularly accessed items (rain jacket, bike lock, sunscreen, reusable shopping bags, frisbee). Going to experiment with 8mm ply with Aluminium right angle reinforcement in the corners and a perimeter of double thickness ply on the top for stiffness.

Mark

mlavis
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Re: A new DIY cargo bike on the cheap.

Postby mlavis » Fri Jan 13, 2017 9:32 pm

Had a productive little while knocking this box up. 9mm ply with Aluminium right angle bolted into the inside corners using hex bolts and hurricane nuts. Doubled the thickness on the top lip in increase stiffness. On the rear I am waiting on some elastic netting I bought on ebay that will be screwed to the three sides of the small rear panel to act as a storage space for frequently used items that you might not want to leave in the main tray. You can also see the music case latches I am using to attach the box to the tray. I need to go back to the welding shop to get the other part of the latch welded to the gal steel bottom tube. Conveniently the part that will be welded to the gal tube fits a 25mm kayak strap through it so it will act as a useful anchor point when the box is not in use too. Will clean it up a bit and hopefully get it sealed and finished this weekend. Also want to get 2 little pieces of flat plate Alu to screw into the bottom of the box to cover the two triangular gaps at the front.

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Mark
Last edited by find_bruce on Wed Nov 22, 2017 7:58 pm, edited 1 time in total.
Reason: Restore photo links

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Cardy George
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Re: A new DIY cargo bike on the cheap.

Postby Cardy George » Sat Jan 14, 2017 8:03 pm

So cool! Just bought a shed (paid a bit much, but they threw a house in to sweeten the deal :wink: ) and my wife has warmed to the idea of a cargo trike now that we live 2km away from the supermarket.

Just need a welder and a grinder and I'm away.

I showed her yours with the cargo box and she loved it.

mlavis
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Re: A new DIY cargo bike on the cheap.

Postby mlavis » Tue Jan 17, 2017 12:57 pm

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Got the box all sanded and sealed. Just a few more small welding jobs to be done on the frame before I can get the frame sand blasted and painted! :)
Last edited by find_bruce on Wed Nov 22, 2017 7:59 pm, edited 1 time in total.
Reason: Restore photo links

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Mugglechops
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Re: A new DIY cargo bike on the cheap.

Postby Mugglechops » Tue Feb 07, 2017 10:17 pm

That is the best thing I have seen all day. Bloody nice work indeed.
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grantw
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Re: A new DIY cargo bike on the cheap.

Postby grantw » Wed Feb 08, 2017 8:03 am

Most impressive :-)
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mlavis
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Re: A new DIY cargo bike on the cheap.

Postby mlavis » Wed Nov 22, 2017 7:28 pm

Just realised that stupid photobucket was disabling its 3rd party image hosting. If anyone is interested in looking back on this project (or checking out the upgrades that are nearly complete-rain cover/shade cover design ) you can take a look at it here:
http://canberrapassivesolarhouse.weebly ... style.html

Cheers,
mark

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Bunged Knee
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Re: A new DIY cargo bike on the cheap.

Postby Bunged Knee » Wed Nov 22, 2017 7:57 pm

Hi mlavis,

You can override it by editing your posts by adding " ~original " in after the "png" in the strings, as mentioned in "Do NOT use Rustedbucket " thread.

mlavis wrote:Image

Got the box all sanded and sealed. Just a few more small welding jobs to be done on the frame before I can get the frame sand blasted and painted! :)


See what I`ve done one for you and you will be able to restore it back after you had previewed it and then submitted to make it come back.

ps, find_bruce had fixed it.
ID please? What ID? My seat tube ID is 27.2mm or 31.6mm depending on what bikes I ride today.thanks...

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find_bruce
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Re: A new DIY cargo bike on the cheap.

Postby find_bruce » Wed Nov 22, 2017 8:06 pm

Too nice a thread to leave photoborked

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ldrcycles
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Re: A new DIY cargo bike on the cheap.

Postby ldrcycles » Wed Nov 22, 2017 9:10 pm

That looks fantastic, I'd love to have a crack at one if i ever get some spare time.
When man invented the bicycle he reached the peak of his attainments- Elizabeth West.

mlavis
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Re: A new DIY cargo bike on the cheap.

Postby mlavis » Thu Nov 23, 2017 12:13 am

(AT) find bruce and Bunged knee- thanks for the workaround on the image hosting issue. I'll post some fresh pics of the latest additions to the machine later this week using your advice.
Happy pedalling!
Mark

mlavis
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Re: A new DIY cargo bike on the cheap.

Postby mlavis » Fri Nov 24, 2017 11:09 pm

As promised here are some pics of the sun shade and rain protection additions to the bike. You'll also notice that it has been painted, has mud guards and a rear rack and the netting for the stash spot has been completed. The hard part now is managing my mum's expectations for the immediate production of grandkids :)

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Bunged Knee
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Re: A new DIY cargo bike on the cheap.

Postby Bunged Knee » Fri Nov 24, 2017 11:29 pm

Nice.

Can you please edit the image name as it got the double "~original " , just remove the one so it had the single "~original " and the image name will get back to picture.

As you`ve got got 5 pics but only 4 pics are shown. it`s the 3rd pic that needed to be edited.

ps, It would be better to stay away from Photoborked and use other one like I always use this http://www.bicycles.net.au/forums/viewtopic.php?p=1412791#p1412791 without the need of hassle.

You can do it with or without account, just copy from your photo gallery.
ID please? What ID? My seat tube ID is 27.2mm or 31.6mm depending on what bikes I ride today.thanks...

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