FrankenCargo Bike

[Elbo]

This project was born out of realising that most of my shopping, commuting and everyday casual riding involves less than a 7km round trip into town. There's one big hill between my place and the centre of town. It's not super steep, but it's enough to discourage casually riding a bike to run errands, which is something I think we should all be aiming to do more of. I wanted to get away from being over-reliant on the car; turning it on, driving 5 minutes and turning it off again doesn't do the engine any good anyway. Using the car given the short distance involved just seemed ridiculous, especially when it's not raining, stinking hot or I have a lot to carry. SoI started thinking that maybe I could still ride the bike even if I did have a lot to carry, it just required a better designed bike.

I looked into trailers and hooking them up to a standard bike, but I didn't like the idea of having something wider behind me that I couldn't see when passing through bollards and narrow bridges on the bike path into town. I wanted the cargo area up front, and with a kid on the way later this year, the idea of one day being able to give rides to the kids up front where they could see everything and be an active part of the trip was too appealing. So that ruled out trailers and ute style cargo bikes.

I looked at ready-made cargo bikes, but couldn't justify the huge price tag ($5k for an entry level one), so went DIY and started chopping up an old Shogun Trailbreaker I had in the shed.

Parts List so far:

Part	Details	Cost
Donor Frame	Shogun Trailbreaker	Originally bought the bike for $70
Main down tube	50x50x2mm RHS	2m for ~$20
Steerer tube extension	Stainless Steel tubing 1.5" (need to check diameter)	6m for $60
Steerer extension	1" Stainless steel tubing	Free offcut
BMX Fork	Sunday(?) with Integrated crown race	Free from a mate
BMX Integrated Headset and Headtube from old frame	Colony BMX headtube and Colony integrated headset	$50 (thanks to Clint at Colony BMX)
Front wheel	Novetech seal hub, 6 bolt disc, 20" double wall Alex Rim	$85
Tyres	Schwalbe Marathon Plus/Performance (20x1.75, 26x2.00)	$85
Steering Rod	10mm Mild steel Pipe	$10
Rod Ends and nuts and bolts	SKF UNF M8 Right hand thread x 2	$64
Steering arm plates	4mm thick flat bar steel	$5
Electric Conversion Kit	Dillinger electric hub-drive kit	$1000
Cargo Platform	TBC - 1.5" stainless tubing made into 50x80cm frame with nylon webbing for carrying cargo	See above
Welding	@spinner with a TIG, gas and a heap of knowledge	Priceless!
Brakes	TBC - but 4 pot for sure, given the weight this thing will be carrying
Rotors	SM-RT66 180mm F&R	$60
Cranks	Need to acquire - probably 1x
Chain	7spd Shimano	$27
Derailleur/freewheel/shifters, etc	Need derailleur and shifter - 7spd	$25
Wasted donor bikes/wrong sizes, etc		$40
Cables/outer	Need to get	$50
Stem and bars	Spares laying around
Pedals	DMR V8's	$30ish
Stand	TBC - RHS and springs most likely	$20
Paint	Undecided as yet
Welding Supplies	Gas, etc
	TOTAL	$1701

Issues:

• General plumbness/perpendicularity of frame: Won't know how good/bad it is until I ride it. We've welded this thing by eye and lining out straight edges, but I think it's pretty good for a one off. I think a jig would be overkill, unless you're going to be making multiple frames.
• Tube sizing availability: I used Phil Vanderlay's cargo bike plans as a launching point and immediately ran into problems. Imperial converted sizes aren't available in mild steel here in Australia (apparently), but stainless steel diameters are converted from imperial and 1" tubing fits perfectly inside a 1 1/8" steerer (to extend it) and 1.5" tubing makes a great longer headtube. Welding stainless to regular steel the way we've done it isn't the best or strongest, but these parts aren't under a heap of load and just have to actuate the steering rod and support my upper body weight and force pulling on the bars. We'll see how it goes.
• Integrated BMX headset: We basically needed the front end of a BMX as a donor fork/headtube/headset. I tried doing it bit by bit and wasted money on incompatible parts.

Whether the thing rides or not remains to be seen, but it's slowly coming together and will be awesome if it works!

 

[Elbo]

Donor frame ready to chop up

Getting pieces cut to size (and square cuts) when purchasing steel helped immensely

Main frame tacked up ready to weld. Don't weld outside with gas on a windy day, otherwise you may as well burn your money. Inside welding from now on.

When we cut the head tube in half (both top and bottom will be used to mount the headset cups) a heap of pressure in the frame let go, so much so the frame 'twanged.' So we decided to cut the top tube to relieve some pressure and re-weld it when everything was in it's final position.
Unfortunately the steerer tube extension isn't exactly the same size as the original steerer tube, so it looks a bit odd, but still does the job.

 

[Elbo]

Drawing up plans in CAD made measuring and cutting holes heaps easier. The top and bottom holes in the main downtube were offset slightly to maintain the head angle from the Trailbreaker, so it was nice confirmation to have the new steerer tube fit right in.

To weld the main downtube to the bottom bracket shell, we sacrificed an old BB as a heatsink, trying to remove as much heat as possible from the area, while also having something with a thread in there to try and maintain roundness. The old BB was toast after welding and I will definitely have to get the BB threads chased again, but hopefully there is enough good thread left on each side for the cutting tool to start chasing the threads.

Originally, the front fork and head tube were designed to be mounted through a hole cut in the main downtube. It was only when we came to actually put the head tube and fork in that we realised this wouldn't work due to the integrated headset and flanged head tube. Our fix was simply to cut the down tube at the hole and weld it on. This will mean I'll have to redesign how the cargo platform attaches, and it may be a bit shorter, but it saves a few hundred grams of overall weight which is nice.

 

[Nerf Herder]

one suggestion ... Think rear hub motor

 

[glenn1529]

Sweet project @Elbo . I’m in wodonga and I’ve got a bit of a stock of spare bits, So shout out if you need something for the build. I can probably throw it over the river to you

 

[Elbo]

one suggestion ... Think rear hub motor

Already ordered one! #braaap

 

[Elbo]

Sweet project @Elbo . I’m in wodonga and I’ve got a bit of a stock of spare bits, So shout out if you need something for the build. I can probably throw it over the river to you

Thanks @glenn1529! Haha, the river is pretty narrow at the Kremur Street boat ramp
I'll consolidate the list of what I need and get back to you!

 

[latheboy]

Home made bike!!!

Home made bike!!

Welcome to the cub of "BUILDING" a bike not just assembling one..

 

[Elbo]

Did a little bit more on the bike this morning, so now steering is all sorted!

Next up is to do a bit of fine tuning on the design of the cargo area. I was originally thinking of making a strong fairly permanent rectangular frame as a cargo platform, however now I'm thinking of focussing more on designing a rock solid and versatile mounting system, which can have lots of different platforms, seats, or boxes attached quickly and easily.

 

[Elbo]

Now have power! Pretty happy with the quality of this kit, just looking at it. Doublewall Alex rim should be pretty solid. I didn't realise it was freewheel only, so that will limit the drivetrain to 1x7 or 2x7, but I'll be looking for a pretty wide range of gears to get this thing up a hill loaded, so multiple chainrings up front will probably have to be a thing.

 

[binner]

Now have power! Pretty happy with the quality of this kit, just looking at it. Doublewall Alex rim should be pretty solid. I didn't realise it was freewheel only, so that will limit the drivetrain to 1x7 or 2x7, but I'll be looking for a pretty wide range of gears to get this thing up a hill loaded, so multiple chainrings up front will probably have to be a thing.

who,where, linky dinky

 

[Elbo]

who,where, linky dinky

Premium Offroad Electric Bike Kit

Please select your size before purchasing that matches the information on the tyre sidewall. The wheel size is written on the tyre sidewall and not on the rim (rim diameter is not wheel size). If unsure, please feel free to contact us before placing your order. Huge power and even bigger range...

dillengerelectricbikes.com.au

They've been out of stock for months, but some stuff just came back into stock, so I grabbed a kit quick. Excellent price for what you get!

 

[binner]

Premium Offroad Electric Bike Kit

Please select your size before purchasing that matches the information on the tyre sidewall. The wheel size is written on the tyre sidewall and not on the rim (rim diameter is not wheel size). If unsure, please feel free to contact us before placing your order. Huge power and even bigger range...

dillengerelectricbikes.com.au

They've been out of stock for months, but some stuff just came back into stock, so I grabbed a kit quick. Excellent price for what you get!

damn...that's a spicy meatball!!!!!

 

[glenn1529]

Now have power! Pretty happy with the quality of this kit, just looking at it. Doublewall Alex rim should be pretty solid. I didn't realise it was freewheel only, so that will limit the drivetrain to 1x7 or 2x7, but I'll be looking for a pretty wide range of gears to get this thing up a hill loaded, so multiple chainrings up front will probably have to be a thing.

I was looking at a similar thing recently, found 9speed screw on cassettes on ebay for about $80 posted from UK.

 

[Elbo]

I was looking at a similar thing recently, found 9speed screw on cassettes on ebay for about $80 posted from UK.

Thanks for the heads up mate. That might work well depending what shifters and derailleur I go for.

 

[Elbo]

Wheels are in and it rolls and turns!
Next step is to acquire more parts, make brake IS tab mounts and work out cable management for the electric components.

 

[Spanky_Ham]

Whoa... this thread is.... bestest thread

S

 

[leitch]

Any more development on the carrying solution? Looks pretty sweet but a flat platform on that main tube is going to bring the weight up quite high. There's a reason people use Bullitts for big loads and not Omniums hah.

 

[Elbo]

Any more development on the carrying solution? Looks pretty sweet but a flat platform on that main tube is going to bring the weight up quite high. There's a reason people use Bullitts for big loads and not Omniums hah.

I haven't given it a lot of thought to be honest.
The reason I steered away from the Bullitt type design was for simplicity of design, the number of welds and workshop level tools required to build something straight and true like a Bullitt. I knew we would be able to do a much better job on a simpler design.

I'm not planning on carrying any super heavy loads. I reckon most cargo I want to carry on the bike isn't 'dense' so to speak, but rather just bulky/lots of volume (boxes, picnic baskets, big pack of toilet paper, jars and bottles for groceries from the bulk foods shop, etc), and it's the bulkiness that stops me from attempting to do more chores on a bike at the moment.

I've got an idea for getting cargo weight down lower, but I need to work on the design a bit more.

Personally I think the ultimate cargo bike design at the moment is the Butcher & Bicycles MK1E, but you're looking at $13k, which is insanely expensive!

If I was planning on carrying bags of concrete, then I'd probably be more concerned with the height of the cargo deck, but in reality, the purpose of this bike is more to remove barriers to using a bike for getting groceries, carrying a child, collecting firewood, riding to friends houses and taking stuff with me, etc, or doing a combination of those things all at once.

I'll have to see how it goes really. Maybe in the long run I'll end up wanting something like a Bullitt or a MK1E (if the price comes down) but I think this is going to be pretty rad and the right tool for the job for so many things.

 

[leitch]

Sounds good! Absolutely understand not wanting the complexity of a Bullitt style frame build. The Bullitts are definitely the most “bike-like” in their handling though In my experience.

The trikes like that B&B one you linked are comfortable but don’t handle anything like a normal bike - a housemate in London had one for his tools and stuff (did shop fitting for a bunch of trendy cafes/shops) and it was indeed good with all the weight on the wide front axle but it drove like a boat. In contrast another friend’s courier Bullitt felt like a rocket ship.

Could be cool to have a modular thing where you have a platform for 90% of jobs and a “packhorse” solution (hanging lower on either side of the central beam) for the occasion you need to carry heavier stuff.