Cargo Rack Bike (Sport Hauler)




Long time bicyclist, bike commuter, bike tourer, recent bike builder/experimenter. I'm an energy ...

You can build a bike out of a commercially available bike extension cargo rack.
Normally this cargo rack mounts behind a standard bike to extent the back wheel 1.5 feet back and makes room for its own large panniers, it has a a wood deck on top and plenty of tie down points for heavy duty hauling.
This project is about minimizing the bike and having a compact "sport hauler" where the rider and passengers all sit on the rack. The rack is the only seat, but(t) it's big enough for a couple of people.

The other two bikes can be seen on my hobby website

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Step 1: Start by Looking at What You've Got

This is the Cargo Bike I was given. The bike frame is too big for me. I had to turn the stem backwards to be able to reach the bars. The stick represents the ground line.
I wanted to make a compact sport hauler where I could sit on the rack and pedal semi-recumbent.

Step 2: General Layout and Cogitating Stage

I lay out various bikes and parts relative to a ground line (represented by the stick) and ponder the possibilities. I try a variety of old damaged bikes form the scrap pile, looking for ones that have the features and dimensions I want.
I used the cargo rack from the big blue bike and the black rear suspension triangle from the Mongoose bike and the front triangle from a different 16" girls bike.

Step 3: Conceptualizing With the CAD System

Because I live in the high tech center of Silicon Valley, I use a sophisticated CAD system in planning my bikes.
CAD (Cardboard Aided Design) employs a full scale cardboard cutout of my: arm length to wrist, torso, thigh, lower leg and foot, crank and area swept bu my foot as I pedal. It has brad pivots at the shoulder joint. hip joint. knee joint and pedal axle as well as at the crank/bottom bracket axle. The movable joints let me reposition it to look at different torso angles (recumbent position or upright or crouched racer position etc. different leg extensions, knee clearance toe heel clearance etc.

A stick represents the ground line and I arrange a few bikes and parts on the ground with the CAD system to get a picture and a feel for the design possibilities, problems, and solutions.

I got the idea for the CAD system from this well thought out design method by
12 steps to design a recumbent

Step 4: Front and Back Triangles Bolted Together

After cutting up the little girls' donor bike and unbolting the rear suspension triangle from a mountain bike I connected them together. I used the seat binder bolt and two 1/4" by 3" U bolts to attach the little girl bike front end to the macho mountain bike back end. ( That reminds me... at Maker Faire a visitor looked at my collection of home built bikes and said it was like Syd's land of the misfit toys from "Toy Story" .) I resemble that remark because I do enjoy combining disparate objects to help people get new ideas.

Step 5: Move Cargo Rack From Big Bike to Sport Bike

Loosening 3 bolts removes the cargo rack and it can easily be moved to the new frame after the shifter cable and rear brake cables are disconnected for the move. It's a great product.

Step 6: Connect Long Shifter Cable and Long Brake Cable

Rear dérailleur (attached to the cargo rack 1.5 feet further back than normal) is fitted with a new long shifter cable.

Step 7: 2 Chains Are Joined to Make a Long Chain

This step is easy if you see the instructable on Using a Bike Chain Tool
Park Tools carries them here Park chain tools

Step 8: Get the Handle Bar Grips Somewhere Within Reach

One method to raise the handlebars up where you can reach them, is to cut a regular stem and weld a piece of tubing between the 2 parts of the stem giving them the big height offset. You can also angle the cut to give you more stem forward or backward extension (called tiller) if desired.

In this simple stem I used a hacksaw straight cut and square cross section thin wall steel tubing the make the stem. I welded both pieces of the stem to opposite ends of the steel tube to make a tall stem.

A non-welded method is to just use very tall bars (like Ape hanger bars, or half moon beach bars turned up) and the regular short stem. You can also buy a stem extension that fits between the stem and the steerer tube.

Step 9: All Ready for Prototype Test Ride.

I can hardly wait.
Notice how compact the new front end is compared to the prior big mountain bike.

Step 10: Shakedown Cruise

The first test ride on the prototype sport hauler.
I noticed the bottom bracket was a bit low causing the pedals to scrape in the turns. So raised it by making some adjustments.

Step 11: Snugging Up the Joint Between the Two Half Bike Frames

The frames are held together by the blue bike's seat post binder bolt and 2 u-bolts.

Step 12: Take It to Maker Faire

I brought it along with nine other bikes to share at Bay Area Maker Faire and let about a thousand people ride them over 3 days in May 2008. People liked the togetherness of hauling their buddies or family around. It also has a faux Harley motorcycle geometry that feels pretty cool. I can't help but make motorcycle noises when I ride it.

Some of the students riding it on Education Day would get up speed, then stand on the deck and hold the bars while doing bike ballet and bike surfing.

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    16 Discussions


    6 years ago on Introduction

    I like the one using the purple kids bike. It has a more comfortable riding position. I think changing to a 20" fork and tire up front would lift the cranks to keep from scraping the ground and provide less rolling resistance from a slightly larger wheel.


    8 years ago on Step 4

    Should have considered leaving it like this just for hilarity's sake.


    9 years ago on Introduction

    I am not sure how this is better than just having a regular bike with a sturdy rack. It looks  about the same length as a regular bike. If you wanted  an extra long seat on  a regular bike you could just add the seat mount hardware to a board and attach a couple or 4 of support tubes  (or even plywood sides) from the board to the rear axle mount.

    2 replies

    Reply 9 years ago on Introduction

    You are right that there are plenty of ways to make bikes, some of them better than the way I make them.  This bike has no separate seat.  The pilot sits on the rack.   Your suggestion of plywood wheel stays is a very workable one I've used on a half dozen bikes that can be seen at 
    One plywood example is the bike in the background.
    I often build bikes to explore ideas, not necessarily to be better than some other design.  I hope they inspire folks to have their own ideas.  Happy building.


    Reply 9 years ago on Introduction

    I did not mean to come off snarky, as I do enjoy the look of the bike, but I just did not understand why it is the shape it is.

    BTW I have spent literally hours being inspired by the bikes your site.


    10 years ago on Introduction

    If anybody is wondering the 'cargo bike kit' used it's an xtracycle. I have just installed a kit on my MTB and it's great... well worth the investment :-D

    1 reply

    11 years ago on Introduction

    Curious, do you not like the company that makes the extended cargo rack? I know they're pricey - that's why I made my variant - I'm just wondering if there's another reason :)

    3 replies

    Reply 11 years ago on Introduction

    I like the product and the way it enables a car free or one less car per household lifestyle. It is very useful! I agree $350 is a chunk of change. But if it lets someone get rid of a car that pays back in 7 tank-fulls alone plus saved insurance avoided depreciation , saved maintenance expense, saved gym fees etc. I offered them a chance to co-sponsor the vehicle with me by providing a used rack. They declined saying they want to position their product as a more serious solution. I plan to approach them again before next Maker Faire on a new vehicle proposal for their fine product. I'm hoping they find what I do helps market their fine product and the one less car lifestyle. Until then the name is omitted to protect the innocent.


    Reply 11 years ago on Introduction

    I totally agree - I've got an instructable on moving house by bike in the works :)

    Not that this isn't a masterpiece but the other day I a coworker said:
    You gotta have the crap pieces before you have your master pieces."

    Perhaps the cargo frame guys haven't heard that in awhile :p But to be fair, their design is well refined and appears to be well designed/engineered (I don't own one, but have used it before).


    Reply 10 years ago on Introduction

    It's definitely a good design. I too winced at the price, but it is so well thought out it is worth the money. I've had one of their sport utility bikes for over a year and am loath to go back to an ordinary bike. I'd have to be a big dummy to do that.


    10 years ago on Introduction

    when I lived in Japan I had a standard housewifes shopping bike with basket on the front and rack on the back. It was way to small for me -6foot /183cms. If I wanted a bike to fit me then I would have had to pay more than $2 for it. no way. so i just took the seat off and padded the rack. easy peasy. I like the vespa-esqueness of your bike


    11 years ago on Introduction

    Your introduction contains a small mistake, I think. You say "You can build a bike out of a commercially available cargo rack." but what I think you mean is "...commercially available cargo **bike**..." I was looking through your project, trying to spot the cargo roof rack... :)


    Reply 11 years ago on Introduction

    The cargo rack has stiff barriers to keep stuff (feet and other valuables) out of the wheels and the company also sells foot rests. I could make some extended foot benches for the whole family. On the odds..., I have not calculated them, but so far so good. The cargo rack is back on a big bike since I use it a couple times per day during "June Bloom" of Dumpster Dipping at a nearby college campus.