Lowrider Bikes

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How to build a sidecar

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How to build a sicecar
You will need :
A complete bike
Extra fork and wheel
3 feet of 1/4 x 1-1/4 – inch steel flat stock
3 feet of 1/8 x 1-1/4 – inch steel flat stock
10 feet of 3/4-inch EMT twin wall electrical conduit
Two 3/4-inch conduit clamps
A 26-inch piece of 2″ x 4″
A Sheet of 1/2-inch plywood
An 8=foot piece of two=by-three
Nails, screw, nuts, bolts, etc

This sidecar rig is a favorite of mine, It will do anything the ice cream cart three wheeler will, and
it will outride andouthandle. Best of all, you don’t have to butcher a good bike to build it. When you get tired of it you can unbolt the sidecar and still have a solo bike.While it doesn’t require welding. It’s tricker to build because it takes some hard bending, and a lot of trial and error to get everything line up tight.But unless you must have a box in front three wheeler, give this a try first.

Putting a sidecar on bicycle is difficult because you have to leave room for the pedals to turn, which doesn’t leave many place to attach the rig. This design is adapted from a 1919 copy of Thr Boy Mechanic and would be a real knockout hooked up to an old American clunker with spring forks and a fake gas tank. painted up it would be great advertising ffor an ecology-minded business. Start by attacking the extra fork and wheel to the bike’s back wheel with a strut. The 1919 version used an elegant truss, but a two-by-four is a lot simpler.

How to build a sicecar How to build a sicecar

Two struts made of 3/4-inch EMT thinwall electrical conduit pipe (get it from an electrical supply shop or large hardware store-it’s cheap) run between the bike frame and the sidecar fork, and are attached with clamps bent from 1.8 x 1-1/4-inch steel. Make the clamps first, and bolt them loosely in place. Then, after checking that the sidecar wheel is lined up right, measure and cut the conduit to fit.

How to build a sicecar How to build a sicecar

The sidecar body is made of 1/2-inch plywood nailed or screwed to two-by-threes. The front of the box must be angled to match the front dtrut. Thr middle strut has to pass through both side of the box, so when you’ve got the plywood pieces all cut, assemble the body loosely, minus the two sides, and put it in place on the bike. Carefully measure where the middle strut goes, and cut or drill holes in the sides to match.

How to build a sicecarHow to build a sicecar

Once the body is finished remove the middle strut and fit the body to the frame, then refit the midle strut before fastening the body inplace. The front of the body is bolted to the front strut with two 3/4-inch conduit clamps (get these where you get the conduit) and the back is screwed down to the two-by-four axle strut.

How to build a sicecar

Use brackets bent from 1/8 x 1-1/4-inch steel to fasten the middle strut to the body where it runs through it. Dont forget these, because they stiffen up the rig considerably.

That finishes it, although some paint would look good on sidecar. You’ll probably have to do some fiddling with the gear ratio to get the rig to pedal easily.

Riding the Sidecar RigRiding a sidecar rig is different, to say the least. Steering a regular bicycle is done almost completely with your body. you dont really use the handlebars much, and as often as not tey’re turn in the opposite direction of the turn (try it if you dont believe me!). There’s no such subtlety in steering a sidecar rig. The bars are turned-hard-in the direction you want to go-which is very spooky, because it goes against everything you’ve ever learned about riding a bike. When the rig corners it doesn;t lean, although you can lift the sidecar wheel if you try. if it’s cornered too fast it drifts (skids) or flips-just like a motorcycle sidecar! To make it even more confusing it’s asymmetrical-the two sides are completely different-so it will behave different depending on which way you’re turning. All this makes riding it very strange at first, and fun!

How to build a sicecarHow to build a sicecar

Troubleshooting – The sidecar whell may not stay in alignment if the clamps on the for stem are not a good fit. the surest fix is to have the clamps welded to the stem so it can’t twist. If welding isn;t available drill through the clamps into the stem with 1/8-inch drill and use a self-tapping metal screw to pin the stem in position. Be sure it’s lined up right first.

The more rigid a rig like this is the beter it will work. If it flexes too much try running another conduit strut from the clamp on the seat stay to the two-by-four axle strut, and fasten it with a 1-1/2-inch #10 screw. This can be a short one attached to the strut next to the box and be attaceh at the far end.


Written by qtechmaria

November 28, 2009 at 4:10 pm

Posted in How To

One Response

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  1. very cool design! Popular Mechanics has one using a front fork too, but the instructions and pictures are missing.
    The sidecar pictured is a different design. Any pictures of the one described?

    I really like how the 3rd strut is mounted directly to the rear wheel, and not the frame. It seems it would be less likely to bend the rear frame in case of an accident.

    I am wondering about how to make it lean…

    Another thing you could use for struts are shock absorbers from a car\truck, even used ones. The ends already accept a bolt. What if you bolt the struts to the bike-side of the car, and make u-joints out of the clamps? Using just struts #2 & #3 would keep them paralleled. Or make a long 2 seater and use all 3 struts square to the bike and car, lol. A crossbeam would help prevent the struts from twisting. And let you mount something useful, like a cup holder or basket.

    Thinking about shock absorbers… How about a front fork from a mountain bike? It would serve as a cushion for the sidecar occupants.

    Easy seats for kids would be car seats or the boosters with the seat backs.

    Thanks for the post! -jag


    January 6, 2011 at 9:34 pm

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