How my home-built bicycle trailer lowers my MPG
 

(Originally written Nov. 06)

Just posted a new page at metrompg about...

How the cargo trailer I made for my beater 10-speed bike is hurting my MPG:

http://www.metrompg.com/posts/photos...r-tranny-s.jpg

(130+ lbs: moving two Metro/Firefly transmissions by bicycle.)

Of course, total fuel used is the most important consideration, but since I typically get better mileage in sub/urban driving than I do on the highway, every time I use the bicycle for a local trip, my proportion of highway mileage for a given tank increases, so my overall mileage drops. http://www.gassavers.org/images/smilies/frown.gif

Other than for avoiding crappy weather, the main reason I use the car for local trips used to be to transport something too heavy/awkward for the beater 10-speed to handle.

But with the cargo trailer, I don't need the car for that any more.

So the MPG suffers. (I was going to calculate a figure, but, nah...)

On the plus side, kids seem to love seeing me hauling stuff behind the bike. It's kind of fun hearing them shout "cool! Where did you get THAT?" when I go by.

http://www.metrompg.com/posts/bike-trailer.htm

People always ask how it's connected to the bike...

Same thing as my brother's kiddie trailer - a stout spring, the ends held in steel tube. If you click into the article on metrompg.com, there's a zoom in pic that shows the hinge close up.

There are also some ball-joint type hinges you can make out of (apparently) common inexpensive hardware store parts. See this site for examples:

Community Bike Cart Design - A simple, homemade, low-cost bike cart for car independence and community

EDIT: the cost of my trailer was an afternoon & about $23. Plus I got exactly the size & shape I wanted.

A safety note about construction...

If you're going to weld/braze zinc-coated EMT conduit for the frame, best to do it outside with a breeze (or fan) http://www.gassavers.org/images/smilies/smile.gif

The fumes of the heated zinc can cause "metal fever".

The thing has turned out to be remarkably useful. I never used to be worried about my beater bike getting stolen, but now that it has half the trailer hinge permanently attached to the rear axle, I sometimes worry about losing it.

Just to clarify, yes, my MPG is actually worse now.

Because of the trailer, I use less fuel overall, true (and that's the important fact).

But by omitting some local driving (where I can achieve my highest MPG figures), my driving is further biased towards highway use. As a result of the higher proportion of (lower MPG) highway driving, my calculated MPG for a given tank is lower than it would have otherwise been had I just driven the car locally instead of using the bike/trailer.

http://www.tomswenson.com/images/bob.jpg

These are neat too.

2 downsides I can see, based on my limited experience:

- heavy loads will directly affect the bike's balance, since there's no torsional "give" at the hinge in the "roll" axis;

- related to that - if you lay the bike down, you could spill the trailer contents, since it has to lay down with the bike. So you'd either need a kick stand, or something to lean the bike against when you park

Small points, but there you go.

Cool! Check that bike cart design website. I think some of the designs use a larger wheel, but they offset the platform so it's not at axle height.

Bikes at Work sells just their trailer hitch, but it's $50, and if you can weld you can probably make the same thing for about $12

Anyway they also have a cool bike-trailer calculator that shows you how much you can supposedly carry (in lbs.) on a bike trailer.

And there's even a pic of someone hauling 1000 lbs of cargo on three trailers with one bicycle. I think they used to have a video of the 1000lb haul, but I can't find it anymore.

http://bikesatwork.com/hauling-cargo...e-trailers.jpg

Awesome pic.

I'd think if you were doing 1000 lb hauls, you'd want to be pulling with a trike! Either that, or be a pro at trackstanding.

forget trackstands, I think the key would be NEVER coming to a stop. :D

Darin, if you tell me you had no part in this, I won't believe you!

bikeTV: Bike Move

Tank MPG is down, but Tank TIME is up - how many extra days are you going between fills now? :)

A good trailer is very handy. I suggest a 3/8 inch throttle joint for the hitch and 1-1/2 inch angle aluminum for the frame would help those who don't weld.

A lot! Looks like I only put 2 tanks of gas through the Firefly in 2010.

2011 was more convoluted because I got the UFO. Probably 4 tanks between them both.

Good idea. Had to look up "throttle joint":

http://ecomodder.com/forum/attachmen...1&d=1327415907


I plan to improve my bike trailer this year. It needs some sides on it (or some kind of bin) so I can just throw stuff "in" it, instead of always having to strap stuff ON to it.

two-wheel Designs
 

https://encrypted-tbn3.google.com/im...xyMWJebtowzXfwhttps://encrypted-tbn1.google.com/im...FSbROQQwp-Sgyw

Bicycle Cargo Trailers, Double Child Bike Trailers, Strollers, Bike Trailers, i10Direct, Aosom

I've noticed there maybe a choice of two wheel mounting Designs..
(I don't think the pic above shows an actual 2-sided mount. But, it would look kinda like the right pic)
It seems like support on both sides of the axial would support more weight..?.

It would be nice to have at least a 200 pound load capacity.

I'm trying to figure out how we can haul stuff (like groceries etc), just in case things get worse,
and gasoline becomes more expensive than Crown Royal whiskies.

If I were you I would build an aero-bin, we have a chariot and my wife refers to it as the Parachute and that's with it in the wind shadow of her recumbent trike.

We will only have to go a few miles max, going very slow.
So, aerodynamics (and speed) shouldn't be a concern.

Some of the baby-twin carriers that I've seen on the bike trails look like they might
be able to haul up to 70-80 pounds, so we would need one on each bike for groceries.
I think those units might be pretty light.. Which could be important to an
elderly person trying to push all that metal & groceries up a hill.


I can't even imagine this guy going up hill... :eek:
http://storiesofcreativeecology.file...ghai_cargo.jpg

Even in the 6-10 mph range air drag reduction is helpful. More places are allowing electric motors on bicycles that have a maximum speed of 20 mph. An Xtracycle frame extension with an electric motor or a tandem trike might be options for older couples. What ever the rig, fairings offer energy savings and protection from the elements. See my pictures in the bike pic thread.

Yeah you are right.. I can draft off my wife at 8 MPH.. :)
But, I'm thinking along the lines of something that won't take up a lot of space in the garage.
Some of the factory-made karts can be folded up small, for storage.

I'm starting to think maybe one of these 100 pound haulers:
Amazon.com: InStep Rocket Aluminum Bike Trailer: Sports & Outdoors

http://ecx.images-amazon.com/images/...tL._AA300_.jpg

Keep the plastic covers zipped up and it might be a bit aerodynamic..

I think hauling our food in one of these, would make it a lot safer..
Since not many people want to drive real close to a baby..
Whereas, they will drive very close to regular old people..
(Unless you aren't wearing your helmet).

Yeah, now I remember seeing a few people in Lexington hauling their food in these things!! :cool: