Wednesday, April 15, 2009

Welcome Katreina's readers

First we'd like to welcome all of our sisters readers from HOME POWER. HI, you know a little of the back story so this post won't be to weird I hope. Both Fritz and I have been working independently on the deeper (psychological) side of sidecar construction. So what I'll do is lay out Fritz's philosophy first and then mine. So if you got questions just ask.


It is a difficult task for some to be creative. Creativity is not something that can be forced, it must be allowed to flow. If this sounds esoteric, it is.

For us, the designs are developed separately in our minds, we think the problem over. We ponder the small details, consider absolute necessities, make running changes and formalize individual concepts. Then we get together and discuss our ideas. Simple sketches are used to relay specifics. In this process there is a lot of listening and verification that we really are hearing what the other is proposing. Occasionally a thread of thought will arise, we will follow it (allow it to lead us for a while at least).
Part of the process is to reject or retain an idea or concept. This is where we list to each other the plusses and minuses then reverse roles. Our egos have to be prepared to let go of a cherished concept or embrace one that didn’t look that good before. Sometimes one of us will talk himself out of a pet idea.

We lay out to each other any new specifics that are unique to the current project. It is already agreed that features which have proven themselves in the past, will move forward without contest. If anyone of these proven concepts must be discarded that requires special justification. We are then to the point that an outline of the new concept in clear in each of our minds and there are very basic sketches of features and general shape.

For the current project the outline is;
24 inch outside wheel
60’s industrial styling (think Corvair/BMW 2002) with a little Frank Lloyd Wright thrown in
Large tray wrapping around the front
1 inch aluminum tubing
Outside or sidecar wheel covered on the inside (open to the outside)
Outside wheel removable by lowering through frame
Entry way ahead of side car wheel
Rear rack/seat
Brakes at all three wheels Sequential rear brakes
8 speed internal rear hub (geared down)
Laminated wood deck
Detachable side car
These are not written in stone.

At this point we begin the wire frame model. As we progress on the model there are opportunities to add or revise features that present themselves, such as integrating a lock box or shelf inside of the side car. This concept went through three revisions to date. Trying bent shapes and their spatial relationships, merits and faults are a good use of the wire model phase. It is also where, once the general shape is solid, details are tried for how they look or fit.
Now the styling begins to show through. The fact is that some things just look wrong and minor adjustments in shape or placement can make them look right. Let’s face it, how something looks is very nearly as important as how it works.
In the case of the Proto III we visualized a top rail that was a flowing line with no interruption. In final form that flow was integral to its personal style. It is interrupted in a few places, but done so that the eye is not drawn there. That top rail really is three tubes. That reformed shape is still in functional, i.e., high inside wall, high front, rearward leaning tail fins. We didn’t know exactly how these things would be until we did them and that’s the magic of creating new ideas.
The entry opening was a feature that I, Heinz didn’t want. It would not be as clean and flowing as my wire model original. Fritz was adamant, it needed a door. I was also worried about it’s compromising the strength of the basket. We argued the merits/ disadvantages. I drew a sketch of it with a possible entry shape, partly to show Fritz how bad it would look. Problem was it looked good, very good really. I hate that, but then I love it too. That means it was obvious that we just needed to ensure that the doors shape was one that retained the baskets strength. We did this by using large radius corners and outward leaning side elements.
In this phase questions are answered, but more questions arise as well. You can define creativity as addressing all these questions. By allowing the mind to “turn over” these ideas while driving, working, riding the process tends to move along. And, when looking at the world around, if you can see analog designs and how you could use them is also beneficial.
I’m not saying copy things, I’m saying be mindful of what’s already been done.
Sometimes a single concept is a jumping off point for a whole new design concept or cleaver feature.
Recently while looking at the Proto IV wire model a thought came to mind for the front basket design. It was to try a front opening shape akin to a F16 intake mouth or a 427 Cobra front opening; a slanted forward loop with a stay that has a flowing shape rearward from the leading edge. Putting this on a wire model will tell us more.
(look for this on Proto V, along with a tailgate)
It can not be illustrated enough that if one feature can be solidified, or even quickly sketched, then sometimes an entire concept “grows” from that. Conversely remember if a concept is too difficult to integrate or even looks wrong you must be prepared to discard it.
Making a second more detailed drawing, after the general shape and some details are solid on wire model, is much easier. This will also be more realistic in terms of the appearance of the bends, the proportions, and the drawn relationship of the tubes. This makes it easier for us to visualize how we need to change the wire model to get the look and features we want.
It is then a continuance of trying bent shapes previously visualized or thought up on the spot while pondering (starring at) the wire model. Options present themselves and they are used or not and the secondary details like shelves, bracing, floor design fall into place. We will discuss the merits and drawbacks of any newly found feature. Refinements can occur in this phase without working on the model.
Then back to drawing single features or trying bending shaped and simply holding them up and moving them around until they “look” right.
When we arrive through trial and error on a model reflecting the features, function, style, and construction that we like, we stop and think the whole thing over for awhile. We discuss details of features we have named, maybe make physical changes but generally get prepare to render the model in full size tubing.
This is as much as we can articulate on this subject, at this time, just remember, that it’s a process that takes time, mindfulness and effort. Look to just about anything for inspiration, ask questions, think out loud and do whatever you need to do to move forward. Don’t be afraid of perspiration.
Thanks Heinz and Fritz.

Our beliefs on Sidecar Bicycles

Having some experience with cargo style sidecar bicycles (please note all of the qualifiers) we may be able to help you conceptualize your vehicle.

First let us think about widths, over all, wheel to wheel, basket and pedal clearance. I’ll work these backwards so we wind up with the overall. I have a size 12 wide foot and I like toe clips so for me a centerline of the bike frame to the centerline of the inside basket frame tube of 10.5 inches gives me the clearance I need. Next I chose a basket width of just over 2 feet, this width allows a standard width wheelchair to fit inside (25.5 inches) and a bike wheel to sidecar wheel distance of 40 inches, because that allows me to ride on most standard sidewalks. Adding all this up gives us just under 4 feet for the total clearance width (Left pedal to outside sidecar tube) the handlebars can be rotated and the vehicle can squeeze through most cycle path barriers.

Our platform is 5.75 inches high in back (so dropping off a curb you do not drag) and 6.75 inches in front so when it gets loaded it dosen’t sag. It also has a 52 inch long platform of which 40 inches is flat (the front lifts slightly). The outside wheel axle center is about 3.5 inches forward of the rear wheel of the bike. On the White Wizard the outside wheel is more forward and that did not work as well (the balance when loaded seems off).

The Blue Ferry has some features that are extremely nice. The elevated inside wall keeps riders hands away from the pedal action and the entry opening makes it much easier for limited mobility riders to enter and exit. The rear rack (20 inches long behind the seat tube) is strong enough to use as a jump seat and forward rake on the front of the basket (29 inches above the ground) keeps people in crowds from getting there heels clipped (they may get bumped by the basket if the driver is not very careful).

The White Wizard has a superior design (by comparison to Old Grey) for deflecting objects struck by the right side of the vehicle The angular clipped outside front corner of Blue Ferry is even a better improvement, that space is almost useless for cargo and inhibits right hand turns. The inside corner is clipped back also giving more room for front wheel clearance.

All of our vehicles have permanently attached sidecars and they are attached at 2 points both front and rear. We also attempted to triangulate our attachment points as much as we could. Strength and dependability have been proven out by Old Grey having used it for ten years now.

The wheels are one of the most important features of the bikes. The side loads compared to a regular bike are incredible. Heavy gauge spokes and high quality rims (not necessarily the lightest, thick single wall aluminum rims in 1.75 width from the early 80’s by ARAYA or UKAI have worked well for us)) are obvious, but strength is also gained by using thick wide spaced flange hubs and a three or four cross spoke pattern. 36 holes or more is a great idea; in fact the 20 inch outside wheel on the Blue Ferry is a 48 hole.
Pre-stressing the wheels when they are first built is a process that requires the wheel builder to lace up and true the wheels, then put the wheel horizontal to the ground and gently press down on the rim with hands opposite each other, rotate wheel 45 degrees and press again, do this until you no longer hear spokes seating, flip it over and repeat the press and rotate trick. True the wheel and repeat press and rotate on both sides. While this seems like a lot of work to go through, Old Grey has had the same set of wheels for almost 10 years of hard use with no distortion or loosening of the front or outside wheels and only 6 broken spokes on the rear. We lost the first set with in the first week. Another trick to strengthen the wheels is to tie and solder the crosses. That is wrapping a thin wire around each place the spokes cross in a criss-cross pattern then solder the wires together

Along the same line is tire choice. You should choose tires before welding frame to bike, a different tire size could tilt your bike left or right or your sidecar forward or back. Be sure to consider wear when choosing tires a flat profile tire (of the same compound) will wear longer but a round profile tire will have less rolling resistance. Another thing, that outside wheel is going to run into things at speed with weight. To prevent rim pinches we took a thorn-proof tube, slit it along the inside center, cut out the stem and pushed it up into the tire. We then put in another Thorn-proof tube and (carefully making sure the bead was well seated) pumped it up to over 75 PSI. Coincidentally higher pressures will give you lower rolling resistances and won’t flatten when loaded. We use the tube-in-a-tube idea for our main wheels to and run them over the rated maximum pressure as well.

Gearing up does not seem that important (speeds over 25 MPH start to get weird, I have had Old Grey up to 28 MPH with about 150lbs in the sidecar, more on that later) but getting a low enough gear to pull a heavy load up a hill or across a field can be a trick. We used a (compact drive) double chain ring up front (the third chain ring is used as a chain guard) and the largest rear sprockets imaginable. The two largest of the rear sprockets are close spaced with a gap before descending regularly down to the highest gear.

We are not completely satisfied with the brakes on our bikes. We think they need killer discs. But we do have an arrangement of brakes that we do like. That is using the left hand for the front like usual, but on the right hand we have two levers the upper one controls the rear bike tire while the lower one controls the sidecar tire. Sometimes you want to brake one side only. There are other arrangements we will get to later.

So you can see that this is no ordinary bike, If you thought you were going to hook a cargo platform up to (just any old bike) and load it up to the max, you should probably head back to the drawing board and do some revisions. Mind you I’m not saying it won’t work but in our experience if a problem can crop up it will be at the most inconvenient time, so don’t just look before you leap think about how you want to land.
Thanks again Fritz and Heinz

1 comment:

JR said...

I am sincerely looking for a mini sidecar for my electric bike (Kalkoff Pro-Connect wave) for my 22 pound dog. Really! Surely you guys have fulminating ideas? please let me know and I'll commission one! Thanks,
Austin TX