El Arbol will not be the first tandem tall bike. Check out this lamplighting bike from Chicago at the turn of the 20th century. Read the Full story here:

http://www.rat-patrol.org/Archives/Eiffel.html

Or how about this family contraption, complete with treddle-powered sewing machine:

Thanks Flickr friend Whymcycles

More recent but also notable, from Chicago Critical Mass, via Georgeaye. The photo has been viewed 4500 times on Flickr.

Above: 36-spoke front and 48-spoke rear wheels with sealed-bearing hubs mean fewer popped spokes and a stable ride when carrying passengers and heavy cargo.

With a max payload of 440 lbs, the Mundo is still the heavyweight of the long-wheelbase cargo bike world. Riders have raved about the predictability and surefootedness of the frame, which become all the more apparent when the bike is loaded down. The 48-spoke tandem-strength rear wheel with its new sealed bearing hub and oversized axle, is a big part of why the Mundo feels so stable when hauling loads.

Above: 4 strap guides keep straps from slipping, and 24 threaded customization points make it easy
to mount running boards, locking equipment cases, custom equipment racks, and Mundo accessories.

The chassis-style loading system has evolved, with welded strap guides, ensuring your straps won’t slip from road vibration. The Mundo is now easier to customize to your unique cargo applications. Threaded braze-on points positioned throughout the cargo rack allow customers and businesses to integrate specific cargo racks, signage, tools, etc. Yuba’s huge and water-resistant GoGetter Bag is a great way to carry smaller and softer loads like food.

Rock The Bike uses Mundos to haul music equipment to their Pedal Powered Stage events.

Bigger kids can sit directly on Yuba’s top deck, and rest their feet on the bags or the Side Loaders. The Mundo’s new customization points make it easy to add full-length running boards to the Side Loaders for a stylish and secure footrest. And as the kids grow up, they’ll be able to ride the same bike mom and dad used to drop them at school. The Mundo’s low standover height and long seatpost accomodate riders from around 5′ to 6’3″, and the adjustable stem can be positioned to give the desired room in the front.

The welded and reinforced rear rack offers chassis style loading for rigid objects like equipment cases.
Previous generations of Mundos had a bolt-on rear rack.

Bike shops and home mechanics who assemble the new Mundo will love the simplicity of assembly. The all-welded cargo system and full-size carton means the build is now well under an hour, with most key parts (derailleurs, brakes, cranks) installed at the factory and in need of only minor tuning.

The V3 Mundo starts at $1099, and includes fenders and a sturdy side kickstand. Most customers will add the $115 GoGetter bag, and a $16 pair of cam straps. A cargo-strength center-stand will be available in early 2010.

My dad’s been suggesting that I test ride El Arbol as soon as possible before sinking the hours into custom fiberglass work on the trunk, roots and branches. Not a bad idea.   OK, so it didn’t have brakes or pedals, but at least now the frame has at lease now been heat treated.

The ride was great. Tall bike people know that a tall object can actually be easier to balance. The classic example: try balancing a ruler in your palm, then try a yard stick. As you can see in the photo below, El Arbol is about a foot taller than Jay’s tall bike, part of his BayView Space Agency fleet. This makes it easier to balance at slow speeds.

On my first coast, I mounted using the hood of a pickup truck and had Ydran and Adam give a running push in the slightly downhill direction on Channing. The ride is solid. No noticeable frame flex, and that’s before the added stiffness of the fiberglass trunk and branch. The balance was easy, even at slow speeds. I only one little adrenaline jolt on the whole test ride, when I took a roundabout and experienced rapid decellaration. By the end I was doing my own running starts and dismounts in both the uphill and downhill directions. It was Adam’s idea to jam some pipe in the captain’s bottom bracket. That was hope stepped up and down onto the frame, as you can see above.

I had been a bit concerned that the small wheels that originally came with the A2B would make the ride twitchy or sluggish, but it was neither. The traction was great, ans slow speed manuevers felt smooth.

I knew that Jay was leaving for his honeymoon yesterday, and that Tuesday would be our last work session. We welded in the cable management for the root-deployment system. I’ll post more photos soon.

On Wednesday I borrowed a truck to get the frame over to Garner Heat Treating in Oakand. The guys were totally pro and enthusiastic about the project.

Apparently there are two ways to restore strength to an aluminum frame after it’s been welded. The more involved one heats the frame to within 30 degrees of liquid, which leaves the frame soft and succeptible to bending under its own weight. Typically at this point bike builders put the frame back in a jig to check alignment. Because El Arbol is a giant frame and a one off, there’s no jig. So we chose the other method, which brings up the frame only to about 300-400 degrees. This method stress relieves the welds but not to the full ‘T6’ strength of the aluminum. With the average wall thickness of El Arbol’s frame being much greater than that of say a Cannondale, I’m not too worried about the strength being compromised.

After bringing the frame back to Rock The Bike, I waited till about 6 last night before ditching the computer and throwing parts back on it. We tied the roots against the frame, since the deployment system isn’t ready yet, and I through an Envy Green Down Low Glow on the bottom tube. Lots of props from the neighborhood, a good omen!

Metrofiets cargo bike scores pottery wheel! Imagine the possibilities — a mobile pottery session / performance ride.