Champion Square-back Cruiser

Photo from BMX Museum, bmxmuseum.com

Another dual downtube bike, a rare Champion Square Back Cruiser. This gold and red number is a flashback from the disco era of 1978. The style is coming back though. Fireman's bikes sells a very similar frame, without the dual downtube madness.

Twin downtube bikes exist!

Twin top tube bikes aren't very common anymore, but they certainly exist. A good example are a generation of BMX bikes in the 80's. The twin top tubes gave the bikes added stiffness and allowed the rider to stand on top of the two tubes for tricks.


The other bike that had twin top tubes were Mixtes. The Mixte design began as a bike that could be used both by men and women. The low top tube allowed the ladies to wear skirts and still pedal the bike, but the bike was still stiff and handled well.


Now on to the downtube twins. They are rare, but examples exist. The most popular examples Were designed by Ernesto Colnago, the Bitubo, Titanio, and the Bi-Titan. These were designed to make the frame stiffer.


There were other bikes with twin top tubes, as can be seen in the photo below:



So it can be done. All I need now is a framebuilder crazy enough to try. :)

If the bike doesn't fold...

How do you bring it with you in a bus or train?

I was thinking of using a light bag, to cover both wheels, and the chain. I also take off the seatpost, handlebar and both pedals. This would result in a long, thin package. Here's the idea, illustrated:


I traced over the Dahon Hammerhead so that I have an idea of how the dimensions work.


This is the drawing without the background photo, for simplicity.
Configuration 1 is the "twin top tube option. The front wheel is tucked in between two top tubes, making the folded bike profile slimmer than if the wheel was strapped alongside the frame. The rear wheel is also tucked in between the rear stays. The stay bridge would have to be removable so that the wheel could be tucked in. This makes the front fork stick out, but the bike will be at tis thinnest.

Configuration 2: Twin bottom tubes: if this is possible, this provides a smaller profile because the fork won't be sticking out as much. The question is - will this provide enough structural integrity to the downtube? I know that there are a lot of bike designs with twin top tubes, but I'm not so sure about twin bottom tubes. Must practice my google-fu.

Keeping it Simple...

I saw this commuter earlier. I think he was on a boy's mountain bike - 20" wheels. He was short enough that the bike was still ok to ride. I don't think I'd fit on that frame. I'd need a seatpost that'll be way too long and the top tube will be too short for me. But it's a good example of what I want to get. If I get a custom frame, I'll like to make the following adjustments:

1) Slightly longer chainstays
2) Taller head tube and seat tube - hence the top tube rises proportionately. This makes the front triangle larger.
3) Custom frame bag for the front triangle. This guy has some cardboard box tied with string, which also works.
4) Twin-top tubes, so that I can stash the front wheel in the front triangle for mixed mode travel.
5) Semi-horizontal chainstays so I can run with gears or SS.
6) Lightweight bike bag for mixed mode commutes.
7) Seatpost rack that doubles as rear fenders.

Basically a BMX for adults.

Bamboo Bike Disaster?

Calfree Design's Bamboo Mountain bike
Photo from calfreedesign.com

Craig Calfree sells a Bamboo mountain bike frame for $ 2,700. That's a frame, not a complete bike. For that price, You get a 10 year warranty. Bamboo bikes have been getting a bit of attention - with their proponents extolling the strength, lightness and ride quality of the bicycles.

There have been some DIY instructions floating around the net on how to build your bike frame using Bamboo - and some have taken the plunge and made their own. AllenG, a member of bikeforums.net is one such individual. He showcased his bike on this THREAD.


AllenG's utility bike is a nice design. Long chainstays, slack angles, nice racks. It's oozing with retro style with its brown Brooks leather seat and canvas panniers. Classic.

A few weeks after, AllenG posted this photo:
He wrote: " Wrecked today. If it were made of metal, all I would have done is pick up my bike and keep going. I'm livid, so I'm not sure that I'm thinking straight, however I am thinking bamboo is nothing more than a novelty. I could salvage the frame, but right now, I don't think it is worth the effort."

Maybe he should have used a different kind of bamboo, I'm not sure. But it took a lot of work to put this bicycle together, it's understandable that AllenG feels bad.

Bikes on the Train

Photo Credit: ruralnet.typepad.com

The MRT/LRT system in Metro Manila is really crowded, so I don't think this is possible. I brought a new bike frame into the MRT once, and it wasn't a problem, but a whole bike is sure to raise some issues. In other countries have better policies when it comes to mixed modal commuting, but then again their trains are not as crowded as ours. BMX bikes are obviously smaller than mountain bikes, so I think if they are properly bagged up they could be passed off as luggage. The only problem with BMX bikes is that they ride like BMX bikes, so any long commute they become uncomfortable.

Suspension forks for Minivelo

What if you wanted to build a 20" wheeled bike, and wanted to add some suspension? The problem is that there is a lack of 20" suspension forks in the market. Most forks are designed with 26" mountain bikes in mind. Still, there are some bike designers that shoehorn these large forks with small wheels. It may look strange to some, but it seems fun to ride.

Airnimal Black Rhino

I first saw the idea on the Airnimal Rhino - an obscenely priced, full suspension, offroad folding bike. The rear triangle swings down, so that if you remove both wheels, seat post and stem, you can pack the whole package in a relatively normal sized luggage - such as a regular Samsonite hard suitcase. Good concept, but at $ 3-4000, not really practical.

The main point here is, you can use a readily available 26" mountain bike fork, equip it with disc brakes, and run 20" BMX tires - the frame's geometry just has to be properly designed for it.

There are other examples that you can find on the internet:

Be.Bike Haze

The Be.Bike Haze, a limited production street bike. It was released in japan. About 100,000 Yen - price varies with components. Not as expensive as the Airnimal. It can't fold, bit I think it can be a very compact package if you remove both wheels. The frame is similar in design to several Louis Garneau and Bianchi minivelos sold in Japan. See the LG frame below, with an appropriately sized 20" fork.

Louis Garneau MV5

Kuwahara Gaap Lite

The Kuwahara Gaap, 170,000++ Yen. A similar concept to the Airnimal Rhino. The Gaap comes in road trim as well, sporting slicks and a carbon fork. Looks weird with all those triangles.


The unlikely lovechild of a Cannondale MTB and a BMX. This photo is from a Korean bike forum. The frame could have been a custom job. The frame logo says Cannondale, but I don't think they ever produced this frame.

Design Idea: Dahon Hammerhead & Smooth Hound

Dahon is the world's largest manufacturer of folding bicycles. Their minibikes are awesome! Of course, I'm showing my obvious bias for 20" wheeled minivelos. The frame of the Smooth Hound/ Hammerhead is what I think I'll use as a basis for the bike I'm getting made.

Dahon's '08 models adds break-away capabilities to thier minibikes - that means the frames break apart and can be put inside regular-sized luggage.



These bikes are light and look good. I just wish they were as readily available in the Philippines as they are in other countries. In the UK, these bikes are on sale at Wistanley's bikes. The 06 flat-bar Hammerhead goes for as low as £199 - reduced from £479.

Design Idea: Frame Bags

I need a way to schlep my stuff around. On bicycles, there are several options. You can use a front or rear rack, a basket, a pannier, a sidecar or a trailer. The frame bag is a less common option. If you think about it, a bag that takes the otherwise empty space inside the front triangle makes sense.

Photo: Epic Designs, http://epicdesigns-ak.blogspot.com/

There are design considerations of course. The bag must be custom made to fit the frame. The bag needs to stay a certain width. If it expands too much, it could hit my knees while pedaling. since it uses the front triangle, it's limited by the dimensions of the bike. That obviously means that small front triangles of BMX bikes accomodate smaller bags compared to the larger triangle of a hardtail mountain bike. If I take my existing hardtail mountain bike as an example, I can only fit a 15 liter bag at the most - about the size of an average messenger bag. Big enough for the daily commute, but not enough for multi-day touring.

I think I can use this on Travelo. You can make the front triangle of a minivelo larger because the wheels are smaller.

Design Idea: The Burro Bike

Greg Ruwaka created the Burro Bike to be an eploration bike. In his words, a "hiker, not a runner".

Dirt Rag magazine ran an article about it HERE. They mentioned that the bike climbs well, bit is slow because of its gearing. The small 20" wheels can also be caught up in ruts.

I think it's a brilliant design!

Design Idea: Tony Rentscheler's Scout

I've spent quite some time reading Tony Rentschler's blog. He's a hobbyist frame maker from Brooklyn NY, and he recently built some interesting Minivelo frames. His blog goes into detail on how he designs and builds his bikes, as well as the ride quality of the different builds. He's built four minivelo frames in a short time, and I particularly like his last bike, the one he calls "Scout". Scout, as typical for minivelos, is based on a compact design, with 20" wheels, and a slack head angle.

Scout. Photo by Tony Rentschler http://web.mac.com/w.rentschler/Bicycle_Site/Blog/Entries/2007/12/18_Scout%3A_Tale_of_the_Tape.html

His blog is an outstanding resource on bike building and minivelo geometry.

The only change i would make on the scout is to make the headtube and seat tube longer. This will bring up the top tube and give a bigger front triangle. Other than that, Tony's Scout is perfect.

I think this bike project needs a name...

For lack of a better name, I think i'll call it the Travel Minivelo, or Travelo for short. Just something I made up as I was typing up this entry.

I want a new bike

A New Ride

I'm planning to get a new commuter bicycle that can be used in mixed-modal transportation. There are several small bicycles in the market, but so far I'm not yet convinced I've found the bike for me. So what's the bike I'm looking for? I've thought about this question a lot, and Ive drawn up a list of requirements.

The new commuter bike I'm looking for needs to be:

• Affordable - let's face it, I'm cheap. I am willing to pay a bit for a good quality, durable bike, but there's a limit to what I'm willing to pay. Right now, the budget is still a moving target, but I'm looking for bang-for-the-buck deals.
  
• Comfortable - good fit is essential. I should be able to stand while pedaling and be able to ride for long enough distances. Speed isn't a primary concern right now.
  
• Small enough to be brought on public transportation. I'm thinking 20" wheels should do the trick.

The Goldilocks of bikes



I already have a steel hardtail mountain bike that's a decent commuter. I like riding "The Haitian". That's the bike above. The photo was on it's first ride as a commuter, and I've added a rack and fenders, and tightened up the slack chainline. It's a comfy, low-key single speed That I can pedal for hours. Its not particularly fast, but as a commuting machine it's just right. I just cant pack it into a small enough package that I can easily bring the bike with me on the bus. Sure, I can take off the wheels and put it into a bike bag, but the package is still too unwieldy.

On the other hand, I also have a small blue folding bike with 16" wheels, a Dahon knockoff that I call Cooper. It's not too bad to ride as long as the roads are smooth. The short wheelbase of the folder makes the ride twitchy, and it just won't do on gravel roads (I've tried). The long stem flexes and feels like it's going to shear off. It also has a hinge in the middle of the frame that makes the bike a bit unstable.

The bike I'm looking for is a mix of the two bikes I already have. As comfortable and reliable as The Haitian, with the size of Cooper. At a price I can afford.