A flat table is key to building straight frames. Melamine chip board is fine for awhile but it will eventually warp, especially if left outside. Build a long lasting, warp-proof flat table out of reinforced concrete with a poured epoxy surface. Find a mostly flat floor to work on. Lay down a strong plastic sheet (Visqueen) that’s at least 4 mils thick. Continue to instructions
Cable Stop Guide for Bamboo
Causes, Prevention and Fixes
Splitting of bamboo is caused mainly by rapid changes in moisture content of the bamboo. This
can be caused by rapid changes in relative humidity of the atmosphere, or the bamboo being dried
unevenly, or getting soaked and then drying out too quickly. Some bamboo species are more
prone to splitting than others. And thinner walled bamboo is more susceptible to splitting. Lastly,
the septums of the bamboo (those little walls at each node) can cause splitting even if the bamboo
dries out slowly. The septum does not shrink along with the rest of the bamboo when it dries and
it resists, causing a split right at the node. That’s why we drill out the septums.
Another cause of splitting is uneven wall thickness, which is caused by the bamboo leaning at
more than 45 degrees while it grows. Those sections are found in the lower half of the “leaner”
and can split because it dries out unevenly – similar to “reaction wood” in wood working.
The best way to prevent the bamboo from experiencing rapid changes of moisture content is to
properly dry the bamboo and later, seal it with a waterproof coating. The best coatings are two
part automotive clear coats. But special equipment and a practiced technique are required for
those. Epoxies also work but as a water proof outer coating, will turn yellowish from solar UV
exposure and won’t protect casting tape, which also breaks down under UV exposure. Of the rattle-
can sprays, the UV resistant Krylon clear seems to hold up the best. Before coating, it is very
important to sand or peel the outer skin off the bamboo because that is made of a waxy material
that resists any coating.
With bamboo bicycles, riding in the rain can allow water to accumulate inside the seat tube if you
ride without a rear fender (mudguard). Water can splash up to the back side of the seatpost and
drip down into the slot of the seat binder, making it’s way to the bottom of the seat tube, where it
can collect and eventually soak into the bamboo. Preventing water from entering the seat tube
with a silicone sealant at the slot can help. Another method is to allow the water to enter but
provide a drain hole at the bottom of the seat tube for it to exit. The professional method is to fill
the lower half of the seat tube with an expanding polyurethane foam and paint the inside of the
upper portion with a waterproofing sealer. This also seals up any passages between the seat tube
and the down tube.
There are three levels of splitting: minor, small and severe.
A minor split is a very small crack that one can catch with a fingernail. They generally don’t
penetrate to the inside of the bamboo. These can be easily fixed with cyanoacrylate adhesive
(super glue) which wicks its way into the deepest part of the crack. A razor blade can be helpful in
getting the glue into the ends of the crack.
A small split is about half a millimeter to a full millimeter wide. These can sometimes penetrate
through to the inside of the bamboo. They can be fixed in a two step process: First with super
glue as above, that is let dried for a few hours and then the wider sections are scraped out with a
razor blade. The second step is to fill the wider portions with a strong epoxy based adhesive like
JB WoodWeld. This may not work on longer splits.
Severe splits have two main methods of repair: The first is to open the split as wide as possible and
fill the inside of the bamboo with twopart expanding polyurethane foam. Don’t try to compress
the bamboo to close the split. Just let it close down naturally but prevent the expanding foam from
expanding the bamboo by using zip ties or hose clamps. After the foam has hardened, dig out the
foam from the split area and fill in the wall thickness with epoxy soaked hemp fiber or other strong
The second method for severe splits starts with filling the bamboo with the expanding foam but
instead of trying to fill the crack with fiber/epoxy, you overwrap the whole tube with an epoxy
soaked cotton fabric, this covers up the bamboo but can offer an interesting style with various
It’s all about the Bamboo
We offer our bamboo bicycle frames in all frame styles and geometries. We enjoy this flexibility as we do not use forms or molds to join the bamboo tubes. As a result, there is no imposed constraint. We are able to miter and join the bamboo tubing at any angle to support complete personalization of the product.
While they have long been popular with enthusiastic racers and endurance road riders, owing to our bamboo’s amazing strength they are increasingly seen in Cyclocross, Mountain and Touring dress. These bamboo frames are much stronger than the carbon frames so popular in these categories. This inherent strength lends itself to mounting and even integration of key accessories such as racks, fenders and lights. Interestingly, all of our frames, carbon included, are Gates Carbon Drive and Rohloff Speedhub compatible. You can imagine the visual and functional elegance of a belt driven, internally geared bamboo bicycle with matching fenders, rosewood bottle cages, complimentary cork grips and even an integrated rack.
Calfee Bamboo bikes have won awards for Best Road Bike, Best Off-Road Bike and Peoples’ Choice Award at the North American Handmade Bicycle Show. Further, they’ve been featured by Time Magazine, Newsweek, Los Angeles Times, Discovery Channel and the BBC, to name just a few of many. Check out the very thorough editorial reviews from road.cc and Cycling Weekly for some objective feedback from discriminating industry insiders.
If you are in the market for a bicycle frame that is more comfortable, more durable, more beautiful and far more unique than the carbon and metal, look no further than a Calfee Bamboo.
How these measurements affect stability :
Rake and Trail:
Fork Rake is also known as Offset, which more accurately describes what it is: the hub’s offset from the steering axis. Not to be confused with the curvature of the fork blades, which some people think of as “rake”. Straight blade forks can have plenty of offset. Fork offset determines trail when considered with head angle (and the diameter of the wheel). Trail is best thought of as the tire patch “trailing” behind the steering axis. Fork offset for road bikes usually ranges from 40 to 55 mm, generating trail figures from 50 to 63 mm. 57mm of trail is considered by many to be an ideal combination of stability and agility. More trail is nice at high speeds (motorcycles usually have 80 mm of trail) but can feel sluggish at slower speeds.
Head Tube Angle
Also known as the steering axis, this angle influences stability in combination with fork offset by controlling “wheel flop”, or the tendency for the wheel to turn when leaned. A steep head angle is more upright and takes less effort to turn the front wheel, especially if there is too much rake or too little trail. A shallow head angle will want to turn too quickly when leaned if there is too little trail or not enough offset. So most shallow angle bikes have plenty of fork offset to compensate. Head tube angles range from 71.5 degrees to 74.5 degrees. Generally speaking, with a proper fork rake to yield a trail from 55 to 60 mm of trail, the head angles in this range are fairly stable at high speeds. The steeper head angle bikes are a little more agile, or require less effort to steer. People are usually very good at adapting to various head angle bikes if they have the proper trail.
Wheelbase, Weight Distribution and Front Center
Head angle also influences wheelbase and front center, which affect weight distribution. Ideally, a rider should have 45% of the bike + rider’s weight on the front wheel and 55% on the rear wheel. (easy to check with a bathroom scale) During high speed descents, proper weight distribution will give the rider confidence in the turns. Too much weight on the rear wheel (common with ultra short chainstays) makes seated climbing more challenging by making it harder to keep the front wheel on the ground. A long wheelbase is nice to have at high speeds, but if too long, it makes it harder to maneuver in a group of riders or just interacting with one rider. There is no rule of thumb about proper front center. Weight distribution is the key measurement. Some people worry about toe overlap. Front center is a handy measurement to see if a bike will have toe overlap when comparing to a known bike.
Bottom Bracket Drop
BB drop seems to have settled at 7 cm for most road bikes. It’s low enough to provide a low center of gravity yet it’s high enough to allow pedaling through corners without scraping a pedal. 8 cm is used by some builders and can feel more stabile. But the rider should use low profile pedals and not very long cranks. Pedaling through corners is riskier with a lower BB drop.
Standard frame measurement terms
ST: Seat Tube: Measured from the center of the bottom bracket along the center to a point near the seat post binder. The exact location of this point may vary between manufacturers depending on the frame design. The main purpose of this would be as a reference point and, if located at the seat binder, would indicate whether your favorite seat post would be clamped above the minimum insertion line.
TT: Top Tube: Measured from the frame size point horizontally to the steering tube axis.
STA: Seat Tube Angle: The angle of the line passing through the bottom bracket and frame size point relative to the horizontal.
SB: Setback: (used as a more accurate way to measure seat tube angle) the horizontal distance from a vertical line passing through the bottom bracket to the frame size point.
HTA: Head Tube Angle: The angle of the steering axis relative to horizontal.
HT: Head Tube length: The length of the head tube (not including headset components)
How to compare frame geometry:
1: Measure the seat tube from the center of the bottom bracket to the point where you want the seatpost to exit the seat tube. Subtract 1 cm. That is the seat tube length and reference point for the next two measurements.
2: With the bike on a level floor, measure horizontally from the seat tube length point to the center of the steering axis. That is the effective top tube length.
3: If you don’t have the published seat tube angle for your frame and you don’t have an accurate protractor or “Angle Finder”, you can measure setback. To do this, hang a plumb bob from the top tube so it passes through the center of the bottom bracket axis. Put a piece of tape on the top tube to mark the spot. Measure horizontally from this line back to the frame size point. That is the frame setback. Seat tube angle can be calculated from setback and seat tube length or you can simply compare setback directly.
4: Measure the overall length of the head tube, not including any headset parts. Measure the spacers between the headset and the bottom of the stem that you will be using. On a new frame, increase the head tube length by the total thickness of spacers you wish to remove.
5: Measure from the floor to the top of the top tube at the point where you would stand over the bike. That is the standover height for that bike.