Sporting Wood

better shot: http://www.flickr.com/photos/fastboy/2120672515/

i think wood — some wood — is more resilient than you give it credit for. think bows, and suspension.

Just give him some wood and he’ll build you a cabinet.” - Finger Lickin’ Good, Beastie Boys

Todd,

Isn’t there a bamboo project based in P-town?

Woods like Bamboo are very hard and I would trust it… not sure about the weight. I might prefer it over carbon…. in terms of safety.

I know…I know…

My degree is in Materials Science Engineering. We did plenty of materials selection excercies for an array of uses. In almost all of them - “wood” was a top performer. Anisotropy results in some very desireable material properties.

“I might prefer it over carbon…. in terms of safety.” I love it! Shouldn’t wood laminate be strong enough for anything, if you can build longbows out of the stuff? Is it going to have the properties you want: i.e. be like steel, but lighter?

Here’s the thing - anisotropic materials like most hardwoods do really well disipating high load and shear. What they don’t do well is handle high loads over a short period of time. They deform (like in a longbow) nicely as long as the load is applied at a rate slow enough for the material to deform properly.

For a handlebar: potholes and other hazards would impart a load very quickly and therefore may cause localized stress - since the wood is unable to deform in time. Introduce a stem to concentrate the area of the load, and potentially introduce crack propegation…and you’re F@#$@$d.

I remember seeing a re-creation of the Wright brothers shop with their homebuilt wind tunnel. A period bike, parked nearby, had wooden handlebars. I think they might have been one of the lightweight parts the Wrights built and sold in their bicycle shop.

I would guess that wood lost out as a handlebar to metal for economic reasons. The bar I saw was steam bent, the grain followed the curve of the bars. The wood would have to be knot-free, tight straight grained, and it would have to be turned or shaved into a rod that had no grain run-out. Then it would have to be bent to shape. So, there are a lot of processes that require attention at each step. Metal bars would be much easier to make in an industrial environment. It probably didn’t help wood that it expands and contracts with humidity, requiring tightening of the stem, and that it would require periodic refinishing.

If you want to see how far you can push wood as a structural material, for transportation, check out “The Splinter” at www.joeharmondesign.com.

Andrew:

Then I’d choose handlebars made of the same wood as professional baseball bats.

Having seen the insides of a carbon bar, after it got garaged, and realizing the industry lacks any governing standards, besides the CPSC, material choice is def a concern. I don’t want to pop off too much about it, as I’m no engineer, but I do wonder if all those Chinese parts are safe.

I don’t mean any company is intending harm, but without robust testing, who knows.

We’re specin’g the latest bike hugger project bike and giving lots of thought to what could break and not break — that whole, when is light too light. Also, carbon for stems and posts ain’t always that light.

True Chris - provided we go from 31.8 stem clamp diameter to 63.6 I’m sure it would be fine :). I’m sure you’ve seen what happens when a pitch comes in on a hitter and they make contact on the thin portion of the bat? That’s that part I don’t want to be around for.

I don’t think hitting a pothole or jumping a curb comes even close to having the same kinetic energy as a pro pitcher’s fast ball hitting a bat swung by another pro…

We’re not talking about jumping off cliffs with MTBs here, are we?

Yeah - I’m sure it’ll be fine, but when I have my hands on the bars and hit a pothole I’m not expecting it can be pretty jaring. But you are right: MLB Pitcher/MLB Batter force is much greater that even the biggest pothole.

I can’t tell from the pic what the diameter of the bar is, but remember that the material is r^2 so a baseball bat has a good deal more wood to help dispense the load.

also, a baseball is not concentrating the force like a stem would. College baseball uses aluminium bats….they last, wood bats break. MLB uses wood for tradition and the because the “sweet spot” for wood; batters would hit even more and farther with aluminium.

maybe handlebars are just too light nowadays. in the old days, if you crashed your Cinelli 64 (340gr) and it bent slightly, you could probably bend it back and ride it for years without it breaking. Today if you went down hard on even a lightweight aluminum bar (sub-220gr), replace it if you see a visible bend. A bend implies that a fair bit of energy went into the bar, possibly forming tiny cracks. If a crack forms, it just travels so fast in today’s thin-walled tubing. FORGET about bending something back.

Right. That’s like when your hoods would get banged up in a crash, you’d just hit them back into place on a bar. Not anymore — you don’t want to score the carbon or even aluminum.

Wood handelbars and a set of Big Apples on a Flax carbon bike www.museeuwbikes.be, could be a good combo, snappy yet pliable.

i am very intrigued by the wood handlebar - so much so that i am going to make one. when you consider the impact loads absorbed by wood hammer handles and more so axes and splitting mauls, i’d reckon that a good hardwood handlebar could take a heap of abuse… but i am almost as crazy about wood as i am about bicycles (and fixed-gear off roading). cheers, chris