I've designed and built a number of high speed wood watercraft. I started with some known stresses and the DA Wood Handbook and just calculated the heck out of it. I suspect that there's no published stress data for road bikes. You might think about reverse engineering a metal road bike, cutting it up to get sections. Wood isn't isotropic which is both its huge advantage and the difficulty of engineering with it. Grain direction and species are very important. Custom carbon is much easier because on can simply add tows if an area isn't stiff enough. Wood is a little bulky for that.
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