Originally Posted by
ljsense
What would the best way to lengthen a carbon steerer, I wonder?
I've been reluctant to use clamp on tube extenders.
However, within reason, one might use an upward angled MTB stem.
As mentioned in
Post 22, I'd probably go with an insert similar to the OP, but design a fairly thick walled carbon fiber insert. Of course, you get something fairly small with the 1" forks.
Move the splice to somewhere mid-head tube. That makes it harder to inspect, but I believe that it minimizes sheer forces.
I'm not sure of tubing source. Carbon seat posts, carbon tubing, used forks, one size smaller, or make a custom carbon tube for the splice. Or, perhaps a combination of methods, for example sourcing a thin wall CF tube, and either building it up on the inside or the outside.
Once spliced, grind down the but joint, and build that up too.
The discussion about plywood above brings up a good point. Fibers running inline with the steer tube are good. Fibers running across the tube help maintain the form, but otherwise don't add strength. So, use a judicious mix of longitudinal fibers for strength, and cross fibers for structure.