Carbon bike 2, this time with suspension

Many years back I built a carbon hardtail frame.

Now after about 20 designs and hundreds of hours of debating every option, but never just doing it, I have dove into the build. I am not 100% sure what the final product will be, but it’s only carbon fiber, how bad can I screw it up? :joy::rofl:

Rough specs should be;
Single pivot
140mm ish travel
27.5" wheels

I will be using a head tube, bottom bracket and seat tube scavenged from a scrapped Trek Slash to speed this frame along, and reduce the amount of molding needed.

This time I am trying a method similar to metal framebuilding where I will make all the tubes individually and then build them into the frame. I might fail miserably but there is oly one way to find out!

I am in the process of building all the tubes now. I have the top and down tubes roughed in and the seatstays rough formed.


Cool, excited to see how all this plays out!

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Scavenging the bits I want from the fancy frame.


Pro tip: you can burn off the epoxy resin of small coupons cut out of the frame. Afterwards you can pluck the different layers appart and see the stacking order and fiber orientation. I’d recommend making rectangular coupons with the long side oriented along the tube so it’s easy to identify the main orientation after burning. If you have a precision scale you can even determine the surface weight of each layer to a surprising precision.

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Got some time to make progress on the frame tubes. I got the intermediate seat tube laid up (carbon over foam with compression wraps), and one of the experimental rectangular chainstays (rectangular molded pvc tube form with inner tube pressure). We’ll see how bad they look tomorrow!

Video links:

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After cleaning up the excess epoxy, it isn’t too bad for a 1st rectangular tube. Still have no idea what I am doing, but I am still somehow making progress!


After a short delay to have my shop flooded and do necessary plumbing repairs, I am back to making funny shapes in carbon. I got a 2nd rectangular chainstay made and have the center of the seattube roughed in.

So that completes the main tubing for the frame, now on to the weird bits.

Next up is somewhere for the pivot bearings to live.

Not too bad an attempt. I’ll make a few layup changes for the 2nd side and possibly redo the 1st


Hell, it is damn near done! Just a couple of last things…


Thanks to Paragon Machine Works I have some beautiful dropouts to work with, and can continue building.