A lightweight rack, mocked up
~95 grams as it sits right now, but it’s got temporary rack tabs so I can do the final adjustments and then braze together the tabbed lugs I’m going to actually be using. The carbon fiber tubing I’m using on this has all the fibers running longitudally, so it’s very strong in tension and compression, but I’m worried that if I put a heavy weight on it I’ll crush the tubes. So it’s going to be a rando-only rack (I’m going to build another one out of 7mm tubing for general use, and I’ll wrap the tubes with a single diagonal wrap of fabric to reinforce it) until I forget and destroy it.
The bicycle this is going on is going to be a di2 machine, so the right rear interior rail lug is extended far enough to hold a couple of threaded eyes to attach a di2 battery or regulated power supply.
The main structure of the rack is stainless steel (lugs) & carbon fiber tubing. The backstop is lightweight aluminum (this is why it’s not a tombstone; the aluminum is sturdy enough to handle the bag if it’s a fairly low & wide semicircle, but a tombstone is narrow enough so that if the bag starts slithering around it it will start bending. But in any case I’m going to use rubber cement to fit the backstop onto the deck, so if I am wrong I’ll be able to extract it and replace it with a new one made of stainless steel or carbon fiber.