Cervelo P-Series Rear Bike Box

UPDATE: I had a mount failure with the box just before the 70.3 in Galveston yesterday. The box and lid are great, but the seat post mount cracked near the GoPro mount and on the side. This was not during the transport of the bike (which was bumpy) or on any of the rides I've done, but rather when it was sitting on the tri rack overnight. I made some changes to the diameter of the mount, and also increased the infill to 100% and it is very strong now - I know some people scoff at 100% infill and never recommend going over 60, but I'm telling you that 100% is stronger and I've done some serious road and stress tests and it's good.

I've designed a 3D printed rear box for my Cervelo P-Series 2023 (56cm). This is version 10 of tests and trials, and incorporates a rear light on the lid (fits the Amazon - Zewdov brand with rubber strap to hold it on, but most rubber band lights should work). I also have a lid version without the light mount. The lid is held on by 4 magnets that are epoxy'd in place (2 in lid, 2 in the box), and the post mount is a design that I saw for another self-made 3D box where it uses a go-pro style mount which I thought was a great idea. The "weakest" part of the whole build is the post mount, and if that cracks for some reason you can just replace it without having to get a whole new box. I printed all parts in UV-resistant ASA (with a good amount of infill especially on the mount), and used stainless hex screws and nuts. I have done a sprint triathlon with no issues (and am about to do a 70.3 in a couple weeks).

The box fits at least a bike tube, two levers, two CO2 cartridges and valve, and a small rag which is what I like to ride with. You could lose a C02 cartridge and put your multitool in there as well, but I like having my multitool up front in the center box for quick access, and I keep a spare CO2 because they can be a bit fiddly.
Happy to make some for anyone interested, I'd just ask for the cost in printing/time/parts/shipping and maybe a tip if you're so inclined...so maybe like $40 plus tip depending on the shipping costs? I'm in Texas. A friend of mine put one on his 54cm Cervelo P-series and it does fit, although it is slightly lower to the tire. I'm just a hobbyist designer so please don't ask me to make a seat post mount for your specific bike, unless you want to $$ for it. ;)

Printed in black Sunlu ASA on Flashforge 5MPro with the following settings:

260 degree nozzle temp
105 degree textured bed
No fan in chamber (preheat bed for like 30 minutes)
Glue seemed to help adhesion, especially on lid and mount
*You could also use a brim if you are having trouble with adhesion, but the glue seemed to do the trick for me.
Lid: 25% infill, no support
Body: 25% infill, organic tree supports
Mount: 100% infill, organic tree supports

Parts needed:
M5-0.8 x 14mm (post mount)
M5-0.8 x 20mm (box mount)
M5 x 0.8mm Nylon Insert Hex Lock Nuts
Neodymium Magnets Disc 9 mm x 3 mm
Epoxy glue
Optional: Zewdov Bike Lights