Modular recumbent handlebar

I designed this handlebar to replace my U bar to:

- Gain some speed, fun and comfort on long distance

- Reduce width, practical on packed cycle lane

- Gain a bit of weight, always appreciable when climbing a hill, even if the actual design is quite beefy. If I feel the need I will run some optimisation one day.  

- Have a better access to my GPS (The 4 M2 inserts are here as provision for interface)

And because I wanted to be able to have a fix angle stem which will fit me so I needed to do some iteration (Prototype in PLA) for the angle.

For the length I did some iteration too but with less waste: just need to shorten the central tube, which for the moment is a steel tube with an OD of 30min and walls of 1,5mm.

I printed the final parts in a mix of PETG-CF 10 and 20%.

The central tube is locked by a slider, which need to be sanded/adjusted. To avoid the tube to turn in the stem I glued a piece of tube on it, which give more adherence than PETG-CF against steel. I advise you to use carbon paste. It should help too with grains in it.

If I redesign the assembly I will use sliders on the fork too, mine having an aluminium tube.

If you want to replace the steel tube by a carbon one I advise you to increase the slider width and design an insert to put in the tube to avoid crushing it.

You will need:

• 3 inserts M5 like this one: https://www.ruthex.de/en/collections/gewindeeinsatze/products/ruthex-gewindeeinsatz-m5-50-stuck-rx-m5x9-5-messing-gewindebuchsen
• 3 M5*20 or 25 for the fork stem interface
• 1 M6*60 or 70 for the direction pressure
• 4 M4 inserts: https://www.ruthex.de/en/collections/gewindeeinsatze/products/ruthex-gewindeeinsatz-m4-50-stuck-rx-m4x8-1-messing-gewindebuchsen
• 4 M4*20 screws to fix the handle bar
• 1 M6*30, nut and washer or more to fix the end part on the tube

I printed with a nozzle of 0.8 or 0.6 depending of the parts, with 4 to 6 walls (at least 3mm).

Be conscious that a T bar reduces accessibility or change it. I got trouble during first rides. Now I take it for shopping.

I nearly forgot: for 25,4mm T bar and 28,6 fork uncut, centering of 100mm to spread the load created by half meter length of bar.

This assembly was supposed to be a bench to validate dimensions for a later monocoque version, but not sure i will go that way. I appreciate the fact that I didn't use epoxy and reuse a steel tube sleeping in my basement since four years at least.

*: all screws dimension mentioned here are approximative, I didn't double check before writing. I advice you to check with the 3D.