Flat bar extensions for bullhorn handlebars

Motivation

- ebikes generally have a bunch of things mounted to the handlebars, which are typically flat unless it's an electric road bike - these often include - brake levers - shifters - controller - computer - throttle - front light - the easiest way to accommodate this is a very wide handlebar - this is unfriendly due the clearances required to fit between cars in traffic - bullhorn bars, on the other hand, are much less wide - as an added bonus, they feature a lot of reach, to counteract the short reach inherent in a lot of ebike frames How to make bullhorn bars work

- short stem to compensate for extreme reach - bullhorn bars feature a 23.8 mm OD, same as drop bars - flat bar components mount to 22.2 mm OD, so an adapter is required Design

- designed to mount approximately these items - Bengal Ares hydraulic brake lever - SRAM GX 10 speed shifter - Aventon controller - Aventon throttle - Lezyne front light Rev 1

Hardware for single adapter

- qty 1 M6 x 100 mm button head screw - 4 mm drive - expansion mechanism from Tektro RX 4.1 bullhorn brake levers - I did consider using a custom 3DP mechanism like a quill stem, but decided against it for these reasons - to expedite testing for feasibility - strength, since this will be the foundation for a brake lever - strength despite relatively small overlap with the handlebar - many bullhorn bars feature a curve at the end, which complicates insertion beyond a certain depth - Installation

- apply grease to the wedge & the mating threads to facilitate later removal Limitations

many of these are the same as with my other project here, the control hoods .

- you need a ton of extra cable length to make this work - this is challenging for - internally routed hydraulic cables - existing electrical connections for brakes, the controller, computer, etc. - Note the kinked rear brake hose

Nearly kinked front brake hose

Rev 2

- features a straight rather than a curved grip, but neither have been tested to date (2025-01-18) Future improvements

- I thought about integrating TPU grips, but decided against it to avoid scope creep - chances are slip on grips like ESI grips would suffice - due to the curvature at the very end of most bullhorn bars, lock on grips will not work - - the only way I can proceed with this project as is, is to address the cable length issue, which I might if Bengal Ares brakes can use standard Shimano BH59 hoses - otherwise, something like this would greatly reduce the cable length requirements -