Motorcycle Front Ends

MFE is a collection of work-in-progress tools for motorcycle front end setup and design. Current tools are intended to calculate static geometry, such as determining trail given a known setup, or taking a known setup and making a change to the fork length and calculating the new rake and trail.

All of these tools are exploratory; as I develop my skills (both mathematical and as a programmer) new versions will evolve. I will attempt to use sensible version numbering (creating a new version if any useful features are added or removed) and maintain links to all "released" versions.

My eventual goal is to produce web apps that can determine and graph kinematic behaviors of various motorcyle front end setups that use sliding and / or pivoting elements and springs / dampers to constrain vertical wheel motion. This would include (but not be limited to) normal telescompic forks, "springer" forks, "girders", and more exotic setups like BMW's Telelever and Duolever, the Yamaha GTS, and Bimota Tesi / Vyrus hub steering.

If you have an interest in helping with this project by offering mathematical or programming advice or assistance, please contact me by creating an issue via my Github Repo!

Sebastian Wiers

Wheelbase and Trail

My first attempts, learning to use the HTML canvas and do some useful trigonometry. I managed this pretty quickly without using any librarys, but am pushing up against the limits of spaghetti code and manual data structuring even with good functional blocking and JSON data. On the other hand, its all one file and uses less than 350 lines of simple javascript, so is a nice readable starting point for anybody looking to do thier own project.

Chopper planner version 0.1: Despite the name, the inputs and outputs of this form can be applied to bicycles and wheelchairs, as well as all styles of motorcycles. Compares a known setup's geometry to geometry resulting from planned changes to wheel size, fork length, etc. Allows you to add your own custom setups to the dropdown list. Also adressed errors in alignment of base / modified image & image fit on canvas.

Single link fork calculator version 0.1: This tool works very much like the one above, but instead of comparing two bike setups, it calculates & draws the axle path of a single link fork cycling through travel (assuming the frame remains level). This may be useful in working out dimensions for springer, leafer, Earles, trailing link, and similar forks. Future upgrades will support anti-dive and spring force calculations. Since this tool does NOT calculate rake / wheelbase / etc changes resulting from a fork swap or modification, you may need to use the "chopper planner" to calculate that, then enter the dimensions into this tool.