P9 Extras

Extra Projects

Beach Cruiseres

This was a 12 month project for Stomp Distribution. Feedback from Mafia bikes dealerships in the US West coast had culminated in the decision to lauch a new brand in the US that would market cruiser style bikes towards the surf culture demografic.

The initial brief for this project was for 3 seperate models to be created, each with a unique frame. 1 flagship model to retail at $500 and 2 base spec models to retail at $300. Bespoke forks, bars and saddles were all within the projects scope. It was also specified that there were to be no cables and so so all moidels must use a coaster brake (a coaster brake is housed in the rear hub, it is enguaged when the rider pedals backwards).

The 10 initial concepts were soo well recieved that the decision was made to expand the project scope to 6 models. This would cbe comprised of the following...

A $500 Aluminium "moto style" model with belt drive

A $300 Steel "moto style" model

A $450 Aluminium "Classic"

A $300 Steel "Classic"

A $450 Aluminium "Ladies"

A $300 Steel "Ladies"

Concept 2 Early Prototype

Concept 2 Render

Concept 2 Pre-production Sample

This project was full of unexpected challenges.

Late supply chain issues meant that we had to work with new aluminium tubing suppliers that couldn't provide the tubes that the original concepts were based on. Fine tuning the steel frames to meet the manufacturing constraints of new suppliers without significantly compromising the aesthetics was also challenging.

A coaster brake works by acting through the hub and against the rear dropouts (essentially trying to rotate the hub cone inside the dropout slot) this was already going to be a challenge with a horizontal dropout (needed to tension the chain without adding an ugly tensioner) and it turned out to be a huge problem on the aluminium dropouts. ultimately steel plates had to be used to reinforce the dropouts.

2 different bespoke handlebars were needed and 3 different forks had to be designed including one chrome plated triple clamp. All these parts had to be prototyped and tested.

3 of the biked were to be sold with a decorative wood panel under the top tube that would be held in place by three brackets. A feature that transformed the look of the frame and gave customers a great opportunity to customise their bike with graphics. Finding a supplier for this type of component was very challenging.

MTB Gearbox

The derailleur drive train is by far the most outdated part of a modern bicycle, especially in gravity fed disciplines such as freeride and DH.

Using a gearbox on a mountain bike is not a new idea but over the years there has never been a design that doesn't come with a significant compromise. The Pinion P1.18 is probably the industry leader at the moment but it suffers from low engagement and a compromised shifter as well as other small issues.

Why is a gearbox better than a derailleur?

The positives... Less vulnerable to damage, less maintenance, potential to eliminate pedal kickback, reduces unsprung mass

The Negatives... Heavier, less energy efficient, requires frame to be compatible

My design allows for a very competitive range of gears 517% (note that Sram Eagle 12 speed is 520%) with no compromise to Q factor. It is optimised for high torque which drives the gear width and therefor the number of gears that will fit side by side resulting in 10 gears. With absolutely no weight saving measures it weighs 2.7g but this will likely be reduced to less than 2Kg.

The crux of this project is the shifting mechanism. I have designed the mechanism to use a regular Sram trigger shifter to control a selector shaft. this shaft rotates to control the position of a carriage that in tern selects a pawl set which engages with the desired gear. The mechanism is fairly complex but robust. I have prototyped the shifter and am working on creating a full gearbox prototype.

Solidworks Model

Key stats and Ratios

Cross section render

E Bikes

This was a project for Stomp Distribution. 2 regular commuter bikes were already in the concept design phase for a new brand set to be launched in 2024. I was bought onto the project to design 2 E-Bikes that would complement the existing designs and enhance the brands high end, sophisticated image while also being unique and "cool" when compared to the competition".

The price point for these bikes was around £1800 and the project scope included 2 frame sets, 1 fork and, 2 handle bars.

Unlike most Stomp projects this one could not rely on custom tubing. All tubes and hardware had to be selected from existing suppliers or from Stomp's own tooling. This meant that a motor supplier had to be selected very early on in order for us to know what down tube and motor brackets were available and to match the rest of the tube selection to be in keeping with that aesthetic.

Original frame concept layout

Prototype Frame

Production Specifiaction - Sport Bike

The biggest challenge on this project was designing a rigid aluminium fork that would be strong enough to deal with the anticipated abuse. Fortunately I was working on another bike at the time that required custom tooling for its own aluminium fork legs. I was able to use an existing steel fork as a benchmark to compare FEA results allowing us to design a fork leg that we knew would be no weaker than our existing steel forks.

This was the first E-Bike that Stomp had worked on and the first batch of prototypes had a lot of small issues that required painstaking explanations and negotiations with stubborn new factories based out in China in order to rectify every last detail. From battery cover gaps to poor motor fitment, every issue had to be explained, justified, resolved and checked.

The project was completed in 2022 with both BOM's and drawing sets being signed off for production.

Aluminium fork validation

Prototype issues

Shopper Vairient