Solving Crank Axis Height

This is something that I’d been doing in my head for years. I was always guessing. An educate guess, but still a guess. Now, I have it solved. Designing dirt going bicycles is difficult. There are many crucial details that need to be figured out and understood to produce a design. If a few hundred … Read more

The Art and Science of Front End Geometry

Let’s talk about the front of the bike. This has been the part of the bike getting renewed attention in the past few years. New stem products and 32″ wheels have gained some traction in the mountain bike marketplace. As these encroach on what I’ve been doing for so long and do the most advanced … Read more

PVD Handlebar Description Refined Method

I’ve long acknowledged  a problem with my method of geometry development. I wasn’t prepared to deal with or thought that I could run the clock. The day has come to get it resolved. Looking back in time, being forced to build my special handlebar systems in 2018, and even before that when I started working … Read more

Master Parts and Weld Table Upgrades

I’ve continued to refine my SolidWorks modeling methodology and have been bringing older files into accordance with the new strategies. A new video explains more of this. I’d just completed the huge project of breaking down the CAD model for the dropouts so that I could build it back up a lot better. This doesn’t … Read more

2024 Math for Bike Geometry and Fork Travel

This is a bit of a continuation of a past post about the new mathematical considerations that the newer all-road/gravel suspension forks have in calculating bike geometry. Because the sliders are set at an angle to the steerer (and thus, the head tube), calculating the bike geometry at a given location in the fork travel … Read more

Numerical Suspension Modeling

I’m probably known best these days for my hardtail mountain and all-road bikes. What some may not know is that I have a long history riding and tuning suspension bikes and sport motorcycle. I’ve had big enduro bikes and downhill bikes. I’ve changed shims, fluid, and springs to alter the performance of these systems. This … Read more

The Art of the Steer

Skateboard steering is a very challenging thing to model. I’m used to doing some incredibly complex calculations for my bicycle projects but producing this calculator pushed me to my limit. It took me three days of full time work to finally get the math correct. I had done a calculator like this 20 years ago. … Read more

You can’t fix it in post.

In photography and filmmaking, the joke is often made that “it can be fixed in post” to justify doing very low quality work. It’s true that there are a several small issues that can be fixed after the image has been captured. Some colors can be shifted, a smudge removed, subtle white balance changes, the … Read more

Hard Modeling

This is an important thing for novice modelers and designers to think about. It’s tied up in this example. While drawing up a tool I was thinking of making, I chose to give it a knurl as it was a handle and that is what you do. Knurls provide grip. We see them all around … Read more

Why we don’t draw on paper

Today, we don’t design on paper…  I was recently reminded of this topic by a message board thread. A kid wanted advice advice on drawing a frame. Countless people chimed in giving horrible advice. I often find that the less someone knows the more they will pass off their opinion as truth, while lacking any … Read more

The wonderful world of torque

I’m a very lazy mechanic. I don’t want to do any more work or pay any more attention than I need to when I’m repairing something or tuning a system. Because of that, like most mechanics, rather than use a torque wrench on every bolt I turn I’ve learned a feel for the metal, parts, … Read more

The stem problem and reverse engineering

The stem is an incredibly important detail on a bicycle. It places the handlebar in the proper position relative to the bottom bracket and the saddle regardless of what lies beneath it. Where the stem holds the handlebars can make a bike fast on climbs, or fast on descents, or great for all day comfort. There … Read more

Trigonometry

I absolutely love trigonometry. It’s how we come to understand circles and curves. I work at the Physics & Astronomy Department at San Francisco State University. Every semester a few students will express their unease, confusion, and problem doing trigonometric work. Over the years, it’s been shown that, all of them, have never been given … Read more