Last March, early in the COVID-19 lockdown, I set out to design and build a new frame fixture for myself. This was need-based on many levels. I wanted something amazing. Something better than anything I could buy. A fixture for a new way of doing things. The result was the PVD Cyberdyne System. I still … Read more

The cutting tool problem and Park tools

Bicycle framebuilding is a particular simple craft. Connect a few bits of material together and strap some wheels to it. What makes good framebuilding difficult is everything that happens around the build. One of the harder issues to get up to speed on when making bicycle frames on a small scale is the lack of … Read more

Forks and Facts

I live in a world divided into small fractions of a millimeter. Often, I spend a great deal of time freeing up just 1/2 of one and feel like a conquering hero. It is my struggle. I was recently sourcing some forks for the all-road bikes that we are about to do. It had been … Read more

Jump Ramps and Kickers

A long time ago, in a galaxy far far away…. (FS rocker shot 1/2 second late. Porter Square, Cambridge MA. 1986) A child of the 1970s, I grew up playing on cheap plastic skateboards. In the early eighties, the new boom in skateboarding and my young teenage years were a perfect storm setting me on … Read more

Why mullets

Hang around any mountain bikers that don’t understand bike geometry for very long and you’ll be sure to hear about the magic of mullets. A 29″ (622mm, business) wheel in the front and a 27.5″ (584mm, party) in the back. It’s amazing how this silver bullet has caught the eye of the retail market. The … Read more

Engineering failures

Klunkers. Dayum. These things keep teaching me some big lessons in bike design and engineering. I have been forced to look at details in entirely new and unexpected ways to solve this riddle and that learning carries to all facets of bike design. In addition to design challenges and growth in tooling and CAD, there … Read more

Cylindrical Seat Tube Post

Here’s a cool modification to the Cyberdyne frame fixture. While I worked to make the fixture as best I could in the initial round, I wasn’t going to be able to do everything I wanted as the project would never end. Now, when I can focus on just finer aspects of the use and refinement, … Read more

Huck to Flat

This is an interesting bit. A week ago, PinkBike posted a video and article, Field Test: 10 Trail and Enduro Bikes Hucked To Flat at 1,000 FPS. This is cheap and easy content for them to produce and makes the little boys and girls happy. I don’t know what it really does other than that. … Read more

The anti-squat problem.

I’ve been working on my suspension bike design for about five months now. There’s no rush and I’m trying to do it right. I can prototype as much as I like in the computer and it doesn’t cost me a thing. What’s expensive is wasting money or time once I start cutting metal.  I’m nearing … Read more

Dropper Post Lengths

This is a question that has been on my mind for the last decade, how much stroke do we need in a dropper seatpost? It’s not a new question but a good one to ask now and then. It’s a moving target. As we speculate on what we need, then eventually use that, our position … Read more

Crackhead “inventors”

Here’s another from the message vault. The other day, a guy posts to the bicycle Framebuilder’s group on Facebook. His claims were that he understood the cause of Chloé Dygert’s recent crash during the women’s individual time trial at the 2020 UCI Road World Championships in Imola, Italy. It was a very gnarly crash as … Read more

Why we hate “Makers”

I recently wrote about obtaining a cool little “Lego”  plate for setting up parts on my fiber laser. I talked a little about problems with the design and how it should have been produced. I made drawings to show my work. I had shared that information with Randy Lint but it seems to have fallen … Read more

The leader of the pack

The other day, I came upon a Facebook post from GMBN to a video: “10 Easy Ways To Get Faster On Your Mountain Bike”. The video gives some perfectly good technical advice but ignores the single biggest problem slow riders have. For almost every one of them, they simply don’t have a good reason for … Read more

Race Face Atlas Pedal Pins

I swapped out the pedals on the Spitfire the other day. The bearings of the Spank Spike pedals needed to be serviced and I wanted to just get going on a ride. I had made a big modification to the Spike pedals four years ago, Nice long sharp pins. It was a really nice upgrade. … Read more

Unreasonable Men

History is rarely made by reasonable men…. – Terry Goodkind  We don’t get gifts in life. The golden ticket or silver bullet are things of fantasy. You’re not going to get ‘discovered’ while walking down the street. You’re not going to ‘invent’ a world changing thing casually after dinner on a Thursday. Success in life … Read more

Passing Gas

The other day, I was chasing down the problem on a slow leaking tire. In the era of tubeless tires with Cushcore, flat fixing, while rare, isn’t trivial. It’s nice when a puncture is obvious but often now, it isn’t. So we need to go to the dunk tank. Until recently this was my kitchen … Read more

Warbird update

I like to do an update on my bikes from time to time. Sometimes, I’m just repurposing them. Other times I’m cleaning them up and I decide it’s time to talk about them. It’s not often a designer talks about how well something is working long after it is released. Doing this gives me some … Read more

The PVD Cyberdyne System

The rise of the machines… TL;DR: This isn’t just another Arctos frame fixture clone. It’s a better solution and one you’ve never seen. The rules of the game have been re-written. If I were to say where this began, it would probably be back at the 2016 NAHBS show in Sacramento. I had spent the … Read more

The Hostage Negotiator

There’s a special power in saying what you’ll do and doing what you’ve said. Action is everything and words just connect actions. That became clearer than ever for me today. After Greg White stole the balance due on my frame fixture, $1901 due on the $4000 sale, I was in a pickle. After three weeks, … Read more

The Bicycle Tool Thief

POST NOTE, 10:35AM: Since going live with this post late last night, I have received about a dozen emails and phone calls from people that have been victims of Gregory White. People whose lives have been truly damaged. Suppliers who are owed thousands of dollars in a tight market. Even people who almost became his … Read more

Systems and Systems of Systems

A while back, I wrote a piece on recognizing expertise in those around us. It’s pretty good, you should check it out. In that essay, I talk about how an expert can recognize systems around them and build those systems into other systems, better, that they can explain all this. I’ve been doing just that … Read more

What does a day of modeling look like?

“I would have written a shorter letter, but I did not have the time.” -Blaise Pascal COVID-19 is a bad thing but many of us keep trying to find and see the good things. One thing that I have enjoyed about the COVIDs is the time I can spend really savoring the design process. As … Read more

SRAM Master Pistons

SRAM Guide and Level brakes work pretty well. I use them. In general, they do what is needed. Not perfect, but nothing seems to be right now. For flat bar all-road conversions that have flat mount calipers, we use the Level levers, not the Guide. This keeps the leverages correct. Level levers can also be … Read more

Windy’s Bird of Prey

This is the time of the all-road bike. It’s been the bike to have for the past 3 months as COVID-19 has brought a whole new mode for my bike rides with my wife, Windy. Many mountain biking areas near us have been closed for a long while. At the same time, Bolinas/Fairfax Road and … Read more

The finish line.

Advice for the aspiring designer; Have lots of patience, keep working hard, don’t ever stop! I’m currently working on producing a new fixture for making my bicycle frames (a mandrel bender also but that is another story). I need a tool that will work better than what I have been using for modern geometries, mopeds … Read more

PVD/RAD Refined

Back in November 2019, I posted  a stream of consciousness, ending in an enlightening concept: PVD/RAD. It looked promising even in that primordial state. The problem with that post is that it was confusing and left folks with more questions about the process than the answers it could have. Six months later, I’m still excited … Read more


Today is my day to eat some crow. Attentive readers will know of my work on brake caliper mount locations and a tool for attaching flat mount caliper bosses in the correct location. I’ve been pretty proud of this work. It cleans up a big mess. Devin Bodony of Lichen Precision, a machinist bro that … Read more

Fork Testing with the Camera

After all the drama of the winter injury season has subsided and the lazy days of COVID-19 are here, I finally got back to the fork test video that I had intended to do on the day I broke my clavicle….and then big toe. Originally, I had intended to do this filming with a GoPro … Read more

Fiftyfifty tires.

2020-04-17 All-road tire test: Subject: Maxxis Velocita AR, 622-40,120TPI, 380g, tubeless. Setup: 50psi with Cushcore CX insert on both wheels, Orange Seal endurance. WTB KOM i25 rims. Tire width measures 42.25mm on the i25 rim. Bike: PVD T-47 Airspeeder All-Road. 40/10-50 gearing. Rider: PVD, 205 lbs, fat, out of shape, expert dirt. Conditions: Dry but … Read more