Making a fork topper for the ICAN TRA01
Introduction
Shortly after I graduated from Chicago’s Lane Technical High School in 2010, the school chose to end its long-standing academic requirement of a manual drafting course. It seemed like an outdated requirement before I took the class – one I put off until the last minute, taking it as a senior alongside the usual freshmen getting it out of the way early in their coursework – but I quickly found a sense of satisfaction in constructing a technical drawing as building a set of facts from each other. In the years since, 3D printing has matured and become accessible, and I’ve recently found a need to make some non-structural parts for my track bike – a perfect time to dust off some part design skills and 3D print a few prototypes.
For the past season, I’ve been racing track bikes at JBMV. There’s a whole thread I could go down about various technical aspects of this sport, but I’ll focus on the equipment side for now. Track cycling occupies a very particular intersection between standard and proprietary parts. On one hand, track bikes have hardly changed in their fundemental standards in the past 30 years. On the other hand, the impact of aerodynamics on performance means athletes seek every possible advantage and won’t hesitate to choose non-standard, quirky, and even problematic products when it fits the need.
Enter the ICAN TRA01, a frame with a standard steer tube but a proprietary fork fairing design and matching stem. The proprietary stem provides a “chin” of sorts, which nestles against the fairing to provide an integrated front-end to the bike. Of course, this is completely unnecessary if you extend the fairing upward with a plug or topper of sorts.
Why would you want to replace the stem? Well, besides being incredibly heavy, the proprietary stem is only available in 95mm and 75mm lengths, which is – to put it lightly – inadequate for most track cyclists today, even at the recreational level. For context, I run a 150mm stem on my TRA01. So a simple, non-structural fork topper solves an immediate problem for me in cleaning up the front-end of the TRA01 while expanding stem compatibility.
Version 1
With a charcoal rub on a piece of paper and a bit of work with digital calipers to double check key dimensions against the fork fairing, I was able to get sufficient accuracy to produce a CAD drawing. Since I use a -6° stem, I built in a corresponding cutout relative to the steer tube angle.
I used a 3D printing service to print the part in nylon 12 with a black dye treatment. To my surprise, not only the external dimensions, but also the internals worked out flawlessly from the first draft. I was expecting to need some sanding or putty to remove or add material for the internal fit, but the first design resulted in a perfect fit that drops in with light pressure and holds firmly in use.
To print your own fork topper for the TRA01, you can use the STL file here.
Version 2
With the success of the first version, I immediately turned around and started working on a more integrated design to replace the headset top cap.
Again, the part fit almost perfectly on the first print. The spacing was all correct, but tolerances from the print led to too tight a fit on the bearing cover portion. With a few more iterations, I was able to dial in the part. Although I do use this part on my own TRA01 now, it’s a bit of a hassle to dial in with micro shims to have correct headset bearing preload and get a flush finish in the front. For that reason, I recommend the simplified Version 1 (download STL file) if you’re interested in using this on your own TRA01 frameset.
Additional notes
The major caveat with the TRA01 is that the steer tube comes pre-cut when you purchase the frameset from ICAN. The exposed length – though a compatible diameter for standard stems – is short enough that the only stem I’ve found to fit safely is the Velobike Elite Longboi Stem, which has a 32mm clamp height. If you’re purchasing the frameset with a plan to use the above solution, please be aware of this limitation.