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Pinion Bike

Pinion Bike
Pinion Bike

Over the many years I have been frame building I have had the opportunity to make some very special bikes. But every now and then I am challenged to make something truly extra special. A rare opportunity to pull together skills I’ve accumulated over the past 30 years and create something unique. This was such a bike.

It was a retirement gift that my client Barry was giving to himself. The planning first started a year ago with the goal to create a lightweight, low maintenance, versatile, expedition bike packing machine. Barry already had a few other bikes some of which were of a similar vain, but this was going to pull together the best traits of all them, plus some significant extras, into the ultimate bike.

I’d been wanting to build a bike around a Pinion transmission for a long time. I had several discussion with clients over the years but none had given me the go ahead until Barry reached out. The Pinion P18 transmission is made in Germany and is a piece of engineering marvel. 18 evenly spaced gears covering a massive 636% range, tightly packed into a beautiful sealed housing. The transmission weighs in at 2.7kg, but that weight is nicely center mounted into the frame using a special “bridge” instead of a traditional bottom bracket. In this case the bridge was beautifully machined out of 6/4 titanium by Paragon Machine Works in California. They make some of the absolute finest frame parts in world. The bridge is CNC machined in two halves leaving the builder to weld them together, and so began this frame. Piece by piece to the bridge materials were prepared and fitted; main tubes, specially shaped chainstays, custom machined head tube, oversize Dekerf wishbone, sliding drop-outs, and all the endless details that go into creating a one-off frame such as this. All the materials were slightly heavier duty than I would normally use to provide additional strength and stiffness for the loads and use the bike would be getting. I took my time on every aspect of the build. Right from the cutting, machining, and fitting of the tubes, to the meticulous pre-weld prep and cleaning that titanium requires, to laying down the double pass weld beads, and with countless checks and adjustments for alignment at every stage. After the final reaming and machining tasks the frame was finished in classic hand brushed raw titanium. And finally the Dekerf decal package and a wax sealer were applied.

Titanium forks are rare and I am one of the few builders to make them. Over the years I have refined my design for all types of applications but this one pushed the boundary yet again with the shear size and the need to handle heavy loads off-road. Again to Paragon Machine Works for their substantial 1.5″ to 1.125″ tapered titanium steerer tube. It again is a machining marvel, starting out as a 14″ long bar of solid 1.75″ thick 6/4 titanium. By the time it’s all done it’s a thoughtfully designed and beautifully machined tapered steerer tube. I know for a fact that they don’t sell many of these as its use ventures into the niche corners of frame building, but it is a perfect steerer tube for this particular application. Strong, light, and beefy. The fork blades themselves at the top are joined to ‘wings’ through an in-house design whereby the wings are machined internally to accept the blades precisely. The shoulder joints are then welded using a unique 3 pass welding method, then hand filed and blended smooth. The lower end of the blades were attached to hooded 15mm thru axle drop-outs, along with the disc mount, and provisions for internal wiring for the front dynamo hub. Finally, ample fittings for ‘anything cage’ were drilled and welded in place along with some guides for the hydraulic line. All in all the fork was a massive project on it’s own but the final result was a perfect match for this type of bicycle.

Welding titanium is not overly complex. It requires the right equipment and certain principals need to be applied but beyond that, the task itself is not complex. First you lay down an initial fusion pass, where you join and penetrate the seam to its core. They you go back and lay down the actual weld bead over top of the fusion. The challenge, the beauty, and real purity of welding titanium is that you only get one attempt at it. There is no going back once it’s done. The outcome from those few minutes of welding will be there forever, for anyone to see. I usually take a moment before I start to weld, relax my breathing, try and clear my mind, and then allow my muscle memory from the thousands of weld beads I’ve laid down before simply happen and flow from my hands. On this fork that all happened as it should. I am so happy with the main fork steerer weld beads!

The third component , the rear rack, was equally challenging as the frame and fork were. Barry and I considered various options and ideas early on but ultimately decided to create a one-off titanium rear rack that attached to the frame in an ‘integrated’ fashion, but yet could still be removable. This required careful planning and machining as the points where the rack attaches needed to be ‘submerged’ into the rear wishbone tubes top and bottom at precise locations and angles. This all had to be done before the wishbone was attached to the frame. Good drawings were key and everything went very nicely. Once the rack was made it fit onto the frame like a glove. No skimpy eyelets for bolting on this rack! The rack literaly snaps into place using modified and repurposed tube splitters, that come in precision machined pairs. The 4 lower and two upper bolts hold the mating halves of the mounts together creating an ‘integrated’ mounting system, but yet is still removable. Super light, super strong, with zero flex in the attachments.

The only titanium component I did not make was the handlebar. We decided to source a Jones H-bar from Jones in Oregon. Barry uses these bars on some of his other bikes and he really likes them. There was no sense trying to copy or make one, Jones already does a fantastic job with these bars so we just ordered one up.

From there it was onto the component kit which evolved into a beautiful no-compromise package. We went with some nice carbon rims from Nobl, paired to an Industry 9 rear hub, and a Son28 dynamo front hub, laced up with Sapim CX Ray spokes. A gates drive belt got the power from cranks to wheel, and braking was handled with nice set of XTR discs. Enve carbon stem and seatpost were chosen along with a Brooks Cambium saddle. RaceFace pedals, Maxxis tires, and of course a Chris King headset. From the front dynamo hub we went with clean and simple connectors and ran the wires internally through the fork leg and up into the steerer tube. Up top we fitted a Cinq5 Plus to plug in a phone or GSP. Hidden inside the steerer tube was a battery storage pack to hold some additional power. Finally the bike was fitted up with full set of Revelate bags to carry everything needed for an adventure. Sitting there fully assembled and with the bags on, the bike has an impressive style to it. The lines and the overall look is balanced and as it should be. It looks large, comfortable, and very capable.

Although I certainly put in a huge amount of time into this special bike, it’s not something I could have done without help. The titanium from Titanium Joe, all the beautiful frame parts from Paragon Machine Works, the Pinion transmission and drive belt parts from Gates, the Pinion bridge jig kindly lent to me by Peter, a fellow frame builder, all the component suppliers, the amazing assembly and mechanical work by Ed and Ryan at Mighty Riders, right down to the fantastic photography by Jenn at Digiwerks Photography and website help from Primal Communication. Thank-you to everyone that helped pull this all together.

Each frame I build is a journey and no two are the same. For me, the mental approach, and degree of patience usually determines how hard or easy that journey will be. In this case, it was a joy to build and I am so pleased with the outcome.

Most off all though, thank-you to Barry for entrusting this special build to me. I loved every bit of the process and hope the bike brings him many hours of health and enjoyment in his retirement.

Chris Dekerf.