It’s that time again. The North American Handmade Bike Show (NAHBS). It will be in Sacramento this weekend and I’ll be there taking photos of the details and doing interviews with folks. Hopefully work hard for a few days and mine some gold in the gold rush city.
The funny thing about NAHBS, you don’t get to see the best of all work in bicycles at the show. That’s a confusion people have. NAHBS is a trade show for whatever Don Walker has deemed ‘handmade’, ‘North American’, or a ‘bicycle’ related product. It’s a venue for commercial sellers to interact with their market. It’s not a bicycle show. A bicycle show is a display of bicycles on their own merit, commercial success or failure isn’t relevant. Don’t get me wrong, some very nice bicycles will be on display at NAHBS but not the very best. You don’t get to see what’s not for sale.
I don’t sell bikes so I don’t have a booth at NAHBS.
Here are a couple of nice pieces of mine that you won’t find at NAHBS that are going into a bike on my jig right now.
The PVD410 Yoke.
This is a pretty wild part. It took a lot of engineering and virtual, printed, and cut prototypes. A lot of tears were shed to produce this part.
What makes it so cool?
- 3-axis machinable in two setups
- 410mm rear center
- 52mm chain line
- 622-66mm (29×2.6″) tire clearance
- PF41/89.5 compatible
- Q156 crank compatible
- 38t chainring
- Slider friendly
- Segmentable
- 192 grams in steel
- Stiff AF
That’s some pretty wild stuff. I call the form, Semi-I-Beam. It takes advantage of some of the good properties of an I-beam yoke (economy, ease of manufacture, single part) but some of the advantages of the clamshell (pocketed support, complex interface). It would be a pretty tricky part to design without that leap.
Many people will try to make a similar solution to the conditions this yoke handles, but they’ll be missing two things, incredible strength and stunning looks. There aren’t any shortcuts here. Just good solid design and engineering with a real goals to be met.
Special consideration was taken to ensure tool clearance when installing Wheels Manufacturing BB86-OUT-SRAMAC type bottom brackets with the BBTOOL-48-44 tool.
The yoke can also be trimmed down the middle for use on 49mm and 45mm chain line bikes. It’s not a perfect solution here but it’s allowable.
The part here is tacked in just 5 places to a scrap bottom bracket shell. I’m showing it to a few folks at the show and needed the part attached to give an idea of its true stiffness as it was designed to use the bottom bracket shell as a mechanical element.
Even though these yokes were designed for easy 3-axis machining, this first small run was cut on a big 5-axis mill in a single setup. Super nice finish from 4140 steel. It’s top notch stuff from the tech capital San Francisco.
(special thanks to the two teammates that helped me make these real)
The PVD 85mm IS41/IS52 Headtube.
A head tube similar to this in 112mm was seen on the PVD Warbird, This tube is quite a bit shorter at 85mm. The dramatic 15.6 degree cone is really something else and should be a fun miter.
Again, I’m finding the real practical limit on the minimum head tube length. Several of my bikes in the Red Five era were done using 75mm ZS44/EC49 tubes. Everything went smooth with those. IS top and bottom adds about 10mm to the length of a tube like that getting us to 85mm on these tubes. I don’t know of anyone outside of crazy hour record bikes using tubes this short.
One of these head tubes is for an aggressive long travel 29er hardtail for a rider of shorter stature who likes a lower cockpit. Melding the bike and rider, that’s the game. A PVDClipOn bar will be fit to the bike to make an otherwise impossible fit happen. Real geometry magic here on earth.
This part was cut by Mark Norstad.
