Ritchey P-650b Build Part 1 – Frame and Fork
Don’t call it a comeback. While the 650b wheel seems to be finally here to stay, Tom Ritchey was designing his first 27.5″ bike in 1977. As what Tom himself called his “first effort into thinking about mountain bikes,” Tom designed a bike for the late John Finley-Scott based on the English Woodsy. Built to explore the farm roads and trails in England, Woodsy bikes used 650b wheels which Tom thought would be a great fit for mountain bikes.
We know what happens next. Mountain bike manufacturers settle on 26″, then years later adopt 29″, and then re-introduce the middleweight 650b. Today, Ritchey offers 3 P-hardtails – one in each wheel size. As sibling to the P-29, the P-650b brings Ritchey’s heat treated, triple butted, Ritchey Logic II tubing to the middle sized wheels for a light weight, efficient trail bike with its own unique Tri-color fade.
Details plus weights after the break…
Like the other frames in the Ritchey line up, the P-650b has been designed by Tom who fine tuned the geometry and tubing choices to keep that “Ritchey feel.” Part of keeping that feel and shaving grams means the use of a 1 1/8″ straight integrated head tube which shaves about 40 grams compared to a tapered tube. Frames require the use of a 41.8mm Campy style integrated headset like the Ritchey Logic Zero WCS drop in.
The Logic II tubing brings a bit of classically refined steel ride characteristic to what are now modern sized wheels. In fact, the wheels are about the only modern standard on the bike with features like a standard 68mm English threadded BB, 28.6mm front derailleur clamp size, and external cable routing.
Every bit of the frame has been tuned for the least weight and best ride characteristics. Running a standard 27.2mm seat post, the frame features a built in seat post clamp. Forged 135mm QR socket dropouts sit behind a new chainstay mounted post mount disc mount that is designed for 160mm rotors. Since the frame is steel, a non-replaceable derailleur hanger is employed.
Designed for use with 100mm travel forks, it’s clear the frame is likely intended for rigid forks like the WCS Carbon fork from Ritchey. While there are a few out there, high end 27.5″ suspension forks with a 1 1/8″ steerer seem to be hard to come by. Fortunately, the WCS carbon fork is quite good with a one piece monocoque construction including the dropouts, 160mm post mount disc tabs, and steerer (compression plug included). Suspension corrected for 100mm forks, vital measurements include a 42mm rake and 459mm axle to crown.
On the scale the fork registered an even 600g uncut, while the frame measured 4.7 lb (2,140g). That means the fork comes in under claimed weight of 615g, but the frame is a bit over the 4.47 lbs claimed for a 17″ frame.
Stay tuned this week for the rest of the build details and first impressions!