News High pivot o no per Neko Mulally?
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- Data di inizio
ymarti
Biker imperialis
- 16/9/03
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- Bike
- Specialized Demo 8 26 oldschool & Nukeproof Mega 29 newschool
Here’s my race bike for the opening round of the World Cup this weekend in Lourdes. This bike is a refinement of my first two frames and is a reflection of where I am in the development process.
This frame uses a unique strategy: I choose a significantly higher main pivot for a bike without an idler pulley, and intend to exclusively use an O-Chain with a large chainring (38t). This allows me to have a more rearward axle path than any modern bike without an idler pulley, while maintaining the simplicity and efficiency of a low pivot design. This frame sits in the space between high pivot and low pivot designs, which is something that wouldn’t have made sense before the O-chain. I’ve ridden this bike a few days now and it rips!
My leverage ratio is 33% progressive in a linear gradient from 3.35:1 to 2.25:1; Anti-rise is around 50%; Axle path comes forward to +10mm at bottom out; pedal kick is pretty high at 11 degrees in the 14t cog, but the idea is that the O-Chain takes care of that.
This bike was modeled by Ben Arnott @wheelsarnott who was my mechanic for two seasons on YT and is great friend of mine. Ben is a mechanical engineer, has designed a few bikes, and knew exactly what I wanted. I did the kinematics in 2D, then Ben did the complete 3D model. The frame was hand built by @franktheweldervt in Vermont.
Ben put a lot of time into refining the design of the CNC parts, retaining the bearings properly, and using production hardware. We leaned on the guys at @cascade_components for the rocker link, which they designed and cut at their shop, solving all my problems from the previous frames. @ride5dev cut this one piece main pivot yoke for me that made alignment more precise. Ben designed the bike to use a complete hardware kit from a Transition Spire along with a SRAM UDH hanger to keep things simple, much better than designing something ourselves.
I’m lucky to have had the help of so many knowledgeable people with this project. Hopefully my finger is strong enough to hold on and show what this bike is capable of this weekend!
In depth video on this bike is up now on my YouTube.
Da instagram Mullaly
This frame uses a unique strategy: I choose a significantly higher main pivot for a bike without an idler pulley, and intend to exclusively use an O-Chain with a large chainring (38t). This allows me to have a more rearward axle path than any modern bike without an idler pulley, while maintaining the simplicity and efficiency of a low pivot design. This frame sits in the space between high pivot and low pivot designs, which is something that wouldn’t have made sense before the O-chain. I’ve ridden this bike a few days now and it rips!
My leverage ratio is 33% progressive in a linear gradient from 3.35:1 to 2.25:1; Anti-rise is around 50%; Axle path comes forward to +10mm at bottom out; pedal kick is pretty high at 11 degrees in the 14t cog, but the idea is that the O-Chain takes care of that.
This bike was modeled by Ben Arnott @wheelsarnott who was my mechanic for two seasons on YT and is great friend of mine. Ben is a mechanical engineer, has designed a few bikes, and knew exactly what I wanted. I did the kinematics in 2D, then Ben did the complete 3D model. The frame was hand built by @franktheweldervt in Vermont.
Ben put a lot of time into refining the design of the CNC parts, retaining the bearings properly, and using production hardware. We leaned on the guys at @cascade_components for the rocker link, which they designed and cut at their shop, solving all my problems from the previous frames. @ride5dev cut this one piece main pivot yoke for me that made alignment more precise. Ben designed the bike to use a complete hardware kit from a Transition Spire along with a SRAM UDH hanger to keep things simple, much better than designing something ourselves.
I’m lucky to have had the help of so many knowledgeable people with this project. Hopefully my finger is strong enough to hold on and show what this bike is capable of this weekend!
In depth video on this bike is up now on my YouTube.
Da instagram Mullaly