Zebra O.T.B. : 21st century mountain penny-farthing
Well, this had to happen. It’s been lurking in a corner of my mind for about two years so it eventually had to get out: A 21st century mountain penny-farthing.
I started working on it barely more than a month ago and coincidentally, as I was about to publish it, the UCI just released the 2019 rulebook allowing for mismatched wheel sizes in downhill racing !
I am SO first on the bandwagon that I might be pullin' it ! Haha :D
Edit : Well this bike has gone kinda viral on flipboard & others so you can like my Instagram or Facebook page (look in the "about" section of my profile) hopefully I should post more bikes or color variants in the future. Thank you :)
Penny-farthings are direct-drive, that's why the front wheel grew bigger and bigger, but this one is a mountain penny-farthing so I thought it needed more gears, hence that big front hub.
It was difficult to pack everything in while keeping a reasonable Q-factor (the Q-factor is the width between the two cranks, narrow is better).
On this side of the front hub is the anti-torque device to change gears on a concentric device, inspired by Rohloff speedhub.
The 203mm disk is overkill (particularly for a penny-farthing...), but it gave more room to fit the brake caliper while keeping the hub flanges wide enough. Due to the huge bearings, I had to widden the disk's spider.
I hope you like my carbon material because I spent a couple of eons refining it until I got something good enough. Note that the saddle is curved to keep the rider in place as you can't pull on the bars as well as on a regular bike.
Like the YT Tues I took inspiration from, the rear suspension is asymetrical, with some axle caps only on the left side. Also you can see the big bolt holding the pegs together.
The slack head angle prevents OTB. Well, at least up to a point. I borrowed the quad tube style of the fork from modern steel penny-farthing as I thought it would add stiffness as well as balance the design with the rear suspension.
While the big wheel would monster-truck its way over pretty much anything, the small wheel would have a hard time clearing small obstacles and could even get stuck and snap the frame in half, so the 150mm of suspension travel make up for it.
This part was trickier than expected, but after a few unsatisfying attempts, inspiration struck with an integrated seat clamp which allowed for a minimalist, squared shape that left just enough room to fit the eeSilk seatpost with 20mm of squish.
A massive 10.5x3.5 Fox DHX2 handles the suspension duty. The suspension isn't there so much to dampen shocks than as a way to give more clearing capabilities to the rear wheel.
Yep’, these are BMX pegs that act as the double step. For maximum solidity, the peg is fixed in a metallic insert in the carbon frame and a big bolt holds the pegs together throughout the frame.
Frame protection and integrated cable routing, front and rear.
A weird blend of concentric unicycle Kris Holm hub and Rohloff speed hub with what would be huge bearings. Is this even possible ? I don't know. The Effigear cranks are borrowed from my previous bikes, and shortened.
Well, obviously these brakes weren’t designed to fit the thigh clearance of penny-farthing bars.
Little details matter... :) And as on the rear, all cables are internally routed.
Full carbon, but without gold accent.
This one is probably faster. Waaagh !
Matte black. Rather boring on this frame.
These colors would work even better with fat tires, but then you couldn't pedal anymore.
Trendy enough in full white. Maybe.
50" ain't dead !
There isn't much free space on this bike, but this seems to be the best spot for a water bottle ;) The mudguard acts more as a "tireguard" for the rider's thighs when turning than as an actual mudguard.
Classic layout shot. You can see the metal insert for the pegs.
Some kind of flowy, calligraphic style...
...however, it leaves the shock unprotected against the rear wheel splatter.
Sorry, no numbers, I thought the geometry of this one was irrelevant :)
Dandy Macaskull with his carbon penny-farthing. And carbon top-hat.
Bunny-hopping is probably impossible... but it's not like you really need it with such a wheel.
—Hey JSB, what d’you think about the new guy ? —I’m not sure… He looks awkward... that big wheel… —Yeah… compensating for the small one, haha… also those bars… —Yeah… looks arrogant… —We should not judge him on looks though, let’s give him a chance…
—Ok big guy, you can’t really ride but you’re a funny blend of past and present, you’re in !