One of the great facts about bicycle design is that there are at least two or three intriguing alternatives for every established way of doing things ... and suspension is certainly one of those established "things." In the past couple of years alone, we've seen leaf shocks, looped wheels and parallelogram seat posts offered up as replacements to the standard shock absorber. UK-based COFA Engineering recently showcased its own unique take on bicycle suspension, known as the NOAH system.
NOAH stands for Normally Operated Articulated Hybrid suspension system, and it was publicly displayed for the first time earlier this month at the Bespoked UK Handmade Bicycle Show in London.
It's a full-suspension system, but instead of incorporating the usual rear shock and front suspension fork, it utilizes two midships-mounted rear shocks. A linkage consisting of two A-arms runs from the telescopic fork to one of those shocks, allowing it to soak up the hits taken by the front wheel. You can see it demonstrated in the video below.
So, what's the point? According to COFA, there are several.
First of all, because the fork legs are supported closer to the wheel, they flex less. Additionally, the fork is lighter, as it doesn't contain any springs, dampers or other shock-absorbing hardware. The weight is instead moved toward the middle of the bike, thus reducing unsprung weight and improving the handling.
It's similar in principle to the single-arm telelever system, used in bikes such as the Scurra Hard Enduro. COFA, however, wanted to boost the amount of travel possible with that setup, while also improving the steering.
"The rear pivot point of the top A-arm is adjustable, allowing the path of the lower yoke to be altered for different riding conditions," COFA's Robyn Taylor explained to us. "For example – the steering angle when not compressed can be set steeper than usual, resulting in a quick-steering bike on the flat. However, when the forks compress the steering angle can be relaxed, aiding handling over rough terrain."
Additionally, the rear suspension layout allows for the use of a Nuvinci N360 continuously-variable hub transmission, eliminating the need for a rear derailleur – although slightly increasing the unsprung weight in the back.
In its current form, the NOAH concept bike has a whopping 230 mm of front travel, although it also tips the scales at 40 lb (18 kg). For that reason, its designers are looking into the use of lighter building materials for subsequent versions.
"The end goal is to produce a limited number," said Taylor. "We had a good response at the London show, but we do accept it's not to everyone's taste!".
Source: COFA Engineering via Bike Radar
Fork tubes require lots of sliding friction. The girder forks of old put all the friction into pivot points, but kept the spring up front. The COFA concept presented here has moved the heavy spring to the centre by using a combination of fork tubes and a girder parallelogram arrangement.
How to overcome the sliding fork tubes? Why slide when you can roll? The Coda concept could be further enhanced by replacing the sliding bushes on the lower outer tubes with a ring of ball bearings, say a ring of three vertical ball bearings at the top and another at the bottom. (When I say ball bearings, I mean an outer ring anna inner ring with caged and sealed balls between). Now it will appear as sliding, but will be rolling immune to mud and dust.
And it was interesting that any such movement phenomenon were directed forwards, not up and down.
Being a friend of Bill Allison, the famous suspension designer in Detroit who designed the Packard Torsion ride that Jay Leno effused about I asked him what was going on. He said that the hard tail bicycles were having to diffuse the errant moves into heat vibrations.
Talking with Clive I discovered that he was a fan of Bill Allison and as a youngster played with a Packard with the suspension enjoying it's self leveling qualities.
Two great minds at work and admiring each other. Neither a slouch.
Bill
Seat LOW, handlebars HIGH. Rider able to put both feet flat on the ground!
And Bill Allison, who you were aware of early on in your life, mentioned to me that your design was a very good one and that hard tail bikes dissipate bounces and jounces as heat while yours helps advance the movement.
It is amazing what happens in advances and what stays stuck in nonsense.
Staying stuck in nonsense is the problem.
bill