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There have been a number of full-suspension MTB platforms over the years that saw the bottom bracket (BB) mounted in the rear triangle instead of the front. Those frame designs boast advantages of less pedal bob and increased pedaling efficiency since pedal force is generated on the same rigid structure that transfers it to the ground — like a hardtail. The disadvantages of those designs might be obvious: with the rider’s body weight on the pedals, the rear suspension becomes fairly rigid and ineffective. Bryan McFarland’s Paradox Suspension design aims to harness the plusses of a rear-mounted bottom bracket while foregoing the minuses of those earlier iterations.
The video above is a rudimentary depiction of how McFarland’s design would function, providing the upward and forward axle path that high-pivot bikes are lauded for. Additionally, this system would do away with chain growth since the distance between the BB and rear axle remains constant. Unlike previous versions of this system, the Paradox cross-linkage design allows the BB to move across a horizontal plane while the rear axle moves up and down through its travel. The horizontal BB movement is thought to forego issues with the rider’s weight above the system while gaining the known benefits of a rigid rear-end and BB connection. What it might feel like to have your feet pulled rearward with every impact is a question for the prototype phase of this bike.
We had other questions for McFarland around mud management with the complex linkage that sits just ahead of the rear tire, and the level of stiffness the frame designer feels will be possible with the original design. McFarland said that the suspension design is the real innovation here and that the frame will change greatly throughout the testing process. He has already redrawn the Paradox frame to include a more traditional downtube after receiving feedback and concerns around the frame’s potential stiffness and the amount of force that will be spread across the links and pivots. Put simply, the bike is a work in progress, and like everyone on Kickstarter, he needs help funding that work.
Paradox Suspension has a Kickstarter goal of raising $94,000 to cover the costs that would see this frame to market. Click over to their Kickstarter page for additional details or to add your support.
14 Comments
Jan 12, 2022
Jan 11, 2022
Jan 11, 2022
Jan 11, 2022
Jan 11, 2022
Unified Rear Triangle.
Twas a thankfully short-live rear suspension design perhaps most widely known by the Trek "Y" bike. It really only works well while seated. When standing it essentially locks up. This design is a bit different but still has the same basic short coming. And let's not even talk about the enormous lateral flex this would have.
I have friends that are engineers, so ya. ;)
Jan 12, 2022
Jan 11, 2022
Klein also made one (Mantra).
Jan 11, 2022
Jan 12, 2022
First off, the high pivots are praised for REARWORD axle paths, not forward like this. Forward is the worst thing you can have.
The way a URT/iDrive/Maverick Monolink works is that your weight is pushing the rear tire down. Since this BB does not have vertical motion, your weight does not impact the suspension. The URT is meant to stiffen when standing so it is more efficient like a hardtail but plush when seated. This design will not change sitting vs standing.
So you don’t get the URT “benefit” but the downsides of forward axle path and fluctuating reach when the suspension moves.
And what is the lower part of the front triangle going to? It doesn’t attach to the BB so why does it drop down in the new drawings?
The Maverick Monolink was the most worthwhile design but should be reserved for XC racing bikes and technical climbers. It just suffers from bad seat tube angle that might not be able to be fixed.
Jan 13, 2022
Instead of wasting people's money get a 3d cad software like solid works Refine your design then get a welder and make a nothing fancy prototype in your garage to see if it works and works well. Then go back to Kickstarter only if your design works and isn't a flop and offer to give supporters a frame with their support. The carbon moulds are the expensive bit. You don't want to waste other people's money on a mould if the design doesn't work. You don't need a fancy carbon fibre prototype for proof of concept!
Or forget the whole thing about trying to be the next Dave W and buy an evil offering and go ride:)
Jan 14, 2022
Jan 13, 2022
Jan 13, 2022
First of all, URTs from the 1990s were dropped for a reason. Creating a new type of URT that functions like a modern mountain bike was said to be impossible. Everything you've ever read about URTs do not apply to this bike. I'll explain a little below, but I encourage people to read the Kickstarter page is it thoroughly explains the bike. -Also, the concept art of the bike should not be taken as a literal example of the bike. I invented the linkage/suspension, the engineers will build a bike around that using contemporary geometry with a structure that resists flex.
The suspension stays active while seated or standing, this is because of the pivot point located above and slightly behind the bottom bracket. There's no unspring mass. This makes a URT active. Previous designs had a pivot forward of the bb which created most of the problems.
The suspension is progressive. Impossible for a URT, right? Well, not anymore. As you will see in the kinematics video of the Kickstarter page, the linkage creates a progressive leverage ratio, very progressive in some variations of the linkage. This means it will have a bottomless feel that modern bikes are known for.
Meanwhile, the axel path is rearward similar to a high-single pivot bike. This allows it to roll square hits with ease. And oddly enough, this rearward axel path does not have to move forward again to achieve a progressive leverage ratio like most bikes.
The most interesting thing about the bike is that it retains traditional URT separation of suspension and pedal forces. This means the suspension is free to respond to obstacles the same way a full suspension bike does when it loses a chain. Remember the DH riders winning races without a chain? Thats what happens when you separate the forces. It makes the suspension buttery smooth and super stable. Likewise, pedaling no longer loses efficiency from chain tension binding or pedal kickback. It the way a full suspension is supposed to feel.
Brake jack must be the worst, just like old URTs. Well, no. This has to do with pivot location. A pivot forward of the bb loves to brake jack and that what old URTs did. A properly placed pivot point on a URT balances anti-squat and anti-rise to prevent squat and brake jack.
If you'd like to know more, visit the Kickstarter page. It's informative and you can see the kinematics for yourself. If you're excited for innovations in mountain bike suspension that can make a trail/enduro bike pedal like a XC bike, then consider supporting the project.
Thank You and Happy Riding!
Jan 13, 2022
Kickstarter projects (when funded) usually finish delivering a first batch of some product to the people who financially contributed to the project, while here you are basically asking for free money to patent an invention and secure all the possible earnings. It's like looking for an investor but saying them you won't share the profit...