We're currently in the midst of some rather nerdy content at Pinkbike. Behind the Numbers
is in full swing, taking a look at the suspension systems of five trail bikes and how the values and curves line up to the way the bikes ride. Our latest podcast
got in-depth with bike setup and how our tech editors prefer to have their bikes working.
Some of you are evidently enjoying this down the rabbit hole approach to the geeky side of bikes. However, some of you think we should just go and ride our bikes. I'd like to say that we do both and am very grateful for the members of the industry, past and present, who like to chin scratch over the numbers and
ride their bikes. Without them we wouldn't be where we are today and the bikes simply wouldn't be at the level they are, allowing you to extract as much fun as possible when you do go and ride. The whole 'just go ride your bike' argument for me is a little invalid.
Unfortunately then, for those amongst you who use that argument, this week’s poll is looking into suspension systems. I've had my head in them for the past four weeks and will do for the coming future so I'm dragging you in there with me.
Maybe this is my drum to beat, but engineering a bike is a practice in the art of balance. There are so many factors involved, each with their unique advantages and disadvantages when you tweak their individual dials that it makes plate spinning while juggling stood on one leg look like a doddle. It's not a check list that you work through, but more constant cycles of iteration that ever decrease in the adjustment size until either your deadline arrives or you sit back and know you've hit it bang on. If those two arrive at the same time then it's a jackpot.
Looking at just the suspension system, which our latest podcast touched on, you have so many factors all at work together. How the bike will compress the shock, how it will rebound, how it will react to acceleration and deceleration, different construction methods, pivot hardware, packaging for the rest of the components on the bike, the list is big. Even the cable routing can be a driver to defining a suspension layout!
Wwith each brand and individual having a different set of drivers to approach each project with, let alone opinions, experiences and environmental factors, it's simply no surprise that we have the vast array of designs out there that we do. I for one find it fascinating and love playing Sherlock Holmes to find out the reasons why certain bikes are the way they are.
Without further ado, we ask you, what's your favourite suspension system? And we've somewhat removed the marketing terms from the categories to see exactly the layout you like, or help you understand which bike is actually which layout.Single PivotExample - Orange bikes
About as simple as a suspension system as you can get. But don't let that simplicity fool you into thinking the performance is lacking, quite the contrary. These bikes have a swingarm between the mainframe and rear axle with that swing arm also driving the shock.
Single Pivot Linkage DrivenExample - Commencal Meta TR
Still a single pivot, with a swing arm between the main pivot on the main frame and the rear axle, but now with a separate linkage system used to drive the shock. Same number of pivots as the four-bar bikes.
Single Pivot with Concentric Rear AxleExamples - Trek's ABP and Devinci's Split Pivot
Still a single pivot with a linkage driving the shock, but the difference comes when looking at the braking characteristics as the caliper is technically mounted on the seat stay and not the chain stay, like the other single pivot bikes.
High Single Pivot with An IdlerExample - Commencal Supreme DH bike
Still a single pivot, but now pushed so high that the amount of chain extension needs to be addressed with an idler pulley, changing the chain line. Most high single pivot bikes drive the shock via a pull style linkage tucked away between the swing arm and main frame.
Long Link Four-BarExamples - Nukeproof Mega and RAAW Madonna
Now we disconnect the rear axle directly from the main frame, and introduce the instant centre. All the frame members, or bars, are long and usually this includes a Horst pivot doing the disconnecting between the main frame and rear axle. The Nukeproof drives the shock with a top mounted link and the RAAW uses a rocker link. You can also drive the shock using a bottom mounted link a la Specialized Stumpjumper.
Short Link Four-Bar, Co-RotatingExamples - Ibis Ripmo and Unno Dash
If we push that Horst pivot, usually out by the rear axle, way closer to the main frame then we come to a short link bike. Still a four-bar system but now with two much shorter links connecting the rear triangle to the main frame. One differentiating point is that the links are rotating in the same direction.
Short Link Four-Bar, Counter-RotatingExamples - Santa Cruz and Intense bikes
Same as above but now the links rotate in opposite directions. The shock can be driven off either the top link or the bottom link.
Four-Bar with a SliderExample - Yeti
Always an advocate for something slightly different, Yeti have been using sliding components to their suspension systems for a long time. Their latest Switch Infinity system has the rear triangle pivoting on a slider that moves up and down as the bike goes through its travel.
High Pivot Four-Bar with An IdlerExample - GT Fury DH bike
Still four bars, but if you so wish you can point the IC up real high compared to other four-bar systems. The same issue arises however as the high single pivot designs - you need to account for the huge chain growth with routing the main chain line higher up and closer to the high IC.
Four-Bar with a Leaf SpringExample - Spot Ryve
Still technically a four-bar, but instead of the lower link pivoting at each end, Spot fix where it mounts the rear triangle and use a leaf spring idea to allow the movement.
LawwillExample - Old Rotec bikes
Back to the idea of the Horst pivot, but now the other seat stay pivot is dragged back close to the rear axle. Looks exactly like popular race car suspension systems, but the wheel and direction of travel is turned 90 degrees.
Six LinkExamples - New Specialized Demo and Enduro and Atherton Bikes
Take a four-bar system, and then add a couple more links. In the case of the new Specialized Demo and Enduro, and Canyon Sender for that matter, the bike's instant centre is defined by the main four-bar system and then the shock is driven from a separate linkage system. So it's as linkage driven four-bar system, but with six links.
In the case of the Atherton bikes, the extra two bars are actually in between the chain stay and the main frame, essentially creating an instant centre for just the chain stay, which then is taken into account when calculating the instant centre of the whole suspension system. The shock is then driven by means of a rocker link. This is then a 6-bar system.
HardtailJust for a laugh
When this suspension system poll idea was trialled out at one of our daily Pinkbike meetings, hardtail came back as an answer. Me gusta, so it's in here as a cat amongst the pigeons.