What's the Deal with Spot's Living Link?
Spot's Living Link from left: Main pivot hardware, lower link with bearings on one end and carbon leaf spring on the other, the aluminum pivot hardware that mounts on the chainstay bridge, and the four bolts that attach it all to the swingarm.
Like a lot of things we use today, carbon fiber leaf springs sound sophisticated but are actually based on a design that first showed up a long, long time ago. Back in the mid-1700s, those old English carriageways were rough enough to rattle everyone's (presumably already rotten) teeth loose, but a bit of comfort came in the form of flat steel bars laid on top of one another with the axle put in the middle of it all.
The steel leaf springs both held up the carriage and hopefully took a bit of the edge off those cobbles and potholes when they flexed vertically.
Leaf springs have been around since the mid-1700s and are still in use today.
Jump forward nearly three hundred years and you'll still find steel leaf springs on many modern vehicles, although they're mostly used on heavy-duty trucks or other machines where a simple, reliable suspension solution is needed. You've likely spotted them; flat, heavy pieces of steel that were probably very rusty and primitive looking.
These leaf spring things sound more farm equipment than high-performance, don't they?
The composite leaf springs on both ends of a Corvette (but not the new C8 model) would say otherwise. Their single-element leaf springs are far lighter and many times more reliable than if steel was used, and its shape and packaging mean that they also add an anti-roll element that over-powered cars like the big Vette benefit from.
Furthermore, because different composite parts can be designed to flex more or less while looking essentially the same, the Vette's leaf springs can be made to act precisely how smart people want them to while still fitting the car's tight confines.
There are, of course, plenty of valid reasons why coil springs are more common, but let's see 'em do all that stuff.
Of course, flexible carbon leaf springs aren't new to the bike world, either, with the crazy-looking Lauf suspension fork probably being the most obvious and current example. But while Lauf's creation uses a bunch of glass-fiber leaf springs to hold the rider up, Spot's Living Link system employs a single, nearly hidden leaf spring that only supplements the bike's Fox shock.
The small section of carbon fiber that makes up half of the lower link is almost completely hidden from view by the Ryve's seat tube and swingarm, but Spot says that it plays a very important role in how the suspension performs.
Spot's new Ryve looks like a normal dual-link bike... Until you take a closer look at the bottom link.
Just like many other dual-link bikes out there, when the Ryve’s rear suspension compresses, both links rotate clockwise; the top link compresses the shock while the bottom link rotates upwards. The carbon leaf spring is completely flat and unloaded at top-out and bottom-out, Spot's Andrew Lumpkin explained to me, meaning that it isn't putting any force into the suspension at those times and the Fox shock is doing all of the work.
But the leaf spring is flexed, or loaded, when the bike is sitting between 25-percent of its travel, otherwise known as the approximate sag point, and 75-percent of full travel. In other words, Spot is using the carbon leaf spring to alter the spring rate in the middle portion of the travel.
Spot says that it wouldn't be possible to have the suspension perform as it does with a normal link in place of the carbon leaf spring.
Why the heck would you want to do that? According to Lumpkin, this lets them create the spring curve they wanted by figuring out their ideal leverage ratios for the beginning and ending parts of the travel. Then they used the carbon leaf spring to tune how the suspension performs in the middle part of its travel where it's loaded and where you spend most of your time.
It's claimed to make the bike very efficient but, more interestingly, they’re also saying that the flexing leaf spring is storing energy that’s returned when the suspension extends. So much so that Spot claims that it can even supply extra “pop” to help you leave the ground. Sounds pretty neat, right? You bet, but I had to reach out to Spot for some clarification on this one.
I mean, does that little carbon leaf spring really store and release energy? And wouldn't the damper just absorb it anyway?
The answers: yes and sort of.
Spot can control how the Living Link flexes by changing the carbon layup (left) to meet their needs. The leaf spring flexes over an aluminum plate (right) that's mounted on top of the chainstay bridge.
First, to understand what's happening, we need to remind ourselves that rebound speed is tied to the spring rate. The firmer the spring, the more that spring wants to extend the shock. Air suspension isn't linear, either, so there will be more rebound force wanting to extend the shock at bottom-out than there is at top-out.
Now let's picture the Ryve's rear-suspension bottomed-out after an impact and starting to rebound.
Because the leaf spring's forces aren't being applied to the suspension from bottom-out to 25-percent extension, the rebound speed will be relatively slow until the leaf spring begins to enter the equation. From that point to 75-percent extension, the leaf spring is flexing and working in conjunction with the shock's air spring. Then, when the suspension extends past that point, the leaf spring goes straight and no longer applies any force, which means a slower relative rebound speed near top-out than if the carbon was replaced with a normal, non-flexy link.
What all that means is slower, presumably more controlled rebound after big impacts that use most of the bike's travel, faster rebound after small and medium impacts in the middle portion of the bike's travel, and then slower rebound (relative to if the link didn't flex) at the top of the travel.
The benefits to all that, Lumpkin told me, is that they can ''preserve the big hit recovery near bottom out, but also preserve the traction benefits of slower rebound near top out.
So, do you think there's something to Spot's carbon leaf spring, or is it just different to be different? I've got a 115mm-travel Ryve in for testing, so stay tuned for a video review and a verdict on the Living Link system.