prototype Spot Brand Living Link full suspension mountain bike

It’s becoming more and more rare to find a truly new suspension design these days, but small city and commuter bike company Spot Brand seems to have done just that.

Designed by none other than Avid founder Wayne Lumpkin, it’s called the Living Link suspension system. What sets it apart is the lower linkage, which is built around a titanium leaf spring coupled with a pivot. The visual effect is a very interesting rear triangle motion, and the performance effect claims to be an enhanced spring curve, efficient climbing, smooth descending, lighter weight and less maintenance. Oh, and it’s extremely stiff laterally…

prototype Spot Brand Living Link full suspension mountain bike

A collet-style main lower pivot with dual row Enduro bearings per side effectively unifies the pivot with the front triangle to make it extremely stiff. Since the leaf spring is a shear plate in the horizontal (left to right) directly, it can’t flex or twist in any other way except the intended one. That makes for a very laterally stiff rear end.

prototype Spot Brand Living Link full suspension mountain bike

We watched as Spot Brand’s Andrew Lumpkin compressed the suspension through its travel and the spring goes from flat to curved to flat again. That means the leaf spring is very relaxed at the top of the travel, not bending to oblivion. In fact, they say it only bends a few degrees. Which is part of why they say the fatigue life is as long or longer than the carbon frames will be. Yep, that’s right, the actual production frames (plural) will be full carbon fiber.

UPDATE: Here it is in action:

prototype Spot Brand Living Link full suspension mountain bike

They say the tensile yield strength of four bearings (two on front of a rocker arm, two on the rear) is 5,300lbf, but this titanium leaf spring’s is 40,000lbf.

When they launch in Spring 2016, they’ll have Boost 148 rear axle spacing and come in two versions: The Rollik 557 with 140mm travel for trail/AM riding, and the Yobbo 657 with 165mm travel for enduro and gravity.

SpotBrand.com

40 COMMENTS

  1. Someone help me out…I remember seeing a soft tail in the 90s with flat chain stays that acted like leaf springs and the YBB type shock up at the seat stays. I thought it was Tomac, but can’t find it.

  2. dodo, if one is going to measure down to the hundredths, wouldn’t tire diameter matter?

    That aside from the fact that you’re wrong in the first place.

  3. Where our leaf spring differs from previous incarnations is the flex behavior. Unlike the systems that integrate the leaf spring into the chain stays (Funk, Black Sheep, Moots, etc), the adjacent pivot allows us to manipulate when and how the leaf spring interacts with the suspension. Instead of serving up more and more force as the suspension is compressed, our spring is relaxed at top out AND at bottom out. The position where the leaf is bent to the maximum (only a few degrees) is near the middle of the travel, where it fills in the gap of the traditional air spring curve for a more linear overall result.

  4. That bike spokejunky was a Castellano Fango, designed by John Castellano who was the guy behind the pivotless Ibis Bow-Ti I believe.

  5. dodo….. why don’t you measuring the actual diameter of MTB tires so called 650b. in my garage they range from a mesured 27.5 for a smallish 2.2 racing ralf to just under 28 with a 2.3 hans damf. the 650b mesure only works out if one were to use a scrawny little touring tire from france. we don’t like calling a 29r a 700c, just because that same rim with a road tire on it is about 700mm in diamter

  6. @dodo, Yes I get your point, however your calculation is based on the assumption that most 650b wheels (584mm BSD) are being used with 2″ tires which if that was the case then that works in fine with the reasoning that a 26″ rim (559 BSD) with a (as was typical for 20 years) 2″ tire is a 26″ wheel. However, in reality most bikes with 650b rims are using 2.25-2.4″ tires. If we do some simple numbers then we see this gives an an outer tire diameter of 27.49″ – 27.79″, so in effect actually 650b is not 650b when used in a mountain bike context, it is actually 27.5″.

    If you consider the original usage of 650b rims it was based on tires being 26 x 1.5″ which ends up being 25.99″ which for all intents and purposes was just another variation of 26″ so even calling 650b a 27″ wheel is still incorrect.

    So….27.5″ actually does exist and is correct when used in a mountain bike context however, when referring to French utility bikes the 650b designation should be used. Neither of these though are 27″ except if one were to use 2.0″ tires which doesn’t seem to happening much due to the move to wider rubber.

    I hope this explanation once and for all puts an end to all future comments and complaints that 27.5″ does not exist. May this serve as a record for all of time for all interweb users around the world.

  7. @Craig. Great explanation that anyone should understand. Unfortunately, it wont end the “27.5” wheels are not actually 27.5″ wheels” campaign that some wont let go.
    My 27.5ers wheels/ tires measure exactly 27.5″

  8. Spot…
    It slingshots the corvette around the track 🙂

    Nice explanation btw. Leaf springs sometimes get a bad name because of poor application, but they are a spring like anything else. This is a unique application as it seems to be a structural member that also modifies spring rate separately from the shock spring. Well done and unique (to my knowledge). Hopefully they are a success.

  9. hello? are the engineers that designed this even sober?

    what is stopping the leaf spring from flexing one way then the other back and forth bucking you off the bike?

    ohhh wait it doesn’t move that much. so you mean it moves just a fraction, so it really does nothing…..right?

    poor excuse of re-engineered 1990’s gimmick.

  10. Ascar…
    Think of it this way.
    A normal 4-bar, but one of the bars not only acts as a link, but a dynamic member that can change the wheel path as well as modify the spring curve that is still supplied predominantly by the rear air shock.

    Or maybe your right, and Spot spent time/money developing and testing a POS

  11. @ascar

    What prevents it bucking one off of the bike?

    The same thing that prevents an sprung suspension from doing so, a damper?

  12. @Ascar and craigsj

    Yes, I am sober when I design bikes. Pretty sober most of the rest of the time as a matter of fact. A good IPA or two has been known to get the better of me though.

    In the two years and thousands of collective miles that we’ve ride tested the 4 iterations of this platform in all weather conditions and many states, not one of us has been bucked off by the leaf spring. We’re working on a development edit showing some test ride footage in which you’ll see yours truly eating some dirt, but I can hardly blame the bike for me running out of talent in a switchback. We feel that places like Trestle Bike Park, S. St. Vrain/Sourdough, Demo Forest, Moab, Scottsdale and Sedona are venues that would expose any theoretical or actual weakness in the system. Early on, we found some things we didn’t like. Later on, we found some more; but like all good engineers we identified and addressed them. Through successive design iterations we ended up with the arrangement you see in the photos- a very solid performer by the accounts of everyone who’s ridden it. Even the not-100%-sober ones.

  13. Thanks to the engineer for popping in with some extra info. I find this a clever way to remove an unnecessary pivot and replace it with something stiffer and lower maintenance. Very interested to see how it rides. The trash talkers are without merit until they throw a leg over it. Good looking and innovative. Nice job! Any plans to integrate the spring with a carbon layup in later models?

  14. @ spot engineer
    Where will the frame be manufactured? I have a Colorado built rocker with welds that are sublime, will this workmanship follow thru?
    Also have you tried the idea of the lower link having the spring had fixed to the front triangle and the pivot on the swing arm. You could incorporate it into a neat cnc bottom bracket detail like on Yetis and turners.

  15. Spot, interesting engineering!

    Seems like a switch infinity rear swingarm movement.
    To compensate airshock at midstroke. (Only this is done radially instead of up down movement in switch infinity) save weight, prototype design and complexity as well. Bravo.

    How about small bump compliance? My guess is air shock is dealing with it mainly. A slow and fast damping with leaf spring flex sounds interesting enough to perk a test ride… 😉

    **Ideally different rider weight would need different leaf spring thickness.
    To super pimp my ride “tune” for world championship!

  16. Am I basically looking at a short dual link system that’s replaced a bearing pivot with a flex member?

    Clever. I like it.

  17. @Dave – Integrating the leaf spring into the layup has certainly crossed our minds. Let’s just say we’re working on it 😉

    @Loyd Flanders – This frame will be manufactured overseas, in a facility regarded as one of the leaders in composites development, and we intend to make use of some fancy Swedish fabric in the construction. I applaud the efforts of operations like Guru and others who are able to produce carbon fiber frames in house, however our production quantities and timelines to satisfy customer demand have outgrown our old, US-based production model. The quality, however, has not slipped with our outsourcing methods. We have modeled, analyzed and prototyped various iterations of leaf spring + pivot, and we feel that this arrangement allows the best combination of stiffness, strength, configurability and longevity.

    @WK – We’ve designed the production bike to allow some leaf spring tuning if that proves to be beneficial. It does preclude Dave’s suggestion of integrating the leaf spring into the carbon layup however. The small bump compliance is preserved, as this is an augmentation to the spring curve, and small bump compliance is more closely related to damper tuning. We’ve found that we can satisfy a range a rider preferences with mostly stock shocks, but this design does flatter a modern, high flow shock with relatively little compression damping. None of us climb our steep local trails with the “climb mode” enabled.

    Thanks to everyone posting encouragement and constructive criticism!

  18. (deleted)
    I get that the new ideas are tough to figure out now. But a flexy lower link on a DW copy is not the answer.
    Keep testing and you’ll see why.

  19. Hello. i live in Hong Kong. When that bike will be available ? Can you ship the frame here ? hope it can stay with that raw color with maybe the spot logo in bloody orange !

    make me happy 🙂

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