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  1. #1
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    Single Pivots vs everything else

    I'm not looking to start a flame war over suspension types. I'm just looking for some info to help me buy my next bike. I expect to move from my current 2013 Trek Cobia HT to something slightly slacker and FS. One thing that I have noticed is that two of the bikes I am looking at (Kona Hei Hei DL Trail and Cannondale Habit) are ostensibly single-pivot bikes. I don't know enough to evaluate the veracity of this, but the reviews on these bikes mention that they are single-pivot and yet they have both gotten rave reviews with no mention of the supposed negatives of this design (brake jack etc.). Also, the single-pivot appears to make for a lighter design. I am also considering something like the Trek Fuel EX, which has a very sophisticated suspension design, but seems a bit heavy at my price point ($3K-$4K) and it't not clear to me that it rides any better than the other 2 bikes. Can someone please elucidate for me why it is that some of these single-pivot designs seem to be so effective or is this a recent trend wherein bike designers have found ways of engineering single-pivot designs so as to minimize the undesirable traits of this suspension type? Or do riders simply ride in such a way (no braking in the bumps) so as to ensure that these traits are not emphasized?

    Thanks!

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    I'm not an expert by any means, but from what I've read and experienced is that all suspension designs have their pluses and minuses. I had an old single-pivot Cannondale and brake jack was a real issue, as well as the high leverage ratio. The single-pivot design with a rocker like the Habit are used by a couple of manufacturers and even some use it on DH bikes. It just depends where and how you ride. Best thing to do is to try and demo one for yourself and see if you like it.

  3. #3
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    I had a single pivot bike, and it worked. I can't compare it against the crazy $$$ multi-pivot FS bikes, but for me it worked. A lot has to do with the shock used, how good of compression damping it's got. My only word of advise though, make sure it uses a thru-axle. With a QR, my FS's rear end would feel really loose unless I cranked down on the QR lever beyond crazy.
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    Thru-axle is a given. After owning my Cobia for a year, I started to make a list of features I wanted in my next bike and that was one of them. Unfortunately, standards and technology have been changing so quickly that I've added quite a few more things to that list since it was first created

  5. #5
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    No braking over bumps is not really feasible. Instead, you learn to ride around the capabilities and faults of the bike you're on.

    You should do a demo day, borrow a friend's bike, or rent one from a local shop and see for yourself. That said, it's absolutely imperative to set up the suspension properly for your weight and intended purpose, because you can't evaluate something that is wildly inappropriate for your usage.

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    Interesting article on the topic of brake jack and single pivots that I found useful when I was making a similar decision. http://www.bicycling.com/bikes-gear/...s-not-here-man

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    Single pivot bikes are the end-all holy grail of all that is bicycle related. Jesus rode a single pivot, just FYI

    In general, they tend to be playful and fun to ride. They do bob. If you try to run a fox float shock on a single pivot, its going to suck. They need good shocks. Not platform, but good shocks with firm and consistent damping. The difference between a cheap shock and a great shock on a single pivot is very large, and very noticeable on the trail. Feels like a different bike. Thats kind of a cool thing though. My old kona dawg was easy to setup, easy to make it feel and respond different, and just generally pretty accepting of whatever you had stuck on there. I could sag it out and it worked well. I could run a shock that hardly sagged at all and it worked well.

    Im on a maestro giant reign now. In terms of pedaling, it really doesnt care what shock is on there. I can run the shock basically deflated and it still pedals great. Going down is another story. Multi link bikes in general seem much more picky. It wants the shock to work a certain way, and the whole suspension tends to want to work a certain way. If you like that certain way, great! If not, too bad, its not gonna change. Theres not much playing with the suspension, you just gotta set it up to work one way and stick with it. A lot of multi link bikes seem to be picky about how much sag you even run.

    The trek fuel doesnt have a sophisticated suspension. It has a single pivot design with some flashy stickers on it, and a lot of markup.

    Brake jack and squat on single pivots is something you sort of have to be mindful of on long travel bikes. But even then its overblown.

    Also be mindful that these are pretty loose generalizations about both. A single pivot bike can be built to have enormous anti squat, and it wont bob at all. Its just not typically how a single pivot is built. An hei hei will function quite differently than say, an orange downhill frame. But still, the loose generalities for single pivots are worth mentioning.

    Single pivot can be a very good design that works very, very well. It also tends to be stiff, and low maintenance. You really have to give a bike a try to see how it feels, just looking at the suspension design alone isnt truly enough to grasp how its going to ride. Some single pivots do suck, a lot. Some are fantastic.

  8. #8
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    Quote Originally Posted by Endoismynamo View Post
    I'm not looking to start a flame war over suspension types. I'm just looking for some info to help me buy my next bike. I expect to move from my current 2013 Trek Cobia HT to something slightly slacker and FS. One thing that I have noticed is that two of the bikes I am looking at (Kona Hei Hei DL Trail and Cannondale Habit) are ostensibly single-pivot bikes. I don't know enough to evaluate the veracity of this, but the reviews on these bikes mention that they are single-pivot and yet they have both gotten rave reviews with no mention of the supposed negatives of this design (brake jack etc.). Also, the single-pivot appears to make for a lighter design. I am also considering something like the Trek Fuel EX, which has a very sophisticated suspension design, but seems a bit heavy at my price point ($3K-$4K) and it't not clear to me that it rides any better than the other 2 bikes. Can someone please elucidate for me why it is that some of these single-pivot designs seem to be so effective or is this a recent trend wherein bike designers have found ways of engineering single-pivot designs so as to minimize the undesirable traits of this suspension type? Or do riders simply ride in such a way (no braking in the bumps) so as to ensure that these traits are not emphasized?

    Thanks!
    Single pivot usually refers to the chainstay as one unbroken member from the frame pivot to the rear axle. This means there is no "virtual" pivot. These bikes sometimes have linkages, like the Trek and Kona, and sometimes do not. Generally, the ones that do not are much more difficult to design with a decent shock curve (spring rate) and it is more difficult to make them as laterally stiff with half the attachment points to the rear triangle. linkages do two important things, they allow the designers to tweak the leverage rates, so the shock doesn't get easier to compress as it goes through the travel (common to a lot of single pivot non-linkage bikes actually), and it stiffens the rear end by adding another attachment point, often pretty far from the other attachment, which contributes to stiffness.

    Designs like the Trek are very good, and also refered to as "single pivot".

    Designs like the specialized FSR, Santa Cruz VPP, Pivot DW-link and Giant Maestro are mostly very good these days. In this case, the actual pivot point for the rear axle is a place in space or in some cases, it changes as the suspension goes through it's travel.

    Many of these designs started off when we were using 2 or 3 chainrings, which meant the designers had a to make a lot of compromises and come up with some pretty complex systems to work decently in both rings. More modern bikes don't have to deal with this, set up as 1x11 or 1x12, where a single-pivot (with linkages) design can actually work just as good as the above "virtual" pivot designs.

    Brake jack is very rare these days, it was more prevalent on older horst-link and similar (GT Lobo/LTS) designs. Brake squat is a little more common, but actually seen as a benefit in many cases, because hitting the brakes at all shifts your weight forward and unloads the suspension, causing the angles to steepen, so this can help to keep the rear end lower and not pitch you over the handlebars as easily. Obviously, there could be a point where it's too much.

    The bottom line is it comes down to the execution and exact bike. A good single pivot can ride amazing and be laterally stiff. A virtual pivot can pedal soggy and be sloppy, but those characteristics can easily be the opposite when looking at other bikes.
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    My first full suspension rig was a Yeti ASX, and that thing had a number of the negative behaviors that folks also refer back to with single pivot bikes. The single pivot bikes you are mentioning are all linkage-driven single pivots, which means that a linkage is used to modify the leverage rate on the shock. This goes a long way toward improving pedaling performance and tuning other aspects of the leverage curve as the bike moves through its travel.

    Other guys have alluded to this above, but modern suspension designs have actually managed to get a bit simpler in many ways while offering better performance. This is a product of better engineering paired with better shocks. I had a Nomad Carbon and a Banshee Spitfire (both 4-bar / virtual pivot bikes) prior to my current Evil Following (single pivot), and the Evil manages to stay more composed in more situations than either of my previous bikes did, and both of them had custom tuned rear shocks.

    The Habit and Kona have both received awesome reviews for being super capable trail bikes, as has the Trek. Trek's pricing is a bit ludicrous on some of their bikes, especially in carbon, whereas I think Cannondale and Kona have priced some of their latest bikes quite well. The single pivot is a simpler design, but is well designed in both the Cannondale and Kona - no reason to drop the extra cash on the Trek just for the slightly more complex suspension design unless you really love the ride that much more.

  10. #10
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    I've got a Cannondale Jekyll which, for a long travel "modern" full suspension bike, has probably the most rudimentary linkage design imaginable, short of the Cannondale Prophet. It's ridiculously fun. And so is the Prophet, my friend tells me. Don't worry about the type of suspension used, these companies aren't going to release crap.
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  11. #11
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    Quote Originally Posted by eicca View Post
    ... these companies aren't going to release crap.
    I wouldn't go that far.
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  12. #12
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    ^^ not to mention that there are suspension designs that are better than others for some use cases, as Jayem went into a little detail explaining.

    but just because it's 'better' doesn't necessarily mean that a particular rider will prefer it. and just because a lot of other people prefer a given suspension / bike, doesn't mean that YOU will prefer it.

    like I said several posts back- ride a few bikes on a trail. ask specific questions after those rides and your research. then buy something.

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    I'm also interested in the Hei Hei, anyone ridden one?
    Last edited by GRPABT1; 06-30-2016 at 07:17 AM.

  14. #14
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    I demo'ed a Hei Hei DL Trail a couple of weeks ago. I really liked it. I currently own an Evil Bikes "The Following" and previously owned a Kona Process 111. I also own a Santa Cruz Superlight 29er. All single pivot bikes, all ride and pedal quite differently. It depends on the main pivot location with respect to the top of the chain ring. ColinL is right, try to demo some. Some Kona dealers have demo bikes. Check the dealers in your area or check Kona's website.

  15. #15
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    Quote Originally Posted by rdb View Post
    I demo'ed a Hei Hei DL Trail a couple of weeks ago. I really liked it. I currently own an Evil Bikes "The Following" and previously owned a Kona Process 111. I also own a Santa Cruz Superlight 29er. All single pivot bikes, all ride and pedal quite differently. It depends on the main pivot location with respect to the top of the chain ring. ColinL is right, try to demo some. Some Kona dealers have demo bikes. Check the dealers in your area or check Kona's website.
    ??

    Evil Bikes' DELTA suspension is not a single pivot. It's an extremely complicated linkage-driven system.

    Single pivot means a single leverage ratio. If it's anything else, it's some kind of a linkage, and the person who engineered it had some goal for the variable leverage ratio, the effects of chain tension, braking and pedaling forces, and so on.

    But you don't have to understand all that stuff - Just ride the bikes. Tune the suspension. Ride some more. And buy what you like.

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    Evil Following has a single pivot suspension. It has unusual linkage system, but it is single pivot system. Very few suspension designs have single leverage ratio and it is not related to single pivot in any way. You can check out the details of many bikes suspension at linkagedesign.blogspot.com

  17. #17
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    Single pivot means theres only one pivot between the bar holding the rear wheel and the front triangle. Evil bikes are most definitely single pivots.

    A single pivot can have an infinite range of linkage ratios and curves, and any number of linkages driving the shock, or it can be directly connected to the swingarm with no linkages. Its still a single pivot as long as the rear wheel is held to and moves on an arc by the triangle by only one pivot.

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    Quote Originally Posted by ColinL View Post
    ??

    Evil Bikes' DELTA suspension is not a single pivot. It's an extremely complicated linkage-driven system.
    Linkage activated single pivot is still single pivot. AFAIK the leverage ratio variations enabled by adding additional links can't do much to modify braking behavior* and it seems to be braking that gets everyone's knickers twisted when it comes to single pivots.

    *Split-Pivot/ABP single-pivots excluded.

  19. #19
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    I have a current-generation Kona Process and previous-generation Hei Hei. So conventional, rigid seat stays and a couple pivots, not the flexing ones.

    I don't notice any weirdness under braking. But I was on hardtails before, so I don't really expect to get a lot out of my rear brake.

    On both bikes, I do notice some pedal bob with the shock all the way open. The Hei Hei has a XC-oriented CTD shock. In 'T,' it has a very solid pedaling feel. I miss that a little on the Process but didn't want to spend over $1000 more to get the fancy dampers. I may do that as an upgrade later in the season or over the winter.

    Try a couple 140 mm bikes before you spend your money. Certainly they're super fun on the trails around me.

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    Quote Originally Posted by ColinL View Post
    Single pivot means a single leverage ratio.
    In mountain biking, it means one single unbroken member from the chainstay/main pivot to the rear axle. There can still be linkages, but they do not affect the main pivot location and axle path.
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  21. #21
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    To nitpick the Treks have ABP which is essentially a split pivot, similar to what Devinci uses, but not quite. That being said I agree that there's a bit of marketing makeup going on.

    IMHO split pivot pedals great, especially when compared to horst link and true single pivots. They're all beaten by proper DW links though, as found on certain Ibis and Pivot bikes to name a few.

    If possible, try before you buy, every suspension design has it's pros, cons and quirks. What I think is great, might not make your list at all.

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    Quote Originally Posted by Vegard View Post
    To nitpick the Treks have ABP ...IMHO split pivot pedals great, especially when compared to horst link and true single pivots.
    The split pivot is a "true single pivot".
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    Quote Originally Posted by ColinL View Post
    ??

    Evil Bikes' DELTA suspension is not a single pivot. It's an extremely complicated linkage-driven system.

    Single pivot means a single leverage ratio. If it's anything else, it's some kind of a linkage, and the person who engineered it had some goal for the variable leverage ratio, the effects of chain tension, braking and pedaling forces, and so on.

    But you don't have to understand all that stuff - Just ride the bikes. Tune the suspension. Ride some more. And buy what you like.
    Evil's Delta is indeed a single pivot, albeit with a fancy shock linkage, similar to Santa Cruz's ABP bikes. It's just wrapped in carbon and clever marketing. It has all the chain tension and brake characteristics as other single pivot designs with similar pivot placements.

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    As mentioned, all designs have their pros and cons. One manufacturer's single pivot design and implementation may not ride/feel like another manufacturer. I have a Yeti 575, which is a single pivot. Some have complain about its wallow-y mid-stroke (blowing thru its middle travel). I personally haven't noticed that, or a flexy rear triangle as some have mentioned. Ride several types/brands and see which just feels better. Sometimes less/simpler is more, sometimes it isn't. good luck!
    Last edited by MASC1104; 07-08-2016 at 07:41 AM.

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    Quote Originally Posted by pdiddy View Post
    Interesting article on the topic of brake jack and single pivots that I found useful when I was making a similar decision. Jack's Not Here, Man! | Bicycling

    That article is correct. Single pivots don't jack, they squat. It is the excessive squat that ruins suspension action with the brakes on.

    It's amazing how wrong almost the entire internet is on this subject.

    I'm also going to say that most single pivots have a main pivot too low. Because the place where you'd ideally put it was full of front derailleur and stuff like that.
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    Quote Originally Posted by watts888 View Post
    That's a great list and yes there have been utter rubbish suspension bikes produced by almost all manufacturers.
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    I just lend my trusty 27.5 Heckler to a very experienced rider and he was impressed how it handled for such a simple and affordable bike.
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    Quote Originally Posted by watts888 View Post
    2,3,7,11,12&13 I either owned or still own, guess that shows my age.
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    Quote Originally Posted by Dougal View Post
    That article is correct. Single pivots don't jack, they squat. It is the excessive squat that ruins suspension action with the brakes on.

    It's amazing how wrong almost the entire internet is on this subject.

    I'm also going to say that most single pivots have a main pivot too low. Because the place where you'd ideally put it was full of front derailleur and stuff like that.
    Sorry, bumping an old thread in hopes of trolling someone to help me understand this. Bought an old "linkage driven" single-pivot bike ('06 Rocky Mtn Element) and am trying to understand the true theoretical trade-offs.

    Not an engineer--let me know if I'm making bad assumptions or using words wrong.

    This 2010 article linked above is claiming that most SP suspensions squat (not jack) under braking:

    Single-pivot bikes, in particular, have been maligned for brake jack. But most single-pivot bikes don't jack. Instead, like almost every other full-suspension bike, they do the opposite: They squat. When you hit the brakes . . . the braking force is applied to the tire's contact patch at the ground . . . opposite the direction of motion. This creates a force that acts on the pivot . . . Depending on the placement of the pivot . . . this will be either a compressive force or an extensive one. And most suspension bikes these days compress, or squat, to varying degrees.
    (Jack's Not Here, Man! | Bicycling)

    In my head, I picture a bike with front wheel locked in a clamp. (Make the fork rigid for simplicity.) Pedaling is going to create a torque that drives the rear tire forward (assume unlimited traction). If the pivot point is below the rear axle--as appears to be true on my bike when weighted/sagged by rider--the bike is going to squat. So braking must be the opposite--as if pedaling backwards on this locked-down bike--it must create a rearward rotational torque that unwinds the suspension--aka jacking.

    According to the article, this picture is just wrong. Why is that? I realize the answer must involve physics, but if you can explain without any formulas I'll have a much better chance of staying with you.

    I can see how a pivot point that moves during travel could be useful. The article makes a really interesting point--that front-end dive plays a much bigger role in the real world.

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    Quote Originally Posted by phile View Post
    Sorry, bumping an old thread in hopes of trolling someone to help me understand this. Bought an old "linkage driven" single-pivot bike ('06 Rocky Mtn Element) and am trying to understand the true theoretical trade-offs.

    Not an engineer--let me know if I'm making bad assumptions or using words wrong.

    This 2010 article linked above is claiming that most SP suspensions squat (not jack) under braking:

    Single-pivot bikes, in particular, have been maligned for brake jack. But most single-pivot bikes don't jack. Instead, like almost every other full-suspension bike, they do the opposite: They squat. When you hit the brakes . . . the braking force is applied to the tire's contact patch at the ground . . . opposite the direction of motion. This creates a force that acts on the pivot . . . Depending on the placement of the pivot . . . this will be either a compressive force or an extensive one. And most suspension bikes these days compress, or squat, to varying degrees.
    (Jack's Not Here, Man! | Bicycling)

    In my head, I picture a bike with front wheel locked in a clamp. (Make the fork rigid for simplicity.) Pedaling is going to create a torque that drives the rear tire forward (assume unlimited traction). If the pivot point is below the rear axle--as appears to be true on my bike when weighted/sagged by rider--the bike is going to squat. So braking must be the opposite--as if pedaling backwards on this locked-down bike--it must create a rearward rotational torque that unwinds the suspension--aka jacking.

    According to the article, this picture is just wrong. Why is that? I realize the answer must involve physics, but if you can explain without any formulas I'll have a much better chance of staying with you.

    I can see how a pivot point that moves during travel could be useful. The article makes a really interesting point--that front-end dive plays a much bigger role in the real world.

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    Quote Originally Posted by kitejumping View Post
    Interesting! Definitely some squatting going on there. Makes me wonder what happens when the ground gets involved.

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    Quote Originally Posted by phile View Post
    Sorry, bumping an old thread in hopes of trolling someone to help me understand this. Bought an old "linkage driven" single-pivot bike ('06 Rocky Mtn Element) and am trying to understand the true theoretical trade-offs.

    Not an engineer--let me know if I'm making bad assumptions or using words wrong.

    This 2010 article linked above is claiming that most SP suspensions squat (not jack) under braking:

    Single-pivot bikes, in particular, have been maligned for brake jack. But most single-pivot bikes don't jack. Instead, like almost every other full-suspension bike, they do the opposite: They squat. When you hit the brakes . . . the braking force is applied to the tire's contact patch at the ground . . . opposite the direction of motion. This creates a force that acts on the pivot . . . Depending on the placement of the pivot . . . this will be either a compressive force or an extensive one. And most suspension bikes these days compress, or squat, to varying degrees.
    (Jack's Not Here, Man! | Bicycling)

    In my head, I picture a bike with front wheel locked in a clamp. (Make the fork rigid for simplicity.) Pedaling is going to create a torque that drives the rear tire forward (assume unlimited traction). If the pivot point is below the rear axle--as appears to be true on my bike when weighted/sagged by rider--the bike is going to squat. So braking must be the opposite--as if pedaling backwards on this locked-down bike--it must create a rearward rotational torque that unwinds the suspension--aka jacking.

    According to the article, this picture is just wrong. Why is that? I realize the answer must involve physics, but if you can explain without any formulas I'll have a much better chance of staying with you.

    I can see how a pivot point that moves during travel could be useful. The article makes a really interesting point--that front-end dive plays a much bigger role in the real world.
    The force resisting acceleration isn't coming from the ground (front wheel locked in a clamp). It's coming from your centre of gravity. Which is around stomach height.

    Tying a rope around your waist and using that to resist pedaling and braking would be a reasonable approximation.

    Spinning up the rear wheel like in that video is not the same situation at all. That only helps if you're trying to tilt a bike in the middle of a jump.
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    Good job! Simplicity

    Unless you are doing red bull rampage this year a single pivot will work just fine. I owned a Kodiak 2 single pivot with a monarch shock and works flawlessly. single pivot contact means less complexity and maintenance. It simply works!

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    Quote Originally Posted by renenavarro002 View Post
    Unless you are doing red bull rampage this year a single pivot will work just fine. I owned a Kodiak 2 single pivot with a monarch shock and works flawlessly. single pivot contact means less complexity and maintenance. It simply works!
    Did you just necro-post?
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  35. #35
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    Quote Originally Posted by Jayem View Post
    Did you just necro-post?
    Single Pivots vs everything else-monty_python_dead_parrot_sketch_by_seekerarmada-d5muzjm.jpg
    It is the Right of the People to Alter or to Abolish It.

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