How much Anti Squat is too much?

Dude! said:

Thanks man. Can you please explain what you see that suggests that Yeti and the latest VPP to be head of the game? Not sure what makes them standout. They all seem to have high AS and pedal feedback, so I am assuming it is more to do with their suspension curves?

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When you start looking at more than just the AS/feedback charts, you'll see how they offer more desirable traits overall. If you're only looking at 1-3 charts mainly, you're not being as a discerning. A good design attempts to optimize everything that can be further optimized, noting any possible drawbacks. Possible drawbacks might be that it's heavier overall, a pivot point might block a long seat tube from being inserted, might create cable routing challenges, rock strike vulnerability of a lower link, be more expensive, and/or might prevent use of a water bottle in the frame.

I personally like high brake anti-rise, around 100%, maybe dropping off a little deeper in travel. Euros that do their little switchback front wheel pivot like a lot less of this, otherwise I don't personally see why it shouldn't be as close to 100% as possible. I find higher brake anti-rise allows you go with more all-out speed in the straights, since stability under braking is outstanding. Since there's less to fear, when time comes to control that speed, you essentially become more fearless. Like they say, you go faster with better brakes, since you're more confident about controlling the increased speed.

The leverage curve on a bike like the SB5c is super dialed for modern shocks for a "trail bike feel". I honestly think they nailed all the sweet spots with their SB5c's suspension traits, to bring out everything a trail bike should be, though people might be sticking up their nose at things like it not being slack enough, having CS that are too long, no water bottle mount, or isn't as stiff as the SB6c and SB 29ers (I would totally defend all these points as having their own good sides). Having a flat 2.45 curve, combined with a spring curve that's more coil-like, creates an extremely predictable force curve. When you can predict what the bike does, there's less uncertainty, less fear, more confidence, and just overall better behaved. Santa Cruz flattened out their curve considerably, but they like a bit more midstroke plushness. Pivot and Turner have ditched their typical older curves to adopt a similar fairly flat curve with light regressive end stroke, to work with modern shock offerings. A lot of respected brands moving this way... my E29 has a similar curve, except it lands on ~2.75 average (prefer it lands closer to a base tune level, like 2.0, 2.5, or 3.0, for upgrade compatibility without needing custom tuning). It's due to the new shocks available, and tuning to be optimized with them. Though, I can see Pivot using their old curve if they really wanted to save weight for an XC bike that couldn't run a EVOL can (6.5x1.5), to get it more coil-like.

In the forces chart, I like to see a gradient as linear as possible, smooth progression towards the end stroke, and with for it to reach full travel without needing too much force (with a standardized rider weight and sag level, like Antonio's on linkage, I prefer 1700 N generally for my trails). I don't like the gradient to be too U-shaped (esp not exceeding 20 N/mm), with the middle requiring too little force (under 8 N/mm too soft for me), as I'm not much for plushness (I consider it wallow), though others might just consider it compliance. I prefer quality travel, over quantity, but I guess it can be worked with through damping, though that becomes a problem if there's fade. Coil-like gradient curves that are consistently in the 10-20 N/mm range are preferable to me (well reviewed Pivots tend to generally nail this, like their Mach 6 and Switchblade).

The flat AS curve at sag, which drops immediately off midtravel, found on the Yetis and latest VPP bikes, is essentially the best compromise between a flat AS curve (that's less sensitive to how much sag you run, more freedom to run different shock setups), and a sloping AS curve (more active beyond sag).

Put it all together to better understand your bike: I just got a RM Thunderbolt frame that I'm building up to replace my Ripley. I got it mainly due to the geo, and to try out 27.5. RM recommends running 35% sag. I look at the AS at 35% (considering the gearing I plan to run, and whether or not the frame is down/upsized for my body), the degree of kickback of a typical compression that uses 1/3 of my travel (so little, so I will be happily spinning this up), my options of upgrading the shock and what how the spring curve would be effected by such a curve (looks more suited to a high vol air can), and how much force it would take to achieve full travel.

R.M. Thunderbolt 2014 - Linkage Design

The progressiveness is off the charts, and a coil-like spring curve like the Debonair isn't going to make it any easier to use up that travel, so I see why they recommend so much sag (like their DH bike). Fortunately, I hear the frame is stiffer than it looks, so that means I'm looking forward to hitting all the optional hucks to flat and trying to boost for more vertical on jumps on my local trail, with less worry about the bike. The low AS just means that I need to keep the bike moving at higher speeds, which I will be inclined to work on by just riding more. Good thing that it's intended to be built up light, and easier to accelerate. Overall, I get the impression that I want to experience what it's like to abusively manhandle such a bike that seems to be such a petite, yet resilient figure (kind of sounds S&M)...

If a design hits all such targets very close to dead on, that's impressive, but once you consider that the target's always moving due to improving shock technology and the change in what consumers demand, it's straight up amazing. It's not really like hitting a lotto, it's a lot of brainwracking work, ever expanding how big your picture is of everything, filling in the chunks of info you have into it, and trying to render it in your mind with higher resolution to better be able to pick out finer grained details, and then be able to translate that into Autodesk Inventor or whatever, from a rough image to a working design. You also don't know what your competition is doing, you're just working off of customer demand really, and whatever the management decides needs attention... you don't want to compete too directly with what other companies have, instead wanting to offer a solution that somehow differentiates itself in a desirable manner. All the while, not being too ahead of the game, as consumers won't buy what they don't know they want, and the lack of credibility doesn't help. Perceived credibility is a tall hurdle Tantrum faces, which generally is fixed by respected brands buying into his idea... just don't want it to turn into a Yeti-like case, which took the Switch idea and ran with it, making it their own, with Sotto Group not really being involved anymore (they're now split with Beale doing Transition's designs and Earle doing who knows what).

Varaxis said:

The leverage curve on a bike like the SB5c is super dialed for modern shocks for a "trail bike feel". I honestly think they nailed all the sweet spots with their SB5c's suspension traits, to bring out everything a trail bike should be, though people might be sticking up their nose at things like it not being slack enough, having CS are too long, no water bottle mount, or isn't as stiff as the SB6c and SB 29ers. Having a flat 2.45 curve with a spring curve that's more coil-like, creates an extremely predictable force curve. When you can predict what the bike does, there's less uncertainty, less fear, more confidence, and just overall better behaved. Santa Cruz flattened out their curve considerably, but they like a bit more midstroke plushness. Pivot and Turner have ditched their typical older curves to adopt a similar fairly flat curve with light regressive end stroke. A lot of respected brands moving this way... my E29 has a similar curve, except it lands on ~2.75 average (prefer it lands closer to a base tune level, like 2.0, 2.5, or 3.0, for upgrade compatibility without needing custom tuning).

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I'd disagree with having flat leverage curves, it makes it too easy to bottom out the suspension unless the shock is stuffed full of volume spacers, and if you do that the air spring curve gets wonky and the rebound is hard to control without some fancy custom tuning on the shock. IMO a straight progressive curve like the one on my Norco Range is the way to go, the ramp up means you're no longer depending on the progressiveness of the shock's air spring to prevent bottoming, and a with a more linear air spring the damper setup becomes more flexible and easier to optimize. And since it's a straight slope it's still very predictable, there's no dead spots, sudden ramp ups, or anything wonky, it's just a smooth progression. Plus I can stuff a coil shock in there for DH days.

As for the RM Thunderbolt, I've ridden one, I had it set at 25% sag and still bottomed it out but I was abusing it enough that I put a wobble in the rims. The jumps & drops where I bottomed it will use up about 85-90% of the travel on my 160mm Norco, and that bike is setup pretty stiff with 20% sag and more volume spacers than the factory spec. Fun little bike, but I just don't have space for one at the moment.

aerius said:

I'd disagree with having flat leverage curves, it makes it too easy to bottom out the suspension unless the shock is stuffed full of volume spacers, and if you do that the air spring curve gets wonky and the rebound is hard to control without some fancy custom tuning on the shock. IMO a straight progressive curve like the one on my Norco Range is the way to go, the ramp up means you're no longer depending on the progressiveness of the shock's air spring to prevent bottoming, and a with a more linear air spring the damper setup becomes more flexible and easier to optimize. And since it's a straight slope it's still very predictable, there's no dead spots, sudden ramp ups, or anything wonky, it's just a smooth progression. Plus I can stuff a coil shock in there for DH days.

As for the RM Thunderbolt, I've ridden one, I had it set at 25% sag and still bottomed it out but I was abusing it enough that I put a wobble in the rims. The jumps & drops where I bottomed it will use up about 85-90% of the travel on my 160mm Norco, and that bike is setup pretty stiff with 20% sag and more volume spacers than the factory spec. Fun little bike, but I just don't have space for one at the moment.

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That's a misconception that flat leverage curves are easy to bottom out. A flat leverage curve merely doesn't modify the spring rate curve.

It's also a huge misconception that classic air shocks were hard to bottom out. Considering how little force it took to make it compress through the middle of its stroke, the final progressive part hardly made any impact on how much total force it took to utilize full travel. A coil sagged to the same % took more total force to use full travel, since the *average" force to use each mm of travel was higher than the air spring's average.

- Spring curves, tuned by amount of force to utilize full travel*

- Spring curves, adjusted to sag at the same % (modified graph from Cane Creek)

* A rider that weighs 175 lbs, with a weight bias on the bike of 65% rear, 35% front would put a fixed amount of force on shocks. The Y-axis on these charts measures this force. For the first chart, draw a line horizontally from this force, and you'll see the Fox's spring curve intersect way earlier, followed up by the Vorsprung air spring line, then the coil, indicating that the Fox would need far less sag (stiffer spring) to be able to not bottom out as easily as the more linear spring curves.

Since a flat leverage curve doesn't do anything to modify the spring curve, you can pretty much just look to the spring curve for tuning. A coil-like curve, feels coil-like. I'm literally calling a coil-like feel, without the progressiveness of a DH bike, to be ideal for a trail bike feel.

I have the BC Edition of the Thunderbolt, which comes with a different shock. The Fox that comes on the others has the classic air can, which requires far less force to go through travel. The coil-like spring curve would mimic a DH bike, due to the massive progressiveness. Antonio modeled it with a typical Fox spring curve.

Compare to a Jeffsy, modeled with an EVOL can's spring curve. Its 2.95 to 2.05, which closely mimics RM's 2.75 to 1.8, to better interpolate what a DebonAir would do to the T-Bolt. Takes 2575 N to utilize full travel on a Jeffsy, vs 2225 N on a T-Bolt. A DebonAir is more linear than an EVOL can.



Also compare a Yeti SB without EVOL (1625 N) and then with (1925 N):



Don't forget the various ways to tune the spring curve, such as with travel spacers. Easier to add progressiveness, than it is to to reduce it, without affecting other things like midstroke support. Without EVOL, the bikes are notably more plush in the midstroke needing only 6 N of force per mm of travel, vs 10 N on the linear springs.

Use this to convert N to lbs: Convert newtons to lbs - Conversion of Measurement Units
- Example references: 1700 N = 382 lbs to bottom rear suspension
- 2500 N = 562 lbs*

* remember that weight is split between 2 wheels, and that this is modeled after an average weight man of around ~165 lbs. A heavier guy running the same sag % will be running a higher spring rate, which would need proportionally more force to bottom out, but can be comparable in terms of G-forces (or a factor of their weight, like 3.5x weight to bottom out).

Long story short, the misconception of the flat leverage curve meaning a bike is too easy to bottom, comes from fallacious logic like the following:
A) Air sprung shock is perceived to be progressive
B) Coil sprung shock is perceived to be more sensitive/supple than air sprung shocks, and not progressive
- Experience of an air sprung shock on a flat leverage curve shows that it's easy to bottom out, blame leverage curve because A) must be true, and it is expected to require more force due to being progressive.
- Without testing a coil-like spring on a flat leverage curve, it can be reasonably assumed since air sprung shock was easy to bottom out, the leverage curve must make coil even easier to bottom out, because B) must be true.

Reality is way different than this failure of logic would have you expect. Your point should be that flat leverage curves generally require less force to utilize less travel than a straight progressive curve, if certain things are kept equal, like the shock and frame geo/design.

aerius said:

I'd disagree with having flat leverage curves, it makes it too easy to bottom out the suspension unless the shock is stuffed full of volume spacers, and if you do that the air spring curve gets wonky and the rebound is hard to control without some fancy custom tuning on the shock.

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Your wonky rebound control is, to others, relatively spritely and lively. Maybe not ideal for traction in repeated big hits, but on a shorter travel bike and large volume air can, muting the rebound around sag but getting a bit more pop out of small compressions or preloads is actually a desirable trait for a trail-shenanigan bike.
On a fast gravity bike, leveling that complaint is absolutely valid, but on a bike designed much more around uphill/downhill performance I think it's much less of a drawback, and with the addition of modular volume spacers in an air spring, it's easy to sell that bike as having a wider range of riders it can appeal to.

I am very much experiencing the limitations of the Rocky Mountain progressive end stroke + DebonAir can on my current setup (long-shocked Instinct - complete with the IFP-compression limitations of the 7.785x2.25 shock) where using 100% travel is a challenge for my 230lb self even running 35% sag, but as a clyde-proof combination I honestly couldn't be much happier. Mid-stroke support is definitely a compromise right now depending on where I have the LSC lever set, but if I cared to take some HSC off it and drop the spring pressure on the pedaling platform I'd be very close to an ideal setup - but for an out-of-the-box M/M/320/S tune on a shock which was only twice the price of servicing my Fox CTE-Evo HV - can't honestly complain.

aerius, that link isn't inconsistent with what I've said. In fact, if you read it carefully enough, you'd realize that they even bring up more points like how telescopic forks don't have a leverage curve, since they're straight 1:1, and a flat-linear rear curve would match that. Wouldn't you suspect that to lead to a less imbalanced ride, to have a similar bump response from both?

They also imply things like how more progressive leverage curves add that "hammock-like" curve back to the resulting bump response (forces) curve, resulting in a plusher/wallowy midstroke.

The main difference between a hammock like air spring curve on a flat leverage curve, and a linear spring curve on a progressive leverage curve, is that the the initial stroke is more supple with the progressive curve. I like the supple initial stroke, but not the wallowy midstroke. It's no coincidence that most popular bikes come with lightly progressive to flat leverage curves now, some maybe with a regressive end stroke to allow for easier utilization of full travel and more air volume spacing tuning.

Regading damping, a speed sensitive damper works smoothest and more predictably with a flat-linear bump response curve. Varying that curve to be stiffer here, softer there, creates more of a contrasting experience that can be felt as spikes and wallows.

Yes, I've read it. It's noted that an overly progressive leverage curve will result in mushy midstroke among other issues. As for forks, I'd argue that the setup requirements are different from the rear because of how the bike is weighted and the impacts it's expected to take; you're not going to land a 7' drop with 80% of your weight on the front unless something's gone spectacularly wrong whereas that's something that the rear end has to deal with on a fairly frequent basis.

Regarding most popular bikes having flat to lightly progressive curves, well, that's because most consumers want bikes that are really plush and use all their travel on 2-3' drops. Almost every aggressive rider I know who owns one of these bikes has stuffed their shocks full of volume spacers to avoid excessive bottoming and a number of them have sent their shocks out for custom tuning as well. It's not a coincidence that every DH bike I know of has a fairly progressive curve, it's what's needed on a bike that goes downhill fast over rough terrain and takes repeated big hits. I ride my Norco Range the same way I'd ride a DH bike; full speed and no mercy so not surprisingly I want the suspension to work the same way.

I'd give you positive rep if I could (need to spread more around). Anything backed with reason to open up the minds of the masses that were brainwashed to think that "open" compression damping is best, and that any fancy susp system that allows it should be desirable.

I don't run as much LSC as you, due to worries about fade and deadening the trails so much that they feel featureless (overkill feel). Typically run it in the middle, adjusting it to be more open for fade-prone descents, and slower for timed runs. I also like how much faster my times are in pedaling sections when running less sag. If only I had a shock that had separately tunable HSR and LSR... that's the main thing I'd want to get custom tuned, running it how you have it, with higher HSR and less LSR. Right now, I run a compromise of slower rear rebound and faster up front. HSC, I don't touch too much, generally keeping it mostly open for casual social riding, and adding a few turns whenever I get serious, proportionate to how hard and recklessly loose I ride, especially if I'm bottoming. Part of my draw to RM's Ride9, was the ability to tune my spring rate according to the rebound tune (lighter/heavier rider positions).

I also stuffed my E29 with a larger volume spacer, 2 sizes up from stock. Came with the smallest one pre-installed, and tested out the shock with more sag, and found it super comfortable while cruising in the saddle, but too sluggish when out of the saddle. Was like a whole new fresh experience when I took my HT out, first time in a while, after riding the E29 with more sag, due to ability to actually hammer out of the saddle with the expected surge of speed with each pedal stroke. Pumped more air in afterwards. Speaking of my HT, I lost some air in my rear tire cause the short CS is so rough on the rear wheel, and noticed that my pedal strokes were causing my rear tire to compress, even causing my ass to bounce on the saddle--this is the same rearward weight shift issue that designers resort to AS to try and address.

Sadly, to a large number of people, suspension is about as much of a black art as any other mysterious technology out there, like geo/fit, rear suspension, wheel building, carbon, or even forging. Also sad when people are willing to just throw money at things, to get better performance, especially if it only takes perceived consensus (trends, AKA numerous up-to-date recommendations) to convince them so.

I'm kind of curious as to how/why regressive leverage curves aren't as sucky as people perceive them to be. I imagine they tend to take more air pressure than normal, and have stiffer initial stroke, which I suppose imparts a more XC-racy lockout feel. I know Scott bikes had a regressive to flat curve, but they run custom shocks (Nude), which are a mystery to me.

Varaxis said:

brainwashed to think that "open" compression damping is best, and that any fancy susp system that allows it should be desirable.

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Yes agree. My target is I suppose "right" damping, whatever that means. If the adjuster is at one or other end of its range of adjustment, it just tells me I have no further scope to adjust. As I enjoy geeking out on the setup I avoid products with damping presets in favour of fine adjustment but it took me a hell of a long time to lose my brainwashed fear of the deeper LSC settings on my Pike. What I did find was that two back to back pinned DH runs that got some proper heat into the fork reduced the range of LSC clicks available on the fork. Cold, the Charger RC damper had a range from 0-10 clicks and a bit of free movement. Hot it topped out at 9, solid. I'd now advise avoiding the last click or two from closed on the Charger LSC as there seems to be some thermal expansion going on.

Going back to the original anti squat question, how does the anti-squat model take the CoG height of the rider into account? If I'm sitting tall (or indeed, standing tall), isn't there going to be more weight shift than if I'm hunched over?

I guess my definition of the sweet spot makes allowance for my habitual body positioning during pedalling, but could it mean that the ideal AS, represented, say, as a percentage for 32/16 at 35% sag varies significantly between riders of different size?

petercarm said:

Trying to relate it to my own recent experience with my Devinci Spartan.

I had a memorable enduro event where I had tried to reduce sag for more efficiency on the links between stages. The pedal kickback was horrendous. Lost minutes on a pedally, rocky stage. Spat traction on every loose climb. The chain wedged its way through my upper guide and jammed the cranks coming into a rooty, steppy corner that I launched through and barely survived. I've had better days on the bike.

I run 34T or 36T front ring. Together with running more rear sag I now avoid the kickback but it puts the problem down at the other end of the travel with it too easy to bottom out. Shock is a Vivid Air R2C which I have been running with 5 bands.

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Interesting. I've ridden my friend's Spartan and I didn't have any issues with pedal kickback even when were riding a trail which was pretty much a flat to uphill rock garden. His bike had a Monarch Plus RC3 and was set with 20-25% sag with the stock number of spacers with the flip chip in the low & slack position. I did notice some mild pedal kickback but it wasn't nearly enough to bother me or mess up my riding though I should note that it takes a lot of kickback before it starts to bug me or get in the way of my riding, even my Norco Range feels fine unless I'm in the granny ring. I found the traction was fine on loose climbs with the way it was set, though I think my Norco had the edge on it. Hard to say for sure since we weren't running the same tires, we are now so I'll try to remember to test that the next time I ride his bike.

petercarm said:

Going back to the original anti squat question, how does the anti-squat model take the CoG height of the rider into account? If I'm sitting tall (or indeed, standing tall), isn't there going to be more weight shift than if I'm hunched over?

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In this linked article, you can see how it's graphically represented (second method, based on chapter 9 regarding squat and dive of Tony Foale's book): Anti-Squat Geometry - Data for Motorcycles. DW also describes how it is calculated in his patent: https://www.google.com/patents/US7128329. This page also sums it up well: i-track suspension

Feel free to load up linkage and check your bike out in various states, and try to better understand it (there's a free demo):

- Spartan sagged in a climbing config (estimated). ~105% AS with extremely high kickback

- Spartan sagged in a slight descent where you can hammer for near max speed (estimated). ~135% AS, still high kickback

Some notes to be aware of:
- On a bike, the rider is considered the primary body of mass. The CoG can be lowered it the rider is super light and the bike isn't exactly light, which can explain why Specialized tends to run a lower CoG (if a rider weighs 125, and a bike weighs 25 lbs, it accounts for 16.67% of the total weight), while others disregard the bike weight in the equation and centralize the CoG according to the rider (typically in front of the belly, in a riding position).
- The lower the CoG, the higher the AS line is in relation to it, and therefore the higher the percent of AS. The further away the front axle is, the higher the AS line is. This is how designers can maintain consistent AS values across a size range, and why downsizing/upsizing, overforking a bike, sag, geo tweaks (flipchips, adj dropouts, offset bushings, anglesets, etc.) can affect the ride.

After reading some of the basics from the articles, you should be able to tell, from just these few images, how it's pretty straightforward how a lower pivot (or instant center) results in lower anti-squat, how the angle of the chain matters, and how the CoG height plays a role.

Have you tried changing out chainring sizes? I'd be compelled to upsize to a 34 elliptical/oval ring, considering how averse I am to high kickback. I'm afraid the Norco Range that aerius is on is even more extreme with the kickback.

I'm still wondering where the "high traction moments" exactly occur, with high AS bikes. Traction comes from sticking to the ground, but individual perception of it tends to either judge traction based on the minimum traction events (especially where high traction is expected), or the highest traction events where it's expected to have low traction. I highly doubt their traction on loose climbs, but I can see how they can give ground hugging traction where there's holes/bumps in which a typical suspension would spend more time in the air, rather than trying to extend back down to the ground quickly.

The i-track description of low AS behaviour:

http://www.i-tracksuspension.com/suspensiontheory2.html said:

In between pedal strokes, there is less weight transfer and tyre force reduces. At the same time, the suspension returns to its normal position (the centre of gravity rises), which temporarily increases the tyre force at the contact patch.
An uneven pedalling action produces a relatively constant tyre force, resulting in more traction.

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The bit that isn't emphasised is that the behaviour is exactly the same in grip/slip conditions.

Low AS:

• Slippage = reduction in driving force
• Reduction in driving force = reduction in weight transfer
• Reduction in weight transfer = suspension returns to normal position
• Suspension returning to normal position = temporarily increases the tyre force at the contact patch

Compared to a neutral AS

• Slippage = reduction in driving force
• Reduction in driving force = reduction in weight transfer
• Reduction in weight transfer = Tyre force at the contact patch immediately reduces proportionately (higher AS will temporarily reduce grip even further as the CoG lowers)

So higher AS provides a tendency that a momentary loss of grip becomes a spin out. The higher the AS, the worse it gets.

As usual, user preference varies greatly and the situation is dynamic; any simplistic description will fail to cover every circumstance and terrain encountered by any particular rider.

aerius said:

Interesting. I've ridden my friend's Spartan and I didn't have any issues with pedal kickback even when were riding a trail which was pretty much a flat to uphill rock garden. His bike had a Monarch Plus RC3 and was set with 20-25% sag with the stock number of spacers with the flip chip in the low & slack position.

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My experience has been very similar to this (2015 Carbon SX with DebonAir shock):

http://www.bikeradar.com/mtb/gear/category/bikes/mountain-bikes/full-suspension/product/review-devinci-spartan-carbon-sx-15-49767/ said:

... the rebound definitely throws up some curve balls. Even with dual speed, position sensitive 'Rapid Recovery' damping there are times when pedal stroke and shock extension combine to create a sudden and severe hop.

If your weight is forward it's enough to hop the back wheel off the ground and it certainly puts a hole in your pedalling rhythm if you're on the gas out of the saddle. The power bounce isn't helped by the noticeably linear stroke of the Dual Position air spring version of the Pike fork.

The Spartan is significantly more controlled with four volume spacers in the shock and a lower pressure that doesn't overload the start stroke rebound so much though.

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Great stuff! I really enjoyed the continuation of this topic.

Last year, I bought a medium Evil Insurgent, which was long bike for me. Though I could ride it through adapting a new riding position/technique, I wasn't having a much fun on some of my tight trails. So I downsized to a small, I noticed two important aspects, 1) the suspension felt more plush I am assuming due to weight distribution, 2) significant increase pedaling-induced feedback. I would pedal and the bike would just start moving up and down, almost like a resonant response. It was so bad, I couldn't ride the bike. I didn't notice this at all with the medium. Based on this conversation, my COG shifted further increasing an already high AS. Is this correct?

Downsizing decreases AS and AR. Anything that brings the front axle back will decrease AS/AR. If you happen to be super light, the frame's lower CoG might be a minor contributor to lower AS/AR. While the AS/AR might decrease, the chain growth doesn't decrease, nor does the resulting kickback. You're just compromising stability in the bike's response to acceleration/braking, and the bike's shock was tuned assuming that the linkage would handle such movement.

Plushness might have come from less breakaway force being needed, or just quirky shock setup. I know the DebonAir shocks can sag oddly on Evils. Can pump anywhere between 175 to 225 psi in it, try to cycle it to equalize chambers, yet you may find it still results in the same sag %. Just to be sure, are you using the terms correctly? Plush suspension generally means it uses a lot of travel in response to bumps. Wallow is the extreme of plush, meaning excessive travel being used. The opposite is supportive, meaning it's more of a solid platform. Harsh is the extreme of supportive. Supple means soft and sensitive. Racy and responsive might mean a direct, feedback rich feel that lets you feel what your tires, letting you feel the surge of your pedal strokes. Pedal-induced feedback is a bit vague and ambiguous. For example, you can better describe them as deep compressions, where if you pedal directly out of a corner, you might feel that it rides so low that you are smacking pedals more often... or you can say that it feels very pronounced when you are just in the parking lot going at 3-5 MPH, bobbing severely (could be an extension and drop back to sag effect).

I'm curious about the different riding techniques that long bikes and shorter reach bikes each favor. Regarding cornering, I believe you're more likely to get your outer elbow up when you turn, getting your core to sort of commit weight behind the front wheel, while letting the rear do its own thing. With a longer bike, you tend to have to trust the front to stay planted as you sort of guide it and let the bike swing around, with you as more of a passenger. The longer the front center or rear center is, the less it pitches on bumps and the more planted it generally is. Longer dimensions likely make it take more effort to purposely lift the bikes wheels and sustain manuals and such, but that's a relatively minor trade off for more speed and comfort.

The longer bike allows for interesting suspension tweaks, resulting in less kickback while still getting the desired amount of AS/AR.

This thread is priceless. Thanks Varaxis and others for sharing your expertise, and taking the time to put your thoughts down so eloquently.

Like Aerius, I too have a 2015 Norco Range (a notoriously high AS bike). It is, without a doubt, the most complex, mysterious bike I have owned in over 25 years. I am on it constantly (almost 2 full 8 month seasons on it now) and yet I am still fiddling with the suspension and learning how to best ride it. Contrast this bike with pretty much any Kona I have ever owned, which (despite whatever negativity anyone cares to have for them) are truly out of the box, plug and play, point and shoot bikes that require zero fiddling and have no learning curve.

Except for when I am on my fixed gear bike, I have always been a very relaxed, seated climber, which I suspect helps greatly with controlling the Range's shock from extending under load. I also use the middle, trail mode setting for the shock (100% of the time) which I also suspect helps control the shock extending. As far as pedal kick back goes, yes - I experience it in the same places on the same trails - flat, heavily rooted stretches are the most pronounced. That said, I seem to be able to completely "beat" or eliminate the kick back with aggressive (and 360 degree) pedal strokes. It's when I am pedalling somewhat passively (or lazily, up and down only) that the kick back becomes pronounced and irritating.

Anyway, I would be so interested in hearing your thoughts on the Norco's AS-impacted riding characteristics, so I can compare them with my real life experiences so far.

I really like the Range and for a big travel, lanky almost mini-DH like performance, it's a very competent climber. I clean almost all trails in my area. That said, that bike mercilessly punishes me when I am not riding strong. When I am feeling strong (good sleep, etc.), that bike is invincible (which could likely be said for any bike). It feels like I can skim or float over the tops of roots, rocks and other gnar on the most technical of climbs. At times it feels almost effortless. But when I am even a little tired, that bike can get hung up more than any bike I have ever owned. I assume all of this is largely attributable to the AS, rearward axle path travel characteristics of the bike.

I know you have precious little time to be catering to requests like this, but if you could give a sentence or two about how you expect the ride to feel for the Range in language I can understand (ups, flats and downs), it would be interesting to compare that to my own, on-bike experience.

I am going to read and re-read this thread. Tons of interesting stuff to be learned, which may help me with my further fiddling of things with my bike. Thanks again for all the very valuable contributions.

PS - I just got back from a ride. Pre-ride I checked my pressures and added 15 PSI to my rear shock. It made all the difference in the world. My SAG was still relatively the same afterwards but the difference on the trail was night and day. I felt like I was floating over everything, instead of living in every trough between roots and rocks. Never before have I had a bike that was so finicky with (and responsive to) suspension adjustments. Then again, never before have I had a bike with so much AS. Not sure if the two are related. When this bike is set up correctly, it is the best overall bike I have had in my life for the terrain in my neck of the woods. But when it is not set up just perfectly, it can literally suck your soul from you.