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The next step in suspension tuning...?

DirtyMartini

Chimp
Nov 23, 2010
25
0
San Diego
I think it’s time the mountain bike community should have a tuning framework for LSC. We have good frameworks for setting sag. But we should also have one for setting LSC.
Perhaps one already exists, if so, please share.

Currently, we have a language and framework for talking about and understanding sag. We know XC should have between 15% and 25% sag, AM 25% to 33%, FR/DH 30% - 40% etc
We say things like “I used to run 30% sag, but when I tried 33% sag the bike felt more lively” and everyone know what that means.

But when we talk about LSC, we hear things like “I put the dial somewhere in the middle and I guess it feels okay.” Which means nothing to anyone else, and usually very little to the person who said it.

LSC is a very important variable in how our bike’s suspension performs, yet the average rider doesn’t have a way to measure it, communicate it, or understand it meaningfully. I think this could change quite easily for the benefit of everyone.

Instead of only measuring “sag” (which is static), perhaps we should also be measuring “dynamic sag” or “bounce sag.” This would be defined as the percent your suspension compresses when you’re bouncing on it as hard as you can in the parking lot.

Parking lot tune:
I know the “parking lot tune” gets a lot of flak from suspension geeks, and deservedly so because riders typically just look subjectively for what “feels good” to them, and what “feels good” in a parking lot may actually perform like dog crap on the trail and visa versa.
Further, I think it’s pretty common for a rider get their suspension to “feel good” to them in the parking lot, while not knowing that what “feels good” in the parking lot very well may under-perform on the trails, but they grow accustom to, and even fond of, their under-performing bike, and then a properly tuned bike that offers greater potential feels strange and undesirable to them. I either have done or am doing this myself. I’m not suggesting a strict one size fits all, but I do think there are some tuning rules that maximize a bike’s potential for everyone, even if it requires relearning what a your bike “should” feel like.

Moving on.
I’m thinking the “parking lot tune” could be very useful if done correctly. Here’s why: On the trail we have two pieces of equipment to absorb impacts: 1) our bike and 2) our body. How hard we can bounce the bike in the parking lot is indicative of our body’s ability to eccentrically absorb impact. Further, the bike’s LSC should be tuned for a) the type of riding and 2) the individual’s ability to absorb impact. Therefore, there exists a meaningful link between how a suspension will perform under a given rider and the percentage this rider can compress the suspension while bouncing in the parking lot (assuming proper spring and sag is already established).

For example, assuming you have the correct spring and sag, if you can blow through 95% of your travel by bouncing up and down in the parking lot, you have too little LSC. If you can use only 40% of your travel by bouncing up and down, then you clearly have too much LSC. But what’s the correct/appropriate range of this “bounce sag?” (please don’t say between 40% and 95%).
It seems like there could be some very good guide lines for tuning LSC according to this “bounce sag.” Maybe the guide lines are a little different for air vs coil (since air is progressive). Maybe the guide lines are a little different between DH, FR, AM, XC. Maybe the guide lines are a little different between platform and non-platform shocks. But it seems like some simple guide lines would easily help us get a starting point for setting LSC.

Just like proper spring sag settings, this is not intuitive or mathematically obvious. I don’t think it’s as though an engineer sat down, opened a physics books and calculated that “All Mountain” riding would do best with 25% to 33% sag. Instead what happened was a bunch of pros and experts went riding over and over while trying a bunch of different spring settings and they just empirically figured out XC should have between 15% and 25% sag, AM 25% to 33%, FR/DH 30% - 40% etc. It seems to me the same type thing could/should happen with LSC; it just hasn’t yet. Maybe it’s time for this happen and for LSC to get some proper love.

Unless you’re an exceptionally experienced rider, it’s very difficult to notice things like your suspension sinking too much through a corner and therefore in need of additional LSC. But the pros and experts are out there tuning and optimizing their suspensions using a talent, experience, and “feel” that most of us just don’t have. Personally, I would like to benefit from the experts’ experience just like we all have regarding spring sag. The good news is that the pros’ & experts’ LSC settings can be easily and objectively measured through “bounce sag.” But “bounce sag” has to first become a THING. Something we measure, talk about, compare, and review.

The best tuning advice I’ve heard so far is 1) set sag 2) set maximum rebound without packing up 3) set just enough LSC to prevent mushy/wallowing feeling 4) increase HSC from min one click at a time to prevent bottom out as needed.

I still think the above is great tuning advice. (It makes far more sense than the overly literal approach minimum LSC setting for bump sensitivity and high HSC setting for big impact.)
However, I think “mushing/wallowing” is too vague and subjective. Perhaps LSC tuning should instead be expressed in terms of “bounce sag” as a percentage.

What do you all think? What's your bounce sag?


(Avy Rider, please chime in. I'd like to hear your thoughts).

If you got this far, thanks for reading! :thumb:
 

norbar

KESSLER PROBLEM. Just cause
Jun 7, 2007
11,346
1,587
Warsaw :/
This is a silly idea. Damping settings depend on personal preferance, trail, bike, shock so how do you want to make a reference like the sag list you mentioned?
You don't need to be an experianced rider you just need to know what the damned dials doo and tweak them instead of asking about them in the forums. If you are less experianced finding the sweet sport will just take you more time.
Not to mention noticing your suspension compresses to much(or other problems) in corners is not really hard. Just know what to look for and adjust 1 thing at a time. I never understood why people make such a big deal out of suspension setup.
 

TWeerts

Monkey
Jan 7, 2007
471
0
The Area Bay
haters gonna hate.

i thinks the idea has some substance...but i think the general knowledge is there among the public, we just dont have a unified way to refer to it. we need to define one end of the dial as (+) and one as (-)

edit: or one define one end as zero
 

bdamschen

Turbo Monkey
Nov 28, 2005
3,377
156
Spreckels, CA
haters gonna hate.

i thinks the idea has some substance...but i think the general knowledge is there among the public, we just dont have a unified way to refer to it. we need to define one end of the dial as (+) and one as (-)

edit: or one define one end as zero
I'm pretty sure we have that. You can have your setting "all the way out" or "all the way in" or a certain number of "clicks in" from "all the way out"

I've heard this used for a while, don't think it's anything new or groundbreaking? :confused:
 

Steve M

Turbo Monkey
Mar 3, 2007
1,991
45
Whistler
Actually there are very good measures of damping (damping coefficients, threshold velocities etc), but they can't be measured without the proper equipment (dyno for starters), whereas anyone can measure sag, which is directly related to the natural frequency (and thus response) of the suspension. For forks, manufacturers should be able to provide recommended baseline settings based on rider weight, but due to the fact that the leverage ratio of rear suspensions vary significantly, there is no way to do the same with the rear. This is a large part of the reason aftermarket suspension tuners exist.

For what it's worth, I understand what you're trying to achieve by looking for a universal baseline LSC setting like we have with sag, but it's realistically impossible without a dyno.
 

Huck Banzai

Turbo Monkey
May 8, 2005
2,523
23
Transitory
Actually there are very good measures of damping (damping coefficients, threshold velocities etc), but they can't be measured without the proper equipment (dyno for starters), whereas anyone can measure sag, which is directly related to the natural frequency (and thus response) of the suspension. For forks, manufacturers should be able to provide recommended baseline settings based on rider weight, but due to the fact that the leverage ratio of rear suspensions vary significantly, there is no way to do the same with the rear. This is a large part of the reason aftermarket suspension tuners exist.

For what it's worth, I understand what you're trying to achieve by looking for a universal baseline LSC setting like we have with sag, but it's realistically impossible without a dyno.
Huzzah! Cool to get an informed answer instead of a dig.

Rep+
 

DirtyMartini

Chimp
Nov 23, 2010
25
0
San Diego
I hear a lots of ney-sayers with no explanations. Unhelpful.

Norbar: Damping settings are not entirely about personal preference. Personal preference does apply, but only within a appropriate range. Personally, I believe the "personal preference" approach has become far over applied due to most people simply not understanding how suspension works. For example, I've seen some guys almost no shock rebound damping because they think it "feels good" to them in the parking lot. Then they slightly short a double and get bounced over the handlebars like a pogo stick, get injured, and think it was just a random crash when in fact their bike was dangerous to ride because they tuned it according to their "personal preference."

Chris King: You very well may be right, but if LSC so sensitive it ought to change according to "too many variables including conditions" doesn't that imply it's a very important setting to understand? If so, all the more reason for riders have something other than "personal preference" to guide their adjustments.

Earmyshorts: What you said sounds macho and cool but is simply unhelpful and not true. Guys who go really fast are not only ones entitled to care about their suspension settings. Proper damping settings can help everyone.

Socket: Thank you for the intelligent, thoughful response. However, I must disagree. I understand metrics exist to measure damping (I'm a mechanical engineer, sounds you like may be also?). I'm not suggesting we literally measure the damping rate, because the required LSC changes with weight, and leverage ratio etc. (Just like the required spring rate). I'm suggesting we measure the net resulting effect of LSC, not the damping rate itself.

This question may help clarify:
Once your spring rate and sag are set, what determines how much the suspension travels while bouncing on it has hard as you can?

Ans: LSC

Just as we determine the required spring rate according to the spring's net effect (in terms of sag), it seems to me we can have some understanding of "how much" LSC we have by it's net effect which can be seen through "bounce sag."
Perhaps you want 80% bounce sag for one trail and 70% bounce sag for another. Great, just make the adjustment (if it's externally available) and be on your way.
 
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gurterno

Chimp
May 8, 2010
32
0
I Think it's an excellent idea. I'm one of those guys who haven't really got a clue and would love some guidelines to set lsc. Like all guidelines it would just be a starting place for further adjustments
 

jutny

Monkey
Jan 15, 2009
306
0
Montclair, NJ
fwiw, I think this is a cool idea to give people a baseline to start from.

I would be at about 70% bounce sag on my Jedi set up for last year. Lost a little weight this year and may be oversprung at this point.

the other thing I think it would be useful to know in terms of tuning for the layman, is how LSC and HSC adjustments effect each other on the various shocks out there. eg some shocks hate to be run wide open, or you need to have LSC and HSC near each other or else it gets funky.

i'm no engineer but I am very mechanically savvy, and I love suspension tech so I'm interested in the outcome of all this. At the very least I'm in for the reading.
 

John P.

Turbo Monkey
Sep 24, 2001
1,170
0
Golden, CO
I think it’s time the mountain bike community should have a tuning framework for LSC. We have good frameworks for setting sag. But we should also have one for setting LSC.
Perhaps one already exists, if so, please share.
...
<A bunch of stuff I don't understand>
...
If you got this far, thanks for reading! :thumb:
I've got a better solution. Whenever possible, just let this guy tune your suspension:
Socket.jpg
 

Tomasis

Monkey
Feb 26, 2003
681
0
Scotland
I heard something new: measure suspension on parking lot?

im not suspension expert but my logics says: adjust all settings except sag and spring on track so it is what exactly you know how the bike behaves on right place ie "dynamically moving" (lol)

My old frame with Horst link and other is Sunday. Both behave very different re "bounce" on parking lot. To go on abstract feelings to determine LSC, Im skeptical for it but I look forward for convincing arguments, discussion here.

If bounce test can be guideline for more fine tuning on track if it is possible and compatible, why not?
 
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Whoops

Turbo Monkey
Jul 9, 2006
1,011
0
New Zealand
Great idea, and perhaps the better companies will come up with a standard (or two?) ;-)

Seriously, I think it's a good idea, but think there will be problems when science runs into marketing. These will be gradually overcome, and it'd be great to see one of the bigger companies with the engineering capabilities and knowledge (SRAM, Marz) expand a bit more on LSC than they currently do in their manuals.

edit - I'm thinking here of fork set up. I think it would be much easier to educate the users and have some relativity in the set up of forks than it would be for frames
 

Steve M

Turbo Monkey
Mar 3, 2007
1,991
45
Whistler
Socket: Thank you for the intelligent, thoughful response. However, I must disagree. I understand metrics exist to measure damping (I'm a mechanical engineer, sounds you like may be also?). I'm not suggesting we literally measure the damping rate, because the required LSC changes with weight, and leverage ratio etc. (Just like the required spring rate). I'm suggesting we measure the net resulting effect of LSC, not the damping rate itself.

This question may help clarify:
Once your spring rate and sag are set, what determines how much the suspension travels while bouncing on it has hard as you can?

Ans: LSC

Just as we determine the required spring rate according to the spring's net effect (in terms of sag), it seems to me we can have some understanding of "how much" LSC we have by it's net effect which can be seen through "bounce sag."
Perhaps you want 80% bounce sag for one trail and 70% bounce sag for another. Great, just make the adjustment (if it's externally available) and be on your way.
Ah yeah, I see where you're coming from, however I think that for all intents and purposes you're still going to find it too inconsistent to make much headway with (and it'd definitely only be possible with a fork, not the rear end). How hard you bounce on it can affect how much travel you use pretty significantly, and that alone makes it very hard to measure - that's before you take into account varying degrees of progression due to air volume ramp up (or in the case of air springs, the progressive end stroke).

However, the idea has merit. It'd be interesting to see how consistently you can hit the same amount of stroke from a hard bounce. Anyone want to test this with me? Get on your bike, however it's currently set up, and bounce on the fork as hard as you can without the front wheel leaving the ground, measure the distance you push the o-ring or ziptie up the stanchion leg each time. Repeat 10 times and record each number, then post it up here and we can compare the variation in personal results.

fwiw, I think this is a cool idea to give people a baseline to start from.

I would be at about 70% bounce sag on my Jedi set up for last year. Lost a little weight this year and may be oversprung at this point.

the other thing I think it would be useful to know in terms of tuning for the layman, is how LSC and HSC adjustments effect each other on the various shocks out there. eg some shocks hate to be run wide open, or you need to have LSC and HSC near each other or else it gets funky.

i'm no engineer but I am very mechanically savvy, and I love suspension tech so I'm interested in the outcome of all this. At the very least I'm in for the reading.
Yeah this is very true - HSC opening affects "LSC" fairly significantly with most dampers. It'd be almost impossible to measure this with the rear end of any bike, and definitely impossible to directly compare between different bikes and shocks due to the huge differences between leverage rates. Entirely possible with the right measurement tools, but not something you can really measure at home.

I've got a better solution. Whenever possible, just let this guy tune your suspension:
View attachment 104086
hahah. Worryingly I think I was actually sober in that photo.
 

ustemuf

Monkey
Apr 8, 2010
198
15
Bay Area
i run 30% sag, shoot for 75% bounce sag, with a big ramp up in the last 25%.
ending stroke rebound is fairly fast, beginning stroke rebound is right above the middle.
 

4130biker

PM me about Tantrum Cycles!
May 24, 2007
3,882
447
I think it sounds like a cool idea- I'm interested to hear more from others.
 

kidwoo

Artisanal Tweet Curator
Chances are if you dont know how to adjust your own suspension you are clearly not riding fast enough to bother about it..
You have no idea just how wrong you are.


I know this is ridemonkey where once you geek out on how a shock works, you suddenly are entitled to thinking you're a capable rider but there are tons of extremely talented and fast people out there who haven't bothered to learn the intricacies of suspension like hacks do who are trying hard to adjust for suck.
 

TWeerts

Monkey
Jan 7, 2007
471
0
The Area Bay
You have no idea just how wrong you are.


I know this is ridemonkey where once you geek out on how a shock works, you suddenly are entitled to thinking you're a capable rider but there are tons of extremely talented and fast people out there who haven't bothered to learn the intricacies of suspension like hacks do who are trying hard to adjust for suck.
heh...gott'em

if fork manufacturers provide info on this, why wouldnt/couldnt the frame manufacturers do the same? even info on just the spec'd shock would be sweet...
 

Vrock

Linkage Design Blog
Aug 13, 2005
276
59
Spain
I think we need numbers.

It's about time that SRAM, Fox, and everyone else start telling us how much damping does their shocks have. Now we have Tune Low, Medium and Firm.... in the future we should have 15lb/in, 20lb/in and 25lb/in or something like that. That way we can compare different shocks or see how the new models work compared to last year.

And it's the same with "clics", they can be measured too, they should give us dyno plots, that way we could say.... I run 50lb/in of LSC, 25lb/in of HSC and 35lb/in of Rebound...
 

Steve M

Turbo Monkey
Mar 3, 2007
1,991
45
Whistler
I think we need numbers.

It's about time that SRAM, Fox, and everyone else start telling us how much damping does their shocks have. Now we have Tune Low, Medium and Firm.... in the future we should have 15lb/in, 20lb/in and 25lb/in or something like that. That way we can compare different shocks or see how the new models work compared to last year.

And it's the same with "clics", they can be measured too, they should give us dyno plots, that way we could say.... I run 50lb/in of LSC, 25lb/in of HSC and 35lb/in of Rebound...
I don't think you realise just how many variables you're asking for there (also damping rates are measured in N.s/m or lb.s/in). With all the high-end forks and shocks, you have external adjusters for compression and rebound (sometimes two for each!) that encompass a huge range. There is really no way for a manufacturer to give that kind of information to the consumer in a realistically useful way. Ohlins have a program that spits out damping curves for their TTX40 shock (not sure if you can still download it anymore though), but that's an entire computer program preprogrammed for a single ($5000) shock, that still needs to be interpreted by an experienced suspension engineer to be any use.
 

Vrock

Linkage Design Blog
Aug 13, 2005
276
59
Spain
It's not that complicated, really. And we really don't need a program, an excell spreadsheet is more than enough. We don't need to know exactly where is the knee of the curve or if the damping is a bit progressive or not. An average number is fine, it gives you a lot of info.
 

norbar

KESSLER PROBLEM. Just cause
Jun 7, 2007
11,346
1,587
Warsaw :/
I hear a lots of ney-sayers with no explanations. Unhelpful.

Norbar: Damping settings are not entirely about personal preference. Personal preference does apply, but only within a appropriate range. Personally, I believe the "personal preference" approach has become far over applied due to most people simply not understanding how suspension works. For example, I've seen some guys almost no shock rebound damping because they think it "feels good" to them in the parking lot. Then they slightly short a double and get bounced over the handlebars like a pogo stick, get injured, and think it was just a random crash when in fact their bike was dangerous to ride because they tuned it according to their "personal preference."


Ans: LSC

Just as we determine the required spring rate according to the spring's net effect (in terms of sag), it seems to me we can have some understanding of "how much" LSC we have by it's net effect which can be seen through "bounce sag."
Perhaps you want 80% bounce sag for one trail and 70% bounce sag for another. Great, just make the adjustment (if it's externally available) and be on your way.
Man I wasn't talking about parking lot riders but more about how different pros setup their bikes and it all works for them. I see what you want to do there but I think you are overcomplicating things. As long as suspension is within reasonable setup range it has to make you feel confident about your bike - hence personal preference. I agree with Socket - baseline settings would be good but you don't need to be a rocket scientist to get a fairly good base setting.
If you want to have a perfect shock setup send it to a tuner or tune it yourself if you have that knowledge. If not learn what the dials do as with the current crop of shocks you can easily set them up as you like them.


PS. Socket actually explains it better than me. Too much variables for something that is fairly easy to set up.
 

Steve M

Turbo Monkey
Mar 3, 2007
1,991
45
Whistler
It's not that complicated, really. And we really don't need a program, an excell spreadsheet is more than enough. We don't need to know exactly where is the knee of the curve or if the damping is a bit progressive or not. An average number is fine, it gives you a lot of info.
Ok, so for say something like a Fox RC4, you have:
12 clicks of HSC
20? clicks of LSC
20 clicks of rebound (could be wrong on actual number of clicks but anyway), which also has an effect on LSC
5 turns of bottom out ramp-up
Air pressure range from 125-200psi in say 10psi increments, so 8 settings

So there are 12 x 20 x 20 x 5 x 8 = 192,000 unique settings available with the shock. Each time you change one of those settings, it will affect at least one of the other parameters. The damping curve of the shock then needs to be cross multiplied with the inverse of the square of the vector array describing the leverage rate curve, in order to work out what it's actually doing at the wheel, so if you change the leverage rate by even 10%, you actually see more than 21% variation in response at the wheel. When you alter the progression of the leverage rate, rather than just the average ratio itself, you then affect the instantaneous motion ratio which in turn affects the requirements placed on the shock in the first place.

So yes, to actually parametrise the performance of the shock in such a way that the average person can understand it is pretty well impossible. Tuning and setup advice is IMO a far more practical way for a manufacturer to help the consumer get their suspension working as best it can. Custom tuners with the right know-how and measurement tools will be able to help you set up your suspension with even greater precision.

However, as Kidwoo said, you can be an awesome rider without having your suspension working very well, or you can be a terrible rider with perfectly set up suspension. If you're going to nerd out on it fully (as I like to do), be aware of the reality of it - nerdery for the hell of it is great fun and for some of us very satisfying, and it can make your bike ride that much nicer, but it's not going to change anybody from a sport level rider to a world cup rider.
 

Vrock

Linkage Design Blog
Aug 13, 2005
276
59
Spain
You have gone to the most complicated shock in the market, one of the few with adjustable Bottom Out and where the IFP Pressure affects the damping....

Take a Vivid, Elka, CCDB, Manitou, Avy, X-Fusion... You only have 3 o 4 parameters with 10-20 clicks.... A Spreadsheet for those shocks is not going to be very big or very complicated at all. Anyway, 90% of the manufactures don't even give setup advice, so there is a loooooooong way to go.
 

norbar

KESSLER PROBLEM. Just cause
Jun 7, 2007
11,346
1,587
Warsaw :/
90% of the manufactures don't even give setup advice, so there is a loooooooong way to go.
You mean that 90% that doesn't count RockShox, Fox, Cane Creek, X-Fusion? You assume a lot but all of these companies explain what all of the dials do and have "tuning/setup tips" on their sites.
 

Vrock

Linkage Design Blog
Aug 13, 2005
276
59
Spain
No, I was talking about bike manufacturers: Trek, Specialized, etc... They give some advice about air pressure in XC bikes and maybe spring rates in DH Bikes, but have you seen any advice on Damping? I don't remember anyone doing that. Maybe DW on the forums but never on an Official Setup Guide...
 

illnotsick

Monkey
Jun 3, 2009
257
0
I think it would be much easier to tune your bike if people just really understood what each adjustment does and mainly what the bike feels like when there is too little or too much of it. If you run too slow ending stroke rebound, your shock wont extend after a bottom out so your bike will feel ____. If you run too fast ending stroke rebound your shock will extend too fast on big hits, so your bike will buck you on hard landings.
 

W4S

Turbo Monkey
Mar 2, 2004
1,282
23
Back in Hell A, b1thces
302 Found

If you go to :50 in the vid you will see Nico testing his LSC, I'm guessing he's better at the testing part than most people would be. I always use the parking lot test to set a baseline for LSC and will adjust it a necessary on different trails. I think SRAM does a pretty good job in their suspension set up docs of giving a baseline for adjustments and a decent explanation of what each function does, I have 2 lyrics and a boxxer and set them up based on the Rock Shox Manual, pretty easy to understand and it covered all the dials.

http://www.sram.com/_media/pdf/tuning_guides/boxxerteam_tuningguide_en.pdf
 

norbar

KESSLER PROBLEM. Just cause
Jun 7, 2007
11,346
1,587
Warsaw :/
No, I was talking about bike manufacturers: Trek, Specialized, etc... They give some advice about air pressure in XC bikes and maybe spring rates in DH Bikes, but have you seen any advice on Damping? I don't remember anyone doing that. Maybe DW on the forums but never on an Official Setup Guide...
They don't manufacture the shock/fork. Only spec it. If you want the guide go to the mfg's website.
Still I don't see why it's a problem. As long as the manual exists what differance does it make who provides it? I don't really see what do you require. For every bike to be shipped with a manual with a given amount of "clicks" for every weight, track, eyebrow separation?
 

tuumbaq

Monkey
Jul 5, 2006
725
0
Squamish BC
They don't manufacture the shock/fork. Only spec it. If you want the guide go to the mfg's website.
Still I don't see why it's a problem. As long as the manual exists what differance does it make who provides it? I don't really see what do you require. For every bike to be shipped with a manual with a given amount of "clicks" for every weight, track, eyebrow separation?


Something like this (along with a custom valved shock ) would make a whole lot of sense for most riders:

http://www.trekbikes.com/pdf/2010/suspension/session.pdf

I truly dont understand why Trek is one of the very few companies to take suspensions set up seriously ...
 

Vrock

Linkage Design Blog
Aug 13, 2005
276
59
Spain
They don't manufacture the shock/fork. Only spec it. If you want the guide go to the mfg's website.
Still I don't see why it's a problem. As long as the manual exists what differance does it make who provides it? I don't really see what do you require. For every bike to be shipped with a manual with a given amount of "clicks" for every weight, track, eyebrow separation?

A fork is always the same, so yes, the fork manufacturer should take care of the setup guide. But a shock works different depending on the bike, so the frame manufacturer is the one that should tell how to setup their bike. Maybe there is no need to go crazy, but they should say something and take into consideration the weight of the rider...
 

DirtyMartini

Chimp
Nov 23, 2010
25
0
San Diego
Sounds like's there's a little confusion about what I'm suggesting.

I'm NOT suggesting I know what your low speed compression setting SHOULD be. I'm only suggesting an easy and consistent way to measure LSC so that we can compare and discuss it more effectively. Consistent communication is the first step to advancement.

Someone mentioned that when suspension geeks geek-out they think it makes them a better rider, or "tuning to make up for suck." I'm sure this happens in some situations, but it has no bearing on validity of the content of what the sus-geek says.
After all, if you want to know details about a rocket engine's design, who do you ask? It ain't the pilots.

Next, I'm a bit a sus-geek, but I also recognize I'm only an okay rider. An intermediate weekend warrior, but part of my enjoyment of the sport is understanding and thinking about the technology of the bikes. In contrast I was recently riding with a local (very fast) pro rider and asking him about how he sets up his fork and he literally said he doesn't know how "all that stuff" works. And that's fine. We don't need to beat each other up over how we each enjoy biking.

Also, I find it amazing how the same guys who assert "It's all just personal preference" will then happily then turn around say "I just got my shock Push'd! It's totally sick, bra!," not recognizing the inherent contradiction.
Do you suppose Push happens to magically know each individual's "personal preference?" Of course not! Push has figured out some great STANDARDIZED damping improvements that most everyone enjoys! (Given rider weight, ratio curve, and riding style) So clearly the success of Push proves it's not just all about "personal preference."

Some may think that this of "bounce sag" may work for forks, but not shocks because of different leverage ratios, and ratio curves (progressive vs regressive etc). But this is nothing new. Leverage ratio curves affect spring selection and pre-load settings similar to how they will effect "bounce sag." In fact, TF tune recognizes this by factoring varying linkage designs into their suggested sag/spring settings:
http://www.tftunedshox.com/info/spring_calculator.aspx

The video of Nico testing his "bounce sag" is not uncommon. Many really great riders are already do a parking lot bounce test with success because they have a "feel" for how a suspension feels in the parking lot will translate to the trail. I don't have the ability to translate parking lot feel to trail, and like so many others I probably never will because I'm just a weekend warrior.

I'm just saying, let's start recording/measuring the LSC that "feels right" so everyone can benefit without needing to develop "feel" for what's right. Just like we already do with spring sag.
 
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DirtyMartini

Chimp
Nov 23, 2010
25
0
San Diego
That's is really great of Trek to provide that information. But notice how all they give you is # of clicks. Granted, that is a very easy to understand, but thinking in terms of # of clicks is not translatable across different frame, shocks or rider weights. # of clicks is somewhat arbitrary. If instead Trek said, start with click 0, then bounce your bike and increase clicks until your bounces uses 75% of travel. For a 140lb rider that may be 3 clicks. For a 200lbs rider that may be 10 clicks, but this way, if you're thinking in terms of 75% bounce sag, you now have a measurements that will translate to different shocks. Say you swap out for a shock or fork not listed on Trek's manual. # of clicks doesn't mean a ___ thing! Who knows what the equivalent # of clicks is between one shock and another for the same rider? But if you're thinking in terms of % bounce sag it's not an issue. Maybe on your new shock, 6 clicks of LSC provides the same bounce sag as 2 clicks on your previous shock.


Something like this (along with a custom valved shock ) would make a whole lot of sense for most riders:

http://www.trekbikes.com/pdf/2010/suspension/session.pdf

I truly dont understand why Trek is one of the very few companies to take suspensions set up seriously ...
 
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