Dual sus

[Robrider]

 

 

That's why I say the energy is lost.

 

 

 

 

 

Not if all the parameters have been checked.

 

 

At the risk of defending JB again.. which is not my intention...

 

If a shock defelcts, the system looses energy. Thats how susspension works.

 

No matter what type of shock it is, air, oil, spring, polymer, car, motor bike, etc. there are two main components acting- a spring, and a damper.

 

Now if the damper was not there, the spring would keep you bouncing up and down many times after the "bump". (This brings to mind some of those Makro dual suspension bikes)

 

Now even the best spring in the world would eventually stop bouncing. why? Because the energy is lost in the form of intearnal heat (molecules of the spring rubbing against eachother).

 

Now if we look at the damper- In the case of a bicycle shock, its usally oil flowing through orifices. And the whole point of that is to slow the motion down. (whether its the initial deflection or rebound is irrelevant). So the damper uses the friction of the oil to slow down the motion... So all that energy is now in the oil, in the form of fluid friction or drag or turbulence or whatever you want to call it, and no longer in the motion of the bicycle.

 

No matter how many parameters you check, Thats how a shock works. If energy wasn't lost, you would be bouncing on a pogo stick.

 

[Bat-ass]

I was enjoying reading this yesterday, and thought i would try something on my ride this morning.... i did 2 back to back sprints. Ok it was outside my house on a flat tarmac road, but i think the principle remains..

As i rode back into my road after my ride, i took 2 markers about 100meters apart. i did the first timed sprint from a stand still with fork locked, BUT rear "bobing"... and the second timed sprint over exact coarse with all suspension locked..... and guess what???? with locked rear suss........ i was noticably faster???? infact it felt plane sh@#t trying to sprint with the back bobing?? JB, i back your engineering savy!!!

[Wyatt Earp]

.Dangle2010-05-28 03:59:14

[LazyTrailRider]

The fact that lockouts are something that can be left activated does nothing to increase or decrease it value. It only shows that people have short attention spans. I believe we've all done it. It's like saying lights on a car is stupid because it drains the battery if left on.

 

Exactly. Someone once asked me how often I used the lock-out on my fork, I answered "probably 20-30 times during a 3 hour ride". They thought I was crazy, but once you get into the habit, my guess is that you safe a significant amount of energy.

 

Johan, I think you covered this early on, not all the energy is returned in "bounce-back" when bobbing around. A little bit of it gets lost in heat dissipation into the damping cartridge. My guess is it goes into the oil?

[LazyTrailRider]

OK, my reply clearly took too long to type, Robrider beat me to it.

[Slowbee]

The fact that lockouts are something that can be left activated does nothing to increase or decrease it value. It only shows that people have short attention spans. I believe we've all done it. It's like saying lights on a car is stupid because it drains the battery if left on.

 

Exactly. Someone once asked me how often I used the lock-out on my fork' date=' I answered "probably 20-30 times during a 3 hour ride". They thought I was crazy, but once you get into the habit, my guess is that you safe a significant amount of energy.

 

Johan, I think you covered this early on, not all the energy is returned in "bounce-back" when bobbing around. A little bit of it gets lost in heat dissipation into the damping cartridge. My guess is it goes into the oil?

[/quote']

unless you finish in the top 10% lockouts dont do a thing. For the average JRA ridder enjoying the outdoors. But I agree, I forget alot of things.

[Wyatt Earp]

Rob rider

 

 

 

Yes and no.

 

You need to check all parameters.

 

Suspension designs, shock designs and we will go on all day.

 

The one thing you mention is the Makro bike.

 

Old suspension designs have been developed much in the same vain as these bikes, the stigma that attached itself to this has never left the impressions of some small minded individuals out there.

 

So yes full sus. gets a bad connotation due to some poorly designed systems and shocks over the years, peeps need to wake up and get with the bigger picture, it's called technology.

 

I will make one comment.

 

Suspension will rob some energy under pedaling forces, the best bike is the one that allows for the least amount of energy to be lost.

 

This becomes a combination of rear suspension design and shocks that have been designed to serve a certain purpose.

 

 

 

We can sit here all day and give pour opinions and impressions, in the end of the day it all means "squat" to me.

 

If I myself or anyone else was clever enough to be a suspension engineer, we would not be sitting here on the hub giving less than expert opinions.

[techguy]

Thank you Dangle, it comes back to my point where these manufaturer's spend hundreds and thousands on r+d,why spend all this money if some plonkers on the hub say that full sussers waste energy? We should all go back to riding fully rigid boneshakers if the consensus on the hub says suspension wastes too much energy...

[Slowbee]

Thank you Dangle' date=' it comes back to my point where these manufaturer's spend hundreds and thousands on r+d,why spend all this money if some plonkers on the hub say that full sussers waste energy? We should all go back to riding fully rigid boneshakers if the consensus on the hub says suspension wastes too much energy...[/quote']

ahhh ha! you see, they do waste energy, thats why I battle so much to ride.

 

But seriously I would exchange the wasted energy for a comfy ride anyday.

[Robrider]

I think you missed my point slightly...

 

I only used the Makro bike as an analogy to show what a bike with insufficient damping feels like. It has nothing to do with my opinion on suspension design, because its a crap bike, and has nothing on oll the technology spent etc.

 

I'm also not saying duels rob all your energy and you shouldn't ride one.

 

The fact is, the suspension is designed to absob the energy of big impacts, and it does a flippen good job.

 

All the money spent on sus design proves that there WAS room for improvement, and if they still spending the money, it could still get better. And yes, shock technology and frame design improvements that stop pedal bobbing are definately making them more efficient.

 

The ONLY thing i was trying to say was that once the shock compresses, energy is lost. And thats a good thing. No amount of design is going to change that, because thats what its supposed to do.

 

If you look at where the technology is heading, its to try and stop your shock moving while pedaling, and only move when you want it to move...

 

So I think we are in agreement, I just wanted to dispell the thought that the energy can be "returned" into the system, which it can't

 

[LazyTrailRider]

The fact that lockouts are something that can be left activated does nothing to increase or decrease it value. It only shows that people have short attention spans. I believe we've all done it. It's like saying lights on a car is stupid because it drains the battery if left on.

 

Exactly. Someone once asked me how often I used the lock-out on my fork' date=' I answered "probably 20-30 times during a 3 hour ride". They thought I was crazy, but once you get into the habit, my guess is that you safe a significant amount of energy.

 

Johan, I think you covered this early on, not all the energy is returned in "bounce-back" when bobbing around. A little bit of it gets lost in heat dissipation into the damping cartridge. My guess is it goes into the oil?

[/quote']

 

unless you finish in the top 10%...

 

Which I did, when I was still racing. Not wasting energy bobbing was naturally only a contributing factor, not the cause.

 

...lockouts dont do a thing. For the average JRA ridder enjoying the outdoors. But I agree, I forget alot of things.

Of course they do a thing (they save energy), it's whether that thing is to the average rider worth the additional hassle of forming a habit that's the question...

[Fitter]

I was enjoying reading this yesterday' date=' and thought i would try something on my ride this morning.... i did 2 back to back sprints. Ok it was outside my house on a flat tarmac road, but i think the principle remains..

As i rode back into my road after my ride, i took 2 markers about 100meters apart. i did the first timed sprint from a stand still with fork locked, BUT rear "bobing"... and the second timed sprint over exact coarse with all suspension locked..... and guess what???? with locked rear suss........ i was noticably faster???? infact it felt plane sh@#t trying to sprint with the back bobing?? JB, i back your engineering savy!!!

[/quote']

 

 Now this sounds more like a JB-type thought experiment - but made real!!!. True to form and well-reasoned!!

 

But could I make a suggestion - go repeat this on a track the MTB was made for - like a rough, rutted sand road with lots of loose stuff, rocks and stones. But do the unlocked sprint first. Then do the locked sprint and let us know the results.

 

Then back the results with some engineering savvy.

 

Yes, we could go around all day arguing the notion of power robbing. We could try and measure the quantum of energy loss occasioned by damper systems heating up. But remember these damper systems are designed to complement the real reason for having suspensions on bikes - comfort, control and efficiency (to quote!). The reality that rider input is only one of the kinetic forces impacting suspension functioning is known and as Techguy pointed out, huge energies and monies get poured into, in particular, compression damping systems to try and minimize their negative effects. Strangely enough, bob in poor designs is more a function of pedal inputs on the chain than rider leg pistoning - lateral weight shifts by the rider account for more of the bob than leg movement as well.

And yes, dampers do dissipate some of the incoming energy but the dynamics of the massive differences between small bumps and massive drops are complex, so compression damping is complex. And energy inputs are variable, not linear and this makes the job of providing comfort and control very difficult. Hence the efforts at designing differing speed circuits in these dampers. And this answers JB's rather deflected reply to my questions. You now acknowledge it is returned, but in a useless fashion:

"If the energy input into a suspension system is returned via an elastic return, it is returned to "the system" but not to the rider. The bounce-back is completely useless and does not provide any forward propulsion at all."

This might be true only if the loading or compression was linear and derived from forward-propulsive efforts. But it isn't - on a MTB the compression is complex and derives from pedal inputs, rider weight shift and trail events.

Hence the argument that lockout might not be as productive as generally supposed. Put another way, the system needs the rebound fed back into it as shock extension would be a critical aspect of suspension operation overall. It has no need to get returned to the rider.

cyclequip12010-05-28 07:22:02

[Johan Bornman]

I was enjoying reading this yesterday' date=' and thought i would try something on my ride this morning.... i did 2 back to back sprints. Ok it was outside my house on a flat tarmac road, but i think the principle remains..

As i rode back into my road after my ride, i took 2 markers about 100meters apart. i did the first timed sprint from a stand still with fork locked, BUT rear "bobing"... and the second timed sprint over exact coarse with all suspension locked..... and guess what???? with locked rear suss........ i was noticably faster???? infact it felt plane sh@#t trying to sprint with the back bobing?? JB, i back your engineering savy!!!

[/quote']

 

 Now this sounds more like a JB-type thought experiment - but made real!!!. True to form and well-reasoned!!

 

But could I make a suggestion - go repeat this on a track the MTB was made for - like a rough, rutted sand road with lots of loose stuff, rocks and stones. But do the unlocked sprint first. Then do the locked sprint and let us know the results.

 

Then back the results with some engineering savvy.

 

Yes, we could go around all day arguing the notion of power robbing. We could try and measure the quantum of energy loss occasioned by damper systems heating up. But remember these damper systems are designed to complement the real reason for having suspensions on bikes - comfort, control and efficiency (to quote!). The reality that rider input is only one of the kinetic forces impacting suspension functioning is known and as Techguy pointed out, huge energies and monies get poured into, in particular, compression damping systems to try and minimize their negative effects. Strangely enough, bob in poor designs is more a function of pedal inputs on the chain than rider leg pistoning - lateral weight shifts by the rider account for more of the bob than leg movement as well.

And yes, dampers do dissipate some of the incoming energy but the dynamics of the massive differences between small bumps and massive drops are complex, so compression damping is complex. And energy inputs are variable, not linear and this makes the job of providing comfort and control very difficult. Hence the efforts at designing differing speed circuits in these dampers. And this answers JB's rather deflected reply to my questions. You now acknowledge it is returned, but in a useless fashion:

"If the energy input into a suspension system is returned via an elastic return, it is returned to "the system" but not to the rider. The bounce-back is completely useless and does not provide any forward propulsion at all."

This might be true only if the loading or compression was linear and derived from forward-propulsive efforts. But it isn't - on a MTB the compression is complex and derives from pedal inputs, rider weight shift and trail events.

Hence the argument that lockout might not be as productive as generally supposed. Put another way, the system needs the rebound fed back into it as shock extension would be a critical aspect of suspension operation overall. It has no need to get returned to the rider.

 

Please don't associate a subjective experiment like that to my way of thinking. Had you been here long enough you would know that I deplore experiments like that. They are generally meaningles. And I'm not criticising Batt-ass' experiment he conducted to confirm something for himself. It is just that it won't hold water without controlled inputs timing etc.

 

Further, I think we all agree that suspension contributes to comfort, control and efficiency. I didn't see anyone argue that suspension doesn't have a role to play in maintaining traction. That's not what the debate is about, the debate is about suspension movements robbing energy.

 

You and your  new chum can also stop telling us how much R&D money is poured into suspension design....come to think of it, you never gave the quantum (now where did I learn that?) but simply try and impress us by suggesting large figures.

 

Budget has nothing to do with the physics and you know that well, so stop dragging around that red herring.

 

You say "Strangely enough, bob in poor designs is more a function of pedal inputs on the chain than rider leg pistoning." Well guess what, it is easy to counter that claim by looking at bobbing on a hard-tail with suspension fork. Bobbing there is purely from the legs acting as heavy pistons in the vertical plane. Transplant that model into a full susser and you have leg-induced bobbing front and back - in fact most of the bobbing comes from that force and not from the chain and therefore most of the energy lost is from the pedalling action you try and argue away.

 

Forget about "trail events" (there is a better word for that....bumps), and other BS. We've not even mentioned those and they go without saying.

  

The fact that energy rebound also goes into shock extension is moot. Of course it goes in there... but the point is that it all requires energy that comes form one depletable source only - your legs.

 

You also say that there is no need for rebound energy to be fed back to the rider. That would be very desirable indeed, so the need is there, we just don't know how to do it.

All that energy is lost to forward motion. Period.

 

Compression damping is not complex like you claim. It is either a one-stage or two-stage affair requiring one or two shims. What's complex about that? Stop trying to hide simplicity in complexity. Multiple valves are in fact a way of trying to save some of the energy lost in bobbing. On the one hand you allude to huge R&D and on the other to suspension not consuming energy. You cant swing both ways on that point.

 

Rider later movement causing suspension movement? I don't think so. That is the one movement that doesn't work on the suspension. Try it, you may find it novel.

 

Given good traction, a rigid bike on a climb is more energy efficient than a suspended one. Stop pooh-poohing around the issue and blowing smoke up selective dissidents' arses.

 

 

 

[Fitter]

Please don't associate a subjective experiment like that to my way of thinking. Had you been here long enough you would know that I deplore experiments like that. They are generally meaningles. And I'm not criticising Batt-ass' experiment he conducted to confirm something for himself. It is just that it won't hold water without controlled inputs timing etc.

Strangely, his experiment is no less thought-out than some of the tripe
you peddle here. And frankly, my tenure on this forum has little to do with my ability to recognize drivel.

 

Further, I think we all agree that suspension contributes to comfort, control and efficiency. I didn't see anyone argue that suspension doesn't have a role to play in maintaining traction. That's not what the debate is about, the debate is about suspension movements robbing energy.

 

Bootstrap this any way you like. The argument is actually about whether all suspension movements are a robbing of energy, or not. See below.

 

You and your  new chum can also stop telling us how much R&D money is poured into suspension design....come to think of it, you never gave the quantum (now where did I learn that?) but simply try and impress us by suggesting large figures.

 

You are coming across all bitter here, JB. Is this because your cloak is slipping? Is this because someone dares question your knowledge (or real lack thereof) on subjects you pronounce on? He is not a new chum - and if you had some background knowledge outside of the limited sphere of reference you do have, you'd understand just how ill-informed you're starting to sound. Please call any of the suspension manufacturers or bigger bike manufacturers to get an idea. I've been in a big R&D design facility and the real expenditure on things like suspension design defies belief. So take it or leave it.

 

Budget has nothing to do with the physics and you know that well, so stop dragging around that red herring.

 

This from the red herring master himself!! Amusing.
Budget has everything to do with it. This would be R&D budget, design, testing, prototyping etc. Are you this ignorant? The application of your dearly-beloved physics has it's home in the expenditure of budget!!

 

You say "Strangely enough, bob in poor designs is more a function of pedal inputs on the chain than rider leg pistoning." Well guess what, it is easy to counter that claim by looking at bobbing on a hard-tail with suspension fork. Bobbing there is purely from the legs acting as heavy pistons in the vertical plane. Transplant that model into a full susser and you have leg-induced bobbing front and back - in fact most of the bobbing comes from that force and not from the chain and therefore most of the energy lost is from the pedalling action you try and argue away.

 

Once again you red herring and bootstrap. Puhleeze stop projecting and debate like a gentleman. Or try, even if you're factually or intellectually challenged. This particular example is no less ill-informed than Bat-Ass. I'm guessing what, as you suggest, and frankly, your assertion that on hard tails, all suspension movement is a function of legs acting as heavy vertical pistons is just nonsense. This presupposes no body movement whatsoever, no lateral rider shift on the saddle, no arm flex, head movement etc and we all know this is not how pedals get turned. Riders typically load significant body leverage into pedal forces, more particularly in low-traction applications. This is actual weight shift, not load shift BTW.

 

Forget about "trail events" (there is a better word for that....bumps), and other BS. We've not even mentioned those and they go without saying.

 

Once again, you clearly show your ignorance. Trail events are not just bumps. They are dips or hollows as well. Not all trail events are positive, JB, and for your ill-informed mind, that's why we sag suspensions - to account for negative trail events. But you didn't know that, or you wouldn't be displaying your ignorance so clearly.

  

The fact that energy rebound also goes into shock extension is moot. Of course it goes in there... but the point is that it all requires energy that comes form one depletable source only - your legs.

 

Once again, your red herring (now where did I learn that?) bootstrapping elevates your assertion into fact. I dispute your assertion that all suspension compression derives from only one depletable source - the legs. This is simplistic, common BS (to quote). Suspension loading, if you'd bothered to apply what passes for your mind, is not this linear leg weight force you make it out to be. It comes from all of the accumulated kinetic inputs, including bump-compression and lateral weight shift by the rider.

 

You also say that there is no need for rebound energy to be fed back to the rider. That would be very desirable indeed, so the need is there, we just don't know how to do it.

All that energy is lost to forward motion. Period.

 

BS!! This is where bootstrapping gets you. Assertions based on false premises. See above.

 

Compression damping is not complex like you claim. It is either a one-stage or two-stage affair requiring one or two shims. What's complex about that? Stop trying to hide simplicity in complexity. Multiple valves are in fact a way of trying to save some of the energy lost in bobbing. On the one hand you allude to huge R&D and on the other to suspension not consuming energy. You cant swing both ways on that point.

 

More BS. More bootstrapping, more slipping of the cloak. You really don't understand suspensions, do you? Compression damping is a method of controlling and disipating all kinetic energy coming into a suspension, and for your ill-informed mind, that damping is most called for when you're bombing downhill - so where are the leg pistons then?

 

Rider later movement causing suspension movement? I don't think so. That is the one movement that doesn't work on the suspension. Try it, you may find it novel.

 

You have to be kidding!!! JB, this is like clubbing seals. Please don't take my word for it - go and read a bit on suspension designs on MTB's and you'll discover that lateral rider weight shift is one of the fundamental parameters requiring addressing. So it's not about what you think - as this post progresses, that is something you more clearly show little aptitude for.

THEN, why not sag a rider on a full-suss bike and see what effect rider positioning/attitude has on the sag measurements. Then come back here and explain how lateral rider weight shift DOESN't affect sag.

 

Given good traction, a rigid bike on a climb is more energy efficient than a suspended one. Stop pooh-poohing around the issue and blowing smoke up selective dissidents' arses.

 

Once again, and just so anyone reading this post gets a clear picture of what bootstrapping is - please see the "Given good traction"!!

Duh!!! In an earlier post I did say that lockout is best used when riding your MTB on a tar road. There is no doubt there are some small gains to be achieved - depending again on the design and setting of the suspension.

But suspensions on MTB's are not made for climbing on tar roads. Or are you so stuck in your little world of ignorance that you can't see this? Can't you understand that so much of suspension design and compression-damping design is about maximizing traction?

Talk about blowing smoke ....... . Trust me, pal, whatever I've had to say in this post is factual, reasoned and verifiable. Including the amounts of R&D monies that are allocated to suspension and compression-damping design. This stands in stark contrast to the buffoon-level tripe you have been spewing. Frankly, I expected better.

 

But I'm under no pressure to pepetuate some myth or hype as being the font of all bicycle wisdom. I'll leave that to you and your saddle.  

 

And if disagreeing with you somehow makes me or anyone else a dissident - FFS pal, just exactly who do you think you are?? I don't subscribe to any other pissant dogma - why should I subscribe to yours?

[Wyatt Earp]

Well well well.

 

JayBee

 

Experimentation is just what it says, it means that people experiment.

 

Calling everything a "red herring" is getting as old and "elongated" as a fan belt on a 1970's truck.

 

The R&D argument is also becoming a drag.

 

I see you make a lot of assumptions, give us the facts, cold hard facts or an entire thesis (even better)

 

In order to give the "hard facts" you would have to invest in some good software, video camera and a few full suspension designs.

 

Then you could video capture each individual design and put this in to the developed software, once you have done this you can start applying mathematics ( you might want to call on Jmaccelari for this)

 

Once all this has been done and all the facts and figures are available then we would have the cold hard facts.

 

Till then I would just assume that you are applying the laws of ASSUMPTION and self proclaimed logic.

 

 

 

I personally feel that the best full suspension bike is the one that "robs" the least energy from rider input.

 

 

 

Personally I will say that BatAss did a test and I will agree it might be inconclusive but at least he experimented.

 

 

 

Till then I will leave all the work to the real engineers who have the financial backing to deliver the latest state of the art bikes available.

 

 

 

Dangle2010-05-31 04:42:47

[CycleJunkie]

 

I want to clarify something about energy lost in a suspension system. I say it is lost' date=' others say it is returned.

 

Well, it is returned, in a completely useless fashion.

 

If you draw a bow, the energy stored in the bow and string, is returned in a useful fashion when you release the string. It propels the arrow forward which is something we want.

 

If the energy input into a suspension system is returned via an elastic return, it is returned to "the system" but not to the rider. The bounce-back is completely useless and does not provide any forward propulsion at all.

 

That's why I say the energy is lost.

 

 

[/quote']

 

NOW THAT WOULD BE AN INVENTION OF NOTE......