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Mkiii demo impressions, pedal feedback, and sag ques.

7K views 71 replies 18 participants last post by  Chris2fur 
#1 ·
So on a recent trip to Northern AZ I had the chance to ride an Mkiii on some of the Secret trails in Sedona. First, my overall impressions of the bike were very good with one noticeable exception, which I'll get to later.
This trail network has a lot of variety, our ride was about 1 1/2 hours, enough to get a taste of how the Mkiii handled different situations
I'm around 190 lbs, the shop mechanic put about 155 psi in the Fox Float R from what I recall, giving a little less than 25% sag, I'm guessing 22/23 %.
From what I had read about the dw-link suspension on this and the ibis forums,
I was expecting a great ride, and the mkiii didnt disappoint, at least not initially.
The first part of the ride was up and down rolling singletrack interspersed with some loose rocky climbs. Traction was very good if not excellent climbing the loose stuff, although not quite as good as my Chumba XCL. The rear tire would break sometimes if I tried to stand completely out of the saddle as I do on the XCL on similar loose stuff. (Tire pressure was not too high, we let some air out to make sure of this)
During this part of the ride everything about the bike seemed to handle very well, didn't notice any pedal stall in rocky climbs like I often did on my previous blurXC. What I did notice, if you were climbing and going over a bump, was that you could feel the suspension start to stiffen slightly at the top of the pedal stroke, but then slacken later on as you were pedaling over the bump.
A very smooth, some might say positive feeling pedal feedback, but barely
noticeable at the pedals, as many have said.
The latter part of the ride was more technical, a lot of sharp rocks with very
uneven transitions over larger rocky outcroppings and stuff, we were climbing in and out of washes and stuff. Here I noticed a cadence changes at the bottom of the pedal stroke during the transition stage after clearing a technical obstacle.
The last part of the ride was climbing up a steep wash, which was mostly a large flowing rock with a lot of g-outs of about 1 1/2 feet. I realized I was feeling
a little pedal feedback, so I decided to increase the sag by releasing a little air from the Fox Float. I didnt have time to measure it, but being familiar with how
it feels letting out air on my other Fox shocks I would say it was in the range of 20 psi, which should have brought it into the recommended 25% sag range I would think.
Anyway, long story short, after this we did that last rough climb about a half a mile up the wash with all the g-outs. The pedal cadence issues were still there, in fact a little worse because of the g-outs. After the ride, my right knee felt like I'd been riding a blur, sorry to say. (I have an old injury, but I dont have this issue on the XCL)
Remembering the figures that Steve_from_JH posted on a thread on the Felt
forum in response to a question I asked about pedal feedback rates of various bikes, the figures Linkage gave now seem to me to be more or less on the mark. The figures were comparing the Ibis Mojo, the Motolite, Ellsworth Id, and blur. I the 32/20 gear ratio the Mojo only about had a third of the pedal feedback
of the blur, but in the granny ring, this increased to about 75-80 % of the blur.
So my conclusion is that you cant escape pedal feedback on a bike that uses
the drivetrain for antisquat. The pedal feedback is very smooth on the dw-link compared to others like the blur, but its still there, whether you feel it or not.
The following day we did a a ride in the Airport Mesa area - I think the trail was called windsurfer -
a much longer, more technical ride overall where I was riding my Chumba
and one of the other guys was on an mkiii. At one point we were doing a climb where you would normally be in the middle ring but we were in the granny because the trail was lined with basketball sized boulders. As I was watching the pedaling of the person on the mkiii in front of me, I noticed he was experiencing the pedal cadence change at the bottom of the pedal stroke just as i did. This had the effect of slowing down his momentum, in this situation the smooth pedal strokes on the XCL translated to better acceleration in this kind of stuff, even though in a smoother climb the mkiii would drop the XCL.

Anyway, long story short, while I was impressed with overall ride characteristics
of the mkiii, the pedal feedback makes it a no go for me.
I was wondering what kind of sag folks that own mkiii's normally run and whether they experience any pedal feedback issues or not.
I know 25-30% is recommended so during the initial part of my ride it was a
little on the low side.
 
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#27 ·
le_buzz said:
The only time I notice any pain is if I am pedaling in too high a gear for the terrain.
One way of describing the effect of pedal kickback is that it will feel as though you were going into a higher gear as a bump affects the suspension. The greater the kickback the higher a gear it will seem to be.

On a bike like a DW-link, where both anti-squat and kickback diminish with travel, the effect will obviously be greatest at the onset of the bump. The fact that it diminishes is probably why riders say they don't perceive it. After the initial perception of the bump impact through the pedals, the easier pedaling gives a smooth feeling that riders like.
 
#28 · (Edited)
Hey Le_buzz,

Check it out, I HIGHLY suggest getting rehab for your knee before going into surgury. Surgury basically will take 4-6 months out your life and getting back on the bike really is a slow process. You basically have similar issure that I had with my knee. There is absolutely nothing (besides a knee replacement) you can do about arthritis besides strengthening the muscles around your knee. On a positive note strengthening your knee really works well to protect the knee from further damage and pain. Biking unfortunately is NOT going to make your actual knee better or make the pain go away. What will make it better is: leg lifts (everyday), swimming and basic knee exercises. This is not difficult stuff at all. Just pick up a book on knee rehabilitaion. Your goal should be to strengthen all the muscles and tendons around your knee so your joint doesn't take all the direct force.

To answer your other question, I have ridin the Blur and I owned a Nomad and I honestly didn't notice any difference in knee pain, just strange pedal kickback in some of the gears, but nothing that I would say causing more knee pain. Now, if my knee was to get kicked off the pedals completely I would have to say that 'yes', that would cause some pain. I have, and I am saying this in all honesty never noticed pedal feedback or kickback on a DW link bike. That is why I like riding them so much, they feel totally nuetral (to me). I think that is why others are reacting here in the way they are in defence of it. But in the end it's all about what works for you and what type of riding your'e doing. It's hard to fault the IH DW-link bikes but nothing is perfect, for me it's very close.
 
#29 ·
le_buzz said:
derby,

I realize that dw-link bikes are superior in the anti-squat department.
I would ideally like to have more antisquat than I have on the XCL, but not
at the expense of pedal feedback. The particular configuration of the horst link on the XCL really accelerates amazingly well, especially considering the 32.5 lb weight of the bike. I recently noticed during granny ring pedaling that there is less bob out of the saddle than when seated. The smooth acceleration up technical granny ring climbs is one of my favorite traits of the bike, I'm finding I'm using less and less propedal as I get more tuned in to the ride.
Le_buzz, I though I was the most "oversensitive" of riders (well maybe Davide is more). But you may be more "oversensitive" to feedback than me. I agree with pretty much all you've noticed in your ride report.

I do think the dw-Link can be adjusted to rider preference using deeper sag for less feedback without loosing as much efficiency as other designs with little sag.

I can sense the feedback like what you are saying, but only before the suspension cycles going from smooth to hitting the first sharp bump, and only in the in the lowest couple of granny gears. The feedback is a bit firm and appropriate for high performance. Repeated sharp bumps loose that sense of momentary feedback of the initial hit, unlike other designs that repeat in feedback or kickback on rough trail (such as high monopivot).

There is going to be performance tradeoffs to stabilize the high centered rider weight on a suspension bike. IMNSH (in my not so humble opinion) the dw-Link does the best at avoiding the sacrifice of shock tuning for traction and comfort at the loss of acceleration and stability.
 
#30 ·
derby said:
Le_buzz, I though I was the most "oversensitive" of riders (well maybe Davide is more). But you may be more "oversensitive" to feedback than me. I agree with pretty much all you've noticed in your ride report.

I do think the dw-Link can be adjusted to rider preference using deeper sag for less feedback without loosing as much efficiency as other designs with little sag.

I can sense the feedback like what you are saying, but only before the suspension cycles going from smooth to hitting the first sharp bump, and only in the in the lowest couple of granny gears. The feedback is a bit firm and appropriate for high performance. Repeated sharp bumps loose that sense of momentary feedback of the initial hit, unlike other designs that repeat in feedback or kickback on rough trail (such as high monopivot).

There is going to be performance tradeoffs to stabilize the high centered rider weight on a suspension bike. IMNSH (in my not so humble opinion) the dw-Link does the best at avoiding the sacrifice of shock tuning for traction and comfort at the loss of acceleration and stability.
Yes, I agree. I was thinking this afternoon after posting that last thing, that the bike was really a lot of fun to ride, we had a good time on those Secret trails.
I noticed only the very slight pedal feedback like you said above throughout most of the ride. The section at the end, where I noticed some cadence
irregularities, was the the climb through the wash with the g-outs, unusual terrain. I didnt really notice any of that until that point, or if I did it was very
slight. The Secret trails is kind of a network of trails right in the city of Sedona.
Very cool. You can live in Sedona and ride your bike to the trailhead.
You have a bunch of different options in there. The route we took climbed in and out of rocky washes several times before that nasty climb through the wash at the end. The bike in general is very well balanced and does everything that is asked of it very well. The antisquat system works nicely, no need for
propedal, the bike I rode didnt even have it.
 
#31 · (Edited)
..

derby said:
Yesterday riding home in the rain I spun my rear tire standing and accelerating from a near stop on a painted crosswalk while in the big ring of my dw-Link in the 27 cog. I was kind of impressed by my unintended "burnout". The XCL probably would have maintained traction there.

The dw-link bikes direct 75 - 100% (rough estimate - more in lower gears) of the rider's pedal effort into forward acceleration due to the high anti-squat rate near sag.

Very few bikes have less anti-squat rate than the XCL. The XCL is directing only 40 - 60% (rough estimates) into forward direction and the rest of the rider's energy into exercising the spring and heating the shock.

Slower acceleration can have higher traction.
Hi Derby,

Just out of curiousity, how did you determine that the XCL is directing only "40-60%" of a rider's pedaling effort into forward acceleration? Statements like that remind me of claims in the past of X amount of pedaling efficiency from a bike - how do you actually measure such a claim in reality (not on paper - but with actual real-world data recorded from riders). Not trying to attack you or anything, I just find your claim really hard to believe based on years of riding the XCL and other bikes.

-A.
 
#32 ·
CHUMBAevo said:
Hi Derby,

Just out of curiousity, how did you determine that the XCL is directing only "40-60%" of a rider's pedaling effort into forward acceleration? Statements like that remind me of claims in the past of X amount of pedaling efficiency from a bike - how do you actually measure such a claim in reality (not on paper - but with actual real-world data recorded from riders). Not trying to attack you or anything, I just find your claim really hard to believe based on years of riding the XCL and other bikes.

-A.
I'm not sure what Ray or others have calculated or measured, but I have calculated efficiency loss for a wide range of bikes (No chumbas, but VERY similar designs) and backed it up with data from a very sophisticated data aquisition system that I built back in 2003 when working on the 2005+ dw-link models.

A shock's job, its sole purpose is to convert mechanical energy into heat, basically to take energy out of the suspension. When you add compression damping to control a wheel's movement under acceleration, this is exactly what you are doing, you are taking more energy out of the suspension as the suspension compresses. To exacerbate the issue, now your suspension is compressed and must rebound, wasting off even more energy as it rebounds to equalibrium (rebound damping values are almost always higher than compression damping). This issue is two-fold, as if you are using extra damping to control the wheel during acceleration, the extra damping is there when you are coasting as well. This translates into less ability for the wheel to react to bumps, and ultimately less cornering traction. (the compression damping can't tell the difference between a low speed pedaling input and a a low speed bump)

The dw-link's position sensitive anti squat curve eliminates the need for additional compression damping, wastes less energy in the damper due to the fact that the shock is not compressing and therefore not rebounding in reaction to acceleration, and at the same time gives full traction when coasting.
 
#33 ·
CHUMBAevo said:
Hi Derby,

Just out of curiousity, how did you determine that the XCL is directing only "40-60%" of a rider's pedaling effort into forward acceleration? Statements like that remind me of claims in the past of X amount of pedaling efficiency from a bike - how do you actually measure such a claim in reality (not on paper - but with actual real-world data recorded from riders). Not trying to attack you or anything, I just find your claim really hard to believe based on years of riding the XCL and other bikes.

-A.
Derby's method of calculating efficiency would lead to the conclusion that a bike with 0% anti-squat would be incapable of forward movement from pedaling.

As far as heat generated in the dampers goes, leaving aside pedal bob, the more heat generated, the more efficiently the bike will be rolling over rough terrain. This does not mean more damping is better. Too much damping resistance will reduce shock movement to the point that less over all heat will be produced. The heat is directly related to the amount of shock movement times the level of damping resistance.

Again leaving aside rider induced suspension movement, the function of damping is to convert into heat what would otherwise be negative work performed on the bike by terrain changes knocking it off course.
 
#34 ·
Steve from JH said:
Derby's method of calculating efficiency would lead to the conclusion that a bike with 0% anti-squat would be incapable of forward movement from pedaling.
Are you sure? What formula have you seen Ray write that would indicate this to you? 0% anti squat would just allow all of the mass transfer due to acceleration act on compressing the suspension, which in turn converts the energy that it took to compress the suspension into heat in the damper. The energy that is converted to heat in the damper is the waste energy. From there an efficicncy calculation is elementary.

Steve from JH said:
As far as heat generated in the dampers goes, leaving aside pedal bob, the more heat generated, the more efficiently the bike will be rolling over rough terrain.
Suspension compliance does not directly equate to heat conversion in your damper. The reason is that damping levels within the damper (i.e. your compression and rebound damping settings) along with damper shaft speed control the amount of energy that the damper can convert for any given damper shaft stroke.

On the rebound stroke, within limits, what you wrote is sort of true. Obviously too much rebound damping would generate more heat, and at the same time not allow full traction. On the same note, on compression stroke, there becomes a level where too much damping doesn't allow a suspension to comress fully to absorb a bump. This generates more heat than a less damped shock. There is an optimal point of rebound and compression damping for each terrain and rider.

Steve from JH said:
This does not mean more damping is better. Too much damping resistance will reduce shock movement to the point that less over all heat will be produced.
exactly

Steve from JH said:
The heat is directly related to the amount of shock movement times the level of damping resistance.
The heat loss in a damper is directly related to the resistance in the damper times the shaft velocity of the damper over a given shaft distance movement. The velocity term is key, amount of movement is irrelevant. If I were to compress a damper 1 inch over 1 second's time versus 1 inch over 1 year's time, the damper would develop more damping in the shorter time scenario, as the shaft velocity, and therefore oil velocity through the damper piston orifaces rises. (creating more resistance and more heat loss)

Steve from JH said:
Again leaving aside rider induced suspension movement, the function of damping is to convert into heat what would otherwise be negative work performed on the bike by terrain changes knocking it off course.
If the bike was undamped, why would the terrain changes perform negative work on the bike? In physics, work increases the energy of a system, and negative work decreases the energy of a system. Its just an odd way of putting things..
 
#35 · (Edited)
..

_dw said:
Are you sure? What formula have you seen Ray write that would indicate this to you? 0% anti squat would just allow all of the mass transfer due to acceleration act on compressing the suspension, which in turn converts the energy that it took to compress the suspension into heat in the damper. The energy that is converted to heat in the damper is the waste energy. From there an efficicncy calculation is elementary.

Suspension compliance does not directly equate to heat conversion in your damper. The reason is that damping levels within the damper (i.e. your compression and rebound damping settings) along with damper shaft speed control the amount of energy that the damper can convert for any given damper shaft stroke.

On the rebound stroke, within limits, what you wrote is sort of true. Obviously too much rebound damping would generate more heat, and at the same time not allow full traction. On the same note, on compression stroke, there becomes a level where too much damping doesn't allow a suspension to comress fully to absorb a bump. This generates more heat than a less damped shock. There is an optimal point of rebound and compression damping for each terrain and rider.

exactly

The heat loss in a damper is directly related to the resistance in the damper times the shaft velocity of the damper over a given shaft distance movement. The velocity term is key, amount of movement is irrelevant. If I were to compress a damper 1 inch over 1 second's time versus 1 inch over 1 year's time, the damper would develop more damping in the shorter time scenario, as the shaft velocity, and therefore oil velocity through the damper piston orifaces rises. (creating more resistance and more heat loss)

If the bike was undamped, why would the terrain changes perform negative work on the bike? In physics, work increases the energy of a system, and negative work decreases the energy of a system. Its just an odd way of putting things..
Hi Dave,

This is Alan from CHUMBA. It was good meeting you at Interbike, and glad to be part of these discussions. I think one thing that is being overlooked that I've found to have a large impact on acceleration is torsional and lateral rigidity of the chassis. One of the reasons why I found Derby's statement about only 40-60 percent of pedaling power making it to the ground on the XCL so unbelievable is because he makes no mention at all of frame rigidity playing a role in energy transfer. Anyone who has ridden a flexy bike and then jumped on a laterally and torsionally rigid bike can immediately see the differences in acceleration without doing any calculations. Although I am sure you can engineer the axle path to help reduce the amount of squat during acceleration, even using a simple measure like a shock o-ring to measure the amount of compression during acceleration will show that the 40-60 percent claim seems far-fetched.

As a disclaimer, this has nothing to do with my opinion of DW Link or Split Pivot, I think they are both great suspension systems.

-A.
 
#36 ·
CHUMBAevo said:
Hi Dave,

This is Alan from CHUMBA. It was good meeting you at Interbike, and glad to be part of these discussions. I think one thing that is being overlooked that I've found to have a large impact on acceleration is torsional and lateral rigidity of the chassis. One of the reasons why I found Derby's statement about only 40-60 percent of pedaling power making it to the ground on the XCL so unbelievable is because he makes no mention at all of frame rigidity playing a role in energy transfer. Anyone who has ridden a flexy bike and then jumped on a laterally and torsionally rigid bike can immediately see the differences in acceleration without doing any calculations. Although I am sure you can engineer the axle path to help reduce the amount of squat during acceleration, even using a simple measure like a shock o-ring to measure the amount of compression during acceleration will show that the 40-60 percent claim seems far-fetched.

As a disclaimer, this has nothing to do with my opinion of DW Link or Split Pivot, I think they are both great suspension systems.

-A.
Hey Alan,

It was great to meet you too. I was pretty sure that was you when I saw your post. I think that Ray was giving some sort of off the cuff estimate. Frame rigidity is a great thing to have. Like many things in life and the natural world, too much is not a good thing, and nether is too little.

Either way, frame rigidity should have very little to do with efficiency, unless the frame is physically converting energy to heat and dissipating it when it flexes. I agree though, a nice rigid frame is a great thing within reason, and one of the aspects that drives many of the dw-link link layouts that are being sold today. (There are a lot of dw-link layouts that would be less rigid, and therefore I am not developing for customers to sell)
 
#37 ·
_dw said:
Hey Alan,

.... I think that Ray was giving some sort of off the cuff estimate. .....
Hi Alan, I was throwing out very rough estimates of relative anti-squat rates contrasting the dw-Link vs. XCL version of a multi-link. The effective swingarm on the XCL is very low-monopivot-like producing a near vertical path near sag. All Horst links type bikes I'm aware of (even FSR) are more rearward in path near sag and produce more anti-squat rate. Only the rarely used BB concentric swingarm design is lower in anti-squat rate than the XCL that I'm aware of. This is all roughly speaking, because wheelbase, BB height, CM height, and sag also factor into specific anti-squat rate situations.

Steve, My amateur understanding it that at about 100% anti-squat at sag, pedal input produces about 100% forward acceleration of the CM with nearly no result in activation of the suspension from pedaling (a little more than 100% rate is needed to also cancel vertical rider oscillation induced activity). It follows that with about 0% (zero) anti-squat rate at sag, pedal input does not move the CM, because the suspension geometry directs the BB lower as the wheel moves forward, so only the spring and damping resistance to the free suspension squat motivate the CM forward. Of course the BB moving lower would change anti-squat rate below 0% and would change the rate into pro-squat, further aggravating acceleration progress.

It's a great honor and education to have Alan, DW, and other pro's participate in MTBR discussions!
 
#38 · (Edited)
I'm not sure of anything but Derby seemed to be equating percentage anti-squat with percentage efficiency. In his most recent post he still seems to be doing so.

As for heat in the dampers, I was trying to deal with a very complex subject by coming up with a single simple generalization. Let me try it a different way.

Consider a pure downhill run, with no pedaling involved. Gravity is the only input force. We use the same bike for repeated runs. It has totally adjustable dampers, front and rear. Both high and low speed compression and rebound can be adjusted from the extreme of a nearly undamped free vibrating spring to the extreme of near complete lockout (i.e. no suspension). We try many settings and find the one that gets the bike down the hill the fastest.

My contention is that theoretically this setting should also generate the most heat.

The reference to negative work done by the terrain means simply that with the damper tuning that gets us down the hill the fastest the kinetic energy in the desired direction would be reduced the least by undulations in the terrain.
 
#39 ·
_dw said:
Either way, frame rigidity should have very little to do with efficiency, unless the frame is physically converting energy to heat and dissipating it when it flexes. I agree though, a nice rigid frame is a great thing within reason, and one of the aspects that drives many of the dw-link link layouts that are being sold today. (There are a lot of dw-link layouts that would be less rigid, and therefore I am not developing for customers to sell)
Hey I don't want to get into this debate about what bike is best, but I figured DW may be able to expand on what he was saying about frame flex. This is not a troll or a challenge, I am just interested in this stuff. I had always thought that flex was eating up the work I was doing because it was absorbing the force (by deforming) that I put into it then moving back to its original shape, so that my force (and therefore work and energy) was being eaten up by returning its potential energy in the wrong direction. I had thought along the lines of stretching an elastic, it gets hot but mostly the energy goes into potential energy that is returned when the elastic goes back to its original shape. I had figured that since it is really hard to bend metal that it was absorbing a lot of my energy. I think my question is (assuming I just haven't missed something obvious) how does the energy I put into flexing my frame get back into forward energy?

If the answer is too tough to put into forum format maybe you could recommend where I would find this info ( i still have most of my first year textbooks from when I thought I was going to be an engineer, so a general subject to look up would be enough)
 
#40 ·
derby said:
Hi Alan, I was throwing out very rough estimates of relative anti-squat rates contrasting the dw-Link vs. XCL version of a multi-link. The effective swingarm on the XCL is very low-monopivot-like producing a near vertical path near sag. All Horst links type bikes I'm aware of (even FSR) are more rearward in path near sag and produce more anti-squat rate. Only the rarely used BB concentric swingarm design is lower in anti-squat rate than the XCL that I'm aware of. This is all roughly speaking, because wheelbase, BB height, CM height, and sag also factor into specific anti-squat rate situations.

Steve, My amateur understanding it that at about 100% anti-squat at sag, pedal input produces about 100% forward acceleration of the CM with nearly no result in activation of the suspension from pedaling (a little more than 100% rate is needed to also cancel vertical rider oscillation induced activity). It follows that with about 0% (zero) anti-squat rate at sag, pedal input does not move the CM, because the suspension geometry directs the BB lower as the wheel moves forward, so only the spring and damping resistance to the free suspension squat motivate the CM forward. Of course the BB moving lower would change anti-squat rate below 0% and would change the rate into pro-squat, further aggravating acceleration progress.

It's a great honor and education to have Alan, DW, and other pro's participate in MTBR discussions!
Just one last thing to add in this discussion about antisquat. Antisquat is not
the only thing to consider when evaluating the overall efficiency of a bike's
suspension system. There's a very complex set of interactions that happens between the rider(mass), the terrain, the suspension. Antisquat by itself will not
necessarily result in a good ride. The dw-link has the best antisquat system that
I know of(without having ridden an equilink, but thats another thread) because it still allows the bike to be reactive over terrain, the suspension doesnt lock out like on most other systems with antisquat, and even helps a little with keeping a riders positioning more upright on climbs. This is all good, I'm sure nobody
here will argue with that.
A horst link bike can be many different configurations, strut based as on the XCL, rocker based as on the older 5-spots.
I'm sure there are others, but none that I know of are designed with any specific system to deal with acceleration squat.
Any antisquat that it may have is there by accident.
But the lack of antisquat does not necessarily mean the bike is inefficient.
I think it depends on the situation. On pavement I will crank up the propedal to
100% on the XCL . On your average everyday climbs I use 2/3 propedal these
days. On technical stuff I usually use 1/2, sometimes less if I dont get a chance to set it or forget, its not a huge deal though either way. I use the propedal because its there, probably more than I need to.
So getting back to my point about antisquat, antisquat can negatively
affect efficiency. An example of this is technical climbing that has to be done out of the saddle. Here the overall efficiency of the XCL surpasses that of the
mkiii. I experienced this on one ride and saw more evidence on my ride the next day. I think the reason more rider energy gets translated into forward motion on the XCL here may be because the action of the damper absorbing heat may allow more fluid motion to be maintained, it seems inertia coming from the
terrain affects the suspension less than on the mkiii. I found I could accelerate
better in this situation on the XCL, it may seem counterintuitive, but I wouldn't
be saying this unless I was fairly positive.
I think the antisquat system on the dw-linked mkiii, makes some of the negative ground inertia coming from the rugged terrain get absorbed by the chain/drivetrain, which gets transmitted through the chain into your body.
Having smooth, consistent pedaling seems to work the best here,
coupling the drivetrain to the suspension seems to put you at more of a disadvantage in this situation. The XCL may also work more efficiently in seated technical climbing as well, but I'm not as absolutely sure about this
as the standing tech, so I wont try to make that claim without riding the mkiii again.
Just my .02 on this latest discussion, I've found the XCL to work fairly efficiently in most of the situations I commonly ride. I think perhaps in a much longer, smoother, more endurance type climb I would notice the lack of
antisquat on the XCL in comparison to the mkiii.
Anyway, mkiii, XCL, its all good. The tech talk from
_dw, derby, and Steve_from_JH, is always interesting too, even if some of its a tad over my head.
 
#41 · (Edited)
le_buzz said:
Just one last thing to add in this discussion about antisquat. Antisquat is not
the only thing to consider when evaluating the overall efficiency of a bike's
suspension system. There's a very complex set of interactions that happens between the rider(mass), the terrain, the suspension. Antisquat by itself will not
necessarily result in a good ride. The dw-link has the best antisquat system that
I know of(without having ridden an equilink, but thats another thread) because it still allows the bike to be reactive over terrain, the suspension doesnt lock out like on most other systems with antisquat, and even helps a little with keeping a riders positioning more upright on climbs. This is all good, I'm sure nobody
here will argue with that.
A horst link bike can be many different configurations, strut based as on the XCL, rocker based as on the older 5-spots.
I'm sure there are others, but none that I know of are designed with any specific system to deal with acceleration squat.
Any antisquat that it may have is there by accident.
But the lack of antisquat does not necessarily mean the bike is inefficient.
I think it depends on the situation. On pavement I will crank up the propedal to
100% on the XCL . On your average everyday climbs I use 2/3 propedal these
days. On technical stuff I usually use 1/2, sometimes less if I dont get a chance to set it or forget, its not a huge deal though either way. I use the propedal because its there, probably more than I need to.
So getting back to my point about antisquat, antisquat can negatively
affect efficiency. An example of this is technical climbing that has to be done out of the saddle. Here the overall efficiency of the XCL surpasses that of the
mkiii. I experienced this on one ride and saw more evidence on my ride the next day. I think the reason more rider energy gets translated into forward motion on the XCL here may be because the action of the damper absorbing heat may allow more fluid motion to be maintained, it seems inertia coming from the
terrain affects the suspension less than on the mkiii. I found I could accelerate
better in this situation on the XCL, it may seem counterintuitive, but I wouldn't
be saying this unless I was fairly positive.
I think the antisquat system on the dw-linked mkiii, makes some of the negative ground inertia coming from the rugged terrain get absorbed by the chain/drivetrain, which gets transmitted through the chain into your body.
Having smooth, consistent pedaling seems to work the best here,
coupling the drivetrain to the suspension seems to put you at more of a disadvantage in this situation. The XCL may also work more efficiently in seated technical climbing as well, but I'm not as absolutely sure about this
as the standing tech, so I wont try to make that claim without riding the mkiii again.
Just my .02 on this latest discussion, I've found the XCL to work fairly efficiently in most of the situations I commonly ride. I think perhaps in a much longer, smoother, more endurance type climb I would notice the lack of
antisquat on the XCL in comparison to the mkiii.
Anyway, mkiii, XCL, its all good. The tech talk from
_dw, derby, and Steve_from_JH, is always interesting too, even if some of its a tad over my head.
Dude, You kill me! You ride the bike once and now your an expert on how it performs.
Do you think that anti-squat is the only thing that makes the dw-link bkes any good?

I went out monday and bought a Chumba XCL. I rode it once and found that the the MK3 performed better in all categories. The XCL was so inefficient and bobbed all over the place and I actually went backwards a couple times. I did have the propedal set at 200% though and after riding I immediately had to go the ER to have knee surgery. I don't even use propedal on my dw-link bikes and I climb up heineous terrain that most people just look at and say no way.

You are such a troll!. A wolf in sheeps clothing. I am amazed at the faith that DW and others have given to your credability which as far as I have seen is none. And it is also amazing that the Chumba guy just happened to see this thread and comment on this whole thing. I have never seen him reply to anything IH related before. I think it was a ploy from the start. And you only rode the bike once and I quote,
"Perhaps a slight stiffening of the suspension under torque could contribute to an occasional tire slip on the mkiii, but thats just a guess. This was simply my experience on one ride.
If I ride one again and have a different experience, I will report it here and make
any corrections to what I have said as necessary. "

Your comments haven't proven anything or enlightened anyone. You "guess" constantly and say things like this, "Yes, I agree. I was thinking this afternoon after posting that last thing, that the bike was really a lot of fun to ride.".
You have merely speculated your opinon as fact based on one ride. And your ability to spin in the negative about the dw-link is superb. I was wondering when you would mention the Felt equilink! A design the was totally ripped off from Kavik.

Here's another quote from your "other" thread!
Not intended to really be a review, as its only one ride, and to be fair, as one of the guys there says, maybe I'd need to check it out again with different sag to
see if there's a major difference. My guess is that it might improve a little,
but not enough to majorly change the overall characteristics.
Anyway, for what its worth.
Not intended to be a review yet you talk about it as fact. What suspension system did you patent by the way?
 
#42 ·
Quote:
Not intended to really be a review, as its only one ride, and to be fair, as one of the guys there says, maybe I'd need to check it out again with different sag to
see if there's a major difference. My guess is that it might improve a little,
but not enough to majorly change the overall characteristics.
Anyway, for what its worth.


And it's worth nothing. :lol:
 
#43 · (Edited)
le_buzz said:
Talking about anything negative to do with it (ie, pedal feedback, the only real negative that there is) results in this wall of denial, seriously its like talking to my fundamentalist christian relatives. :
Hmmm, I am not religious anything, so I don't get that quote above. I just didn't see any point in your review, and I still cannot see what you are trying to do with this thread. I would like you to define what you meant by "performance" because I read this article while back about a Giant's pro rider comparing a hardtail race bike with a full suspension race bike on a same course. The rider "felt" (as matter of a fact, he was sure) that he was going much faster on the hardtail, but he was wrong. He was actually much faster on a full suspension bike which he felt "slow". I think It is just not a good idea to mesure a performance of a bike by human "feelings".

So what are all of us talking about here? Are we trying to find out which bike feels better on Le_buzz's injured knees? Because even though, we keep talking like this, nobody is going to find out anything. It would have much been better if Le_buzz said "I like the feeling of XCL better than that of MKiii's", then I would not have commented on this thread at all.
 
#44 ·
walrasian said:
I had always thought that flex was eating up the work I was doing because it was absorbing the force (by deforming) that I put into it then moving back to its original shape, so that my force (and therefore work and energy) was being eaten up by returning its potential energy in the wrong direction. I had thought along the lines of stretching an elastic, it gets hot but mostly the energy goes into potential energy that is returned when the elastic goes back to its original shape. I had figured that since it is really hard to bend metal that it was absorbing a lot of my energy. I think my question is (assuming I just haven't missed something obvious) how does the energy I put into flexing my frame get back into forward energy?
Hah! here's something that i actually understand! The frame doesn't have any damping, so it functions as a big spring, storing energy. All that muscle you're putting in to flexing the frame (laterally, in my experience) at the beginning of your pedal stroke comes back to you near the end of the stroke as the frame returns to its original shape. I don't notice it with mtb's, but the effect is pretty noticeable on my 63cm steel road bike with a 44t low gear and my 225lb ass on top.

It's the same thing with crank arms. Flexy crank arms twist down during the top of the pedal stroke, then as you let your weight off them they transfer that twist back into the chainline, since your foot is preventing them from twisting back up.
 
#45 ·
wormvine said:
Dude, You kill me! You ride the bike once and now your an expert on how it performs.
Do you think that anti-squat is the only thing that makes the dw-link bkes any good?

I went out monday and bought a Chumba XCL. I rode it once and found that the the MK3 performed better in all categories. The XCL was so inefficient and bobbed all over the place and I actually went backwards a couple times. I did have the propedal set at 200% though and after riding I immediately had to go the ER to have knee surgery. I don't even use propedal on my dw-link bikes and I climb up heineous terrain that most people just look at and say no way.

You are such a troll!. A wolf in sheeps clothing. I am amazed at the faith that DW and others have given to your credability which as far as I have seen is none. And it is also amazing that the Chumba guy just happened to see this thread and comment on this whole thing. I have never seen him reply to anything IH related before. I think it was a ploy from the start. And you only rode the bike once and I quote,
"Perhaps a slight stiffening of the suspension under torque could contribute to an occasional tire slip on the mkiii, but thats just a guess. This was simply my experience on one ride.
If I ride one again and have a different experience, I will report it here and make
any corrections to what I have said as necessary. "

Your comments haven't proven anything or enlightened anyone. You "guess" constantly and say things like this, "Yes, I agree. I was thinking this afternoon after posting that last thing, that the bike was really a lot of fun to ride.".
You have merely speculated your opinon as fact based on one ride. And your ability to spin in the negative about the dw-link is superb. I was wondering when you would mention the Felt equilink! A design the was totally ripped off from Kavik.

Here's another quote from your "other" thread!

Not intended to be a review yet you talk about it as fact. What suspension system did you patent by the way?
Uh, yeah, I guess I was trying to be as 'fair and balanced' as I could be having
only 1 ride. I do say 'observations' BTW as opposed to 'expert analysis'.
Some things are obvious enough that even after one ride that you can say,
to make a bad analogy, 'if it rides like a duck, its a duck'.
Things like the changes in chain torque in some of the technical stuff, are not
going to change no matter how many rides I do on it. I did enjoy overall except
for the last section, as I said. When people make what I perceive to be misleading statements I feel compelled to at least to offer a viewpoint that
may becloser to reality. If you cannot handle that, I'm sorry.
While I still think the dw-link is a great suspension innovation because of its
lack of the strong negatives associated with other anti-squat designs out there,
I dont think its perfect, sorry to offend anyone. I'm a harsh critic I guess, when it comes to things like suspension and espresso. You dont see me on these forums touting one design as being completely superior to all others.
I've found that there is alot of marketing hype out there involviing suspension.
The dw-link is not as hyped as others I've seen, I've seen some pretty
ridiculous claims out there. But 2 of the '7 reasons' from the dw-link website I now know to be hyped up a little, not totally false, just a little exaggerated.
The 'Least Pedal Feedback' claim is true if youre only considering similar
chain-based antisquat bikes like vpp, maestro. If you expand that to include all bikes, then the 'Least Pedal feedback' claim is ridiculous. It is physically
impossible for a dw-link bike to have less pedal feedback than a (real)horst link.
I've seen experts on this forum try to massage the pedal feedback issue by separating it into good and bad, but thats beside the point.
The other one of the '7 reasons' that is misleading is the 'Best traction'.
Yes, it still has great traction, probably one of the best, but saying its THE best
seems a bit of a stretch. Having ridden both bikes on two days, it seemd fairly
obvious that the XCL's traction was a little better. Like I said above, if I rode it again with 33% sag, maybe that wold improved it to be on par with the XCL.
I've tried to give props to the dw-link/mkiii where props is de, and mention the
'negatives' without sounding like I'm nitpicking. I think you're missing the the point that I still thought it rode great. If you're for people with onlypositivethings to say, perhaps you'd be better off sticking to the magazines.
 
#46 ·
scottzg said:
Hah! here's something that i actually understand! The frame doesn't have any damping, so it functions as a big spring, storing energy. All that muscle you're putting in to flexing the frame (laterally, in my experience) at the beginning of your pedal stroke comes back to you near the end of the stroke as the frame returns to its original shape. I don't notice it with mtb's, but the effect is pretty noticeable on my 63cm steel road bike with a 44t low gear and my 225lb ass on top.

It's the same thing with crank arms. Flexy crank arms twist down during the top of the pedal stroke, then as you let your weight off them they transfer that twist back into the chainline, since your foot is preventing them from twisting back up.
Good to see someone else whose thought about this question. I'm a little bigger than you and have an old fully rigid steel mtb that I still use occasionally. So when I'm on it I think about the frame flex and what it all means. Lots of riding= lots of thinking about this.

I still don't get how the energy gets back into the chainline. I know that the system isn't losing much energy, I just don't get how the crank or frame returning to its original shape is driving the crank forward. The way I picture it is with a theoretical crank that has no flex being spun in a circle. If there are springs on either side of the crank (lets say they only compress at 90 degrees to the cranks for ease of picturing) when I spin crank the springs compress because I don't move in a perfect circle/ in one plane. When the spring compresses it stores my energy and releases it back in the same plane that it absorbed it ie 90 degrees to the plane of my pedaling.

So I see the spring as frame or crank lateral flex, is this why I can't picture whats actually going on, is it maybe in a different plane, or maybe it is a twisting flexing type thing that is storing the energy??? I may need to do the little force diagram thingys. Any insights are appreciated.
 
#47 ·
le_buzz said:
Uh, yeah, I guess I was trying to be as 'fair and balanced' as I could be having only 1 ride. I do say 'observations' BTW as opposed to 'expert analysis'.
And your claims based on a one day observations have to be right.

le_buzz said:
Having ridden both bikes on two days, it seemd fairly
obvious that the XCL's traction was a little better. Like I said above, if I rode it again with 33% sag, maybe that wold improved it to be on par with the XCL.
Yeah setting up the bike is kinda important and maybe compare using the same tires.

Anyway quack on!
 
#48 · (Edited)
le_buzz said:
When people make what I perceive to be misleading statements I feel compelled to at least to offer a viewpoint that may becloser to reality. If you cannot handle that, I'm sorry.
I'm a harsh critic I guess, when it comes to things like suspension and espresso. You dont see me on these forums touting one design as being completely superior to all others.

Having ridden both bikes on two days, it seemd fairlyobvious that the XCL's traction was a little better.
I've tried to give props to the dw-link/mkiii where props is de, and mention the
'negatives' without sounding like I'm nitpicking. I think you're missing the the point that I still thought it rode great. If you're for people with onlypositivethings to say, perhaps you'd be better off sticking to the magazines.
Le_buzz, I think you are missing the point. People are not reacting to your negative review but how you are presenting the review. I know you are trying to be "right" about your review, but there is no way you can prove those things that you claim without scientific observations. If you would have said "I like the feeling of XCL here and there" or "XCL has more lively and responsive feelings here and there", nobody would have argued with you. Instead, you are saying definitive things like "it seemd fairlyobvious that the XCL's traction was a little better". That is why people go "On what ground? Did the bikes have the same wheelset, tires, air pressure?". Fox is known to be good at creating "good feeling" with their rear shock rather than the "pure performance". Often time, suspension setup of pro riders' bikes feel not so fun for recreational riders. Where do you draw a line on the performance? I love reading everyday people's review on MTBR because I value their feelings. I also like to read scientific reviews on bikes, but your review is neither. And I don't think it is a good idea to put down people by saying things like "If you cannot handle that, I'm sorry" or " If you're for people with onlypositivethings to say, perhaps you'd be better off sticking to the magazines". That is just not nice.
 
#49 ·
Well said Designer;

I have been giving Le_buzz the benefit of the doubt with his posts trying to rationalize and find substance in what he has to say, but his last post was just plain insulting. I have ridden and owned many different suspension designs throughout the years and believe that the DW-Link is superior, but I'm not touting this in other competitors forums and trying to discredit their technology because of my opinion.

To me this just sounds like buyer’s remorse or insecurity as he feels the need for justification and re-assurance of his Chumba purchase by finding any fault he can (make himself believe) in the DW-Link MKIII. :p
 
#50 ·
DirtDiggler said:
Well said Designer;

I have been giving Le_buzz the benefit of the doubt with his posts trying to rationalize and find substance in what he has to say, but his last post was just plain insulting. I have ridden and owned many different suspension designs throughout the years and believe that the DW-Link is superior, but I'm not touting this in other competitors forums and trying to discredit their technology because of my opinion.

To me this just sounds like buyer's remorse or insecurity as he feels the need for justification and re-assurance of his Chumba purchase by finding any fault he can (make himself believe) in the DW-Link MKIII. :p
I totally agree with DD and Designer and I am glad I am not the only one who saw the review as baseless. I mean, how can you compare traction unless you have the same tires at the same psi? Maybe he is trying out for MBAction!?
 
#51 ·
wormvine said:
I totally agree with DD and Designer and I am glad I am not the only one who saw the review as baseless. I mean, how can you compare traction unless you have the same tires at the same psi? Maybe he is trying out for MBAction!?
THE DESIGNER said:
Le_buzz, I think you are missing the point. People are not reacting to your negative review but how you are presenting the review. I know you are trying to be "right" about your review, but there is no way you can prove those things that you claim without scientific observations. If you would have said "I like the feeling of XCL here and there" or "XCL has more lively and responsive feelings here and there", nobody would have argued with you. Instead, you are saying definitive things like "it seemd fairlyobvious that the XCL's traction was a little better". That is why people go "On what ground? Did the bikes have the same wheelset, tires, air pressure?". Fox is known to be good at creating "good feeling" with their rear shock rather than the "pure performance". Often time, suspension setup of pro riders' bikes feel not so fun for recreational riders. Where do you draw a line on the performance? I love reading everyday people's review on MTBR because I value their feelings. I also like to read scientific reviews on bikes, but your review is neither. And I don't think it is a good idea to put down people by saying things like "If you cannot handle that, I'm sorry" or " If you're for people with onlypositivethings to say, perhaps you'd be better off sticking to the magazines". That is just not nice.
Guys, I didnt mean to offend anybody by that last post.
What I was partly responding to in those negative comments is that if you say
any bike does 'X' better than a dw-link bike its perceived as slamming on the bike, even if youre giving it lot of praise in the meantime. If you look at what I posted earlier in this thread and in the thread on the Chumba forum I mention
that the Mkiii has advantages over the XCL in long hill climbs.
I wasn't intending to slam the mkiii, what I wanted to do was draw comparisons,
what I liked better about the mkiii and what I liked better about the XCL.
I felt like my observations about the pedal feedback were pretty accurate given
that, at that later point in the ride, I would have had around 140 psi in the shock. For a 195 lb rider w/ gear results in a little
more than 25% sag, probably 26%, by my calculations, and that might be a slightly low estimate. This was within the recommended sag range for a dw-link
My traction observations were mostly based from earlier in the ride, when the sag would have been at 22/23%.
At the first sign of rear tire slippage, we let some air out of the tires to make sure they had optimum air pressure. The tires on the mkiii were a lot newer than the ones on my bike, so there was more tread, which should have given the mkiii the edge on traction. Maybe running higher sag throughout the ride
would have made a difference, hard to say without riding it again.
I feel I have made every effort to be as fair as possible. It is not my intention
to denigrate the mkiii or justify my choice of the XCL.
I just wanted to share my observations and opinions, and get other people's
opinions. I think sometimes we are all prone to get a little overenthusiastic
about our bikes, its just in our nature as mtb enthusiasts.
We all have our opinions, but remember they are just opinions, what appeals to one person may not appeal to somebody else.
A lot of things said pro or con about bikes on these forums are not based on
scientific evidence, dw-link bikes included. Let's face it, riding a bike is a lot easier to understand than fancy diagrams with a lot of math. But the physics
is based on math and science, thats where things like the Linkage program come in handy.
Anyway,this thread is starting to get redundant,so I think its time to move on.
 
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