finally an intelligent post on a dumb thread
Bad ideas and dumb builds
- Thread starter 4xBoy
- Start date
I'm certainly going to argue with that one! :biggrin:
Agreed. I was under the impression that damping problems stemmed from the fact that, whereas with the coil the heat generated in the damping circuit is more or less free to conduct/radiate out to the surroundings, the damping circuit in comon configurations of air shocks is surrounded by the big, insulating air spring, which is why air shocks are more prone to "damping fade" over long runs. But yeah, no practical experience to base this on. Just e-rumours, and a sound knowledge of physics.
I don't see the whole point of an air DH shock....so you can save 250 grams...lol...D
I hope you have never run a ti spring before....
Sorry to call you out on this, but take a look at a Sunday lev rate curve next to a Turner for example. The curve is for all intents and purposes, linear. Leverage rates aside, when you look at actual wheel rate curves for the DHX air on the Sunday there is a big "dip" in wheel rate through the middle of the travel. If I were to change to a leverage rate that would overcome this dip in spring rate you would make the bike completely unusable in the mid travel. Shaft speeds would be very high mid stroke. This causes a cascade of issues, but ultimately you would end up with a bike that has very little cornering traction and a huge bottom out issue.
Ride the shock on the bike and then lets talk about it.
I really want to believe you on the prog to linear thing (you built the damn bike 
), but the only curve i've seen is a reasonably even upside-down hump - can't really call it linear at all. It was also brought up in this thread http://www.ridemonkey.com/forums/showthread.php?t=167916 but you didn't post a version of your own there either.
It might have been an imperfect mapping of it - do you mind mapping the actual curve and showing us? It just makes sense to me that it would be regressive near the end especially given that you suggest winding the bottom out adjuster all the way in to begin with... if the rate isn't falling, why wind the bottom out all the way in?
I definitely will ride the shock on the bike and post what I think (waiting for delivery)..... still have the coil so there's no reason I can't swap them in and out if/when needed too.
), but the only curve i've seen is a reasonably even upside-down hump - can't really call it linear at all. It was also brought up in this thread http://www.ridemonkey.com/forums/showthread.php?t=167916 but you didn't post a version of your own there either.It might have been an imperfect mapping of it - do you mind mapping the actual curve and showing us? It just makes sense to me that it would be regressive near the end especially given that you suggest winding the bottom out adjuster all the way in to begin with... if the rate isn't falling, why wind the bottom out all the way in?
I definitely will ride the shock on the bike and post what I think (waiting for delivery)..... still have the coil so there's no reason I can't swap them in and out if/when needed too.
Here's what linkage spits out - the drawing was done by a guy called spencer williams who seems to have done a lot of the bikes in the linkage library, but ultimately it'd only be as accurate as whatever photo he used.
I'd like to see your version and maybe a dead side on CAD pic of the production frame that anyone could use to get the correct data from.
I'd like to see your version and maybe a dead side on CAD pic of the production frame that anyone could use to get the correct data from.
just a question about the above post. what is the label on the Y axis?!?
it is very east to skew results to what ever outcome you want when you don't supply all the information.
edit: also, what is the Title for the graph?!? that can be a graph of almost anything without the two missing pieces of information.
it is very east to skew results to what ever outcome you want when you don't supply all the information.
edit: also, what is the Title for the graph?!? that can be a graph of almost anything without the two missing pieces of information.
Skewing results? whoa slow down there buddy
I just posted a graph that was created by someone else (I said it may be inaccurate) and asked if a more accurate one could be posted by dw to match what he claims.
As for the title - have you tried using your eyes? There's 7 tabs directly below the graph, and the one titled Lev. Ratio is clearly selected. The y axis (it really should be obvious if you have any clue as to what's been discussed here) is the leverage ratio at any given point in the travel.
I just posted a graph that was created by someone else (I said it may be inaccurate) and asked if a more accurate one could be posted by dw to match what he claims.
As for the title - have you tried using your eyes? There's 7 tabs directly below the graph, and the one titled Lev. Ratio is clearly selected. The y axis (it really should be obvious if you have any clue as to what's been discussed here) is the leverage ratio at any given point in the travel.
As I've mentioned before, this leverage rate curve that you have posted for the Sunday is not even close to accurate. Plenty of info on that written in the past. I think that SKC actually copied it into the Sunday thread... I will not be posting an actual leverage rate curve, as it is proprietarty information.
This linkage program cracks me up. As if clicking on a picture is somehow an accurate representation of actual geometry. +/- 1mm=useless conclusions.
This linkage program cracks me up. As if clicking on a picture is somehow an accurate representation of actual geometry. +/- 1mm=useless conclusions.
So effectively we just have to take your word for it that the curve is progressive to linear, and you won't actually show us the curve.
If it's not (noticeably) regressive at the end, then why recommend cranking the bottom out adjuster all the way in by default? Surely on a frame that ended with a linear rate that would make it overly progressive, (ie wouldn't be neccessary) especially with today's progressively damped shocks.
On a different note - if someone buys the frame, surely the leverage curve can be worked out precisely (unlike mapping points in linkage), hence the patents to stop it being replicated. I can't see why you can't show us the curve - unless it was something other than you claimed it was.
As always, dw wins by default here.
If it's not (noticeably) regressive at the end, then why recommend cranking the bottom out adjuster all the way in by default? Surely on a frame that ended with a linear rate that would make it overly progressive, (ie wouldn't be neccessary) especially with today's progressively damped shocks.
On a different note - if someone buys the frame, surely the leverage curve can be worked out precisely (unlike mapping points in linkage), hence the patents to stop it being replicated. I can't see why you can't show us the curve - unless it was something other than you claimed it was.
As always, dw wins by default here.Yes
Not sure how you're coming up with the idea that a linear rate would make the bike overly progressive, but I can assure assure you of two things.
1) I know exactly what the leverage rate progression on the bike is, what this does to wheel rate, how these parameters manipulate the different damper types on the market, and how to tune them to get the results that I am looking for.
2) We (meaning Sam Hill, Duncan Riffle, Lars Tribus, Dave Smutok, Len Hornidge, and I) have done a huge amount of testing to verify results and provide suggested tunes for riders like you.
I say go for it. This might not be as easy as it sounds to do, but if you have access to a CMM and the time to do it, then by all means go for it! I am pretty sure that you have an idea what I am all about, so you can bet that there is no way in heck I would tell you that the lev rate was one thing when it's another.
Thats the idea!
while we're at it he should post all blueprints and CAAD code of the design and even the contact lists of welders, powdercoaters, and all production involved people. Perhaps even remove the patents on the design. Hell at that point they might as well start giving away DW link frames in cereal boxes.
Bad threads that don't die.
Who started this thing anyways.
Who started this thing anyways.
sorry to dig up this tread, but i forgot about it and never replied to when i read about the dhx loosing damping.
i guess me saying that it looses all damping was wrong. but the rebound damping does speed up when it over heats. and this was in dirt mag, when they were testing 5-6in bikes on 10+munites dh runs. they found that the rp23 was much better in this sence.
edit, i am sure this would never be a problem for most riders. just passing on what i know.
edit2 typo
i guess me saying that it looses all damping was wrong. but the rebound damping does speed up when it over heats. and this was in dirt mag, when they were testing 5-6in bikes on 10+munites dh runs. they found that the rp23 was much better in this sence.
edit, i am sure this would never be a problem for most riders. just passing on what i know.
edit2 typo
Dude, the Rp3 and the DHX air have the SAME volume of air
ok, i can't be bothered to dig up the details of whether the dhx air was a longer stroke or higher levarage ratio then the rp23 on test. those difference could have done it.
and maybe its the just damper that cant handle to heat or something.. anyways.. i am not going to argue about it... just saying that it happens.
and my personal peferance to take a rp 23 over a dhx is that i dont use much compression and if you wanna save weight, go all the way. not like its gonna be a big difference in performance, like you said. same air volume.
and maybe its the just damper that cant handle to heat or something.. anyways.. i am not going to argue about it... just saying that it happens.
and my personal peferance to take a rp 23 over a dhx is that i dont use much compression and if you wanna save weight, go all the way. not like its gonna be a big difference in performance, like you said. same air volume.
Yeah, but there's no bottom out on the RP3. I had one on my 5" bike and it ruled, but on a V10?
Well, the characteristics are not similer to the coil shock. The DHX Air blows through the mid stroke travel, uses more travel than it should on impacts, and leaves very little travel for the next impact when you start picking up a lot of speed in rough terrain. The damper in the DHX Air is different from the one in the DHX coil. I feel the DHX Air can actually give a more "plush" ride at certain speeds in certain terrain, but it's very limited due to that mid stroke wallow, and if you want a much better all around ride that is much better controlled, go with the coil.
A lot of us have experienced this. Push has verified this. I think the DHX Air is popular due to that "very plush" feeling in certain terrain, unfortunately it is not indicitive of the shock in other situations.
the RP3 worked ok for a couple months on mine
So, does anybody actually ride bikes anymore, or do they just exist to argue about on the internet?
It is true that data taken from a photo is not going to be very accurate, but it's certainly better than no data. Every file in the program has a quality rating; so it should be quite obvious which files can be trusted, and which files are simply to be viewed as a visual for how a linkage operates, and nothing more.
Since manufacturers are often unwilling to give us this information, it is up to us to find out ourselves. There are programs out there (like the linkage program) that can accurately graph suspension rates, wheelpaths, etc.. Taking measurements by hand should be accurate enough for making these determinations. You don't have to be within a millimeter accuracy of actual data for a graph to be useful. (But certainly within a few)
yes, we do.So, does anybody actually ride bikes anymore, or do they just exist to argue about on the internet?
i used a dhx air all last year and "liked it".
its def not a coil and it would blow through
med travel. i decresed my rate to keep it
from bottoming hard but then lost some
of a light feel at the first.
Under 150 i would say can make it work
on most bikes 3-1 LR and under.
this year i am using 2.5 LR and a whole lot
of rate adjust so i can use coild or air shocks
for most all riders.
air is different feel, if you hop our bike a lot
its for you, if you plow i would stick with coil.
alex
so you are saying that fox make a 2.75x8.75 rp23? where did you get it from?
Actually, in many instances, it is NOT better than no data. Introducing completely inaccurate and/or baseless data into an argument to try and prove a point is worse than leaving it out entirely. Unless data was introduced into the mapping program that was taken with accurate measurements, bringing it up is useless.
When you write a paper, do you cite an anecdote that your brother heard once as a reference? No? So why would you do it here? If I eyeballed a photo of a Sunday for some measurements and hand-drew some pictures in MS Paint, would you take it seriously or dismiss me entirely? What's the difference here? The CAD program is no more accurate if not supplied with good data - garbage in, garbage out.
I think it's also a little silly to be requesting that DW post proprietary information about his shock rates and such. Just because the guy is here and tries to be helpful doesn't mean he's going to share thousands of hours worth of self-generated data that he makes a living from. Tell you what, shoot Santa Cruz an email and ask for all the output from whatever recent FEA they've done on the V-10, see what they say. After all, if you bought the frame and did precise measurements and analyzed the types of metals used, you could do the FEA yourself, so why would they not just post it on their website?
Thats not what im saying, it was a 2.5/8.5
I was just curious, can't you pull most of the info that you're after from (#5 Show Animation):
http://www.dw-link.com/reasons.html#
You can clearly see how the leverage is effecting the shock, simply by studying the corresponding pivot angles in relationship to where the shock is in stroke. Obviously this will not give you a detailed dimensional lay-out... as previously mentioned, that type of data belongs to Dave... but if you are of the analytical type and understand how a shock goes into falling rate, you'll be able to answer your own questions.
Exactly, if you don't understand where the data comes from or how accurate it is, why in the world would you make concrete conclusions about a bike's performance with it?
I never said that companies should be releasing specific suspension related graphs. One can most likely find out this information in ten minutes by doing some simple measurements. We have to keep these companies honest. Not every company is as upfront about their designs as Ironhorse.
i was asking coz i want one, oh well.
this thread makes my brain want to explode
instead I think I will put my fox 40 on my hard tail.
But santa cruz don't come on here saying their linkage does this, does that and is the best thing since sliced bread and everything else is crap.
I think its completely fair to request this information due to the claims made and the way this forum is used to promote the design. This place has been slowly turning into another Hcor
It is seriously like a religion, you guys just accept what is told to you and regurgitate it without questioning why, and when someone does ask why and to provide evidence of said claims they get smacked down. Lame.
Udi, it wouldn't be that hard to measure everything up exactly with a tape measure and verniers for the critical dimensions, and then punch the co-ordinates into matlab and preform a vector analysis. You would be able to determine the force, displacement, velocity and acceleration characteristics of every moving point on the frame, including the rear wheel axle. Compared to some of the vehicle linkages, such as a double wishbone that move in 3d space, modeling the bike should be a piece of cake as its only in the x/y planes.
Cheers dude.
I started writing a reply last night but saved it and left it, because all i'd get is the standard dw auto-response - "sam hill said it works, so i'm right".
Yes, they do. They buy advertising space. Just because DW happens to have an account on here doesn't make it any different. All the companies have information they are unwilling to divulge to the masses.
Requesting is fine, but the response was "Sorry, it's proprietary" and that's perfectly reasonable. It doesn't automatically disprove the claims, it just means you need to find another way to disprove or prove them.
No, what's lame is that you are trying to call me out when you have no clue what you're talking about
. I am the last person to accept things at face value. Just because I can recognize the uselessness of a CAD drawing that was produced from crap data, or see why not sharing proprietary information is reasonable doesn't mean I'm accepting all claims made at face value.Perhaps you'd like to, you know, provide some evidence as to why you think I've swallowed the pill? Maybe point out some posts where I've espoused the virtues of the DW-link with no evidence to back me up? Provide a shred of proof for why you believe my recognition of reality is actually just a fanboy acceptance of everything DW says?
Gee, that might provide a little bit of useful data! Imagine that, and without DW providing his proprietary data or without guessing via estimates based on a poor quality JPG of the frame.