How to Determine and Design Leverage Ratios
- Thread starter TrumbullHucker
- Start date
When I was in grad school I tool a linkage design course as an elective. At one point I used some optimization routines in mathematica to perform 4 bar linkage design. Define a number of points in the linkage path, and an acceptable area for the pivot location. If a solution existed it would bang out an answer pretty quick. I think my code only solved for 3 points on the curve. It wouldn't be difficult to increase that but the number of solutions diminishes quickly. I kind of feel like firing that shit back up.
Ridemonkey Communal Design Services is now open fer bizznuz
What about the belt around your neck? Please tell me within five years you've at least gotten that far.
that program sounds awesome.. would not know where to start with that
ayyyyyy
Haha, crazy about the timing! I actually was googling about leverage rates etc and came upon this old thread. I'm looking forward to see what you come up with... Are you still looking at BB concentric main pivot? I was thinking you could get a burly idler below the traditional chainline mounted to the main frame to get some anti squatzors, but you lose the whole singlespeed with no tensioner benefit... Anyway, been having fun kicking around ideas myself, I'll post up when I have something more concrete than "dual suspension that is rideable"
Hi,
So, here it is, the theoretically perfect leverage ratio curve:
This.
Just do this.
It really just should be this.
Haha, crazy about the timing! I actually was googling about leverage rates etc and came upon this old thread. I'm looking forward to see what you come up with... Are you still looking at BB concentric main pivot? I was thinking you could get a burly idler below the traditional chainline mounted to the main frame to get some anti squatzors, but you lose the whole singlespeed with no tensioner benefit... Anyway, been having fun kicking around ideas myself, I'll post up when I have something more concrete than "dual suspension that is rideable"
im far off from that complex haha. I will try to find the old SLDWRK part file and continue with that design. and yes the original frame design was a concentric BB......
right now im just sketching a new 2D.. getting wheelbase x and y's and bb x/y..
patent this shit now !!MOAR!!
Intense M1
have you owned one? a misaligned one that also blew up? or did you just read about it on the innerwebz and repeat it over and over again for lulz?
Last edited:
I've owned two brand new intense frames.
Neither were straight. And one had the rear end so splayed I had to make my own brake mount to get the caliper in a straight line since it pinched so much once bolted up.
And literally everyone I rode with who had any generation of M1 had it crack within the first two years. Headtubes and swingarms
How many have you owned?
Fortunately I'm talking about a bygone era and things seem better now. Anything else?
Neither were straight. And one had the rear end so splayed I had to make my own brake mount to get the caliper in a straight line since it pinched so much once bolted up.
And literally everyone I rode with who had any generation of M1 had it crack within the first two years. Headtubes and swingarms
How many have you owned?
Fortunately I'm talking about a bygone era and things seem better now. Anything else?
nope. that should suffice.
i wish i could have seen the front/rear misaligned bikes be ridden down mountains though. just for lulz.
i guess i should count my blessings that my 2010 frame was properly aligned and has not spontaneously combusted beneath me. accordining to the innerwebs i should be dead, i think.
i wish i could have seen the front/rear misaligned bikes be ridden down mountains though. just for lulz.
i guess i should count my blessings that my 2010 frame was properly aligned and has not spontaneously combusted beneath me. accordining to the innerwebs i should be dead, i think.
Here's a shocker for you: some things on the internet.........are actually based in reality
My uzzi was pretty fucked but considering what I went through to get it, and intense really going out of their way to atone for someone else's really really bad deed, I was happy to have it. But it wasn't straight.
And the 6.6 I had worked fairly well with a wheel redish, although it was way way higher than the published geo.
Here's another shocker for you: some of the people on this forum have been riding a really really long time. Don't get all bent out of shape just because you like your uzzi. I liked my 03 turner dhr but the fucker still cracked within a year. And I still ride a turner dh bike.
Here's some homework. I'm the guy on the uzzi at the end as well as a red demo 8.
http://www.ridemonkey.com/threads/video-of-my-head-bobbing-in-the-woods-with-a-bunch-of-dudes.188976/
My uzzi was pretty fucked but considering what I went through to get it, and intense really going out of their way to atone for someone else's really really bad deed, I was happy to have it. But it wasn't straight.
And the 6.6 I had worked fairly well with a wheel redish, although it was way way higher than the published geo.
Here's another shocker for you: some of the people on this forum have been riding a really really long time. Don't get all bent out of shape just because you like your uzzi. I liked my 03 turner dhr but the fucker still cracked within a year. And I still ride a turner dh bike.
Here's some homework. I'm the guy on the uzzi at the end as well as a red demo 8.
http://www.ridemonkey.com/threads/video-of-my-head-bobbing-in-the-woods-with-a-bunch-of-dudes.188976/
Mmmmkay. Will you be selling custom "woogenuflectioncushions" soon on your website, or should I make my own to avoid achy knees?
I don't care what you do.
Just stop being like a child Donny, who just walks into a room...........
Just stop being like a child Donny, who just walks into a room...........
so basically
to determine axle paths, leverage ratios, shims.. it seems like i need to start with Bike Checker, not Solidworks?
to determine axle paths, leverage ratios, shims.. it seems like i need to start with Bike Checker, not Solidworks?
Solidworks is certainly better but it's a much steeper learning curve.
I think that bikechecker/linkage program is a good start for general concepts. I'm not sure I'd base precise measurements on something modeled in it.
I suck at solid works but I've done a few things on linkage first and then refined them with someone that knows the real program better.
I think that bikechecker/linkage program is a good start for general concepts. I'm not sure I'd base precise measurements on something modeled in it.
I suck at solid works but I've done a few things on linkage first and then refined them with someone that knows the real program better.
How did we ever make it through the 20 inch handlebar era?
SolidWorks doesn't have a really good native way to analyze or plot motion ratio curves. You have to do it through macros or pulling data out to Excel and plot that way. It's not as simple as "I'm going to move this pivot point 5mm up and see and instant result on a motion ratio curve".
Other programs can do that. ProE/Creo and Catia are much more powerful software packages that can do that kind of thing in a heartbeat. That's also the difference between something that costs $3-5k for a seat and something that costs $50-70k for a seat.
Also, annoyingly, you cannot make a functional part file of a compressible coil spring in SolidWorks. You can make a swept helical thing that has external references and will try to rebuild itself multiple times a second as you cycle it through its range, usually crashing the program. Again, no issue for the higher end programs. It would be really nice if it did that so you can do quick checks for coil bind, but noooooo....
Other programs can do that. ProE/Creo and Catia are much more powerful software packages that can do that kind of thing in a heartbeat. That's also the difference between something that costs $3-5k for a seat and something that costs $50-70k for a seat.
Also, annoyingly, you cannot make a functional part file of a compressible coil spring in SolidWorks. You can make a swept helical thing that has external references and will try to rebuild itself multiple times a second as you cycle it through its range, usually crashing the program. Again, no issue for the higher end programs. It would be really nice if it did that so you can do quick checks for coil bind, but noooooo....
Or, you can just make an active spring from a bunch of sections. They work fairly well. I'll see if I can track down the video to make it.
http://www.bikerumor.com/2015/10/12/eb15-the-alutech-icb-2-0-crowdsourced-full-suspension-mountain-bike-becomes-a-reality/
This is a bike "designed by internets". Single pivot, no linkage. It's not rocket science. Just put the lower pivot in a place that affords good pedaling with a single ring (about at or just above the top of the ring), and mount the shock in such a way that the lever arm shrinks as it goes through travel, rather than grows. The cannondale gemini is a good example. In the top mount, it's relatively linear, and in the bottom, it's a falling rate. Just avoid the falling rate and you'll get a pretty decent riding bike. Linear, progressive, linearly progressive...those all will ride pretty well. Messing around with crazy stuff isn't really worth the time...
Looks flexy.
This explanation helped me start wrapping my head around single pivot leverage rates, and linkage has been fun to look at a whole bunch of bikes and see what's been done leverage rate-wise. I'm looking at bikes like the GGDH, and yakuza as a reference for nice single pivots. Not sure if I want to design with coil or air in mind. Unfortunately, it's seems with single pivot (with no linkage to drive shock) there's no great way to make it plush off the top with an air shock without having a really wallow-ey mid stroke. So I'm leaning towards coil, even for short travel 29.MTBR frame building KTM250 said: