[FactoryCostcoDH]

I know a few people have heard about the computer program Linkage, and I thought it'd be cool to see some different ideas that people have come up with. So if you have any homemade designs, post them here! If you're not aware of the program I recommend checking it out. It makes things a lot easier if you're the kind of person that spends a lot of time drawing up different designs that you've thought up during work or class

I'll start it off with one of my recent designs. It's called the jesus... nobody fvcks with the jesus... nvm, bad reference haha. anyways it's called the TBR Gravity. enjoy

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[rbx]

Very nice design, low cg, nice compression curve. i like it!

Whats the chain growth? Did you calculate your ant-squat vs the sunday?

I would like to post mine put i dont think LINKAGE is ready for a VPP type linkage with gearbox design...:biggrin:

 

[MobileChernobyl]

I'll start it off with one of my recent designs. It's called the jesus... nobody fvcks with the jesus...

Thats funny, the design I'm working on right now is called "The Jews" a 13 inch travel behemoth with 17 linkages and 143 bearing, oh and its got 3 shocks. I decided 1 gearbox was played out, so its got 2 gearboxs AND a transfer case. I also put a Greddy blow-off valve on my seat.

 

[FactoryCostcoDH]

It has .4" more chain growth than the sunday, but if you wanted to get really picky you could just add a roller


and about that vpp, there's a jackshaft option on the program that you could use and afterward just draw the frame with a cradle around the bottom bracket. It's pretty legit once you get to know how to use the program. That is if you have the $25 personal version

 

[SquadraCorse]

I also put a Greddy blow-off valve on my seat.

 

[FactoryCostcoDH]

Here's a few more old vpp designs I've done.

First one's called the Slayer. It's a 9.5" travel v-10 style frame with a 10.5x3.5 shock. I realize that it's very similar to the m6, but I designed the bike before I had even heard or seen pictures of it.

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This next one's called the Terracide. It's a 5.5" travel mini DH/FR bike with a Lawill style vpp setup. I haven't got a chance to paint it though

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[Sam B]

Is that leverage ratio curve for the Sunday accurate? That is a strange curve...

Roughly 3:1 moving to 2.6:1 and right back towards 3:1 - this would be "rising rate" for the first half of the travel and then "falling rate" for the last half of the travel. I put that in quotation marks because those terms are completely inaccurate but get the point across - AKA regressive to progressive. Whatever you want to call it.

 

[MobileChernobyl]

Is that leverage ratio curve for the Sunday accurate? That is a strange curve...

hate to sound like an ass... but DW's said it a million times - NO!

The linkage program is not perfect for reverse engineering, unless you have a laser point scanner or something that can scan points and plot them with something around .001"/.1mm accuracy, and thats just OK. most of the saved linkage files were plotted off a .jpeg of a side view of the bike. Take into account screen resolution, and shakey hands and poof you're already off .0625"/1.59mm EASILY and the actual leverage ratios are out the window.

On the other hand the program is fine for regular design to fabrication method, and I and many others on here have used coordinates from the linkage program to draft up 2d or 3d solid models in a cad program.

 

[FCLinder]

Two designs I have been working on:
Both get 8" of rear travel

I am still working on them now and you may see one built by next summer.

O'Yes they are extremely Flexy!!!!!!

 

[RideRMB]

Your 2nd one looks like the Marin Quake.

 

[NY_Star]

If you all have a hard on for leverage ratio graphs you should look into the RaceTech shock clock. We have one at work and it works great.

 

[Sam B]

hate to sound like an ass... but DW's said it a million times - NO!

The linkage program is not perfect for reverse engineering, unless you have a laser point scanner or something that can scan points and plot them with something around .001"/.1mm accuracy, and thats just OK. most of the saved linkage files were plotted off a .jpeg of a side view of the bike. Take into account screen resolution, and shakey hands and poof you're already off .0625"/1.59mm EASILY and the actual leverage ratios are out the window.

On the other hand the program is fine for regular design to fabrication method, and I and many others on here have used coordinates from the linkage program to draft up 2d or 3d solid models in a cad program.

Easy there tiger! I don't have time to surf the forums all the time, so I have not heard DW say that "a million times" but that was what I was implying... that the leverage ratios in the graph were weird/wrong/unorthodox.

So, back to the question... how far off is that graph? I haven't used the "linkage" software before, so I didn't realize they have stored data for production bikes. I've only ever used AutoCAD and Excel to generate that info with real frame numbers, never worked backwards from a JPEG.

 

[dhkid]

yea, i know it looks like a commencal. get over it.

graphs of all the numbers are on my computer in bristol. so thats all for now.

drawing up stuff on the linkage program is neat, but trying to get everything to fit in 3d sucks balls. sometimes i wish i could take an e hammer and hit everything into place.

oh yea, about the bike. nothing special about it, the linkage just gives a slight rising rate. pivot point at the height of a 38t chain ring. the main goal behind the bike is to try and get a shorter travel bike (6in) have traits of a dh bike, handling wise.

 

[MobileChernobyl]

Heres two designs I whipped up when I was just learning solidworks like 1.5 years ago. They're pretty simple, and were more based on practicality of fabrication than fancy solid modeling. I knew I wasn't going to have much CNC access, except for maybe the shock driving linkage - So the designs reflect this.

This guys a standard singled pivot, with an underswinging shock driver link thats pushed. It was the most practical design I made before I started getting into transmissions. The leverage ratio is similar to the giant faith on linkage, without the sharp drop the last 1/8th of travel.

This I was just fulling around with a design I called the "inverst horst" it was the first design I came up with so naturally I wanted to draw it up in solidworks. The idea was to have the brake carrying member not rotate at all almost, but still rotate forward a degree or two to avoid brake jack (jack, not squat) - note this was before I really understood the idea of brake interaction so that definition seemd good enough for me at the time! haha. It was also simplified as much I could for fabrication means, so theres not many fancy CNC'ed pieces that are so easy to get carried away with in solidworks. Theres some problems with it as a DH frame with 8", but it would work fine as a 6" bike. Again I haven't realy messed around with axle path modifying linkages on bikes since I ventured into transmission frames, so I never corrected the problems this one had (like not having a brace for the upper pivot). The leverage ratio is almost exactly like the giant faith on linkage.. dont ask lol.

This design was focused on just getting the basket and linkages milled. I went with a concentric rear pivot design here, and retained the goal of the "inverst horst" - having minimal brake arm rotation, while simplifying things. This was my last conventional frame because I was just like ahh f' it im tired of coping with deraillures and all that. This was my favorite conventional design, it has a nice low CoG, and the rear pivot was back pretty far, mainly for shock clearance and intereference issues. I think the only way I got everything to fit was by going to igus bushings.

 

[LMC]

Two designs I have been working on:
Both get 8" of rear travel

I am still working on them now and you may see one built by next summer.

O'Yes they are extremely Flexy!!!!!!

this one looks great, nice and simple. any plans to make it?

 

[FCLinder]

this one looks great, nice and simple. any plans to make it?

I have been looking at building it out of steel to test out before building it out of Carbon. We will see.

 

[BJ-]

Anyone have any tips on how to use Solidworks?

Im having trouble coming from AutoCAD. I have no idea how to do tubing on an angle and building things as assemblies to the proper dimensions. Anyone know of any tutorials that could help me? Or any tutorials that could relate to frame building?

Thanks.

 

[MobileChernobyl]

FCLinder - I didn't really look at your first design until i checked out this thread again today. If I were to draw out the rest of my last design, its basically the same. I mean theres not much uniqueness when you get to single pivots, but we were both after the same goal it looks like. Mine axle path was only rearward to about 130mm however, so the whole swingarm was alot lower, well all of the workings were in turn because I opted for a less rearward axle path (and no idler).

 

[Kanye West]

DW can say it until he's blue in the face, but you'd have to be way more than a mm off on ALL the pivots for the curve to get rid of that general shape. It is what it is and thats what lets the Sunday use all of it's travel over square edges (and every small drop you come across).

Just a note - perhaps one of the most useful features of that program is the "axle path perpendiculars" option which shows the pivot migration for non-single pivot bikes. Would like to see how some of the VPP's people have posted come out as that will determine how it will pedal and if it's migratory pivot follows the counter of your chainring (essentially the only thing special about VPP's/DW's/Maesto's/any quadlink).

 

[MobileChernobyl]

The "general curve" can go quite arai in less than a mm on any pivot if your dealing with a short link style vpp/meastro/DW. Its pretty simple to replicate. The shorter the links - the less forgiving inaccuraces are as the angular velocitys increase indirectly proportional to the length of the linkages (again in a vpp/meastro/DW/you get the point its really kinematics and not fancy marketing names that dictate a 4 bar linkage). Thats being a little over simplified (maybe too much, that does seem a bit broad, hopefully you get the point i was trying to make) but its easier to understand and if you get the point I'm sure you understand it more in depth so theres no need to waste a page on why. I just want to ride a bike I make.... pshh some day

 

[Kanye West]

The "general curve" can go quite arai in less than a mm on any pivot if your dealing with a short link style vpp/meastro/DW. Its pretty simple to replicate. The shorter the links - the less forgiving inaccuraces are as the angular velocitys increase indirectly proportional to the length of the linkages (again in a vpp/meastro/DW/you get the point its really kinematics and not fancy marketing names that dictate a 4 bar linkage). Thats being a little over simplified (maybe too much, that does seem a bit broad, hopefully you get the point i was trying to make) but its easier to understand and if you get the point I'm sure you understand it more in depth so theres no need to waste a page on why. I just want to ride a bike I make.... pshh some day

Oh I realize this. They'd still have to be a long ways off to change the curve through the last half of the travel. The angles of the two links compared to the swingarm and each other and the angle of the damper to the upper link would have to be entirely different through the last half of the travel to get rid of that rise in the leverage. There really isn't a physical way to get rid of that by moving things around +/- 1mm, probably even more.

I always thought the Giant was the less-hyped Sunday that was heavier but actually worked for more than a day at a time. Perhaps the actual DW leverage curve was plotted when all the Sunday bearings collapse which is representative of it's normal riding conditions?

 

[***MTB***]

Anyone have a link to where I can find the program "linkage" to download. I had no idea something like that was available.

Thanks in advance guys.

 

[LMC]

Anyone have any tips on how to use Solidworks?

Im having trouble coming from AutoCAD. I have no idea how to do tubing on an angle and building things as assemblies to the proper dimensions. Anyone know of any tutorials that could help me? Or any tutorials that could relate to frame building?

Thanks.

its been a long time since i used solidworks but AFAIK the simplest way would be to create a new anglular plane at the base of the tube you want to create, then extrude the tube from that plane

 

[LMC]

Anyone have a link to where I can find the program "linkage" to download. I had no idea something like that was available.

Thanks in advance guys.

its at www.bikechecker.com

get the personal version, means u can save your work and its only something like $25

 

[Kanye West]

its been a long time since i used solidworks but AFAIK the simplest way would be to create a new anglular plane at the base of the tube you want to create, then extrude the tube from that plane

Easiest way in SW is to create your geometry first by placing axis where your tubing is going to be. In all honesty, SW is kind of a pain for bike frames. I much prefer ProE but that software is not as easily accessed.

 

[LMC]

Easiest way in SW is to create your geometry first by placing axis where your tubing is going to be. In all honesty, SW is kind of a pain for bike frames. I much prefer ProE but that software is not as easily accessed.

it is a pain for bikes!! and not very user friendly in general i find, thats why i dont use it anymore. i prefer solidedge myself

 

[Kanye West]

it is a pain for bikes!! and not very user friendly in general i find, thats why i dont use it anymore. i prefer solidedge myself

It's user friendly to a certain point since it kinda holds your hand through everything. I don't like the way it edits and makes parts within assemblies though.

 

[PepperJester]

very ruff 5 bar I guess, I don't have a real cad program at the moment, just illustrator so I can't test the suspension on screen yet but my plastic mock ups seem to work. surly would ride like crap thou haha

 

[MobileChernobyl]

Perhaps the actual DW leverage curve was plotted when all the Sunday bearings collapse which is representative of it's normal riding conditions?

Lol good one

PepperJester - thats a cool idea. Not sure if theres really a need for a 5 bar bike, but you never know. Reminds me of the linkage on the arm's of excavators, but with another degree of freedom. Could you test it in the Linkage programe? or is 5 bar not an option? It would have a pretty big "envelope" it seems. Did you design it with some thought put into the members lengths, and ratios - or did you just make it look cool? Just trying to figure out why you made the member that pivots on the BB the way you did with it mounting to the CS and SS links - it looks fine but i've never seen something like it on a bike before.

 

[xxFRESHxx]

cool idea indeed. but i have to agree with MobileChernobyl, there should be more thought put into the lerverage ratios. in other words, the ratio of the parallelogram is insanely high.

just a quick idea but i would also consider moving the single pivot upwards to achieve a rearwards wheelpath for good small bump response on the first couple of inches of travel. big hits could be handled by the parallelogram and it's vertivcal wheelpath when the single pivot reaches it's limit.

 

[Pslide]

I'm struggling to get to grips with that 5 bar (not many designs that stump me, so well done PJ!). I can't even envision the axle path / area It certainly looks cool tho! But won't it be unconstrained with that many degrees of freedom? Flippy floppy!

 

[SquadraCorse]

it is a pain for bikes!! and not very user friendly in general i find, thats why i dont use it anymore. i prefer solidedge myself

I don't find it a pain at all. A bike is a weldment...SW has a weldment application.

I usually just sketch a point diagram where i want all the relevent components to be located (BB axis, axle axis, HT, etc.) Connect the dots with however you want your tubing configured. Highlight the lines and assign the proper profiles to it. Trim some bodies and your done.... Even add fillet welds, gussets, etc. etc.

Do the mates right and you can just move your swing arm and have a great view of how everything is going to function.

SW is the cats ass for frame design.

 

[PepperJester]

I'm struggling to get to grips with that 5 bar (not many designs that stump me, so well done PJ!). I can't even envision the axle path / area It certainly looks cool tho! But won't it be unconstrained with that many degrees of freedom? Flippy floppy!

yeah flippy floppy ness worrys me. But I don't have rear cad so can't test on the comp yet. the posted design was basically just concept art. I did fab up the linkage out of plastic, nothing would bind during the travel but thats about as much as I could sort out form a prototype made out of old signs.


Time to invest in a rear cad program. . . then a welder.

 

[Kanye West]

I don't find it a pain at all. A bike is a weldment...SW has a weldment application.

I usually just sketch a point diagram where i want all the relevent components to be located (BB axis, axle axis, HT, etc.) Connect the dots with however you want your tubing configured. Highlight the lines and assign the proper profiles to it. Trim some bodies and your done.... Even add fillet welds, gussets, etc. etc.

Do the mates right and you can just move your swing arm and have a great view of how everything is going to function.

SW is the cats ass for frame design.

This is where ProE and true top-down design surpasses SW.

 

[ohio]

I did fab up the linkage out of plastic, nothing would bind during the travel but thats about as much as I could sort out form a prototype made out of old signs.

Unfortunately, you've got too many degrees of freedom and the linkage can move without compressing the shock. You either need to add a control arm
(6-bar) or fix two of them together (4-bar).

5 bar linkages work to trace a path in 3 dimensions (e.g. independent auto suspension) or provide multiple degrees of freedom (think live rear axle on, say, a mustang) but not in 2 dimensions (motorcycles and bikes).