TRX250R.ORG
Workshop => Suspension and Chassis => Topic started by: andy@maultechatv on February 03, 2014, 08:06:32 PM
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Just checking interest here to see if anyone would be interested in seeing how we go about designing a new suspension linkage? I'm planning on designing tomorrow if we get a big snow like they're talking (no customers stopping by). I figured I would use the GoPro and record the process if there's enough interest. And no this won't be for the 250R, we already tried that and there's too many things that won't let it work on a stock frame!
UPDATE: Here's the video you came to see.
[video=youtube_share;SW9G0o-Nytk]http://youtu.be/SW9G0o-Nytk[/video]
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Uhhh let me think about that.... DUH!! :)
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Of course we want to see it, and some people may not know about your 450r tt link, so you might as well show it off too!!
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I have a couple other videos I'd like to make also but I'm always open to suggestions
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Why would it not work On a stock frame? Just curious.
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You lured me in with your title.. And then disappointment! I wish there was more options for stock frames that's all I have right now. Could anyone make a raised upper shock mount that we could weld on for a no link setup or something?
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Call LS. They can do the mod. Not sure if they would give up the dimensions for the me for you to do your self.
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I got some pictures of a stock frame with a no link mod somewhere...
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If Im not mistaken Walsh used to have a kit for no link. Yes the upper shock mount is moved up on a no link but some are move forward towards front of the bike. If you have an oem frame next to an aftermarket frame its easier to see the difference, the upper rail that the shock mount is on sits higher as well.
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Std 250r link suspension
(http://i832.photobucket.com/albums/zz242/04450r/photo3_zps4e16cf1a.jpg) (http://s832.photobucket.com/user/04450r/media/photo3_zps4e16cf1a.jpg.html)
Lsr no-link
(http://i832.photobucket.com/albums/zz242/04450r/photo2_zpsaf691c0c.jpg) (http://s832.photobucket.com/user/04450r/media/photo2_zpsaf691c0c.jpg.html)
Houser no link hybrid
(http://i832.photobucket.com/albums/zz242/04450r/photo3_zps936b0ca7.jpg) (http://s832.photobucket.com/user/04450r/media/photo3_zps936b0ca7.jpg.html)
Laeger cr500
(http://i832.photobucket.com/albums/zz242/04450r/photo1_zps415649e0.jpg) (http://s832.photobucket.com/user/04450r/media/photo1_zps415649e0.jpg.html)
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The problem we found is not the linkage it's the clearance from the swingarm to the airbox and exhaust. You will destroy the stock airbox or a stock exhaust with a suspension that has the correct up travel of the rear wheels. I don't want to make a new linkage and then get calls all the time because they destroyed their airbox that you probably can't buy anymore. The frame is still 3" off the ground when clearance issues are a problem!
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For a minute there I thougt we were going to finally have a true fix for mounting up a 450R swingarm to the 250R. Is that what you were refering to Andy? Either way I watch them all, over and over and over....
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For a minute there I thougt we were going to finally have a true fix for mounting up a 450R swingarm to the 250R. Is that what you were refering to Andy? Either way I watch them all, over and over and over....
This linkage will be a newly designed 450R linkage for TT racing. I will have a few pro riders running it this year at the EDT Nationals, MWEDT and NEEDT. I haven't taken or had the time to try the 450R on a 250R yet. I explain why we are changing to this design in the video so stay tuned.
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Andy, many of us dont run a stock air box. I would still like to see a LT linkage option for the R. A lot of guys run airbox eliminators. Lets see the 250r option some day soon. ...haha.
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I'm with Burns. Would love to come up with something for the R in the future but for now MORE than happy to learn something from the video as I always wondered how you figure this stuff out.
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Add me to the list. I ditched my air box long ago. if a custom intake is the price to pay for a LT rear linkage I'm game all day.
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Just checking interest here to see if anyone would be interested in seeing how we go about designing a new suspension linkage? I'm planning on designing tomorrow if we get a big snow like they're talking (no customers stopping by). I figured I would use the GoPro and record the process if there's enough interest. And no this won't be for the 250R, we already tried that and there's too many things that won't let it work on a stock frame!
Is this a joke? Of course we want to see the video!
The problem we found is not the linkage it's the clearance from the swingarm to the airbox and exhaust. You will destroy the stock airbox or a stock exhaust with a suspension that has the correct up travel of the rear wheels. I don't want to make a new linkage and then get calls all the time because they destroyed their airbox that you probably can't buy anymore. The frame is still 3" off the ground when clearance issues are a problem!
I understand the problem. However, like several others mentioned, we would love to see a solution for this even if it meant ditching the air box or going with a 450r swinger setup. I think there is some real potential to keeping our R's alive by be able to use a 450r swinger and special linkage setup (similar to 450r linkage). You could make the linkage exclusively and make lots of money off all of us happy customers!
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Yfz linkage appears to be similar to cr500. Modifying the frame and more would be worth it to have the option of swapping in readily available components.
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Correct, but yfz uses a really long rear shock. There was a guy on atvriders that started to do this swap and bailed. Not sure why, I will try to find the link.
http://www.atvriders.com/vbb/showthread.php?423445-My-MX-National-bike-build-thread
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The upper shock mount, linkage, lower link mount, swingarm length, swing arm linkage mount, Counter sprocket location relative to the swingarm pivot, angle of swingarm relative to chain (anti-squat), angle of the rear shock thru the travel, ride height, frame clearance, etc... are all are geometric factors, just slapping in a another swing arm or linkage from another bike is not always a good idea. The entire system must be accounted for when experimenting with this. It is possible to design a new link or adopt a link for stock frames, but you need to ask what problems are you trying to fix? Too much progression, not enough progression, traction, up travel, down travel, etc... What works for one is not always universal, just my couple of cents...
Regarding the original topics I would like to see the videos myself, I love the technical videos!
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Exactly Troy!! There was another thread here somewhere when we dug into this subject a little deaper.
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http://trx250r.org/showthread.php?1760-Cr500-link
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Suspension geoemetry is very interesting to me, I'm a student of the game. The nerd in me actually spent the time over my Christmas break to solve the 4 bar linkage equations out by hand for all types of suspensions CR links, Walsh/JB style links, Stock 450, No Links, etc... I then created a spreadsheet/macro/solver to calculate leverage ratio and Force ratio curves to compare each design and plot the curves, and then of course be able to adjust parameters to ultimately design my own links, swingarms, etc.... This is just one part of the overall picture though, but it starts to paint a picture of what's going on mathematically for each linkage. If I remember I'll try and post some pics.
I also did some investigating on "infintely adjustable progressive spring stacks", basically looked at wave spring stacks, vs. common coil springs. The technology just isn't there yet, but the potential is interesting, I think. The idea of having even more spring rates vs. 2, 3, 4, 5, etc..., basically takes the linkage out of the equation and you can design progressive spring rates for any type of riding, at least from a spring standpoint, plus they are super light! Valving though is another topic.
Here is an example of a wave spring, you can stack these as thin as 1 wave spring, to build up a "stack" with different rates... http://www.smalley.com/
One major flaw though with this idea, is wave springs don't have the duty cycles that coil springs do so they can take a "set" quickly and then you're done. So technology would have to improve. Interesting though to think about.
I think to determine what is "better" is very subjective. Like Laz mentioned validation and testing to develop a "system" together, i.e. linkage and shock is what it takes.
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here is some food for thought:
http://www.promecha.com.au/leverage_linkages.htm
http://www.promecha.com.au/springs_advanced.htm
john
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^ x2
:)
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The upper shock mount, linkage, lower link mount, swingarm length, swing arm linkage mount, Counter sprocket location relative to the swingarm pivot, angle of swingarm relative to chain (anti-squat), angle of the rear shock thru the travel, ride height, frame clearance, etc... are all are geometric factors, just slapping in a another swing arm or linkage from another bike is not always a good idea. The entire system must be accounted for when experimenting with this. It is possible to design a new link or adopt a link for stock frames, but you need to ask what problems are you trying to fix? Too much progression, not enough progression, traction, up travel, down travel, etc... What works for one is not always universal, just my couple of cents...
Regarding the original topics I would like to see the videos myself, I love the technical videos!
I actually addressed some of these things in my video today. Hope this gets people thinking too.
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Ski Doo has a linkage set up in their new sleds that separate the spring and the shock and have different linkage ratios in each. Just some food for thought.
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Not to get off topic but being 250r owners our choice of parts is limited daily. The 450 conversion going to have to become a reality at some point in time if we are to survive in the future. Aftermarket swingarms are expensive and hard to come by where the 450r stuff is cheap and readily available. Nothing is perfect but I'm sure some kind of linkage can be made to make it work well.
Looking forward to the video Andy.
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drum roll please. LOL Enjoy. I'm going to post this also at the top of this thread too so anyone clicking on this doesn't have to scroll through to find it.
[video=youtube_share;SW9G0o-Nytk]http://youtu.be/SW9G0o-Nytk[/video]
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Very cool Andy, thank you for taking the time to make videos for us!!
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Just finished the video. Thanks, Andy, for making the video. I enjoyed it quite a bit.
I still can't help but think though, that the 450r swingarm could be adapted to run on the 250R using a new type link like you made. The geometries are not that different from one another. I just think it may take a custom made link and maybe a custom dogbone. I think this could play into the option of having an LT suspension for the rear.
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Just finished the video. Thanks, Andy, for making the video. I enjoyed it quite a bit.
I still can't help but think though, that the 450r swingarm could be adapted to run on the 250R using a new type link like you made. The geometries are not that different from one another. I just think it may take a custom made link and maybe a custom dogbone. I think this could play into the option of having an LT suspension for the rear.
Agreed 100%, the conversions I've seen they just swapped swingarms and links and didn't actually try to figure it all out. It may not take much at all, new link or something. Someone just needs to put some effort into it.
With that said, I like my stock 250r linkage on the 89 better than the stock 06+ 450r linkage. I just measured my 450 with MX tires and the pre-load set as low as possible (stock shock and link, mind you) the ass end (rear of seat) sticks up 1"+ taller than the 250r which has 20" tires...
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I wonder if GThunder made a new linkage for their 250R project? I know Laz put a 450r swing-arm on that project. I don't think he'd do it without doing it correctly.
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The progression on the stock 250R link isn't bad at all from what I mapped out. (It's really hard to do it on paper though due to measuring errors). I'd like to get a string potentiometer hooked up with a program to calculate the changes but just haven't done it yet. Or what would be better is to have the solid works program and do it on there but that's WAY out of my price range.
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Andy I have solidworks and can do all of that. I also have an industrial 3D scanner and I've scanned in Laeger frames, 250r frames, 450r frames, swingarms, etc... I can provide that leverage ratio and % rise in rate if someone is interested, I just haven't put too much time into as I didn't know if was warranted...
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Andy I have solidworks and can do all of that. I also have an industrial 3D scanner and I've scanned in Laeger frames, 250r frames, 450r frames, swingarms, etc... I can provide that leverage ratio and % rise in rate if someone is interested, I just haven't put too much time into as I didn't know if was warranted...
I'd be very interested in seeing that. I'd like to see a comparison graph of each. I'll do some checking into a solidworks program and would be more than happy to do the foot work to make this if you'd be willing to share the frame scans. I'd share my info here for everyone to see.
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I'd be very interested in seeing that. I'd like to see a comparison graph of each. I'll do some checking into a solidworks program and would be more than happy to do the foot work to make this if you'd be willing to share the frame scans. I'd share my info here for everyone to see.
Here is just a start of what I've done.
04-05 450R Frame Scan
(http://i1345.photobucket.com/albums/p669/robl-engineering/Frame%20Scans/0405-Frame_zpsaab94ff8.jpg) (http://s1345.photobucket.com/user/robl-engineering/media/Frame%20Scans/0405-Frame_zpsaab94ff8.jpg.html)
Laeger 250R Frame CR500 linkage
(http://i1345.photobucket.com/albums/p669/robl-engineering/Frame%20Scans/Laeger_CR500_Linkage_frame_zps7f14f7b0.jpg) (http://s1345.photobucket.com/user/robl-engineering/media/Frame%20Scans/Laeger_CR500_Linkage_frame_zps7f14f7b0.jpg.html)
How I layout the suspension geometry, (as an example): The 3 lines represent ride height (middle) max up travel and max down travel. Up travel set with 1" frame clearance, max down with 13" frame clearance total 12" of travel
(http://i1345.photobucket.com/albums/p669/robl-engineering/Frame%20Scans/Suspension_Layout_zps7f2eb89d.jpg) (http://s1345.photobucket.com/user/robl-engineering/media/Frame%20Scans/Suspension_Layout_zps7f2eb89d.jpg.html)
How I calculate suspension Leverage Ratio and % Rise in Rate, I have this for all styles of linkages.
(http://i1345.photobucket.com/albums/p669/robl-engineering/Frame%20Scans/SuspensionProgression_zps7898dfe7.jpg) (http://s1345.photobucket.com/user/robl-engineering/media/Frame%20Scans/SuspensionProgression_zps7898dfe7.jpg.html)
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I tried zooming in on that last page but it's too blurry to read. Very interested
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Andy - great video as always!
Troy - you just took this thread up a couple of notches - very cool stuff here!
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Troy - You've got all the really COOL toys!! That scan is AWESOME! This will really help our community really understand this topic - Thanks for taking the time in doing all that! :)
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Hmm.......... plasma cutter, CNC mill, tig welder, water jet, solid works....... doesn't everyone have these in their garage????
More like........ torch, drill press, arc welder, garden hose, crayons and paper, oh and can't forget duct tape and bailing wire !!!!
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I'll post more details of this information as well as my calculations. I just wasn't sure anyone was interested. I love this stuff, :D
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I'll post more details of this information as well as my calculations. I just wasn't sure anyone was interested. I love this stuff, :D
Yeah Troy keep it coming! Make sure some of the good technical stuff gets in the Tech Sections too!:redbull:
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Very cool Troy. (http://www.4smileys.com/smileys/drinking-smileys/cheers_smiley.gif) (http://www.4smileys.com)
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I'll post more details of this information as well as my calculations. I just wasn't sure anyone was interested. I love this stuff, :D
Awesome. Clearly the gang likes the technical stuff.
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Glad to see you posting again Troy and Andy
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Very cool. I hope this can lead to some new parts!
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Very cool. I hope this can lead to some new parts!
Yeah would be very cool to just have a billet factory linkage replacement option! Andy.. hint hint :D
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Yeah would be very cool to just have a billet factory linkage replacement option! Andy.. hint hint :D
If I get someone close to me that would like to do the conversion then I would be willing to tackle it.
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Somebody please send this man a frame!
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Here's the problems we came up with last time we started doing this on the R. The clearances were less than I'd like to see with 20" rear tires for the proper up travel of the rear tires. It would work great with 18" tires but not so much with over 20" tires
Exhaust clearance
(http://forums.trx250r.org/vbulletin_imports/196_549_2017-04-18_5657.jpg)
Airbox clearance
(http://forums.trx250r.org/vbulletin_imports/196_550_2017-04-18_7840.jpg)
Chain and sprocket clearance
(http://forums.trx250r.org/vbulletin_imports/196_551_2017-04-18_2514.jpg)
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Yeah that doesn't look too good.. Would be interesting to see what length extended swingarm would get around this (+6 for example).
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What about with center mount exhaust and airbox eliminator?
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I had a customer that had the ESR center mount exhaust and it was way worse than stock for clearance.
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I'm running 18" tires and I can raise my exhaust and airbox. Coolant overflow is up front now.. So can you make me a link? Pretty please :)
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With posts like these and the members we have here...why would you want to own a 450!! Great job Anday and Troy. Looking forward to seeing this project finally get the proper linkage.
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I can't take credit for anything, Andy is the one building links and setting up shocks. All I'm able to do is calculate leverage ratio curves, % rise in rate, and draw up stuff in Solidworks. I'll delete my pics.
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Andy, I can't speak for the entire group, but for the group racing mx, the majority of us are running 18" tires already and I would even go as far as to say we deleted the coolant overflow bottle. I know I have. There are always sacrifices or limitations when it comes to achieving something like this. If you could make some sort of LT linkage or some linkage that would allow a 450r swinger to work, I think there would be several of us that would be all for it, especially us doing mx.
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Maybe you guys should just buy 450r's! :fighting0061:
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Maybe you guys should just buy 450r's! :fighting0061:
...Or better yet stick the R motors in 450r chassis's and not look back... :quad:
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...Or better yet stick the R motors in 450r chassis's and not look back... :quad:
If the 450R wasn't so damn ugly I would seriously consider that option but I would stick it in a YFZ or an LTR before I went down that road! LOL
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That will probably be my next project Troy! Just gotta get some other stuff finished up first.
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I have a Yfz chassis I was going to drop a Zilla engine in but my friend decided to bail on the project. If your interested lets talk and I can send ya Pic.
Personally I would do the smoker in the trx450 chassis, actually may be soon if I don't get the 4 banger runnin.
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I hope it don't run.:sign0108:
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...Or better yet stick the R motors in 450r chassis's and not look back... :quad:
here ya go:
http://www.atvriders.com/vbb/showthread.php?412670-450r-250r-hybrid&s=
john
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I am guessing the same linkage issues with the 400ex swingarm.
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I am guessing the same linkage issues with the 400ex swingarm.
I’d say yes same issue
Joe