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  1. #1
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    Default Watts Link geometry

    I'm working on the design for the watts link in my car and have a very basic watts link geometry question. I will mount the center link to the chassis and the outer links to the axle (represented by the centerline). The outer links are parallel in both cases.

    Of the two options below, which is preferred and why? Is there a better option?


    Name:  watts_link_geometry.jpg
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    From a packaging standpoint, option 2 is preferred but if Option 1 is better from a design standpoint, I will go that route.

    Thanks!


  2. #2
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    Quote Originally Posted by feeble View Post
    I'm working on the design for the watts link in my car and have a very basic watts link geometry question. I will mount the center link to the chassis and the outer links to the axle (represented by the centerline). The outer links are parallel in both cases.

    Of the two options below, which is preferred and why? Is there a better option?


    Name:  watts_link_geometry.jpg
Views: 1557
Size:  76.3 KB


    From a packaging standpoint, option 2 is preferred but if Option 1 is better from a design standpoint, I will go that route.

    Thanks!
    The only way a symmetrical Watts link will work "correctly" is if the end mounts have the same vertical separation as the center to center of the pivots on the bellcrank (closer to your figure 1). The links do NOT have to be parallel at ride height, as long as the mounts are the same vertical distance apart.

    Ray Kaufman - Wyotech Chassis Fab and High Performance Instructor. Words of Wisdom from an old master... at Asylum Custom Interiors website

  3. #3
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    Option 2 will geometrically bind, or is completely constrained. Since both links need to get longer/shorter for the bell crank to move up or down. Basically this is a complicated panhard bar.

  4. #4
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    Thanks for the insights guys, I have a constrained sketch now that works as it is supposed to. I should have done that first.

  5. #5
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    Default

    Wikipedia has a nice video of a Watts link. It will be centred on the curve when it's setup with links parallel to each other and ground and perpendicular to the bell crank at ride height.

    http://en.wikipedia.org/wiki/Watt's_linkage
    Duane
    '74 AMC Javelin AMX

  6. #6
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    www.fays2.net
    It works great and I am working on getting one down road as I get my Monza on road with new rear suspension.
    Lee Abel
    AFTERMARKET PERFORMANCE

    1977 Chevy Monza 2+2:Project "Cheap Trick"
    1984 Caprice 2dr 402BBC: Project "What If,,,?(dead project, no title)
    1978 C10 Long bed , On air and trailer puller
    2006 Buell Blast ,Just a bike to ride and for mileage
    1966 Caprice 4dr Sports Roof fact.327/now 350/SOON 454!!!!!

  7. #7
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    I bought the 5" propeller from Fays2, is a very nice quality.



    Design in progress:


  8. #8
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    Quote Originally Posted by feeble View Post
    I bought the 5" propeller from Fays2, is a very nice quality.



    Design in progress:


    Nice design. Where will your coilovers mount?

  9. #9
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    Quote Originally Posted by Bryce View Post
    Nice design. Where will your coilovers mount?
    Thanks. Coilover selection and mounting is one of the things in process. I need to finish up the rear housing model and the mount for the propeller first though. I have definitely taken some inspiration (if not the actual design) from your build thread.

    You wouldn't happen to have an accurate 9" housing center section modeled up would you? I found one on GrabCAD but it doesn't seem to match my housing very well. Your housing looks the same as mine.

  10. #10
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    Quote Originally Posted by feeble View Post
    I bought the 5" propeller from Fays2, is a very nice quality.



    Design in progress:

    I bought the same center link that you have. It is a nice piece.

    Here is how I made my watts link. I wish I had the cad skills that you guys have. I need to take some classes. I just went all rudimentary and welded some steel together after getting ALOT of good advice from the folks here including Bryce. JR



    Some details of the parts used can be seen here.

    http://www.pro-touring.com/showthread.php?55420
    What I write is opinion, none of it is factual. 2010

    Even though I'm conscious it doesn't mean I'm coherent. 2011

    I'm getting better with age. Best thing about old age is I don't know any better. 2012

  11. #11
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    Quote Originally Posted by feeble View Post
    Thanks. Coilover selection and mounting is one of the things in process. I need to finish up the rear housing model and the mount for the propeller first though. I have definitely taken some inspiration (if not the actual design) from your build thread.

    You wouldn't happen to have an accurate 9" housing center section modeled up would you? I found one on GrabCAD but it doesn't seem to match my housing very well. Your housing looks the same as mine.

    Thanks for the compliment. I do not have an accurate model. I just roughed one in for visual. Maybe Jason at GMR could help?

  12. #12
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    Thanks again for the info and pics guys.

    The further I get into this, the more I am seeing the advantage of what both of you (and Jim Fays) have done for the axle clamps holding the ends of the horizontal links. Very adjustable. No point reinventing the wheel if I can't improve upon it.



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