Rear beam triangulation. Whats the reason ?

Discussion in 'Chassis' started by Paul-R, Jun 16, 2010.

  1. Paul-R New Member

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    from the Berg Cup build in the members section.

    He has added some extra triangulation to the rear beam, terminating under the rear shock absorbers, why ?

    I don`t understand the reason for doing this ? Does it stiffen up the rear ? I know Golfs don't have independant rear suspension, does this work in the same way as a big ARB ? [:s]

    On a track car, isn't there a chance these could touch a kerb if you cut a corner ?
     
  2. Dave

    Dave Pedantic Old Fart Paid Member

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    [​IMG]

    Yes

    No

    No
     
    Last edited: Jun 16, 2010
  3. Paul-R New Member

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    Oh, thats cleared that up then [:s]

    I still have no idea what they do! :lol:
     
  4. danster Forum Addict

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    The axles can flex and this changes the toe and camber which is not ideal. The added tie bars try to keep the trailing arm from flexing. As Daved's fine sketch shows.:thumbup:
     
  5. fthaimike Forum Addict

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    Last edited: Jun 16, 2010
  6. Dave

    Dave Pedantic Old Fart Paid Member

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    Is the upper photo your's Mike?
     
  7. fthaimike Forum Addict

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    Last edited: Jun 16, 2010
  8. Paul-R New Member

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    Thanks for the info. I`ve never come across that before.

    I'm assuming they are fabricated with some Mild steeltube, some plate and rose joints ?

    Can the threads on the rose joints be adjusted to change the toe, or is the aim just to stop it changing ?

    fthaimike, are you doing it to yours at some stage ?
     
    Last edited: Jun 16, 2010
  9. Dave

    Dave Pedantic Old Fart Paid Member

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    High Strength Steel tube. Extruded if possible.

    Threaded joints are only for getting everything snugged up tight, to stop movement away from desired toe and camber. Toe and camber usually set with tapered spacers.

    The lower of Mike's pictures is the better solution, IMHO, with regard to the towers, as they are directly below the centre of rotation of the circular tube, that forms the trailing arm of the beam!

    Reeves beam is a really good example of simple expedient engineering though!
     
    Last edited: Jun 16, 2010
  10. fthaimike Forum Addict

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    Exhaust might need relocation too.
     
  11. A.N. Other Banned after significant club disruption Dec 5th 2

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    Another variation on the theme, with centre adjustability, shown here on Gatan Hayot's epic Mk1.

    The origins of these beams are two-fold: race and rally.

    The rallyists would readily reduce rear beams to scrap with a few sideways dinks, whilst the racers gained great toe control from them (as did the rallyists). There are schools of race thought on whether the toe control is needed (as opposed to OEM characteristics, supposedly aiding turn in, via natural toe out / less camber from sideways force). I think this boils down to driving style, various noisy debates on Vortex in the past clearly showing the 2 camps.

    During the Formula 2 technical race in the late '90s, the kitcar regulations permitted these on Mk3 Golfs, and they were also seen on Seat Ibiza Evo 1s ('96 - mid-97).
     
  12. A.N. Other Banned after significant club disruption Dec 5th 2

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  13. RobT

    RobT Forum Junkie

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    I reckon that they might be a good idea on a fairly weedy mk1 axle, but as time has gone by, the axle has got much stronger with much more oem bracing

    my concern in doing it, is making an already very heavy component even more heavy - bolting an ARB on adds a lot of weight, cross braces too.....blimey.....
     
  14. fthaimike Forum Addict

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  15. A.N. Other Banned after significant club disruption Dec 5th 2

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    Picking up where Vortex left off :lol: if weight is outweighed by handing, then that's a net gain.

    But you have to take the net gains connected with that set up - if that's not the desired set up, clearly there's no point.
     
  16. Dave

    Dave Pedantic Old Fart Paid Member

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    Gosh, you is well built!:clap:

    And, also very, very pretty!:thumbup:

    What more could a man want?[:$]
     
  17. RobT

    RobT Forum Junkie

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    if....but we dont know either way do we? speculation is all we have (for a change....)

    mk1 golf axle - quite weedy

    [​IMG]

    mk2 ibiza axle (lower pic) - considerably beefier

    [​IMG]

    I am not convinced at all that these braces are required on later cars - on a Mk1 golf, maybe - the beam does look a bit flimsy
     
  18. A.N. Other Banned after significant club disruption Dec 5th 2

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    All I see is an articulation of set ups - and a pointed query addressed as to whether additional weight is counterproductive.

    I recall triangulation being a topic around 2005 - if you still haven’t decided, hey, ho.

    Note the design of axles has changed partly because the V-cross section beams twist along their lengths much more willingly than the T-section Mk1 beam, giving them less dependent behaviour (more obvious on an ARB-free non-GTI beam).

    That's not a Mk1 Golf axle you've pictured btw ;)

    Bristolfish, Danster + TSC have all laid claim to Miss daved's hand! ;)
     
  19. matthew85 Forum Member

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    Thats a mk 1-2f style rear beam. but with an ARB so its from a G40 or GT
     
  20. RobT

    RobT Forum Junkie

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    google came up with that picture as a mk1 golf axle - looks pretty similar to me but thankyou for pointing it out - regardless, the point made is the same - its likely that we cannot simply extrapolate data between quite different versions of a component

    it is true that I have not made up my mind on this issue - I have not seen and definative data one way or the other - if anyone has seen such data, I would be interested to hear about it
     

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