Rear beam triangulation. Whats the reason ?

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

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

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    No club racer ever got anywhere by insisting on laboratory-style data before donning the garage overalls.

    The simple answer is to buy a welder and try it. If it doesn't work, take it off.
     
  2. matthew85 Forum Member

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    Hah read that post again and i sound very pedantic!

    Im in two minds regarding improving the rear beam also. Am I right thinking companys sell weld on kits (im sure have seen them listed), and how do these compare with the type of ARB fitted to dogwoods rear beam? Im not sure about making the rear beam too strong as I would rather bend a rear beam than the chassis at the rear if i was to clout a curb etc!

    Has anyone studied the effects of the different solutions? the mk1 polo is a light car, especialy at the rear so i am unsure if it'll make much difference anyway!
     
  3. A.N. Other Banned after significant club disruption Dec 5th 2

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    The ARB on Dogwood's beam is either a U-section or a blade, but this isn't the same as triangulation.

    People sell weld on kits (well, one in the US I've seen) but with a bit of effort, one could be made for relatively little money. The biggest cost is the 4 rosejoints.
     
  4. RobT

    RobT Forum Junkie

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    Really? is that how its done? Cool :thumbup:

    And there's me thinking there was substance behind bold statements.

    Its always a pleasure to take such wise and reasoned advice from such an accomplished racer :lol:
     
  5. RobT

    RobT Forum Junkie

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    Dogwood is of the opinion that cross bracing is not necessary.
     
  6. fthaimike Forum Addict

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  7. fthaimike Forum Addict

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    Last edited: Jul 1, 2010
  8. A.N. Other Banned after significant club disruption Dec 5th 2

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    You think you have some sort of racer's pedestal as regards advice, against a backdrop of you procrastinating over this triangulation topic for 5 whole years? :lol: I have news.

    The fact is it'll cost ? to get one made elsewhere, which could theoretically all go to waste if it doesn't work, and this has clearly held you back. Answer? Bridge the gap, and do it for cheap. Welder, post drill, M12 tap etc etc + time = done.

    Which bold statements?

    I've been very clear throughout this thread that there are 2 schools of opinion. The suggestion to "try it" is intentionally made from a impartial standpoint, stood between those schools.
     
  9. mickey marrows Forum Member

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    What appears to be missing from this 'argument' is that there are two different applications to the diagonal bars. If thier outboard pickup point is high and close to the trailing arm that they are used to eliminate unwanted toe changes under heavy side loads and impacts (more suited to rally cars), but quite a few GpH cars run them with a lowered outboard pickup point far away from the trailing arm as this induces a negative camber increase with side load..... (more suited to circuit cars)
     
  10. A.N. Other Banned after significant club disruption Dec 5th 2

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    Indeed, ground clearance being the issue with those mounted lower down, hence being worthless for rallying.

    There is potentially more toe-in tendency for 'tarmac' bars, the bars being longer, passing through a wider arc under travel. It's all limited by the amount of travel being used, of course.

    These really are crude upgrades, but seem a fairly effective way of beefing up a basic and cheap rear suspension system, all the same.
     
  11. infinity

    infinity Forum Member

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    I think it depends on the car set-up, driving style etc etc, there have been many tests on here where people are trying components on there cars for example : ball joint extenders and front splitter designs and fancy top mounts, i've not not seen any hard data on those either other than owners comments.

    Everyones car is individual to them, a mod on my car may not suit yours or your driving style.

    My rear triangulation arms take 5 mins to remove so only track testing or lap times will show any gains. Unfortunately I don't have any works style data logging equipment. I'm sure there's a few engineers out there that can do calculations to work out all the forces..??

    I first saw beams like this on the beetle RSi cup cars and of course the G3 Kit car. I think its a matter of how much grip you think your car can generate because all of those forces are essentially counter-acted by the beam..... clearly i've set my hopes high by putting them on mine....:lol:[:^(][8(]
     
  12. mickey marrows Forum Member

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    I'm sure I've read a report somewhere where someone tested one of the KWL mk1 Sciroccos and after a few laps of the ring suggested the bars be fitted..


    As for Chris's comment.. you're right, although I never looked at it before, the length of the bars could induce some toe in.. which definatly a good thing..

    I can see a set of bars appearing on the Time Attack polo before Cadwell Park...
     
  13. mickey marrows Forum Member

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    I prefer to think of it as 'genius'
     
  14. A.N. Other Banned after significant club disruption Dec 5th 2

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    :lol:

    I give you expensive genius...

    Seat Ibiza Kit Car Evo 2 rear beam:

    [​IMG]

    [​IMG]

    [​IMG]


    Golf 4 Kit Car rear beam.

    [​IMG]


    These have centre bearings on the main beam axis though.
     
  15. A.N. Other Banned after significant club disruption Dec 5th 2

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    Do these cars race to historic regs? If so, wouldn't that preclude?

    Toe in better than non-braced, non-steady state toe out I suppose, but it could possibly induce mid corner understeer.

    Theorising.
     
  16. mickey marrows Forum Member

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    Yeah, which is why they were ommitted.. but the Scirocco runs 10" rears... not good..
     
  17. StuMc

    StuMc Moderator and Regional Host - Manchester Moderator

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    Hold on...

    Haven`t you recently, in essence at least, `nailed` a piece of MDF/Ply to the front of your car to `see what, if any, difference` it makes before committing to a CF version?

    Same `suck it and see approach` as described here, as far as I can see... ;)
     
  18. RobT

    RobT Forum Junkie

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    Yep, same approach. Things I think might be a benefit, I build and test. I dont waste my time making things I dont think will be an advantage on my car. But like I have said already above, if anyone does do any tests on such a system, especially on later-model axles, I am more than happy to be convinced otherwise.
     
  19. StuMc

    StuMc Moderator and Regional Host - Manchester Moderator

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    So you were just arguing for the sake of it? Cool... :thumbup:
     
  20. RobT

    RobT Forum Junkie

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    I'm not arguing - merely discussing

    2 pics relevant to discussion:

    the first is a Seat Ibiza Evo 1 rear beam, the second off a car believed to be a german circuit racing golf (note very smart (factory?) integral blade arb)

    both are factory-developed parts, neither have triangulation braces

    one looks to have come off a rally car, one is off a circuit car

    [​IMG]

    [​IMG]
     
    Last edited: Jul 2, 2010

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