Martin's VTR 1000 Adventure Sidecar Build

Discussion in 'Hacks' started by m_cliffhanger, Nov 4, 2016.

  1. m_cliffhanger

    m_cliffhanger Momentary Lapses of Reason

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  2. SQD8R

    SQD8R Eat squids and be merry

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    Toured the East Coast of Canada on a VTR, same colour. Loved it, never should have traded it in.
  3. Pete-NZ

    Pete-NZ Long timer

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    I imagine a trials sidecar would use quite small rose joints...
    both my leaner units use 3/4" UNF moly rose joints as the main
    pivots & 12mm steel for the lean limiter they never give any issues..

    I do carry a spare of each just in case...




    .
  4. L_Bomb

    L_Bomb Strewth and blimey

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    The problem with rose joints is that they work perfectly fine until they fail catastrophically. There is generally no sign they are about to let go.

    An early lesson as a mechanical engineer in the Formula Student competition is that you don't use rose joints on suspension components. One of the judges has a passion for this.

    I think my sidecar swingarm rose joints may have been 1/2 inch

    I should note that they would normally fail at the thread unlike mine which had the threads welded up.

    DSC_0003_3.JPG
  5. RoundOz

    RoundOz Plenty of seasoning

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    I can definitely see your point about catastrophic failures. Ball joints rarely do that without wearing out first. Rose joints are pretty popular in race car suspension systems, but in these applications they may be changed out on a regular basis.
    It looks like in your application they were welded. I'd be a little concerned that the heat treatment was compromised - this effect can be concentrated where the piece is thinnest, or where there are transitions, rather than where the weld is. It looks like this breakage was where grease nipples are threaded in. Maybe a better bet is the non-greaseable style and just change them out routinely. In service there should be no movement, so grease nipples seem a little superfluous to me. Or this particular situation may have been better served by ball joints if adjustments need to be made to angles.
    Rose joints are designed for longitudinal loads, not for side loads - I say this because it's hard to get my head around how they are used in the photo.
    Geoffreywh, Old Mule and Bobmws like this.
  6. m_cliffhanger

    m_cliffhanger Momentary Lapses of Reason

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    That's quite a failure, however, looking at the remnants, I would speculate that those were a low quality rod end (rose joint). The wall thickness of the race does not look to be more than 2 or 3 mm, and it was further weakened by the grease nipple hole (as RoundOz observed). I'm in no way an expert on rod ends, but I have found that rod ends with grease nipples are usually found in industrial applications, rather than in racing or aviation. I also think that by welding the threads, and by the size of the bead, a lot of heat was introduced, that weakened the race further.
    Your experience has obviously turned you off rod ends (rose joints), but with the right quality and sizing, I have no concerns about using them.
    brstar and Hookalatch like this.
  7. Geoffreywh

    Geoffreywh old bike bloke.

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    You cannot do that to rose joints and not expect failure, a better solution was to use a car drive shaft universal joint, but please, no welding.