Featured Thruxton ‘r’. Beware! Front Wheel Fitment

Discussion in 'Thruxton, Scrambler & Trident' started by Ken walburn, Jun 23, 2019.

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  1. Callumity

    Callumity Elite Member

    Feb 25, 2017
    3,358
    800
    Nr Biggar
    Sometimes it helps to understand what you are trying to achieve......

    And, as I have always understood it.....

    Assuming all parts of the assembly are in the correct order, the main axle nut is tightening everything between the left hand fork leg and the shoulder on the thick end of the axle. The right hand fork is then aligned parallel and clamped to the axle. Self evidently a twin disc setup dictates RH fork alignment but it is the LH fork that provides the datum start point.
     
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  2. Paul Mac

    Paul Mac Member

    Apr 3, 2020
    39
    18
    Durham
    I agree , I'm not 100% sure what some are inferring but the LHS fork leg is ,as you say , the reference/datum point . Having clearance between the RHS fork leg and the wheel bearing is irrelevant , in fact i would suggest necessary, for the fork to settle at the correct clearance . But there should certainly be no forcing of the fork leg into position or manufacturing of spacers .
    The main point is to make sure the pinch bolts are slack enough to allow the right fork to find it's correct position
     
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  3. Dave Roxburgh

    Dave Roxburgh Well-Known Member

    Jul 5, 2019
    63
    68
    Suffolk
    Brilliant, brilliant vid, mate. Yep, explains it all.

    Haynes did not mention applying the brakes to get the calipers perfectly aligned before torquing them up - that's now my job for this weekend!!
     
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  4. Kinjane

    Kinjane Active Member

    Oct 15, 2017
    234
    43
    Bristol, Land of Enger
    But what if the reason the fork leg has to be levered out is because the mudguard is pulling it in out of parallel to begin with? I've had this on previous bikes and don't see why Triumph should be any different.
    If this were the case and you shimmed out the mudguard the fork lower would be sit further out without requiring any force
     
  5. Dave Roxburgh

    Dave Roxburgh Well-Known Member

    Jul 5, 2019
    63
    68
    Suffolk
    I would suggest:

    The original Triumph guard *shouldn't* be doing this - it should be the right size and not stiff enough to deflect the fork.

    In any rate, if you suspect the guard is causing problems take it off and fit it last - after everything's seated right. If it don't fit when the forks are set up right then modify or change the mudguard.
     
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  6. Paul Mac

    Paul Mac Member

    Apr 3, 2020
    39
    18
    Durham
    Second that , there is no way you should let an ill fitting mudguard alter the forks natural parallel travel .
    That can cause serious wear and compromise the suspension , potentially being dangerous
     
  7. Callumity

    Callumity Elite Member

    Feb 25, 2017
    3,358
    800
    Nr Biggar
    Dog tail, tail dog!
     
  8. Kinjane

    Kinjane Active Member

    Oct 15, 2017
    234
    43
    Bristol, Land of Enger
    #28 Kinjane, Aug 2, 2020
    Last edited: Aug 12, 2020
    The right hand fork leg will find its natural resting position a lot easier when the front wheel is no longer resting on the ground ;)
    Thought I’d better check my Speed Twin which has the same arrangement. Slackened the mudguard, raised the wheel, checked the gap, slackened the spindle clamp bolt and tightened it, measured the gap again to find it had increased by 0.5mm .Lowered the wheel. Tightened mudguard.
    Gap with legs now parallel measures 1.3mm.

    Edit - Totally different bike to ride now that the front forks no longer suffer from assembly line misalignment and I don't think its down to the current heat levels thinning the fork oil viscosity. The forks definitely feel more supple.
    Why these bikes don't come with idiot proof axles that lock the forks down in one position is beyond me - both of my Honda middleweights have them and they were certainly much much cheaper to purchase than the Triumph.
     
  9. timboo

    timboo Senior Member

    Oct 17, 2021
    275
    113
    Cambridgeshire
    Sorry to resurrect this thread it came up when I was researching my front brake woes.
    Can I ask when the front end of your bike is on a paddock stand and you rotate the front wheel should it spin freely if so roughly how many rotations or should the pads touch the disc a little and reduce this rotation somewhat?
     
  10. MightyBoosh

    MightyBoosh Member

    Mar 29, 2023
    47
    18
    Uk
    With the wheel off the ground it should spin fairly freely. Really if you put your fingertips on the tyre it should push round easily enough. You'll quite likely hear a faint swishing or scraping sound as the pads are obviously very close to the disc. How many turns? Well, depends how hard you spin it for a kick off, but certainly ought to go a turn or two if you give a good wind up as it were. Watch closely as it comes to a stop and see if it stops gradually or if there's a slight judder which might indicate a sticking pad. Turn the wheel slowly and see if there's any resistance. TBH if the pads are too hard on and are causing your problem you ought to know once you've spun the wheel.....:)
     
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  11. timboo

    timboo Senior Member

    Oct 17, 2021
    275
    113
    Cambridgeshire
  12. timboo

    timboo Senior Member

    Oct 17, 2021
    275
    113
    Cambridgeshire
    Well

    It seems even following the bulletin doesn’t work the offside calliper is catching the brake disc.
    No amount of wiggling is sorting it.
    The yellow line shows which part of the calliper is catching the disc top and bottom on the side furthest from the wheel

    IMG_7648.jpeg
     
  13. TRIPLE X

    TRIPLE X Well-Known Member

    Sep 1, 2021
    228
    93
    Downham Market, Norfolk
    Which wheel spacers do you have, grooved or non-grooved ? Is there a gap between the spacer and inside face of the right hand side fork leg bottom ? If there is no gap and you have the non-grooved spacers then it might be that you need to change them to allow the fork leg to move across ?
     
  14. timboo

    timboo Senior Member

    Oct 17, 2021
    275
    113
    Cambridgeshire
    Hiya

    I have the grooved spacers.
    I’ve stripped it down 3 times.
    I finally realised that the bottom of the forks rotate. The triumph technical note is adamant that u do not apply the brakes.
    It simply does not align unless u do so and causes the disk on the side of the pinch bolts to rub against the calliper.
    Since applying the front brake and torque up the callipers at that point it gives the clearance even when pushing the callipers towards the wheel
     
  15. Randol

    Randol New Member

    Sunday
    0
    0
    Indiana USA
    Thanks for posting this up, I ran into this issue as well.
     
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