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Radial truing

bobbydigitalbobbydigital Posts: 254
edited October 2017 in MTB workshop & tech
Initially when tensioning the spokes is there some sort of pattern order in which to tighten the spokes in order to get the wheel in to a radial true state?

I.E like doing up wheel bolts on a car or cylinder head bolts, you have a set pattern in order to get equal placement of the part in question.

I've always gone around the rim in a clockwise motion but this, to me, doesn't seem like the correct way to get the rim and hub central and can't find much information when it comes to the initial tension of the spokes.

Posts

  • cyclecliniccycleclinic Posts: 6,865
    edited October 2017
    dont radially true. Focus on intial tensioning getting the wheel roughly straight, stress the spokes by graping check dish and correct. then even out tensions and continue to increase to full tension keeping the wheel dished. then get the wheel straight and the tension even on each side. stress the spokes by grasping alot until there is no futher tension drop and correct trueness. The stressing is really important and even though i do this every day my hands hurt every time i do it. the last thing i check is radial trueness. accept the rim how it is truing it out will mean tension unevenness which is not good. if the rim is not radially stiff so can be trued radially without big tension changes then you know there will be big tension changes and spoke failures as you hit bumps in time. If the rim is not that round then throw it away and get another one.
    Radial truing is what people who thing a good wheel has to be round with in 0.2mm but do that at the expense or increased tension variation. A good wheel has less than 5% tension variance around the mean and straight. I will be acceptably round too (1mm roundness or better for disc brake rims which are normally o.k to poor for roundness except for kinlins they are normally very good), it may even be very round (0.2mm roundness or better) but that is pot luck if the rim is actually round. With most rim brands, DT Swiss, Stans, Mavic e.t.c the disc brake rims are acceptably round i.e greater than 0.2mm roundness but rarely over 1mm. You can try and true it out but really what the point.

    When tensioning I apply up to 4 turns initally normally to each spoke going round the rim (I know how many to do each side for many builds to get the dish in the ball park) and the wheel is round if the tensions are fairly even if they are not it is not. the thing is you cant harm the wheel, i have tried i have had rim several cm out due to tension variations and it ends up round and straight with even tensions when all is done.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • Awesome reply thanks.

    I have a mavic x223 disc rim to true, (quite old rim but a cheap test rim) I think it might have a bit of a flat spot in the rim somewhere then, there's a little hop, which is probably about 1mm in deviation but with a tyre on the rim it isn't noticeable, even when spinning the rim in the forks as fast as I cannot notice the hop/flat spot.

    I have loosened all the spokes and am ready to try again in the manner which you have suggested. fingers crossed.

    There's something very rewarding about learning all this.
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