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Mickle's tip of the - Season to be Jolly: Wheel truing.

Discussion in 'Bicycle Mechanics and Repairs' started by mickle, 6 Dec 2011.

  1. Spokes

    Truing your wheel or replacing spokes is well within the capabilities of any home mechanic. Bike designer GEOFF APPS explains all. So not my tip at all really. Whatever. Take it or leave it. :thumbsup:
    stool.jpg

    TOOLS REQUIRED

    Spoke key
    Ruler or length of string (or wire)
    Medium to large screwdriver
    Heavy duty wire cutters
    Piece of chalk

    PARTS LISTS
    The spare parts you should have to hand:
    Grease (or Vaseline)
    New spokes of the correct length
    Non-oil penetrating lube

    Although the skill and craft of wheel-building may seem daunting, you can easily sort out a buckled wheel. Before beginning, either mount your bicycle in a workstand, or turn it upside down, putting a piece of carpet or anything soft but firm under the saddle and handlebar to protect them. The point is to have your wheels rotating freely.
    Removing buckles and truing the rim can be done with the tyre in place on the rim, but to renew a broken spoke or detect concentric deflections in the rim you will need to remove your tyres.
    Spin one wheel at a time and spray a penetrating lube onto the nipples. WD40 (or similar) is ideal for this, but make sure the label says it will not damage rubber. Spin your wheels again to allow the lube to penetrate the threads by centrifugal force. The more time you can allow for this process the better.

    (1) GENERAL SPOKE TENSION
    You can expect to have some variation in spoke tension, possibly with one or two spokes quite loose. This is sometimes due to poor tolerances at the manufacturing stage and/or subsequent damage to the rim. You may even discover a broken or missing spoke. Since you want to achieve trueness in the rim, having all spokes at the same tension is less important. I have worked on wheels that could have up to three spokes completely removed without affecting trueness.

    Grasp a pair of spokes on each side of the wheel, using the index finger and thumb of each hand (four spokes in all). Squeeze the spokes together and feel for any marked differences in tension. Begin this process at the valve and work round until you get back to it again.
    Tighten any spokes that seem to be loose, but only up to roughly the same tension as the others. This may or may not make the wheel more wobbly, so refer to 3 to true the wheel.

    dt_swiss_wheelset.jpg

    If a nipple has seized, you will have to break the spoke with a pair of heavy-duty wire cutters (or pliers) and refer to 2 to renew it.

    (2) REPLACING A BROKEN SPOKE
    If a spoke is missing or you have had to break it, you will need to find out the spoke length as accurately as possible by measuring one of the good spokes in the wheel. Find the distance from the centre of the spoke head to the surface of the rim and add 2mm. If you do not have a suitable ruler, use a length of string pulled as tight as possible, or a length of wire.
    If the spoke has pulled out of the nipple complete with thread, use it when you buy spares, to be sure you get the same length. If you want to buy some extras for future use, check the lengths on both sides of each wheel - on the rear wheel, they vary. Even if the shop doesn't have one of the right length, they will be able to cut and thread one for you from a longer spoke.
    Remove the wheel from your bicycle.

    Remove the tyre and tube. If you a replacing a spoke on the freewheel side of your rear wheel, you will probably need to remove the sprockets first.
    Put a dab of grease on the threaded end of the new spoke and feed it through the hole in the hub, ensuring that the spoke head is the right way round.
    Weave it in and out of the existing spokes, working the end gradually towards the new spoke's hole in the rim (below).

    When deciding whether to weave inside or outside, follow the same pattern as the other spokes.
    If you have woven it correctly, you will be able to feed it through the spoke hole in the rim.
    Hold the end of the spoke in the centre of the hole and put a nipple through the rim and onto the spoke end.

    Take up the initial slack using a screwdriver in the slot in the head of the nipple.
    Bring the spoke up to tension with a spoke key.
    Having replaced all broken spokes and taken up the slack, refer to 3 to true the rim.

    (3) BUCKLES OR WOBBLES
    This is often referred to as 'truing' or 'centring' the rim. Look at your hub with the tyre close to (and aligned with) your nose. Looking beyond the tyre and focusing on the hub, note that each spoke is attached to one or other side of the hub. Tightening a spoke attached to the left side of the hub pulls the rim to the left, and vice versa.

    Despite what most experts say, buckles are almost always caused by one spoke alone. There is no need to worry about working in pairs or opposite spokes or any stuff like that; unless the peak of the wobble happens to fall exactly between two spokes, then you work on the spokes either side of the peak. However, once you have reduced the buckling, you may have to tighten or loosen few other spokes at some other point in the wheel -just keep repeating the 'check-and-adjust' process until the rim runs true.

    To avoid your wheel going egg-shaped, use only a half-turn at a time when tensioning the spokes. Check the results before making further adjustments and reduce your adjustments to quarter-turns as the rim runs more true.
    Always have by you something (clothes peg, bulldog clip, blu-tak) that you can attach to the spoke you are working on in case you're distracted, then you can easily identify that spoke when you come back to it.

    Provided your wheels are in generally good condition, a rim that does not run true is not dangerous at all. It will interfere with rim brake operation, although if you have hub or disc brakes, you don't need to worry about a buckled wheel.
    Rotate your wheel slowly and hold a stick of chalk steady against the fork or seat-stay (above), gradually bringing it closer to the braking surface of the rim flange until it just touches it, marking the peaks of any lateral deflections.

    Identify the single spoke which is causing the problem at the point of maximum deflection. If the spoke is attached to the same side of the hub as the chalk mark on the rim, the spoke tension should be loosened; if to the opposite, it should be tightened.
    If the deflection appears to cover a number of spokes, mark the spoke where the deflection begins, and the one where it ends. These two marked spokes should be attached to opposite sides of the hub.

    The same principle of tightening and loosening applies - same side spokes should be loosened, opposite side spokes should be tightened.
    Continue the 'check-and-adjust' process
    until the rim runs true in the side-to-side plane.
    Spin the wheel and check to see if the rim moves up and down in relation to the brake block (or other fixed point). If it does, you have an egg-shaped wheel and should refer to 4 to sort that out.

    (4) EGG-SHAPED WHEELS
    (A) Remove your wheel from the bicycle.
    (B) Remove the tyre and tube.
    (C) Concentric deflection is detected by using a similar technique as used for sideways deflections but marking on the edges of the rim flanges instead.
    Rotate your wheel slowly, and gradually move the chalk towards the rim from the outside. Mark the peaks of deflection.

    To adjust in this plane you have to tighten spokes in pairs to pull the rim in (obviously in pairs - one to each side of the hub - to avoid introducing a new wobble).
    If the rim goes in towards the hub, it is unlikely that loosening the spokes will drop it out, but do try; it sometimes works. Otherwise, tighten all the other spokes a tiny bit - quarter turn maximum.

    Continue the 'check-and-adjust' process until the rim runs true in the side-to-side plane.
    After doing any spoke adjusting, you should always finally check the spoke ends to see that they don't protrude through the nipple so far that they could puncture the inner tube. If you think they could, you can simply file the end down until is flush with the nipple head.
    Give this a go. You can't do any real damage to your wheels, you may learn a useful skill to dazzle your friends and, should you get into a right pickle, you can always back out of the project and take the wheel to the bike shop and let them sort it.

    Read More:
    Your Own Home Workshop
    A bunch of mickle's tips
     
    3narf, RhythMick, contadino and 25 others like this.
  2. Chris S

    Chris S Über Member

    Location:
    Birmingham
    Thanks for that - it should make things a lot easier.
     
    Randallrunbike likes this.
  3. Mort

    Mort Interstellar Overalls

    I thought that was a really well written tip - thanks mickle and Geoff. I liked:

    I've done that before!
     
  4. Fnaar

    Fnaar Smutmaster General

    Location:
    Thumberland
    Nicely written and informative tip. Thank you.
    I'm off to spray WD40 on my nipples :smile:
     
  5. PpPete

    PpPete Veteran

    Location:
    Chandler's Ford
    Take it or leave it you say?

    I'll leave it, thanks all the same.
    Any guide to wheel truing or building which includes phrases like " having all spokes at the same tension is less important " is highly suspect.

    If you aim to get your spoke tensions even within about 10% on the Park gauge - or if no gauge, get them to within one semitone of each other when plucked, then your wheels will stay true a lot longer. This is more important than trying to get your wheels true to within 10ths of a millimetre.
     
    2IT likes this.
  6. Have a different opinion by all means but, Geoff Apps advice? 'Highly suspect' ??

    Every single one of the very many professional wheel builders I have worked alongside (I'm not a wheelbuilder of anyone else's wheels but my own - I'm no expert) has trued and built wheels without the aid of a Park guage and without plucking them.
     
  7. PpPete

    PpPete Veteran

    Location:
    Chandler's Ford
    No disrespect to Geoff Apps( or indeed to yourself Mickle) but the article above is the first time I can recall ever seeing it suggested that even spoke tension is of secondary importance.

    Every other on-line or in-print guide that I've read (and believe me I''ve looked at a lot) suggests otherwise.

    My own experience, after building a fair few wheels for myself and for friends and family, and most crucially trying to correct deficiencies in low-end factory wheels, is that even spoke tension is critical to wheel's ability to stay true.

    Certainly it's possible to true wheels (and indeed build them) without a tension gauge of some sort (Park happens to the be the cheapeast that is widely available) but to try and do so without using the sound of the spokes as a guide to their relative tension would, in my opinion, be the height of folly..... unless of course you are able to charge £££ every time the wheel is returned to you for re-truing.
     
  8. threebikesmcginty

    threebikesmcginty freeloader...

    Location:
    ...on the slake
    I haven't bothered to read it but I thought it was excellent - well done chaps!
     
    Postmanhat, Cubist and mickle like this.
  9. RecordAceFromNew

    RecordAceFromNew Swinging Member

    Location:
    West London
    +1. Certainly Jobst Brandt and Gerd Schraner clearly said so in their books, and Gravy (about 8 minutes into this). I suspect when quality components are used a seemingly true wheel with unequal spoke tension probably indicates inbuilt instability.
     
  10. Glad you like it!
     
  11. I refer the honourable member to the answer I gave a few moments ago.
     
  12. PpPete

    PpPete Veteran

    Location:
    Chandler's Ford
    If I'd built as many wheels as Gravy (or indeed Mr Brandt or Mr Schraner ) I'd probably be able to equalise the spoke tension by sense of smell ^_^
    But however it's done.... I'll say it again .... if you are building your own wheels, or just truing them, if you want them to stay true, my opinion - and Mickle and I will just have to agree to disagree on this - is that getting the spoke tensions as even as possible is of paramount important.
     
    Crankarm likes this.
  13. 2old2care

    2old2care Well-Known Member

    Therefore what you are saying is that the spokes can all be different tensions, and using a tension meter is superflous:smooch:
     
  14. Red Light

    Red Light Guest

    +1 The loose spokes will loose tension completely on bumps and over time loosen off making the wheel go out of true. Not a problem if you are a pro who has their wheels checked after every ride but a real problem for the rest of us.