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Spoke tension

sextoke1sextoke1 Posts: 133
edited December 2017 in Workshop
A friend has a Park Tool spoke tension meter, which he has not used yet. I borrowed it to check my three sets of wheels. My winter wheels are a set of new Fulcrum Racing 5 LG, I have around 100km on them. Front wheel has 16 to 17 on the scale which is OK. The back wheel has 17 to 18 on the drive side and 13 or 14 on most and down to around 6 in about three. Tried to bring the NDS up to around 14 and the DS stayed at 17/18. I noticed a wobble in the wheel and the rim now was pulling to the NDS side. Returned the wheel to it orignal settings and the rim is true and centred......Next tried out my early 2017 Fulcrum quatro LG wheel set which have done around 2000km, and front OK at 16/17 and the rear was ok as well, DS at 17/18 and the NDS at 15...Next checked my Mavic Ksy Elite 15c 2014 wheelset. Front ok at 14. Back was like the Fulcrum ,5 NDS around 13 with about three at about 6.....Wheels seem ok, just wondering in case I will crake or twist the rim out on the road.

Posts

  • imposter2.0imposter2.0 Posts: 11,277
    What is it you are trying to achieve with this? If the wheels were not giving you any problems, then just leave them alone and carry on riding.
  • sungodsungod Posts: 13,630
    ^^^this

    don't assume that the meter is accurate

    with care it may give reasonably consistent comparative readings, but as far as absolute value goes i'd be extremely wary
    my bike - faster than god's and twice as shiny
  • sextoke1sextoke1 Posts: 133
    Imposter wrote:
    What is it you are trying to achieve with this? If the wheels were not giving you any problems, then just leave them alone and carry on riding.
    Just testing. Why not. The spokes that the tension meter had indicated were not as tight, felt that when I flex them. As I asked in the end, is it possible with these "loose" spokes that in time the wheel will twist under pressure if more force is apply to them, that all.
  • veronese68veronese68 Posts: 24,331 Lives Here
    Ideally all the spokes should be about the same tension on each side. You could try increasing the tension in the loose spokes and backing off the others either side to keep the wheel true and get the tensions more even. That is to say you tighten a loose drive side spoke then back off the adjacent spokes on the drive side. Ignore the non-drive side for the time being. You really need the wheel in a stand or mounted in the frame so you can spin the wheel and make sure you aren't making matters worse.
    But, there's a lot to be said for "if it ain't broke don't fix it" as you could make matters worse. Also, with a used wheel spoke tension could be fighting a rim that doesn't want to run true. As the others have said if they are running straight and true without giving problems best bet is to leave well alone. If the uneven tension causes problems in future that is the time to fix it.
  • Rims are not perfect and as a result, tensions cannot be perfect. The spread of tensions on the same side of the wheel is a function obviously of the quality of the rim and quality of the build, but also of the number of spokes. In high spoke count wheels it is relatively easy to achieve very uniform tensions, in a low spoke wheel any rim imperfection leads to greater differences in spoke tension.
    I have always been reluctant to tinker too much on those low spoke count factory wheels, unless there was an obvious problem.
    More on wheels here
    https://whosatthewheel.com/2017/11/12/t ... -dynamics/
  • sextoke1sextoke1 Posts: 133
    Rims are not perfect and as a result, tensions cannot be perfect. The spread of tensions on the same side of the wheel is a function obviously of the quality of the rim and quality of the build, but also of the number of spokes. In high spoke count wheels it is relatively easy to achieve very uniform tensions, in a low spoke wheel any rim imperfection leads to greater differences in spoke tension.
    I have always been reluctant to tinker too much on those low spoke count factory wheels, unless there was an obvious problem.
    More on wheels here
    https://whosatthewheel.com/2017/11/12/t ... -dynamics/

    Thanks for that. My main question is will the loose spokes cause a problem in the near term. Yes the rim is true and I aways check the brakes after a wheel movement to make sure it is centered. In 12 years of tough cycling across Fulcrum 7, 5, quatro and Mavic wheels, I never broke a spoke of bent a rim,
  • lesfirthlesfirth Posts: 1,164
    sextoke1 wrote:
    Imposter wrote:
    What is it you are trying to achieve with this? If the wheels were not giving you any problems, then just leave them alone and carry on riding.
    Just testing. Why not. The spokes that the tension meter had indicated were not as tight, felt that when I flex them. As I asked in the end, is it possible with these "loose" spokes that in time the wheel will twist under pressure if more force is apply to them, that all.

    Why not? If you are short of something to worry about ,OK worry about your spokes. Otherwise I suggest you chill out and ride your bike.
  • cyclecliniccycleclinic Posts: 6,865
    leave the wheel alone. I build 24 spoke wheels reguarly and you can get even spoke tension easily BUT while the wheel is true radially it may be out by 0.5mm even hed rims can show up to 0.7mm out of roundness. Truing that out will lead to the situation you have with the fulcrum wheel. That fulcrum wheel is machine built and there will be a tight roundness spec <0.2mm and the only way to achieve this is vary spoke tensions to correct for the inperfections in the rim get small deviations in the rim to make it round you need fairly big spoke tension changes.

    essentially this is the thing with factory wheels they appear round and true but this sometimes (not always) comes at the expense of spoke tension uneveness. This is also one of the reasons why spokes break. Also you dont just raise the NDS spoke tension. You have to raise the DS as well to keep the rim centred. The problem is what is 18 on the Tm-1 how close are you to the tension limit of the rim. campag wheels are tensioned to 1300-1500N DS so I would not be raising the spoke tension any further. Also any twist in the spoke will affect your tension measurements so you may have a false idea of the ammount of variation. In short leave well alone. when a spoke breaks replace the wheel.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • sextoke1sextoke1 Posts: 133
    leave the wheel alone. I build 24 spoke wheels reguarly and you can get even spoke tension easily BUT while the wheel is true radially it may be out by 0.5mm even hed rims can show up to 0.7mm out of roundness. Truing that out will lead to the situation you have with the fulcrum wheel. That fulcrum wheel is machine built and there will be a tight roundness spec <0.2mm and the only way to achieve this is vary spoke tensions to correct for the inperfections in the rim get small deviations in the rim to make it round you need fairly big spoke tension changes.

    essentially this is the thing with factory wheels they appear round and true but this sometimes (not always) comes at the expense of spoke tension uneveness. This is also one of the reasons why spokes break. Also you dont just raise the NDS spoke tension. You have to raise the DS as well to keep the rim centred. The problem is what is 18 on the Tm-1 how close are you to the tension limit of the rim. campag wheels are tensioned to 1300-1500N DS so I would not be raising the spoke tension any further. Also any twist in the spoke will affect your tension measurements so you may have a false idea of the ammount of variation. In short leave well alone. when a spoke breaks replace the wheel.
    Thanks for that. As you say leave the wheel alone. If it were to go out of true, can these be centred on a jig or are they only fit for the bin. A part from the Mavic wheels, it has been Fulcrum all the way. Can some one give advice on the best options, factory or hand build and for Alu rims, what price range do you need to be getting a above average wheel?
  • cyclecliniccycleclinic Posts: 6,865
    Define average. For any wheels the components used and and how well tensioned/how even the tensions are makes all the difference to how long the spokes last. this question is about as easy to answer as how long a piece of string is.

    If the wheel is out of true correct it.

    It is not about price so much £300 to £400 can get you a light enough, stiff reliable wheelset from many builders or manufacturers. I build wheels cheaper than that they are still reliable but are heavier.

    You throw your current wheels away when a spoke breaks or you replace all the spokes.

    Any good wheel is stiff. Many wheels described as stiff when riding are actually not. Stiffness (lataral and radial) is important for spoke life but little else. The stiffer wheel wheel the lower the spoke count can be.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
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