more tension in these spokes??

Discussion in 'Cycling Equipment' started by shazzy, Feb 26, 2008.

  1. shazzy

    shazzy New Member

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    Hi,
    I've built around 50 pairs of wheels and have never until now had them returned with loosening spokes... until now!

    I guess the answer is more tension, but it did get me thinking... this is for a heavy rider, but no heavier than some I've build for... so what makes him heavier on wheels, than anyone else???

    Is cranking the bike hard over and then stomping on the pedals on a hill the worst thing you can do to a bike wheel? i.e. is this a way of side-loading the wheels?? The reason I ask is that track riders using my wheels keep the bike pretty upright for hard starts (and the wheels stay taught and true), and only some road riders have an extreme "honking" style on steep hills.
    Thx,
    Shazzy.
     
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  2. alfeng

    alfeng Well-Known Member

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    Just out of curiosity:

    What was the original tension on the spokes?

    Straight gauge OR Double-butted?

    Number of spokes per wheel?

    What was the tension on the spokes when the wheel was returned, if measurable?

    Were ALL the spokes loosened?

    Was the rim undamaged?

    What rim/hub/spokes?
     
  3. shazzy

    shazzy New Member

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    Just out of curiosity:

    What was the original tension on the spokes? 90 kg

    Straight gauge OR Double-butted? DB

    Number of spokes per wheel? 36

    What was the tension on the spokes when the wheel was returned, if measurable? all over the shop

    Were ALL the spokes loosened? nope, non drive side only

    Was the rim undamaged? yes

    What rim/hub/spokes? Alpina spokes (which I always use), Ambrosio excellence rim, shimano hub.
    Thanks for asking....
     
  4. alfeng

    alfeng Well-Known Member

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    FWIW. Okay, take this as coming from someone whom some in this Forum who like to measure stuff without thinking about real world circumstances disagree with regard to what makes a "strong" wheel (I think this may partly be a "what is 'is'" use of words) ...

    I've built wheels for decades ... and, something I do when I'm not lazy is to lace the driveside x3 (sometimes, x4) and the non-driveside x2 (and, x3 if the driveside is x4). The theory (not mine) is that using a shorter spoke [i.e., about 286mm for the particular rear wheel in question instead of the ~292mm/(whatever?!?) it currently is] allows you to achieve a slightly higher tension on the non-driveside which will result in less imbalance in the tension between the two sides (someone else can probably describe it much better). Lacing is more tedious ... and, it helps (me) to have another wheel which is already laced with the pattern to look at! So, that's my recommendation (x2 lacing on the non-driveside) as a resolution for the existing rear wheel for the particular rider.

    You could lace x1 on the non-driveside. I laced one front disc wheel 32x4 on the disc side & 32x1 on "right"/non-disc side, once ... I had the spoke heads facing out (for cosmetic reasons) on the x1 side [they all have to be on the same side unless you want to put a severe bend in the spokes on the x1 side, which I wouldn't want], but it probably would have been a slightly better wheel if the spoke heads had been on the inside of the flange.

    Regardless, I know a lot of people (including myself) try to tension their spokes at 95-to-100 kgf ... but, if you've had success with 90 kgf, I don't know if you should change that spec.

    AFTER THE FACT. In the future, for a heavier rider, I guess I would suggest the Ambrosio Excursion rim (rather than the Excellence rim) which is a little beefier & would presumably flex less under the weight of the rider.
     
  5. daveornee

    daveornee New Member

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    100 kgf on drive side spokes is a good target. Spoke support angle will determine the tension on the non-drive side. Offset spoke beds like those on Alex Crostini 1.2 or Velocity Synergy OC, etc. will help even up the tension some.
    I have taken to using Sapim S.I.L.S nipples for left rear spokes when I think there is a chance that those spokes might go slack under dynamic loading. Nipple unwind happens when there is no tension, even for a very brief time... unless you take some measure to prevent it. There are all kinds of dynamic load conditions that cause it, but as rider mass + load (Panniers, etc.) increase so does the load conditions. For me it was "bunny-hopping" and not always landing without adding to the side load... while commuting and carrying lunch, projects for the day, and clothing. Heavy rider "Honking" up hills while riding over who knows what in the way of bumps, etc. is another example. Yes, there are pot-holes to avoid while trying to stay out of the way of cars/trucks/busses/bridges/curbs/etc./.
    Stiffer rims help as do more spokes, and better cushioning from wider tires.
    Putting the spoke heads all to the outside on the left rear has a small, but measurable way to decrease the spoke support angle there and when the rim is properly centered it will make the left side spoke tension higher. Take a look at spocalc and see what will work for you and your intended applications.
    Sheldon Brown suggested the "Half - Radial" rear wheel build with all left side spokes built with heads out. When you look over spocalc you will see what the different crossing patterns and heads in Vs. Heads Out will do.
    I agree with Alfeng on selecting the stiffer rim, if available.
    The stiffer the rim and the higher number of spokes, the stiffer the wheel.
     
  6. shazzy

    shazzy New Member

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    Thank you very much for your detailed answers, I have replaced the nipples on the non-drive side with nyloc type nipples and send the wheel out with closer to 100kgf on the drive side. I'm hoping not to see this particular wheel for some time.

    Really appreciate to time you've both taken.
    S.
     
  7. Peter@vecchios

    [email protected] New Member

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    Too low tension and/or not the best choice of rim, or spoke number or spoke gauge.

    I've had heavy guys never have a wheel issue and light guys beat the crap outta their wheels.
     
  8. Peter@vecchios

    [email protected] New Member

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    Sorry, not trying to get into a pissing contest but lacing 2 cross VS 3 cross, the tension won't be any different with a 6mm shorter spoke. What keeps the left side tight is right side tension.

    100-105 kgf, no less, with proper rim, spoke number and gauge will make for a reliable wheel.
     
  9. alfeng

    alfeng Well-Known Member

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    Actually, I don't think that it is the length of the spoke as much as the angle at which the interlaced spokes cross one another (in conjunction with the hub) which results in the slightly greater stiffness ...

    Like you, I had to think about how the different crossing could be different ... you know, sometimes ALL of us do things blindly because someone said such and such (like using double-butted spokes vs. straight gauge, but I digress); but, it finally became an "of course" situation as to why the x2 lacing might be better after refelcting on what I had eventually encountered with the x1 lacing.

    FWIW. For those who don't know, and for those who still contemplate tying their spokes, there actually was a time when spokes were NOT interlaced ... and, the crossing spokes never touched -- as an extreme example find a MODEL A Ford (or, most any pre-1936 car) and you will see the spokes are not entwined. No doubt, tying the spokes was the original solution until someone had the clever notion to interlace the spokes.

    Tying spokes is like wearing suspenders WITH a belt ... there ARE reasons in some circumstances, but it isn't necessary, IMO (which you, of course, may discount if you choose!).
     
  10. alfeng

    alfeng Well-Known Member

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    Yes. For double-butted spokes, you should probably use a slightly higher kgf rather than the 95-100 kgf that I suggested (but, I usually use straight gauge spokes, so that's my excuse for offering a different range!).
     
  11. Peter@vecchios

    [email protected] New Member

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    Well, in most wheels when you Do see a broken spoke, it is often at the hub on the left, non drive side. To eliminate or at least reduce that spoke movement which can be greater in the case of a slightly wacked rim, I often T&S left side spokes. Squeezing spokes on a non T&S left side and then on a T&S left side, you can see there is no spoke movement at the gub flange, a GOOD thing, IMO. Is it a big deal-no. Does it make the wheel stiffer, maybe, but not generally why I do it. For people that are tough on wheels in general, we often T&S their rear wheel spokes. 'Seems' we see less problems with their wheels but the first step is choosing proper rims, spoke gauge and spoke number for the individual. THEN building well.
     
  12. alfeng

    alfeng Well-Known Member

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    THANKFULLY, I haven't had the wheel-related problems which you encounter in your shop!

    I know that some wheelbuilders seem to be indifferent to ensuring that the non-driveside spokes are tensioned evenly ...

    Regardless, if I do start to break spokes (particularly, on the non-driveside), I'll follow your lead & T&S my spokes -- nothing wrong with belts with suspenders, too!
     
  13. kdelong

    kdelong Well-Known Member

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    Just getting post above spam
     
  14. Russ Reynolds

    Russ Reynolds New Member

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    My theory with loose spokes, loose bars, loose saddle etc..........if in doubt, get the welder out. ( I turn down the amps a bit for spokes though )
     
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