Loaded Rack / Wheel Truing

This topic contains 2 replies, has 3 voices, and was last updated by Avatar of MacGyver MacGyver 1 year, 9 months ago.

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  • #789070
    Avatar of richfieldkid1
    richfieldkid1
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    Hi,

    I am wondering if it’s normal for a wheel to go out of true when it is loaded down for a tour. Last May I had the wheels trued by the LBS as a part of a tune up package before doing a 10 day tour. After the first 40 miles, my back wheel was significantly out of true. (Luckily I had a spoke wrench and it was an easy fix).

    Second question: Either before the tour or after (I can’t remember!!!) one of the spokes randomly broke (I only ride pavement). The LBS told me the wheel may not have been properly tensioned by hand, and the factory/machine tension is usually not sufficient even if it’s trued. Is that accurate? and could there be any connection between the lack of proper tension and a true wheel going out of true from a loaded rack?

    I’m trying to treat these as two separate questions since i don’t remember if the mechanic trued it all up before the spoke broke or after. :/ Any insight is appreciated, you don’t have to lay out all the wisdom of wheel science but I am just curious about this stuff. Depending on finances, I may or may not take a wheel building class before my tours this summer, and your responses will probably guide whether I do that.

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  • #793516
    Avatar of Caaveman82
    Caaveman82
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    Just as a for instance scenario, when we get wheels from Handspun about 90% of the time they are pretty good. However the rest of the time, they are way off. After you ride a new wheel for about 100 – 200 miles it would never be a bad scenario to get them trued. So no your LBS was not blowing smoke up your rear.

    As far as the wheel going out of true while loaded, I think that depends on the wheel. I ride my bike hard and never had wheel trouble because my wheels are thick and heavy. I’ve got DT Swiss 350′s laced to DT Swiss TK540 rim with straight gauge spokes and when I went on a tour on labor day I hit a pot hole, nothing out the norm really, but it threw my wheel out of true. So I would assume the more weight hovering over the top of your rear wheel the easier it would be to toss it out of true.

    #793517
    Avatar of MacGyver
    MacGyver
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    Wheels intended for touring are built a little burlier than, for example, fast and light road wheels. What kind of bike are you riding, and what are the specs of the wheels?

    A broken spoke will make any wheel go from nice and true to surprisingly out of true in an instant. Remember that every spoke is sharing the load and pulling evenly to hold the rim in suspension all the way around the wheel. Each spoke is holding up to 220 pounds of tension. When one spoke suddenly lets go, that’s a lot of force to suddenly be absent, and the rim is going to shift quite a bit to find a new equilibrium.

    Spare spokes are a really good idea for touring or other kinds of long riding. Figure out what lengths are needed for your wheels and carry a few spokes taped to the frame when you’ll be away from home for a while. Better yet, check into a product called a FiberFix Spoke. It’s a length of kevlar cord with all the necessary hardware to lace it into your wheel in place of a broken spoke. You don’t need to remove the old spoke fully or take the cassette off, either, since you have several options for how to attach it. The best part is that it’s easy to install and works for any length spoke. I keep one in my tool bag all the time; The whole kit stores in a little cylindrical case about the size of a AA battery.

    What brand of spokes are on the wheel that suffered the broken spoke? DT Swiss and Wheelsmith are the two most common “good” names. Anything else is usually going to mean cheap spokes that love to break after a while. Look at the heads of the spokes. If they have a capital “W” or an overlapping “DT” logo, you’ve got good spokes. If they have anything else (“S”, “n”, “N”, “*”, blank, etc.), then don’t be surprised if you break spokes periodically. Unfortunately, when you factor in the cost of having a spoke replaced and the wheel re-trued by a shop, you exceed the cost of the wheel once you’ve had it in for spoke work about 4 to 6 times. It’s better to buy a more expensive wheel made with good spokes upfront than to keep repairing a cheaper wheel. Figure $20 to $25 per repair times 32 spokes, and that cheap wheel gets really expensive if you take it to the hypothetical extreme.

    I’ve found that spokes breaking usually has far more to do with the quality of the spoke than it does the tension. Too little tension can shorten the life of a good spoke by exposing it to more stress fatigue from being tensioned and de-tensioned slightly every time the wheel rotates, but you’re unlikely to see the results of this for many thousands of miles. Way over 90% of the spokes I replace are on fairly young wheels built with the aforementioned cheapo spokes. Every now and then, I see a broken Wheelsmith or DT, but it’s surprisingly uncommon, even on old and well-loved wheels.

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