.5mm is fine as long as the tension is fairly even.
On Oct 1, 12:31 pm, NickBull <[EMAIL PROTECTED]> wrote:
> When should I care about hops and flat spots for a "PBP wheel"? I
> just built up a rear wheel with a Velocity Aerohead OC rim. The
> spokes are all very evenly tensioned, and the wheel is horizontally
> true, but I decided that 1/2 mm out of round is "good enough."
> Getting from 1 mm out of round to 1/2 mm required a lot of back-and-
> forth to get the spoke tensions evened up again, at the same time
> going around and re-truing horizontally, while not at the same time
> making the vertical true worse. Is 1/2 mm "good enough for government
> work" (as government contractors say)? Or would you look at that
> wheel and say I should either do another round of truing or start over
> for PBP quality?
>
> Thanks,
>
> Nick
>
> On Oct 1, 9:50 am, Peter Jon White <[EMAIL PROTECTED]> wrote:
>
> > The job of the wheelbuilder is to build a round wheel. To build a
> > round wheel, you need to start with a round rim. Of course I try to
> > determine if the rim isn't round before starting the build, but very
> > often the irregularities don't show up clearly until you have tension
> > on the spokes. It's not that the rim starts out round, it's that the
> > rim isn't round, but for whatever reason you can't see the problem.
>
> > There's only one shape of an untensioned rim that I want to recreate,
> > and that's the shape of a round untensioned rim.
>
> > On Oct 1, 1:43 am, "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
> > wrote:
>
> > > Well, Swan is clear in what I quoted. and in the rest of his
> > > post.http://search.bikelist.org/getmsg.asp?Filename=classicrendezvous.1080...
> > > that the non-concentricities are there, and are best ignored because
> > > they are hard to correct. He earlier claims that the job of the
> > > wheelbuilder is to build a tensioned wheel which well recreate the
> > > shape of the untensioned one.
>
> > > I know, PJW, that you have been building wheels for many years. Have
> > > you tried, say with Sun rims, to identify these flat spots and hops
> > > before the building begins? I know you've posted about them at your
> > > webpage? Again, I'm asking whether you have tried to identify and
> > > quantify the out-of-roundnesses ahead of time.
>
> > > Harry Travis
> > > Washington, DC
>
> > > On Sep 30, 11:17 pm, Peter Jon White <[EMAIL PROTECTED]> wrote:
>
> > > > If the out of roundness in a rim is small enough to have no effect on
> > > > the performance of the wheel, yes, you should ignore them and get the
> > > > spoke tension as even as possible. But you can be faced with a
> > > > difficult choice when the rim isn't quite round. If you're using an
> > > > inexpensive rim because you're just riding the bike a few miles back
> > > > and forth to work, you would be silly to start all over when you find
> > > > that the rim isn't perfect. You rarely find these flaws before you've
> > > > spent a lot of time lacing and tensioning the wheel, so do you want to
> > > > start all over with another rim which may be no better than the first?
>
> > > > On the other hand, if you're building wheels for PBP, your standards
> > > > need to be quite a bit higher.
>
> > > > On Sep 30, 9:23 pm, "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
> > > > wrote:
>
> > > > > Jamie Swan offered this opinion to a first-time amateur wheel builder
> > > > > over at Classic Rendezvous (bikelist.org). He has trued over 400,000
> > > > > wheels.
>
> > > > > _____________________________
>
> > > > > The big issue is: are those hops and/or flat spots the true shape of
> > > > > the rim or did you put them there as you applied tension to the
> > > > > spokes? If those minor eccemtricites are the actual shape of the rim
> > > > > then you shouldn't try to change them. You should just support them
> > > > > with uniform spoke tension.
>
> > > > > Jamie Swan
> > > > > Centerport Cycles Inc.
> > > > > Northport, New York, USA
> > > > > ___________________________________
>
> > > > > Any opinion here from other wheelbuilders? Is it feasible for amateurs
> > > > > to mark non-concentricities in rims against a perfectly drawn circle,
> > > > > and so not make mistakes in trying to correct them? Or are they too
> > > > > subtle to see?
>
> > > > > Harry Travis
> > > > > Washington, DC USA- Hide quoted text -
>
> > - Show quoted text -
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