On Saturday, September 7, 2013 2:10:56 AM UTC+3, jim beam wrote:
> On 09/06/2013 08:33 AM, AMuzi wrote:
>
> > On 9/6/2013 9:17 AM, jim beam wrote:
>
> >> On 09/06/2013 02:19 AM, wrote:
>
> >>>>>>
>
> >>>>>> unfortunately, i don't think there's any one magic
>
> >>>>>> bullet on
>
> >>>>>> wheel building books. jobst's book will allow you to
>
> >>>>>> calculate spoke length from first principles [although,
>
> >>>>>> not
>
> >>>>>> allow for the elongation that happens as they tension],
>
> >>>>>> lace, true and tension, but it'll also have you
>
> >>>>>> over-tension, bend spokes unnecessarily, and he gives
>
> >>>>>> you a
>
> >>>>>> very iffy "stress relief" method. you'll also have no
>
> >>>>>> initial clue on how to position a hub so the label aligns
>
> >>>>>> with the valve hole, as per conventional practice.
>
> >>>>>>
>
> >>>>>> gerdt schraner's book will solve the hub label position
>
> >>>>>> problem, and have you stress relieve better, but you'll be
>
> >>>>>> reliant on others for spoke length. his lacing method is
>
> >>>>>> also unnecessarily complicated.
>
> >>>>>>
>
> >>>>>> sheldon brown's online guide is very good on lacing, hub
>
> >>>>>> positioning, but repeats a lot of the garbage that jobst
>
> >>>>>> bullied into him. and his stress relief method blows
>
> >>>>>> chunks.
>
> >>>>>>
>
> >>>>>> if you can find it online, the mavic wheelbuilding
>
> >>>>>> guide is
>
> >>>>>> pretty good. absolutely the best stress relief method. but
>
> >>>>>> it tells you nothing about spoke length calculation,
>
> >>>>>> presumably because if you're rebuilding a mavic wheel,
>
> >>>>>> you're already using spokes of predetermined length.
>
> >>>>>>
>
> >>>>>> so, "don't read that book in isolation" is my advice. and
>
> >>>>>> if you're thinking you want to understand wheel mechanics
>
> >>>>>> and don't already have a strong understanding of
>
> >>>>>> mechanical
>
> >>>>>> principles and materials, it'll badly **** you up
>
> >>>>>> because a
>
> >>>>>> lot of what he says is just plain wrong.
>
> >>>>>>
>
> >>>>>> as to building wheels for yourself, we've discussed this
>
> >>>>>> before. there are definitely benefits to learning in that
>
> >>>>>> most people don't have access to a good builder.
>
> >>>>>> statistically, that includes you. once you can build
>
> >>>>>> yourself, and you take the time to do it right, which most
>
> >>>>>> shops seldom invest, you can have a wheel that remains
>
> >>>>>> true
>
> >>>>>> and stable almost indefinitely. that's a rare beastie in
>
> >>>>>> "other people built" wheels. my mtb wheels, complete with
>
> >>>>>> unconventional rear spoking pattern*, have remained
>
> >>>>>> completely true despite some fearful abuse. same for my
>
> >>>>>> townie fixie on san fran's pot-holed, cable car tracked
>
> >>>>>> streets.
>
> >>>>>>
>
> >>>>>>
>
> >>>>>> * convention is that you go
>
> >>>>>> trailing-leading-leading-trailing when looking at the four
>
> >>>>>> hub sides, theory being that this allows the spokes with
>
> >>>>>> increasing tension from drive torque to distort the
>
> >>>>>> wheel's
>
> >>>>>> dish less. with a disk braked rear, if you're following
>
> >>>>>> this principle, you need to lace
>
> >>>>>> leading-trailing-leading-trailing because braking reaction
>
> >>>>>> opposes drive torque. it's a little more complicated to
>
> >>>>>> lace, but it's specified in the shimano hub manual.
>
> >>>>>>
>
> >>>>>>
>
> >>>>>
>
> >>>>> Good overview.
>
> >>>>> That rear spoking pattern for disc/drum rears is also
>
> >>>>> the preferered
>
> >>>>> 'old guy' way for fronts, which need no particular bias.
>
> >>>>
>
> >>>
>
> >>>
>
> >>> thanks for the comprehensive wrapup,
>
> >>> took the time to setup thunderbird w eternal september
>
> >>> again so I can
>
> >>> crosspost at will ;-)
>
> >>>
>
> >>> My CXP-33 is laced over-4 whatever that means and the
>
> >>> ceramic open pro
>
> >>> is over-3
>
> >>
>
> >> "three cross" is conventional with an open pro. "4x" on a
>
> >> cxp33 is not something i'd do because it's not got as much
>
> >> socket angle available as the open pro - which is precisely
>
> >> what "4x" requires. i'd therefore expect spokes to be more
>
> >> likely to break at the threads.
>
> >>
>
> >> presumably the builder was looking to make the cxp33 a
>
> >> slightly "softer" ride - the cxp33 is very deep and thus
>
> >> rigid so it can ride "harsh" compared to others. ["4x"
>
> >> spokes are longer and thus theoretically slightly more
>
> >> elastic.] i'd have gone with a lower spoke count and "2x"
>
> >> personally.
>
> >>
>
> >>
>
> >> [another criticism of "the book" - jobst has succeeded in
>
> >> making most people think of "spoke crossing count" as one of
>
> >> the parameters for spoke length calculation. this is
>
> >> somewhat misleading since you can compute a result for
>
> >> 2.7179 "crossings", even though no such thing is possible.
>
> >> the fact is, the "crossing" number is in fact the number of
>
> >> hub hole offsets from the "key" position, and this doesn't
>
> >> have to be an integer.]
>
> >>
>
> >>
>
> >>> not sure how that meshes with
>
> >>> leading-trailing-leading-trailing
>
> >>> and trailing-leading-leading-trailing
>
> >>
>
> >> doesn't for "crossing" count.
>
> >>
>
> >>
>
> >>>
>
> >>> For next year cross competition I wonder if I'd reuse my
>
> >>> roadbike
>
> >>> to get a 26"er or 29"er. Though the latter is a bit too
>
> >>> portly
>
> >>> for competitions, I think
>
> >>>
>
> >>>
>
> >>>> interesting.
>
> >>>>
>
> >>>> in that vein, old guys used to tie and solder. jobst went
>
> >>>> out of his way
>
> >>>> to pour scorn on that practice, but doesn't do it in what
>
> >>>> is an actually
>
> >>>> scientific way, just a pseudo-scientific way - i.e. the
>
> >>>> scientific way
>
> >>>> is "objective, methods, results, conclusions". he just
>
> >>>> leaps from method
>
> >>>> to conclusions, omitting actual results. yet he blithely
>
> >>>> accepts spoke
>
> >>>> interleaving as "stabilizing the spoke structure" with no
>
> >>>> analysis
>
> >>>> whatsoever.
>
> >>>>
>
> >>>> [i know, broken record, but i really can't understand why
>
> >>>> other people
>
> >>>> don't see this stuff when reading - you don't need to be
>
> >>>> an engineer to
>
> >>>> have logical inconsistency slap you in the face.]
>
> >>>
>
> >>> it's the "blond gene". you don't have to understand it,
>
> >>> just accept "as is"
>
> >>
>
> >> cringe.
>
> >>
>
> >>
>
> >
>
> > Not enough information.
>
> >
>
> > 4x 48 spokes builds to an optimal spoke angle. 4x 40h is good, better
>
> > than 3x.
>
> > 4x with 32h is a clusterf**k. 4x 36 is failure prone, far from ideal,
>
> > not recommended. And yet guys do it with 50-50 results, despite our
>
> > admonition.
>

4x36 was developing figure8th before I changed the wheelbuilder
and last guy apparently did a faitly good job, that or I haven't
ridden long enough after the last rebuild


>
>
> indeed. so as we know the rim is cxp33, 4x is inappropriate given that
>
> it's either 28 or 32 hole.
>
it is a 36 hole cxp-33

I could recount the spokes but I belive I did ask for 36 and that's what I got.
In fact the open pro is similarly overbuilt being 36-holy
(but cross 2)

can't get cxp-33 in 40 or 48 hole versions. I think.

for 40 or 48 I guess I'd have to get some sort of a touring rim
not that it's a bad thing since I value reliability over weight/speed

what are my options for mtb rims in 26" and 28" in 40 or 48?
(if any)