+/- 40kgf tension. wheel doomed?

ant said:

im no expert. ive built several wheels, all of which have thus far had happy lives. but ive never
had a tensiometer until now. just plucking away, and feeling spokes.

...

Quoted message said:

anyways, i was aiming for 100 kgf all around, and after the necessary fiddling i have a wide range
of spoke tensions. i read in the archives that +/- 20kgf was good, and that 10 was great. mine
ranges from (according to my spankin' new park tool) 70- 110, with the large majority of the
spokes in the 90-95 range, IIRC.

70 - 110 is 90 +/- 20 kgf, so it looks ok to me, especially since most are in a narrower range.

Peter <[email hidden]> wrote in message news:<%imXa.60026$o%2.30132@sccrnsc02>...

Quoted message said:

ant said:

im no expert. ive built several wheels, all of which have thus far had happy lives. but ive
never had a tensiometer until now. just plucking away, and feeling spokes.

...

Quoted message said:

anyways, i was aiming for 100 kgf all around, and after the necessary fiddling i have a wide
range of spoke tensions. i read in the archives that +/- 20kgf was good, and that 10 was great.
mine ranges from (according to my spankin' new park tool) 70- 110, with the large majority of
the spokes in the 90-95 range, IIRC.

70 - 110 is 90 +/- 20 kgf, so it looks ok to me, especially since most are in a narrower range.

The tensions do not sound right unless you are comparing among the spokes on one side of the rear
wheel. The right (drive) side always has higher tension then the left when the wheel is centered
between the dropouts. Roughly, the difference will be about 25% (sometimes more, but you have to
apply whatever it takes to get the wheel centered. Less, but still significant differences will
exist with OCR rims. So, if you can get the left side to have say 80 to 100 Kgf and the right side
to have roughly 110 to 130 it would be normal. The important thing in tensioning the rear wheel is
to have sufficeint tension in the left side so that none of those spokes approach 0 in use while
keeping the right side tension from becoming too high. Then, the wheel will stay true and last long
assuming you stress relieve the spokes.

But, you must know the above if you have built wheels previously and they perform well. Why did you
not mention details for the rim and hub? It would be helpful to know this.

Anyway, if you end up with a circular and wobble free wheel and the spoke tensions are within 10%
among the spokes on a side of the rear wheel, that's great. If you have a 20% difference, the wheel
is not going to fall apart either. Much more then 20% and you have to question how circular and
planer the rim was to start with.

Before I use a new rim, I lay it against the rim of a built up true wheel just to see what I'm
starting with. I have had good luck with rims from Mavic, Velocity and Bontrager.

Steve Shapiro

Steve Shapiro [email hidden]

Peter <[email hidden]> wrote in message news:<%imXa.60026$o%2.30132@sccrnsc02>...

Quoted message said:

ant said:

im no expert. ive built several wheels, all of which have thus far had happy lives. but ive
never had a tensiometer until now. just plucking away, and feeling spokes.

...

Quoted message said:

anyways, i was aiming for 100 kgf all around, and after the necessary fiddling i have a wide
range of spoke tensions. i read in the archives that +/- 20kgf was good, and that 10 was great.
mine ranges from (according to my spankin' new park tool) 70- 110, with the large majority of
the spokes in the 90-95 range, IIRC.

70 - 110 is 90 +/- 20 kgf, so it looks ok to me, especially since most are in a narrower range.

ah. simple math. stumped again.. 😉

i feel much better now. and ill stop posting in the middle of the night.

anthony

[email hidden] (Steve Shapiro) wrote in message

Quoted message said:

The tensions do not sound right unless you are comparing among the spokes on one side of the
rear wheel.

Ah- i thought i had mentioned it, but perhaps not. the wheel is a dishless wheel, as in equally
spaced flanges. single speed. thus, i would expect all tensions to be relatively equal.

Quoted message said:

So, if you can get the left side to have say 80 to 100 Kgf and the right side to have roughly 110
to 130 it would be normal. The important thing in tensioning the rear wheel is to have sufficeint
tension in the left side so that none of those spokes approach 0 in use while keeping the right
side tension from becoming too high. Then, the wheel will stay true and last long assuming you
stress relieve the spokes.

the lowest tensioned spoke works out to around 72 kgf right now. i am hoping that this is enough to
keep from dropping to 0 under power. will it stay true? i dont know, the bike this is built for was
only finished today, so ill start finding out when this rain clears up 🙁

Quoted message said:

But, you must know the above if you have built wheels previously and they perform well. Why did
you not mention details for the rim and hub? It would be helpful to know this.

before i forget-- 😉 mavic open pro, white industries eccentric singlespeed hub, 32h.
14/15/14 DT

Quoted message said:

Anyway, if you end up with a circular and wobble free wheel and the spoke tensions are within 10%
among the spokes on a side of the rear wheel, that's great. If you have a 20% difference, the
wheel is not going to fall apart either. Much more then 20% and you have to question how circular
and planer the rim was to start with.

lets see, within 20%. that would be something like 76-114 kgf around my apx average tension, 95kgf
(my estimate). i suppose thats around where i am. im probably more like within 25%.

Quoted message said:

Before I use a new rim, I lay it against the rim of a built up true wheel just to see what I'm
starting with. I have had good luck with rims from Mavic, Velocity and Bontrager.

yep. so do i, usually. dont know why i didnt this time, but i didnt. maybe i incorrectly assumed
away the imperfections, as this is by far the most expensive set of wheel components ive built with.

after i tensioned and trued some, it seemed a little out of whack. i didnt feel like unlacing the
wheel just to find out where i started from. my gut at this point is that the rim is the problem. i
built the wheel twice, essentially, with identical results. i checked archived posts about the open
pro, and it would seem that a bad weld, or other rim defect, sneaks through quality control from
time to time.

thanks,

anthony