True wheel has slack spoke, doesn't stay true

Tad Marko wrote:
My first handbuilt set of wheels I built with the help of the LBS.
Without knowing what to choose, I went with DT Revolution spokes and
aluminum nipples to lace my Chorus hubs to Open Pro rims. The front
wheel has been fine and has only needed truing once to fix a few spokes
that had been left with some wind up in them. Since then it has stayed
true.

The rear wheel, however, has been a real pain. I have one spoke that is
one spoke away from the weld on the non-drive side that only has a few
kg of force on it. No matter what I do, if the other spokes are
tensioned properly and the wheel is round and true, this one spoke will
only have a little force on it. I can't see that the rim has anything
more than the usual amount of out of round near the seam and there is
no damage. It's been like this since new. This wheel never stays
perfectly true even through one ride, and I suspect that this plus the
aluminum nipples has something to do with this.

Should I just accept a bit out of roundness on that part of the wheel
to get some tension there, or are there any other suggestions?

Thanks,
Tad

couple of things:

1. bike shops don't always allow for the elongation in tension that
revos exhibit compared to other spokes. that often leaves then a little
too long for their application, so it can be hard, particularly on a
revo, to get any more tension if the thread is bottomed out - because
they just twist.

2. as mentioned by everyone else, flat spots are common at seams.

3. don't use revos on the drive side - they are too elastic.

4. make sure the spokes are adequately "stress relieved" or bedded in.

wrote:
David L. Johnson wrote:

The rim has a flat spot. Not really uncommon at the seam. You can
try to push it out some; people have suggested removing the spokes
in that area and pressing the rim out with a car jack. I haven't
actually tried that, though. You might also construct a jig with
the proper curvature to re-shape the rim.

I've removed flat spots from my rims several times. It didn't take a
car jack. I used a bench vise and blocks of wood.

I took a piece of 1" x 4" board, perhaps 10" long, and fastened a
block cut from 2" x 4" on each end. The blocks have an angled
surface, to match the rim's angle. This supports a span of the rim
from the outside. Another block of wood presses against the flat
spot on the inside (i.e. hub side), with several spokes removed for
clearance.

The sandwich fits into my bench vise. I tighten bit by bit, loosening
occasionally to check if I've moved the rim enough. It's a bit fussy,
but not too bad. Way easier than buying new components and building a
new wheel, and much cheaper.

- Frank Krygowski

I can almost visualize, it but I can't figure out how all the parts hold
together without flying apart. Do you have a schematic/pictures?
--
Phil, Squid-in-Training

Tad Marko wrote:
My first handbuilt set of wheels I built with the help of the LBS.
Without knowing what to choose, I went with DT Revolution spokes and
aluminum nipples to lace my Chorus hubs to Open Pro rims.

The LBS needs to get a clue with regards to Revs spokes in any rear,
IMO..ditto for aluminum nipps.

The front
wheel has been fine and has only needed truing once to fix a few spokes
that had been left with some wind up in them. Since then it has stayed
true.

The rear wheel, however, has been a real pain. I have one spoke that is
one spoke away from the weld on the non-drive side that only has a few
kg of force on it. No matter what I do, if the other spokes are
tensioned properly and the wheel is round and true, this one spoke will
only have a little force on it. I can't see that the rim has anything
more than the usual amount of out of round near the seam and there is
no damage. It's been like this since new. This wheel never stays
perfectly true even through one ride, and I suspect that this plus the
aluminum nipples has something to do with this.

I suspect that the tension is low...since it doesn't stay true, it is
not round and one spoke is slack. Unless you hit something there and
the rim is pushed in there.


Should I just accept a bit out of roundness on that part of the wheel
to get some tension there, or are there any other suggestions?

Thiker spokes, brass nipps. BUT make sure the tension on the right side
Revs is proper. 100 kgf. The only way to get this with certainty with
these spokes is with a tensionometer.

Thanks,
Tad

Tad Marko wrote:
Around 100 kgf according to the Park tensionometer.

Good then. I'd say that you indeed have a flat spot, there at the seam.
Raise the right side spoke tension around that spot, two spokes up on
the right side in both directions...then raise the offending spoke
tension, and the two up from that but yer gonna have a flat spot. I
wouldn't recommend banging the flat spot out. Aluminum doesn't like to
be bent back and forth.

Generally tho, new Open Pros are pretty round.

Generally tho, new Open Pros are pretty round.

That alone is reason enough to get a warranty replacement. Gotta love Mavic
quality these days, huh?
--
Phil, Squid-in-Training

jim beam wrote:
1. bike shops don't always allow for the elongation in tension that
revos exhibit compared to other spokes. that often leaves then a little
too long for their application, so it can be hard, particularly on a
revo, to get any more tension if the thread is bottomed out - because
they just twist.

Assume: 300 mm spoke length, modulus 200 GPa, spoke tension 100 kgf

Variable: 1.5 mm vs 2.0 mm spoke diameter

Difference in elongation: 0.36 mm

--
Dave
dvt at psu dot edu

On Wed, 7 Dec 2005 10:36:26 -0500, "Phil, Squid-in-Training"
wrote:

Generally tho, new Open Pros are pretty round.

That alone is reason enough to get a warranty replacement. Gotta love Mavic
quality these days, huh?

Particularly if your idea of a fun time on a Friday night is relacing
a wheel.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

In article .com,
says...

My first handbuilt set of wheels I built with the help of the LBS.
Without knowing what to choose, I went with DT Revolution spokes and
aluminum nipples to lace my Chorus hubs to Open Pro rims. The front
wheel has been fine and has only needed truing once to fix a few spokes
that had been left with some wind up in them. Since then it has stayed
true.

If this was your first set of wheels, you really should not have gone with
revolutions. Because of their thin mid-section, they are harder to build
with. You need to be able to feel them wind up and then back off the
spoke nipple the appropriate amount.

The rear wheel, however, has been a real pain.

rear wheels are more difficult to build.

I have one spoke that is
one spoke away from the weld on the non-drive side that only has a few
kg of force on it. No matter what I do, if the other spokes are
tensioned properly and the wheel is round and true, this one spoke will
only have a little force on it. I can't see that the rim has anything
more than the usual amount of out of round near the seam and there is
no damage. It's been like this since new. This wheel never stays
perfectly true even through one ride, and I suspect that this plus the
aluminum nipples has something to do with this.

The aluminum nipples may not be the best choice, but that has nothing to do
with your out of round wheel. It is very important that the tension on the
same side of the wheel be even. If the tension is not even, then you will
get some spokes that won't hold their tension. This will also happen if the
tension is too low.

Should I just accept a bit out of roundness on that part of the wheel
to get some tension there, or are there any other suggestions?

A little out of roundness with even tension is not bad. I would suggest that
you buy, or borrow, a copy of 'The Bicycle Wheel' by Jobst Brandt. You can
then learn more about what makes a good wheel and how to build it.
--------------
Alex

Phil, Squid-in-Training wrote:
wrote:


I've removed flat spots from my rims several times. It didn't take a
car jack. I used a bench vise and blocks of wood.

I took a piece of 1" x 4" board, perhaps 10" long, and fastened a
block cut from 2" x 4" on each end. The blocks have an angled
surface, to match the rim's angle. This supports a span of the rim
from the outside. Another block of wood presses against the flat
spot on the inside (i.e. hub side), with several spokes removed for
clearance.

The sandwich fits into my bench vise. I tighten bit by bit, loosening
occasionally to check if I've moved the rim enough. It's a bit fussy,
but not too bad. Way easier than buying new components and building a
new wheel, and much cheaper.

- Frank Krygowski

I can almost visualize, it but I can't figure out how all the parts hold
together without flying apart. Do you have a schematic/pictures?

Sorry, no digital camera lives here. I can try with ASCII art -
tedious as that is!

Here's a top view. The rim would be horizontal, the hub toward the top
of the page.

Sqeezing the vise shut makes the rim more concave upward in this
sketch.


| vise jaw |
| ___________|
------------
| | wood block bearing on
"inside" rim surface
----------

- - - -- -Rim goes here - - -

---------- ----------
| \ / |
Two wood blocks
| \ / |
fastened to 1 x 4
----------------------------------------------------------------
| 1 x 4 |
---------------------------------------------------------------

---------------------
| |
| vise jaw |

- Frank Krygowski

Phil, Squid-in-Training wrote:
wrote:


I've removed flat spots from my rims several times. It didn't take a
car jack. I used a bench vise and blocks of wood.

I took a piece of 1" x 4" board, perhaps 10" long, and fastened a
block cut from 2" x 4" on each end. The blocks have an angled
surface, to match the rim's angle. This supports a span of the rim
from the outside. Another block of wood presses against the flat
spot on the inside (i.e. hub side), with several spokes removed for
clearance.

The sandwich fits into my bench vise. I tighten bit by bit, loosening
occasionally to check if I've moved the rim enough. It's a bit fussy,
but not too bad. Way easier than buying new components and building a
new wheel, and much cheaper.

- Frank Krygowski

I can almost visualize, it but I can't figure out how all the parts hold
together without flying apart. Do you have a schematic/pictures?

Sorry, no digital camera lives here. I can try with ASCII art -
tedious as that is!

Here's a top view. The rim would be horizontal, the hub toward the top
of the page.

Sqeezing the vise shut makes the rim more concave upward in this
sketch.


| vise jaw |
| ___________|
------------
| | wood block bearing on
"inside" surface
-------------

- - - -- -Rim goes here - - -

---------- ----------
| \ / |
Two wood blocks
| \ / |
fastened to 1 x 4
----------------------------------------------------------------
| 1 x 4 |
---------------------------------------------------------------

---------------------
| |
| vise jaw |

- Frank Krygowski