True wheel has slack spoke, doesn't stay true

Frank Krygowski writes:

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 have a rim straightener tool that pulls such zones out but before
someone gave me that, I loosened the six spokes to either side of the
middle of the flat spot completely, put a 2x4 through the wheel and
hung it across intersecting rafters so that I could hand on the wheel
lunging enough to pull that section out. I could check progress by
the truing stand. This returned a dinged rim that got that way by a
hard flat landing on a rough road.

Afterward you couldn't see that the wheel wasn't pristine.

Jobst Brandt

wrote:
There is a commercial tool for pressing flat spots out of a rim.
It works similarly, but the various blocks are metal and attached
to a metal frame, with a screw handle for doing the pressing.
I don't know if it is made any longer or who made it - my old LBS
in Santa Cruz had one hanging on the shop wall.

A Muzi wrote:
This one? It's well made, easy to use.
http://www.yellowjersey.org/photosfr...st/RIMTRUE.JPG

wrote:
The one I saw was very like that, I think not identical, but
in materials a similar age and style. Thanks for posting the
picture. I always wondered if this tool would work on the
deeper sectioned rims that are more common now, as well
as typical single-wall or box section rims.
I can imagine home brewing a similar tool by nailing sections
of wood (about 1x1 strips) to a flat board, and using a large
C-clamp with a wood block to do the pressing.

Most modern rims are a larger overall shape but much thinner
and dent easily. Depends on the rim.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Andrew Muzi writes:

There is a commercial tool for pressing flat spots out of a rim.
It works similarly, but the various blocks are metal and attached
to a metal frame, with a screw handle for doing the pressing. I
don't know if it is made any longer or who made it - my old LBS in
Santa Cruz had one hanging on the shop wall.

This one? It's well made, easy to use.

http://www.yellowjersey.org/photosfr...st/RIMTRUE.JPG

Hey, that's my tool. Some nice guy gave it to me because I always
built his wheels and fixed ones that got dinged.

Jobst Brandt

wrote:
before someone gave me that, I loosened the six spokes to either
side of the middle of the flat spot completely, put a 2x4 through
the wheel and hung it across intersecting rafters so that I could
hand on the wheel lunging enough to pull that section out. I
could check progress by the truing stand. This returned a dinged
rim that got that way by a hard flat landing on a rough road.

Afterward you couldn't see that the wheel wasn't pristine.

Doing that with an Alesa 913 flattens the inner wall without
correcting the flat zone (missed jump over a steelplate)....

--
MfG/Best regards
helmut springer