Can't true my wheel (roundness)

chrisc said:

I got the side to side down. But when I work on the roundness, I can't get
it right. The wheels only have about 800 miles on them. I trued them
according to the repair manuals and parks web site. They are rideable
though. First I do lateral (which comes out good, but not perfect). Second ,
i do roundness . I tighten at the high spots to pull the wheel inward
towards the hub and loosen at the low spots on the opposite side. Then I go
back and check the lateral . I can't get the roundness good enough to where
I want it. ( You defiinetely see the wobble up and down in the roundness).
Could the rim be bent that way? Or can they only be bent laterally? Thanks

try roundness first, then lateral. this is particularly easy on dished
rears where the drive side spokes essentially take care of roundness,
the non-drive side, true.

Chris C? said:

I got the side to side down. But when I work on the roundness, I
can't get it right. The wheels only have about 800 miles on them.
I trued them according to the repair manuals and parks web site.
They are ridable though. First I do lateral (which comes out good,
but not perfect). Second , i do roundness . I tighten at the high
spots to pull the wheel inward towards the hub and loosen at the low
spots on the opposite side. Then I go back and check the lateral .
I can't get the roundness good enough to where I want it. ( You
definitely see the wobble up and down in the roundness). Could the
rim be bent that way? Or can they only be bent laterally? Thanks

I prefer to get the wheel round first, this being the more forceful
adjustment when trying to pull in a high spot. Besides, although it
isn't likely, you should either stress relieve to see that the wheel
is not too tight already or measure tension with a tensiometer.

Make sure you have lubricated the spoke nipple to rim joints and the
spoke thread to spoke nipple point. These spokes should turn freely.
You didn't say how many spokes you wheels have but that could be a
problem. Fewer than 32 spokes makes this greatly more difficult.

Lateral alignment is simple compared to roundness and can be aided by
pulling the rim toward the side the spoke in question is pulling.
This unloads the threads and makes adjustment easier.

Unless you got a ding in the rim from a hole in the road, I doubt that
it is bent beyond truing.

Jobst Brandt

chrisc said:

I got the side to side down. But when I work on the roundness, I can't get
it right. The wheels only have about 800 miles on them. I trued them
according to the repair manuals and parks web site. They are rideable
though. First I do lateral (which comes out good, but not perfect).

You probably want to do a bit at a time - fix the worst roundness
error, then the worst lateral, then repeat. Make sure to check the
dish at some point as well.

Quoted message said:

Second ,
i do roundness . I tighten at the high spots to pull the wheel inward
towards the hub and loosen at the low spots on the opposite side.

Ah, that might be part of your problem. There isn't necessarily a low
spot opposite every high spot. Try going round just tightening at the
high spots, and remember to check it regularly to make sure you haven't
overcorrected - it's surprisingly easy to do.

Quoted message said:

Then I go
back and check the lateral . I can't get the roundness good enough to where
I want it. ( You defiinetely see the wobble up and down in the roundness).
Could the rim be bent that way? Or can they only be bent laterally? Thanks

It's possible that the rim isn't radially true, but you should be able
to correct for it with spoke tension (unless you remember whacking the
rim off a kerb recently).

chrisc said:

I got the side to side down. But when I work on the roundness, I can't get
it right.

Is there one particular spot where it's out of round? With some rims, there
will be a slight hop at the point where rim ends are joined (opposite the
valve hole). If that's the case, and the variation is less than 1mm, I
wouldn't sweat it.

Art Harris

read JB-experience teachs that
me ? not much experience like you.
problem is the axle-determines actual spoke length in relation to total
wheel-
the axle floats with your so called adjustment.
your problem is to get the axle in the center.
but to do this the spokes need be much tighter than the spokes are for
getting lateral correct.
lateral correct is done with the first 1/4 turns tighter than lightly
seated. very low torque. minimal.
problem is-that lateral trueing torque will not stretch the spokes into
a running-on road-seated position to center the axle.
so where's the point A where spokes are seated and lateral true is more
or less in order?
that's where the roundness correction begins
IF!! the rim and axle are in agreement for center at this point and
agree that the rim was fairly round to begin with.
IF NOT!! then the roundness trueing takes place somewhat before point
A.
if the whole rig is out of whack then your in for a round dance whatzit
a dozee dough? in and out of the Point A with both lateral and round
until you pass Point A with both rim, axle, and your general good mood
intact.

the roundness trueing starts with full 360 sections. say you have a 40
degree lump (using a magic marker held stationery on turning braking
surface) sticking out. i'll bet that's a place also under some lateral
out of whack pressure. the other 320 is loosened, and the axle moves
toward the loosening section-possibly bringing the lump with it.
you see, some people will reef on the lump trying to force it down-but
there's nowhere for it to go!

its an interesting game.

buy 3 rolls of colored tape, each different.

Quoted message said:

read JB-experience teachs that
me ? not much experience like you.
problem is the axle-determines actual spoke length in relation to total
wheel-
the axle floats with your so called adjustment.
your problem is to get the axle in the center.
but to do this the spokes need be much tighter than the spokes are for
getting lateral correct.
lateral correct is done with the first 1/4 turns tighter than lightly
seated. very low torque. minimal.
problem is-that lateral trueing torque will not stretch the spokes into
a running-on road-seated position to center the axle.
so where's the point A where spokes are seated and lateral true is more
or less in order?
that's where the roundness correction begins
IF!! the rim and axle are in agreement for center at this point and
agree that the rim was fairly round to begin with.
IF NOT!! then the roundness trueing takes place somewhat before point
A.
if the whole rig is out of whack then your in for a round dance whatzit
a dozee dough? in and out of the Point A with both lateral and round
until you pass Point A with both rim, axle, and your general good mood
intact.

the roundness trueing starts with full 360 sections. say you have a 40
degree lump (using a magic marker held stationery on turning braking
surface) sticking out. i'll bet that's a place also under some lateral
out of whack pressure. the other 320 is loosened, and the axle moves
toward the loosening section-possibly bringing the lump with it.
you see, some people will reef on the lump trying to force it down-but
there's nowhere for it to go!

its an interesting game.

buy 3 rolls of colored tape, each different.

I liked your post last month (the one in clear English) better.

When you stumbled across the keyboard, "axle-determines
actual spoke length" came out. That wasn't in my copy of
'The Book'

I didn't get the rest of it either. Are you describing a
problem or recomending a technique?
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971