How to get rid of up-and-down in my rear wheel?

[Simonb]

I have been trying for an hour now to true my rear wheel for roundness (I
hit a pothole this evening). I understand that to remove up-and-down I have
to tighten the spokes at the point where the rim is 'highest'. Problem is, I
cannot tighten these spokes any more without making them dangerously taut?

What to do? Is this rim a write-off?

Simonb

[Huw Pritchard]

On Fri, 19 Sep 2003 22:07:12 +0100, Simonb did issue forth:

> I have been trying for an hour now to true my rear wheel for roundness (I
> hit a pothole this evening). I understand that to remove up-and-down I have
> to tighten the spokes at the point where the rim is 'highest'. Problem is, I
> cannot tighten these spokes any more without making them dangerously taut?
>
> What to do? Is this rim a write-off?

Not necessarily. Try slackening the spokes on the opposite side, or even
go right the way around the wheel, slackening everything off by half a
turn.

If you end up with huge differences in the spoke tension, then maybe your
rim is actually toast.

Huw

[Simon Brooke]

"Simonb" <sbennettatwiderworlddotcodotuk> writes:

> I have been trying for an hour now to true my rear wheel for roundness (I
> hit a pothole this evening). I understand that to remove up-and-down I have
> to tighten the spokes at the point where the rim is 'highest'. Problem is, I
> cannot tighten these spokes any more without making them dangerously taut?
>
> What to do? Is this rim a write-off?

Gently ease off other spokes. Consider a bicycle wheel as a thing of
balanced tensions. Within certain limits, you can relatively tighten
one spoke by relatively loosening all the others. But do it gently,
and gradually. Ease off the spokes at either side of the 'high' point
first, and then if you have an egg shaped wheel progress around away
from the high point easing off a little on both sides. And when I say
a little, I mean a little - ease each spoke a quarter of a turn at a
time.

In my experience unless the rim is dented or buckled it's rarely a
write off. It's possible that it might be good to replace the spokes
and nipples in the 'high' area with new ones, if you genuinely believe
you've overtightened them.

Truing a wheel is (for me anyway) a matter of patience and small
adjustments.

However, of course, you also have to value your own time, and if the
rims are cheap ones and/or old, it may be more cost effective to
replace them.

--
(Simon Brooke) http://www.jasmine.org.uk/~simon/

;; lovely alternative to rice.