Pringled rim - is this beyond repair?

On 9 Sep, 08:30, Grufff wrote:
I managed to fall over last night whilst wheeling my bike over/through
a cycle lane barrier. I fell on top of the bike and rear wheel was
trapped against one of the low elements of the barrier was twisted by
my weight.

The result was this:

http://www.youtube.com/watch?v=SHYmyN7efGE

I'd like opinions on whether it's safe/sensible to fix that rim, or if
I should bin it and rebuild with a new one.

The video was taken after I'd taken out the tension in all spokes, so
what you see is the shape of the rim itself now. It's aluminium, disk
only, 26" and has had only light use.

I can see no physical damage to the rim, other than the obvious
deformation. Certainly no cracks or dings/bulges.

The (Alfine) hub was undamaged, as was the rotor.

I've built wheels before, I'm no expert, but with time and care I can
do a good job. I'm happy to attempt to push this one back into shape
and re-tension, and true it etc, but not sure how repairable damaged
rims are.

Can it be salvaged, or will I be flogging a dead horse?

It looks like a simple double bend and I think it will be worthwhile
at least attempting to correct it. Leave the rim connected as is.
Get four house bricks. Put two on edge at 180deg to each other, place
the other two at 90deg. locate the rim on the bricks so that the
largest deviation is aligned with the bricks and push down so that
the rim touches all four bricks. The difference in height of the
supports is usually appropriate for this correction. Put it back in
the jig to check. If it's within 1/8" (3mm) your rim is good and a
little more manipulation to get it within 1/16" will be preferable to
ease the retensioning..

Put two on edge at 180deg to each other, place
the other two at 90deg.

Is that to say "put bricks at 12, 3, 6, and 9 o'clock positions, each
on-edge"?

Just tryin' to draw a mental picture...

Thanks.

On 10 Sep, 04:59, notme wrote:
Put two on edge at 180deg to each other, place
the other two at 90deg. *

Is that to say "put bricks at 12, 3, 6, and 9 o'clock positions, each
on-edge"?

Just tryin' to draw a mental picture...

I missed the point I wanted to make. Two of those bricks are flat,
two are on edge. Place the rim so the bulges meet the on edge bricks
and press from the bulges the other side to meet the flat bricks.

Thank you, for pointing out my ommision.

On Wed, 9 Sep 2009 21:44:26 -0700, someone wrote
(in article
):

I missed the point I wanted to make. Two of those bricks are flat,
two are on edge. Place the rim so the bulges meet the on edge bricks
and press from the bulges the other side to meet the flat bricks.

So, bricks on edge at 12 & 6 o'clock; bricks flat at 3 & 9. Place "taco" on
bricks such that the high points are over the flat bricks. Then press.

Right?

On 10 Sep, 06:07, notme wrote:
On Wed, 9 Sep 2009 21:44:26 -0700, someone wrote
(in article
):

I missed the point I wanted to make. *Two of those bricks are flat,
two are on edge. *Place the rim so the bulges meet the on edge bricks
and press from the bulges the other side to meet the flat bricks.

So, bricks on edge at 12 & 6 o'clock; bricks flat at 3 & 9. Place "taco" on
bricks such that the high points are over the flat bricks. Then press.

Right?

That's another way of putting it. Identifying the 'high points' is
where most of the time should be spent. It pays dividends to get the
location right. Simple double bend buckles can revert to normal
without any evidence bar the scratches the bricks make. You can
protect against this if it worries you, but I don't think when
rescuing a rim the mechanic usually thinks of this being a problem.
The correction may not bring satisfaction so cosmetic protection is
secondary.

Well, thanks to everyone for their input.

I realised late last night that I had forgotten all about the other
(front) wheel from this pair, which I had stored in the house. Given
that I had an identical rim to hand, it seemed most sensible to do a
straight transplant so that's what I've done.

I'm inclined to agree that the rim could be salvageable with some
effort, but as I'm no expert wheel builder, and also a heavy rider, I
think the final result would have likely been unreliable in my hands.

Thanks again.