MA 2 rim-flat spot

[Jb]

I have a new Mavic rim with a noticable flat spot at the joint. I didn't realize it until after I
built wheel & began to true. Are there any tips/methods that I may use in an attempt to cure it? Any
legitmate advice would be appreciated. thx, JB

 

[David L. Johnso]

On Sun, 06 Apr 2003 13:30:15 +0000, JB wrote:

> I have a new Mavic rim with a noticable flat spot at the joint. I didn't realize it until after I
> built wheel & began to true. Are there any tips/methods that I may use in an attempt to cure it?
> Any legitmate advice would be appreciated.

I recently used MA-2's and found this to be the case as well, on both wheels. There are tricks to
push out a flat spot. One method I have heard of but have not tried is to remove a few spokes on
either side of the seam, and apply outward pressure. I would go slow with that.

--

David L. Johnson

__o | "It doesn't get any easier, you just go faster." --Greg LeMond _`\(,_ | (_)/ (_) |

 

[S. Anderson]

"JB" <[email protected]> wrote in message news:[email protected]...
> I have a new Mavic rim with a noticable flat spot at the joint. I didn't realize it until after I
> built wheel & began to true. Are there any tips/methods that I may use in an attempt to cure it?
> Any legitmate advice would be appreciated. thx, JB

Define noticeable. Unfortunately, there is usually some defect around the rim joint. Most are fairly
good and don't require much beyond the usual flat-spot/high-spot truing techniques. Sometimes these
flat-spots are physical in nature, that is, the rim is physically deformed during construction and
the only way to remove it is to physically bend the rim straight. If this is a new rim and you are
unsatisfied with the resulting build-up, I would recommend you take the wheel to where you bought
the rim and tell them the rim is not good enough. They can try to correct the problem and may agree
to replace the rim.

Cheers,

Scott..

 

[S. Anderson]

"David L. Johnson" <[email protected]> wrote in message
news:[email protected]...
> On Sun, 06 Apr 2003 13:30:15 +0000, JB wrote:
>
> I recently used MA-2's and found this to be the case as well, on both wheels. There are tricks to
> push out a flat spot. One method I have heard of but have not tried is to remove a few spokes on
> either side of the seam, and apply outward pressure. I would go slow with that.
>
> --
>
> David L. Johnson
>
> __o | "It doesn't get any easier, you just go faster." --Greg LeMond _`\(,_ | (_)/ (_) |
>
>

Yes and I had a tool that I used to do this on some wheels. Usually, for high-quality stuff though,
I recommended replacing the rim rather than using this technique. On training wheels or wheels that
just weren't that great I've used this method and it works ok. It's never perfect afterward though.
Depending on how bad the join is, I'd try and get a new rim with a better join. There'll always be
an argument though as to what constitutes "too much" of a deviation from round.

Cheers,

Scott..

 

[Jobst Brandt]

JB who? writes:

> I have a new Mavic rim with a noticable flat spot at the joint. I didn't realize it until after I
> built wheel & began to true. Are there any tips/methods that I may use in an attempt to cure it?
> Any legitmate advice would be appreciated.

How do you define "legitimate" and why so secretive?

When the wheel is as tight as you plan to make it, loosen two spokes at least six to eight full
turns on either side of the joint. Run a 2x4 (on edge) through the wheel supported on both ends (on
rafters in your garage or whatever) above your head so that you can hang on the wheel. Lunge with
your full weight with increasing force, each time checking for effect, until you see a change. If
the flat spot is not extreme, this can make the rim round.

Jobst Brandt [email protected] Palo Alto CA

 

[Mikeyankee]

When MA-2's went out of production I bought half a dozen of 'em for future use; that's probably a
lifetime supply for 2 bikes, including spares.

One had an apparent flat spot of 1 or 2 mm near the rim joint, which I noticed during a radial
truing phase of the build. But it was only on one side of the rim (i.e., left or right). If you
followed the rim's hook (bead), or the inside boundary of its braking surface, no flatness or
eccentricity was apparent, nor was the joint uneven.

I checked a few other MA-2's. Holding them perpendicularly at arm's length and looking at the arc of
the outer flange in the seam area, using the other flange as a "horizon", I could see a very slight
variation (on the order of 0.5 mm) in most of them. This suggests to me that some material around
the seam is ground off in a finishing operation; that would also explain why my particular "flat
spot" was only on one side.

Mike Yankee

(Address is munged to thwart spammers. To reply, delete everything after "com".)

 

[Jobst Brandt]

Mike Yankee writes:

> When MA-2's went out of production I bought half a dozen of 'em for future use; that's probably a
> lifetime supply for 2 bikes, including spares.

> One had an apparent flat spot of 1 or 2 mm near the rim joint, which I noticed during a radial
> truing phase of the build. But it was only on one side of the rim (i.e., left or right). If you
> followed the rim's hook (bead), or the inside boundary of its braking surface, no flatness or
> eccentricity was apparent, nor was the joint uneven.

> I checked a few other MA-2's. Holding them perpendicularly at arm's length and looking at the arc
> of the outer flange in the seam area, using the other flange as a "horizon", I could see a very
> slight variation (on the order of 0.5 mm) in most of them. This suggests to me that some material
> around the seam is ground off in a finishing operation; that would also explain why my particular
> "flat spot" was only on one side.

So quit sending your wreck.bike postings to my e-mail already. What are you trying to accomplish
with that?

Jobst Brandt [email protected] Palo Alto CA