Re: [CR]Ma2 brake pulsing-Fix?


Example: History:Ted Ernst

Date: Fri, 14 May 2004 09:43:19 -0700 (PDT)
From: Ted Baer <wickedsky@sbcglobal.net>
Subject: Re: [CR]Ma2 brake pulsing-Fix?
To: t.kielman@comcast.net
In-Reply-To: <051420041355.6195.40A4CFBF00039C7F000018332200750744020E03040A0705D29B@comcast.net>
cc: classicrendezvous@bikelist.org

Hi Todd,

I spent 5 years working at Wheelsmith here in Palo Alto and have done this a million times. (Before anyone jumps down my throat, I do not claim to be "Mr. Expert.") But here is how to do it:

1. Remove the tire and tube.

2. Place the wheel in a truing stand or in bicycle fork with bicycle turned up-side down.

3. Find a very FLAT wrench (cone wrench is best.)

4. Place the cone wrench (length-wise) over the outer side of one side of the rim seam.

5. Look down at the seam. If the cone wrench does not "teeter" over the seam, or you cannot see an indentation at one half of the seam, then this side of the rim is most likely aligned.

6. Place the cone wrench length-wise on the opposite outer rim side. Look down at the seam. If the cone wrench "teeters" back and forth, this means that one side is flaring out too much and needs to be pushed back into place. There is a tool to do this (rim pliers). The rim pliers are somewhat of a goofy tool and if not used properly will leave marks on new rims. But the easiest way is to take the wheel out of the truing stand and lay it sideways on a wooden bench and use the hard side of a mallet to bang the flared side of the seam back into place.

7. If you place the cone wrench over the seam as in step #6, and it does not teeter BUT you can see that one side of the seem is pressed inward, do the following:

a.) Hold a cone wrench flat against the outside of the rim.

b.) Look down at the area between the cone wrench and the outside of rim/seam area. Observe which side of the seam is bent "inward."

c.) While holding the cone wrench firmly in place lengthwise against the outer side of the rim, take a small crescent wrench and tighten it over the outer side of the cone wrench and the inner wall of the rim ON THE SIDE OF THE SEAM WHICH IS PUSHED INWARD.

d.) Using the crescent wrench and cone wrench, carefully pry the pushed in side out until it is aligned with its neighboring side.

e.) Run your fingers over the seemed area and repeat all steps above as necessary until there is no pulsing of the rim.

f.) As a final measure, use a vernier caliper to take measurements of outer-to-outer section rim section distances in random spots around the wheel. Then take a few measurements around the seemed area and see if you have indeed corrected the problem.

A few more things to keep in mind:

-The VERY LAST RESORT TO CORRECTING THUMPING IS TO SAND THE RIM. And this is ESPECIALLY true if these ARE NEW RIMS AS YOU MAY VOID THE WARRANTY. I have never, ever had to sand a NEW rim to correct brake pulsating.

-THE SHOP THAT SOLD YOU THESE RIMS SHOULD HAVE TAKEN CARE OF THIS PROBLEM BEFORE YOU EVEN WALKED OUT THE DOOR. Most "new" wheels out of a box are not fully tensioned, trued, or completely dished. And the rim seem has not been checked. THIS IS THEIR RESPONSIBILITY as a professional bicycle dealer to check these things for you.

Hope this helps,
Ted Baer
Palo Alto, CA


--- t.kielman@comcast.net wrote:


> Experiencing an annoying brake thump on a new set of

\r?\n> wheels.Anyone have a tried and true rememdy for

\r?\n> fixing an uneven seam on a rim,in this case an

\r?\n> Ma2?Can't find anything in the archives.

\r?\n> Thanks,

\r?\n> Todd Kielman

\r?\n> Chicago