Uneven front braking

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Since my front wheel was trued up I have noticed that the brake pulses quite dramatically. I checked the rim with vernier calipers and found that almost half of the circumference is about 1 millimetre narrower than the rest - so the brakes grab on the wider section then ease off on the narrower part. Is this something that can be fixed or will it sort itself out as the wider rim wears down? The pulsing isn't a big problem but I am concerned that it would be in an emergency braking situation as I would have much less control of braking force.

Any advice would be most welcome.

Originally posted by Rod Parker-Rees
Since my front wheel was trued up I have noticed that the brake pulses quite dramatically. I checked the rim with vernier calipers and found that almost half of the circumference is about 1 millimetre narrower than the rest - so the brakes grab on the wider section then ease off on the narrower part. Is this something that can be fixed or will it sort itself out as the wider rim wears down? The pulsing isn't a big problem but I am concerned that it would be in an emergency braking situation as I would have much less control of braking force.

Any advice would be most welcome.

It sounds like your rim is damaged. 1 mm is quite a bit of difference.
I build wheels to 0.3mm of true.
I won't use a rim if it has more than 0.1 mm of variance.
Most times there is a variance of well under 0.1 mm, and it is concentrated at the rim joint.
David Ornee, Western Springs, IL

Originally posted by daveornee
It sounds like your rim is damaged. 1 mm is quite a bit of difference.
I build wheels to 0.3mm of true.
I won't use a rim if it has more than 0.1 mm of variance.
Most times there is a variance of well under 0.1 mm, and it is concentrated at the rim joint.
David Ornee, Western Springs, IL

Thanks David,

The shop agreed to replace the front wheel. The first one they tried, from the store-room was even worse so they ended up taking one off another bike in the showroom and this one needed a bit of work to smooth down the join area. At least now I enjoy smooth braking.

Rod