Lightly grinding a rim

[Andy R]

What I can't yet fathom is why lightly grinding the surface off the rim makes it super-sharp in braking and super-destructive to pads, and yet a rim with the surface worn to a concave shape gives feeble braking and does nothing to the pads. Has the concave surface been super-polished as well as worn away?

If you persevere with a lightly-ground rim for a while, do the pads gradually polish the surface back into a less ferocious state?

Because if you abrade a rim to give sharper braking the striations are at right angles to the rotation, as opposed to on a worn/normally used rim, where they are in line with the rotation.

If the surface is only "lightly ground" you could polish it out with wet or dry I suppose, rather than letting the brake pads do this over time (which they would).

 

[lewis1641]

the ones i have seen have not been deglaged-they have had grooved cut in across the rim (ie from the bottom of the rim to the top rather than ROUND the rim like a brake would score it.)

cant find a picture of what i mean

 

[amedias]

like this....

 

[lewis1641]

yeah that's what i've seen.