srjones1989

My 2012 Brompton has a crack in the braking surface of the rear wheel. I've booked it in to have the rim replaced, but i'm wondering about the front one now.

Would someone be able to provide a bit more clarity for me on how the wear indicator on a Brompton wheel works? I thought that rim wear indicators worked on the basis that as long as the grove that runs around the middle of the brake track is visible, this means that the rims are okay.

However the owners manual says "As the rim wears, a void will appear in the braking surface. At this stage the rim should be replaced." So in the case of Brompton's, does a visible line which is running around the braking surface mean they are worn out?

Thanks in advance!

fietsbob

I see a black indicator groove in my single wall rims, a double wall front, much newer ,

features no indicator groove..

ideally you have a way to measure the sidewall thickness.. ...

2_i 

Rim wall thickness should not go down below 0.5mm. Some people recommend taking the rims off already at 0.7mm. The most convenient way to measure the thickness is with dental calipers. A way to measure the thickness with regular calipers and a contraption out of a spoke was put forward by Chris Juden.