How do you know if your rims are worn?

[edscoble]

^ This very much.

If I have half a penny for every customer whom think "it'll be fine"...

[Glover Fan]

Certainly, it's worth buying new rims just for reassurance. My wheels didn't turn up til today and I rode a 200 on the old wheels on Saturday. Descending into Winchcombe wasn't as fun as it should be when the nagging "what happens if..." is in the back of your mind.

[drossall]

So after my ride in last week's 100 Miles of Suffolk Lanes event ended suddenly in Wickham Market like this:



I put an Iwanson gauge on the rim today (front and rear were older Ambrosio Evolutions). Most of the way round I got 1.3mm,  but I did find a couple of places where it was like this:



Not at all concave though, which is why both I and the person I bought the wheels from thought that they were OK to ride.

Anyway, the new rims arrived mid-week, so that's tomorrow's entertainment sorted then

[LittleWheelsandBig]

I modified the jaws of my Iwanson gauge because the points were originally too wide where they contacted the rim. They were unconservatively measuring curves in the cross-section, rather than the thinnest cross-section thickness.

I usually replace my rims when I notice they are noticeably less than 1.0mm thick, so I probably wouldn’t have replaced the rim if I saw that measurement.