When to ditch a rim?

[M_Chavez]

Hi All,

I've got an old rim from a bike I bought a wee while ago that I can lace into a road bike front wheel.
There's no wear indicator on the rim and the braking surfaces appear worn but OK. I know nothing about the rim history.

Bought a cheapo dental caliper and it's showing about 1.0mm remaining wall thickness.

When would you ditch a rim? Is it worth lacing this one into a hub and running on my commuter over winter? (already have a hub and used set of spokes in the right size for it). Or will it leave me stranded in the middle of nowhere in the dark, wet & cold with a cracked rim?

 

[Jamesbike]

Usually when the braking surface is concave.

If it's pretty uniform then it isn't badly worn!

Although I have a few that are a bit worn for
local summer evening riding!

 

[M_Chavez]

Yep... But the surface is worn & almost perfectly flat (to my surprise). Hence the dental caliper.

 

[pigman]

Just to scare you, when a rim goes because of braking surface wear, it's not just a cracked rim job. I have seen 2 go and on both occasions the riders weren't actually braking. The tyre pressure eventually causes the failure. The whole rim disintegrates and the tyre explodes like a gun. Dread to think if this happens on a speedy descent.

 

[grantoury]

I just measured two different solid road rims: 3mm

 

[M_Chavez]

@grantoury
How did you measure them?

A slightly worn Mach1 road rim with 0.4mm of wear indicator is measuring 1.6mm and brand new weinmann 26" rims are measuring 1.6-1.7mm.

Wear indicators seem to be about 0.5-0.6mm on 1.5-1.6mm rims, which is telling me that a rim that measures 0.9-1.1 with cheapo dental calipers is probably better off in a skip.
What a shame - I had a set of DT swiss spokes that were just the right length, but I don't want to end up paying for some dentist's new klein.

The wisdom of the internets suggests that under 1mm should be ok for light use, but better off replaced, and anything under 0.7mm is a trip to A&E.

 

[grantoury]

Aah, dental caliper, didn't read that properly.

 

[M_Chavez]

Yeah, the thing reaches right into the bead channel - quite handy.

Decided to ditch the rim - Cheap enough to buy a new one, absolutely not worth the risk.

 

[grantoury]

Agreed

 

[Imlach]

My rim is pretty worn but I found that a nice soaking in saltwater and baby oil does the trick.