I never know what rims will walk through my door, the freshness of the tooling on the day they were made, the chain of custody from the factory, etc. So I have a prebuild ritual that involves quite a lot of inspection. I don’t want to call it a checklist — I’m just creating opportunities to notice what’s in hand. If attention is given to each facet, anything awry stands out.
On alloy rims I like to visit every spoke hole with a chamfer tool or a handheld drill bit. This puts a subtle profile in the hole where the head of the nipple rests. Sometimes there can be a coil of drilling chaff attached to a spoke hole — a chamfering pass breaks them off and smooths any burrs. When I visit the joint I look at the internal sleeve, if any. Does it interfere with nipple fit? And so on.
Measuring is inspecting
Measuring your own ERD can indicate a lot. Use the measuring step to test fit washers if using them. Do the washers sit nicely in the rim? Measuring will tell you if your rim round or oval. All else being equal the rounder the rim, the better the expected result in terms of alignment and tension balance. If your rim is oval, take a deep breath and expect to spend a little longer at the bench if chasing numbers is your thing. Have you ever found a job difficult and doubted your skills? It could be the rim but more comforting to know than to guess.