fred_dot_u

Parameters:
single wall rim
26 x 2.1 tire/tube, schrader valve
all spokes recessed in nipples
no nipple turning done
rim is wonderfully true
original rim strip was rubber
replaced with polyurethane rim strip
second rim strip added later
tire rated to 65 psi, inflated to 60 psi during testing

original puncture located about two o'clock from valve stem
replacement tube punctured about same location
I'll never use slimed tubes again

next replacement tube punctured as shown in photo, adjacent to valve stem
failure appears to be aneurysm style in all cases
"pending" aneurysm on opposite side of valve stem in photo

tire is easy to seat, uniform around the wheel, tube is partially inflated to ensure no overlapped areas, no folds, etc. No tools used to seat tire on rim. Inflation by floor pump, slow but safe, tire checked during inflation for uniform seating.

reading the forum leads to a possibility this is a deep well rim
1125209-tube-keeps-puncturing-near-spoke-hole-2 (can't do url)

I'm not permitted to post the detailed images/photos I've taken until I reach the ten post count.

I've worked on bicycles since I was a kid in the 70s and up to now, used to think I knew what I was doing. The rim is flawless, no nicks, burrs, protrusions, etc.

I'm considering to buy self-adhesive rim tape, the stuff I used in the 80s if it's available and cut segments to fit between the nipple heads, layering it, maybe even using a hole punch, to fill in the radial gap difference, then put the poly rim strip over it.

Suggestions are encouraged and welcomed.