Rims

[nobachi2000]

My rim cracked. My tire was okay, but the brakes were another matter.
When I took off the rim, I found out that it broke where there was a
unwelded seam on the outside that cannot be seen on the inside.  Are
all rims made this way? Just to clarify what I mean, inside rim can be
seen because you can see how the spokes are attached to the rim and
the outside rim cannot be seen unless you remove the tire.

[RussellSeaton]

Rims are put together two ways.  One, a metal spline/piece is stuck between the two ends of the rim and this metal piece holds the two ends together.  Mavic Open Pro rim uses this method.  Two, the two ends are welded together then the weld is ground down, cleaned up.  On the spline/piece method it is easy to see the two ends of the rim opposite the valve stem.  You can see the line in the rim wall.  Welding you probably won't see the ends come together.