chas58 said:
I decided to have my local bike shop build my second wheel. $40 in labor $25 Weinneman deep V [...]
That's a really narrow rim. So narrow, in fact, that you can get unpleasant symptoms related to crowding two thicknesses of tire sidewall, two thicknesses of tube, and a Presta valve inside the narrow rim channel. I have a few wheels with that rim (the Weinmann DP18, I assume) and a couple with the related but deeper Origin 8 Track Attack.
The chronic kind of flat folks get with the DP18 and similarly narrow rims happens when a relatively thick-walled city/utility tire (or cheap tire) is mounted on it. After mounting the tire, the sidewalls pinch up the valve of the tube so that it doesn't sit on the rim bed. Inflating the tube just binds everything up more tightly, and still the valve does not come down and sit on the rim bed-- but the tube bubbles out on either side of the valve, to fill the void underneath it. Sooner or later one of these bubbles pops, and you have a sudden puncture that can be difficult to patch due to its proximity to the valve.
When using a narrow rim like the Weinmann DP18, remember to pull the valve all the way down into the rim channel before inflating. If it won't come down, pop it out and moisten the area around the base of the valve with something (spit, if you're out in the dust somewhere) to make it slippery enough to pop down it there. A little shot of silicone bike polish or Armor All would do the job, and endure long enough to remain a little slippery at subsequent tire changes.
I would use up to a 40mm or so tire on a DP18 without qualms. Wider than that, I think I'd have to use more pressure than otherwise would be necessary, just to stabilize the tire and keep it from rolling sideways. I used tires up to a nominal 26 x 2.6" on the similarly narrow Matrix Iso-C rim back in the day, but I got spat off the bike a few times as a result.