Charles Nighbor wrote:
> For the below why couldn't one just place a piece of thin metal with
> the proper presta hole size and width under the rim tape. That would
> convert Schraeder-valve rims to Presta and the air pressure on the rim
> tape and the rim tape would hold the metal pice in place. I suggest
> you try it first.
>
+++++++++++++++++++ Good suggestion, and I did try that first, about 1970. At the time, the issue was a bit different: SuperChamp (58?) rims have a deep center "well", and I had problems with valves that did not sit down in the well. So, used various combinations of metal and even silicone bath caulk to build up the area.
Since then, it seems that Presta valve construction has changed. The base of the valve is more slender, but actually close to the diameter of the Schraeder hole. In the particular instance this week, with another deep-well rim, I did make a thin metal washer adapter, but the hole size that fitted the valve didn't leave side clearance for the washer in the well. The grommet has the drawback of being visible, but the a advantage of being easy to do and very compliant.
So, thanks for reminding all of us of this alternative.
harvey sachs
mcLean VA