Tandem Tom

Abit too cold and icy to ride this afternoon so I thought I would work on our LHT's. The project I had on my list of getting ready for our next tour was to drill out the rims to accomodate Presta & Schrader valves.
I built the wheels up, along with the bikes, this fall using Velocity 26" AeroHeat rims. I emailed Velocity and asked them if I would have any problem doing the conversion. They said no problems. So yesterday I stopped at my LBS, where I still work a few hours down and again, I borrowd a tapered reamer. I decided to pull the wheels and take the tires & tubes off then go down the basement next to the warm boiler and do the work. I started with the reamer but decided to just "creep up" in 1/64" increments until I had the right diameter hole. Then I used a round mill file and emery clothe to deburr the holes. While at the LBS I made out with some "stepped" Presta valve nuts. These keep the stemm centered in the larger hole.
All 4 wheels are done and tires & tubes re-installed and wheels mounted!
A necessary job? I wanted the flexibility to use either Presta or Schrader while touring as I understand it might be a bit difficult to always find the Presta.

robow

For many many years, I did the same thing because at the time most large department and sporting goods stores did not carry tubes with presta valves. Today, it's becoming less of a concern but in the more rural areas, you could still be out luck. When I was in that situation, I would always keep a few very small rubber "O" rings to slide over the presta stem before mounting in the rim to prevent the tube from expanding into the larger opening and being at peril of puncture.

Tandem Tom

I did not think about the tube expanding into the larger opening. I guess I will be removing all 4 tires and tubes and getting some O rings!!
Thanks for the heads up!!

alan s 

Friction tape wrapped around the stem will do the same thing. Won't be able to thread the retaining nut on the stem, but it's not really a necessity.