Joined: Jul 2005
Posts: 1,341
Likes: 1
From: Orange Park, FL
Bikes: Ever changing..as of 2-24-09: 2003 Giant TCR Team Once, Sampson titanium, 1992 Paramount Series 3, 2003 Cervelo P3, 70s Raleigh Record fixed gear, 70s Fuji SL-12 commuter, mid 90s Klein MTB. Plus two or three frames lurking, plus 5 wife/kids rides
You can improve the weatherproofing of the old PTs with some work. First, make sure it has both the inner and outer o-rings present, as well as an o-ring on both screws. If it doesn't, remedy that first. Then, you can use a good layer of grease around both the inner and outer lips of the caps to seal against the o-ring. They didn't design the o-ring seal very well; it doesn't have a groove to capture/compress the o-ring, but the grease usually seals it decently.
Finally, if you really get annoyed, you can caulk the cap with clear silicone..that worked very well for me and I'd just cut the silicone when I needed to pull the cap to change batteries.