On Sat, 08 Jan 2005 23:47:40 GMT, "Mike Jacoubowsky/Chain
Reaction Bicycles" <[email hidden]> wrote:
[snip]
Quoted message said:Yep. So much so that Bontrager began drilling small holes in many of their
rims so the water could escape. I'm not sure I understand the mechanism
whereby water can get into a rim so easily yet not get out, but experience
tells me it *does* happen, and the small holes definitely help to remove it.
If you want to see examples, go to a Trek dealer and look at a Bontrager
RaceLite wheelset (found on many of the $1800-$3000 road bikes). They might
be on others as well, but I just physically verified their existence on the
RaceLites.
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
IMBA, BikesBelong, NBDA member
Dear Mike,
If a wheel is submerged in water, water pressure will force
water into the rim through any holes, such as the valve
hole.
If a wet wheel, spoke, or valve is spinning, the film of
water is thrown to the outside--right down the spoke or
valve and into the hole.
But once the water is inside, there's almost no wheel
position in which gravity will force water back out. The
clearance is so small that surface tension encourages most
of the water to drain down to the bottom of the rim as drops
too big to slither out between the valve and the rim or the
spoke and the rim.
Designs that encourage water to get into the rim might
benefit from small but well-placed holes to let it back out.
Carl Fogel