Zipp 303S filling with water

[GT3RS]

I've had a set of Zipp 303S for a few weeks now and have found them really good. They are not too heavy and a bit aero, a huge improvement on the old school mid section rims I've ridden in the past. I bought them to see how I got on with them before investing in more "premium" options and so far so good. However I've discovered that what I thought was sealant sloshing around is in fact water inside the rims (it rains a lot here) which I'm guessing has got in through the spoke/ nipple holes. There doesn't seem to be anywhere for this to drain out. Has anyone else had this problem?

[alcatraz]

Look for tiny drainage holes on the sides on the rims. If they don't have holes you have to wait for the water to evaporate.

The water doesn't really go in in any large amounts unless the inner edge of the rim is submerged.

Does that happen often? If yes then you might want to look into adding drainage holes. It's a very small drill like 2.5mm I believe and you drill on the side under the rim bed. I'd use a brand new super sharp drill so that the carbon fibers get cut and not frayed.

[GT3RS]

Thanks, I've had a look round the interwebs and it looks like I'm not the only one experiencing this phenomenon with these wheels. Wonder if there's maybe a tiny bit more room round the spoke holes than usual or something. I've got 4 sets of 30 - 35mm carbon wheels and none of them have drain holes that I can see and I'm not aware of them having filled with water before. I think you're right and I might have to consider some diy modifications if it keeps happening. Shame really as other than this I think they're a great pair of wheels for the money.

[trainergav]

My 303S's also fill up with water and I end up standing around shaking the water out through the tubeless valve. The process is made harder by the fact the wheels are set up tubeless and I can't actually just take the valve right out. This is a long and painful process. Pretty sure there aren't any drain holes in the rims themselves.

My Enve 4.5AR's do the same thing but I think that the water only goes in through the valve.

[trainergav]

I've had a set of Zipp 303S for a few weeks now and have found them really good. They are not too heavy and a bit aero, a huge improvement on the old school mid section rims I've ridden in the past. I bought them to see how I got on with them before investing in more "premium" options and so far so good. However I've discovered that what I thought was sealant sloshing around is in fact water inside the rims (it rains a lot here) which I'm guessing has got in through the spoke/ nipple holes. There doesn't seem to be anywhere for this to drain out. Has anyone else had this problem?

PS. I also thought it was sealant until the shop told me it that it was water. Oops.

[GT3RS]

Thanks for the replies, it's reassuring to know that it's not unusual for this to happen.

[WorkonSunday]

how did water get in without air coming out? when i overfilled my 303, some sealant gone to the rim chamber (not the air chamber with outer tyre) and subsequently leak out via valve/rim interface, was that the bit that holds all the water?

[alcatraz]

Air can pass through nipple holes easier than water. So it's not hard to displace the air as long as there is a way in, like the valve stem.

The OP could try to seal around the valve to avoid the water from entering there. That's likely the main point of enter.

[snaxez]

you can try those to get a better seal for valve hole
https://www.bike24.com/p259328.html

[kervelo]

The latest version of 303S has drainage holes to get the water out.

My wheelset from autumn 2020 does not have any holes, but my other set from summer 2021 has holes.

[timbo43x]

I can also confirm the latest model has drainage holes. One hole on each side of the rim at 6pm to the Zipp 303S logo.

I didn't let the bike shop release them to me without getting that confirmation.

[req110]

I have 303s and drain holes are only on front wheel.
I was purchasing front and rear wheel separately within one order from bikeinn. Nevermind.