dr_max

Hi everyone, just installed Zipp 404 firecrest tubeless wheelset and even after adding sealant 3 times to the rear tire the pressure is losing about 1 PSI per hour. I feet the air is leaking around the valve itself.

any tricks you have to make the valve more airtight?

thanks

alcjphil

I am not familiar with those wheels, but most of the time air leaking at the valve is because there is a problem with the tape elsewhere along the rim bed. Once air gets into the hollow rim, it will escape at the valve

eduskator

Yep - it's probably not the valve itself, but a leak somewhere due to poor installation of the tape or a hole somewhere. Just bring it back to wherever you bought them and ask them to fix it. If that's not an option, then I would inspect the tape, make sure it's properly installed, replace if needed, and inspect the valve as well.

dr_max

thanks for the help

they were bought online unfortunately

will inspect it and see if there is a hole that could explain the problem

thank you

Koyote

Probably correct...Though it could be the valve itself if it's not forming a good seal against the rim.

It would help to know if the wheels are new, and whether OP is using the valves supplied by Zipp.

Mojo31

How much loss is normal? Our three sets all loose air overnight to varying degrees, but all in the same ballpark.

I've always topped off air before a ride, even on consecutive days.

msu2001la

1psi per hour means the tire would be completely flat after just a few days. This is not normal.
My guess is the same as others - look at the tape job. It's probably that, but could be the valve itself, particularly if they're not the factory Zipp valves.

FWIW - I'm still using the factory tape on a pair of Zipp wheels that were purchased new in spring of 2021.

Canker

An easy to try trick that works a good bit of the time if it is the valve. Take the wheel off and bounce it with the valve at 6 o'clock so you are splashing sealant around the base of the valve.

Chandne

Tighten the nut at the base of the valve too. If that does not fix the issue, you will have to examine the tape. If you replace the tape, put a tube in overnight, The tube will put huge pressure on the tape and make it much less likely to ever let sealant and air in under it. It squishes the tape down really nicely...far better than you can do by hand. When poking the valve through new tape, I usually cut a very small cross-shaped cut with a sharp utility knife to let the valve poke through. Never had issues this way. You could also burn a tiny hole with a hot tiny screwdriver or something similar but you don't want to take the hole too big. Also, overlap the tape 8+ inches over the valve hole area.

dr_max

thanks I’ll try that

JohnJ80

yeah, could be the tape. Hope it's not because it means taking everything off the wheel, peeling the tape off, wiping the sealant off of everything, letting it dry and then re-applying the tape. The tape is actually the easy part. I'd put my bets on the valve though.

I have had valves that didn't mount well in a given wheel. In fact, for me, it's been a much bigger problem than the tape leaking. My go-to valve/stems now are the Muc-off stems. They come with several different shaped seals so it's possible to select one that matches the rim better - it's shown at the link in a picture. That seems to help. It's also an easy fix - deflate the tire, push the bead past the stem and change it out, then with a compressor re-inflate the tire and reseat the bead. Lots easier than replacing the tape.

You should be able to tell if it's leaking around the valve stem. Put some dish soap in water and put it around the stem. It should blow bubbles even if it's a slight leak.

J.