Mountain Bike Reviews Forum banner
1 - 7 of 7 Posts

·
uofabill
Joined
·
213 Posts
Cracked

I assume you are running tubeless? If you are, I had the same problem and I had a hairline lateral crack at the valve core hole. I am afraid you have a hairline crack somewhere on your rim. Another possibility if you are running tubeless is that your valve stem is not fitting properly or is not tightened down enough.
Stan's sealant will seal it off or you can try thicker gap filling superglue, if you can find the crack.
I have two sets of CrossMax wheels, they are stiff and incredibly light but I have had to give up on them. Deciding that they are ultralight racing wheels and not really suited for hard everyday XC use. I am a clydesdale and on both sets of rear wheels they have cracked around the nipples, on one of the wheels three spokes ripped out on a climb and a fourth one broke at the hub. A friend of mine has a set too and after mine self destructed I looked at his closely and his are cracking around the nipples as well. I hope you have better luck than I did.
 

·
Premium Member
Joined
·
48,238 Posts
nathasm said:
I'll have the check the rim tonight. The leaking is not occuring around the valve stem and is strictly coming from two adjacent spoke nipples. So it sounds like it IS a crack...curses!
.nathan.
It could still be the valve. If it is just leaking at the inside rim wall it would not bubble at the valve stem.
 

·
Registered
Joined
·
232 Posts
Agree with valve stem seal......

My 2001 Tubeless UST CrossRoc wheels started air leaks at the spoke nipples; turns out the inner rim Mavic square rubber washers on the valve stems were shot; I could not get them sealed with superglue, etc. So bought new Mavic tubeless valve stems from LBS at $12 apiece, and problem solved. IMO, this is a major cause of "tubeless tires not holding air overnight", especially in older UST wheelsets. Stan's gives you a false sense of security in that it may partially help seal the defective valve washer, and the air leak slows down. Otherwise, Stan's is without a doubt a major advancement in reducing flats. It also seems the the Mavic tubeless valve stems work on all of their current tubeless rims....CrossMax included. An obvious clue to the valve stem inner washer not sealing is the simple fact that the valve stem turns when trying to tighten the nut against the O-ring and rim, and the valve stem remains "loose". I would like to believe that cracked rims are a much rarer problem! ;)
 

·
uofabill
Joined
·
213 Posts
Like Shiggy said..

nathasm said:
I'll have the check the rim tonight. The leaking is not occuring around the valve stem and is strictly coming from two adjacent spoke nipples. So it sounds like it IS a crack...curses!
.nathan.
On my cracked rim the bubbles weren't coming from around the valve stem. The O-ring in the nut on the Mavic valve stems seals that off. The air leaked out of the tire through the crack on the inside at the valve stem into the inner cavity of the rim and then out various nipples.
Good Luck!
Bill
 
1 - 7 of 7 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top