Mountain Bike Reviews Forum banner
Cancel
Create thread New Forums

What am I missing - Tubeless massive leaking...

Jump to Latest
1 - 20 of 20 Posts
J

jbsmith

· Registered
Joined
·
832 Posts
Discussion starter · #1 ·
Setup my 3rd set of tubeless over the years just the other day. Stan's FLOW EX with some specialized PRO tires. Stan's rim tape and sealant.

Rear tire sealed up just fine, little to no pressure loss overnight.

The front is another story. From onset it had some leaking of sealant around the bead...that seems to have stopped, but it seems to loose about 20psi overnight (pump to 40, down to 20 the next day). Once it looses that initial pressure it seems to hold for a while.

During initial setup I saw no stan's sealant leaking through the sidewalls or anywhere else but at the bead/rim edge. I put another 2oz of stan's in the other day and did a ride around on the streets, and bounced the wheel...still lost 20 overnight.

Tonight I did a soapy water test looking for bubbles...none, none at bead, sidewall, or valve. Hard to soap around the nipples but didn't see anything there either.

:madman: what am I missing - where is it leaking from???
 
Discussion starter · #3 ·
^Man really - daily ride (not complaining) I guess every set is different. The last two sets setup just fine with 2-4 oz of sealant and no riding...even oozed through the sidewalls.

Tape is stretched super tight...it's not doubled - never done that before, but it's overlapped at least 1/4 to not pull off.

I even assembled with a tube at 50psi the first night to set the tape.
 
#9 ·
They all seal the same. The tape has to conform to and seal the rim. The stem base needs to seal against the tape. The entire inside of the tire, bead and tape needs to be wetted with sealant. If it's leaking, one of these three conditions haven't been met.

IMO, it's better and less frustrating to adopt methods that help ensure all three conditions have been met rather than try to troubleshoot a leaking setup.

What I do is thoroughly clean the rim bed with solvent, carefully apply the tape with tension, pierce a hole in the tape, and install tube for a period of time to shape the tire and help the tape conform and adhere to the rim. Remove the tube, dip the base of the tubeless valve in sealant and press it firmly into the rim bed with my thumb while finger tightening the nut. Add 2-3 oz of sealant and enough air to fully seat the beads and then shake/swish the wheel in a way that ensures sealant coats everything. A rough ride will help accomplish this. Additional sealant won't help unless your setup and methodology was so flawed that much of what you put in leaked out.
 
Discussion starter · #10 ·
Lone Rager said:
They all seal the same. The tape has to conform to and seal the rim. The stem base needs to seal against the tape. The entire inside of the tire, bead and tape needs to be wetted with sealant. If it's leaking, one of these three conditions haven't been met.

IMO, it's better and less frustrating to adopt methods that help ensure all three conditions have been met rather than try to troubleshoot a leaking setup.

What I do is thoroughly clean the rim bed with solvent, carefully apply the tape with tension, pierce a hole in the tape, and install tube for a period of time to shape the tire and help the tape conform and adhere to the rim. Remove the tube, dip the base of the tubeless valve in sealant and press it firmly into the rim bed with my thumb while finger tightening the nut. Add 2-3 oz of sealant and enough air to fully seat the beads and then shake/swish the wheel in a way that ensures sealant coats everything. A rough ride will help accomplish this. Additional sealant won't help unless your setup and methodology was so flawed that much of what you put in leaked out.
Click to expand...
Yep trust me I'm not lying here. That is exactly the procedure Ive always followed and did this time - except for the sealant on the valve. So no Idea why this is the only one giving trouble.

On the plus side...it doesn't seem like it lost much pressure last night. Certainly not half like it had been.
 
#12 ·
My experience, when I tape a new wheel to run tubeless, I always install a tube, at least over night and inflate to 30-40 PSI to help properly seat the tape down. When I "punch" the valve hole, I use a nail or philips screwdriver that's heated so it goes through cleanly and doesn't cause tears. Always inflate without sealant to make sure that it's setup properly, tape, valve etc, then add sealant after. I only use Maxxis EXO tyres, they seat the bead easy with a floor pump and will normally sit aired up without sealant no issue, if not, it's normally something minor and once I add sealant, that normally does the trick - this is a very rare thing to need to do for me. If that fails, then a decent ride usually does the trick - maybe somehow something got between the tyre bead and rim bead I didn't see, small error installing the valve.
 
#13 ·
Man, not sure what the issue is, I would probably pull it apart and start again. Never had issues even close to that, and I don't follow any of the other advice to ride around or install a tube first. Mine seal up and hold (Maxxis tires with Flow's). I have had issues after removing a tire where a lever cut the tape, just needed to be re-taped. That is something to check on.
 
#15 ·
A short ride has always been the best remedy for a slow leaking tire that has just been setup tubeless in my experience. Don't start troubleshooting and tearing things apart until you can confirm that it still leaks after a few rides. IF that doesn't cure the leak, then do the dunk test to look for bubbles before tearing things apart or assuming what is leaking. Find the source of the actual leak and address it.
 
Discussion starter · #17 ·
Fingers crossed but I think it sealed last night. Not sure why or what did it but it hasn't lost any pressure. Gonna hit the trails this evening so it'll be interesting to see what they end up at tomorrow am.
 
Discussion starter · #19 ·
Seemed to have fixed it inadvertently. I added more sealant the other day through the valve...I'm assuming by reinstalling the valve core it sealed it up - must have been leaking through the core (i think it was probably just not tight - i didn't clean it or anything.)
 
#20 ·
I wanted to share my tubeless sealing issues and recent solution. I've had trouble with all my bikes since I went tubeless, 4yrs ago or so. I've tried a lot of different things to fix this, many of which are mentioned in this thread, but none has really worked 100%. Recently I've been 3 for 3 with my tubeless success. Previously it was more like 1 in 5 that worked, and never 100%. One thing I think I finally noticed was that when I'd pull a tire back off I'd see the tape was pushed away from the edge of the rim and more toward the center. I imagine that when I put the tire on the very tight bead flops over the rim lip and then slams down on the edge of the tape and proceeds to slip down into the center arch of the inner rim well, taking the tape with it. I noticed on a Stans help video the guy was using tape that was wider than his inner rim width by a fair bit. He also used rubbing alcohol to clean the rim first. Along with the rubbing alcohol cleaning, I recently tried using Stans tape that was at least the exact same width or (ideally) 2-4mm wider than my inner rim and I have yet to have one fail! I'm not even shaking up the fluid afterward! I also notice that the tape is not rolling over like it has in the past. Anyway, hope this helps someone, I know there's probably a thousand ways you can have a leaking tubeless setup, but here's another one for the list! Good luck!

PS, I was always getting leaking around the valve in particular. So this fixed that.
 
1 - 20 of 20 Posts
About this Discussion
19 Replies
14 Participants
Last post:
SonomaBiker
Mountain Bike Reviews Forum
posts
16M
members
534K
Since
1990
A forum community dedicated to Mountain Bike owners and enthusiasts. Come join the discussion about bike parts, components, deals, performance, modifications, classifieds, trails, troubleshooting, maintenance, and more!
Full Forum Listing
Explore Our Forums
General Discussion Downhill - Freeride California - Norcal Shocks and Suspension Passion