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Discussion Starter · #1 ·
I looked around on mtbr and the google and didn't find any others with my experience. Usually the report is that dents don't affect tubeless much.

I have a fairly new p35 rim and ardent 2.25 ust on the rear. When I first built up the wider wheel (wider b/c p35), I quickly put a couple of minor dents in it. minor as in you can just tell that they are there, but only if you look for 'em. The newer, wider rim really made bottoming out (at the same pressure as I used with the narrower rim much easier), much to my surprise.

On my last ride the wheel started leaking. If I pump it up to 35-40psi, the leaking stops, but after a couple of miles the tires squishy again and I have to repump. Finally I put ~45psi and it held the rest of the ride, but went flat overnight.

The wheel has new sealant in it and plenty is bubbling out when i rotate it so the sealant flows to the gap, at high enough pressure (>40psi) bubbling stops. I'm using tubeless slime(from autozone, supposedly different from the stuff you add to tubes), which has worked great for me in the past 2 years, even sealing up wide gashes from glass.

Sooo, other than

1) straighten out the dent, 2) rotate tire on rim so new spot on bead contacts tire, and 3) add some more sealant just in case I had too little to start with, 4) maybe sealant that sat for 6 months in a bottle (with almost all the air removed before storage) has lost its effectiveness, and 5) slime isn't the best for mtb tubeless

Any other ideas?
 

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1) straighten out the dent, 2) rotate tire on rim so new spot on bead contacts tire, and 3) add some more sealant just in case I had too little to start with, 4) maybe sealant that sat for 6 months in a bottle (with almost all the air removed before storage) has lost its effectiveness, and 5) slime isn't the best for mtb tubeless

Any other ideas?
due this in reverse order.
 

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Not that this has anything to do with sealing but I think your tire is to small for the p-35. I have them and run 2.4 and have not had any issues with bottoming out at 20-23 psi. I've also had no issues running tubeless with stans and tubeless ready tires.
 

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I've straightened a few dents in my P35 front and narrower Blunt rear, using hand pliers. Go slow and easy to avoid cracking the metal. It doesn't need to be perfect, just pretty straight inside to hold tubeless air. It does scratch the finish, that a Sharpie can touch up, but better than a rim that won't hold tubeless air.

I've always used Stan's sealant with good success. And I've found "ghetto rim strips", a split 24" inner tube and trimmed after mounting, air up easiest and never ever burp.

I did see a rim dent repair tool somewhere in a magazine not long ago. Probably less likely to mar the finish. Maybe Park tools makes one.
 

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Discussion Starter · #8 ·
And I've found "ghetto rim strips", a split 24" inner tube and trimmed after mounting, air up easiest and never ever burp.
I think I'll try this technique. I'm currently just taping up the spoke holes and the tires mounts to the rim. I occasionally get burps, but mostly (until this problem) it works well.

I'm committed to using slime for the moment, as I like that I don't have to go to a shop to get it (and its cheaper), but switching sealant seems to be the last of the low hanging fruit once I've done the rest. I'll try a few things before I bite this bullet.

And I agree with you Jeff that the 2.25 is a bit narrow for the p35. I had hoped to buy a frame that would accommodate a 2.4, but I hate spending the little money that I have :)

Julio, your experience is what I was expecting; the wheel will hold air even with a substantial dent. Your dent is much worse than any of mine.


Thanks for the ideas, y'all!
 

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Discussion Starter · #9 ·
So I opened 'er up last night and saw just thin green liquid and little fiber spheroids.

It would seem that I forgot to shake the bottle of slime before adding it to the tire and all the latex must have been settled on the bottom. I just cleaned it out and added fresh slime (shaken this time). A quick ride seems to indicate all problems solved.

I thought I'd imagined all the possibilities, but nonetheless I found one I overlooked!
 

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I put a small dent/nick in my tubeless rim and used a file to smooth it out a bit, added a little more Stan's and it holds like a champ.
 

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Discussion Starter · #12 ·
You shouldn't need a rim strip with those rims if you're using a tubeless ready tire (TLR). I've used various tlr tires on those rims and have never had a burp at the lower pressures in my above post.
I must have different p-35's than you, as mine take regular nipples through holes drilled through both walls of the rim, necessitating a rim strip.

UPDATE: So I've tried everything so far except using a 24" tube hanging over the bead as the rimstrip. Stan's, new slime, nothing makes a difference, the tire leaks at the same spot. It even seems to be getting worse. Last night I did a 15 mile ride and had to pump my tire from 5psi to 40psi 4 or 5 times. I know I can put a tube in and get a bit more life out of it, but I'm so spoiled never having to fiddle with thorn induced flats anymore.

I'm tempted to contact maxxis about warranty, but the tire is 2/3 of the way through its tread life; a discount on a new tire to reflect this would be great, but I've never heard of a manufacturer doing this. I'm in grad school and paying for my wedding and honeymoon in 3 weeks, so buying new tires is a bigger deal than for most people.

The thing that really convinces me that the tire is at fault is that the same spot(on the tire) leaks even when I rotate the tire around the rim. The tire airs up great, the sealant stops all the leaking, but at some point I hit a bump, disturb the sealed bead and air starts leaking out.
 

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...
The thing that really convinces me that the tire is at fault is that the same spot(on the tire) leaks even when I rotate the tire around the rim. ...
I've repaired tubeless (converted) tires with a hole too big that sealant wouldn't hold air pressure while riding.

Remove the tire, clean and dry the inside surface where the damage is, then super-glue a regular inner tube patch or a snip of inner tube. Let the super-glue cure with pressure or weight on the patch. When completely cured and dry after a few hours, then mount up with sealant.

40psi seems too high for a p35 and tubeless, and sealant has more problems holding air on sharp hits. But if you are denting the rim often then maybe it's required. If you can get away with lower pressures, traction is improved and easier and smoother rolling over rocky and rooty trail.

Congratulations and Best Wishes to your fiancee on your wedding plans !
 

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Discussion Starter · #15 ·
I've repaired tubeless (converted) tires with a hole too big that sealant wouldn't hold air pressure while riding.

Remove the tire, clean and dry the inside surface where the damage is, then super-glue a regular inner tube patch or a snip of inner tube. Let the super-glue cure with pressure or weight on the patch. When completely cured and dry after a few hours, then mount up with sealant.

40psi seems too high for a p35 and tubeless, and sealant has more problems holding air on sharp hits. But if you are denting the rim often then maybe it's required. If you can get away with lower pressures, traction is improved and easier and smoother rolling over rocky and rooty trail.

Congratulations and Best Wishes to your fiancee on your wedding plans !
Thank You!

The problem is that a visual inspection of the tire indicates no problem. It's as if the bead has gained flexibility in one small spot allowing deformation that disrupts the seal created by the sealant and thus leaking. The problem seems even more precise than a stretched bead, as the issue repeatedly arises at a specific spot on the bead.
 

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I must have different p-35's than you, as mine take regular nipples through holes drilled through both walls of the rim, necessitating a rim strip.

UPDATE: So I've tried everything so far except using a 24" tube hanging over the bead as the rimstrip. Stan's, new slime, nothing makes a difference, the tire leaks at the same spot. It even seems to be getting worse. Last night I did a 15 mile ride and had to pump my tire from 5psi to 40psi 4 or 5 times. I know I can put a tube in and get a bit more life out of it, but I'm so spoiled never having to fiddle with thorn induced flats anymore.

I'm tempted to contact maxxis about warranty, but the tire is 2/3 of the way through its tread life; a discount on a new tire to reflect this would be great, but I've never heard of a manufacturer doing this. I'm in grad school and paying for my wedding and honeymoon in 3 weeks, so buying new tires is a bigger deal than for most people.

The thing that really convinces me that the tire is at fault is that the same spot(on the tire) leaks even when I rotate the tire around the rim. The tire airs up great, the sealant stops all the leaking, but at some point I hit a bump, disturb the sealed bead and air starts leaking out.
First congrats on the wedding.

Could you have maybe damaged the bead on the tire when the rim dented?

And for now I would just put a tube in it until you can replace it.
 

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Discussion Starter · #17 ·
First congrats on the wedding.

Could you have maybe damaged the bead on the tire when the rim dented?

And for now I would just put a tube in it until you can replace it.
Thank You.

I think it was precisely this. I inspected it again and though I can't see through the material where the sidewall meets the bead, it looks like air is maybe bubbling out there and not between rim and bead. I took a stout needle and some dental floss and sewed a bunch of stitches across so the hole isn't under as much stress and maybe the sealant will hold. Worth a shot. Tube is next.
 

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Discussion Starter · #19 ·
The p-35 uses rim tape to seal the holes and a tubeless valve, it doesn't need a rim strip with an integrated valve.
ah, I see the discrepancy. To me rim tape is a type of rim strip. a rim strip with an integrated valve is also a kind of rim strip. I've never heard of a rim that you couldn't just stick a presta valve through and tape up, but instead requries a special integrated valve-(non-tape)-strip.

I am only aware of rims that have holes drilled in them for conventional nipples and rims that don't have those holes to make tubeless easier but have some unconventional nipple that doesn't enter from the tire-side of the rim.
 

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ah, I see the discrepancy. To me rim tape is a type of rim strip. a rim strip with an integrated valve is also a kind of rim strip. I've never heard of a rim that you couldn't just stick a presta valve through and tape up, but instead requries a special integrated valve-(non-tape)-strip.

I am only aware of rims that have holes drilled in them for conventional nipples and rims that don't have those holes to make tubeless easier but have some unconventional nipple that doesn't enter from the tire-side of the rim.
Mavic makes such for their UST rims, needing no rim tape. This is their AM/DH rim. Not very wide, about 28mm outer width I think, but very stiff, light, round, and relatively dent resistant.

EX 823 Disc - rims - mountain bike - Mavic
 
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