Tubeless repair

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Miller
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by Miller

Don't expect this will get to 20+ pages like tubular repair but it deserves a topic.

This spring I've been using Ultremo ZX tubeless in the time trials I've been doing. Last evening on particularly grotty and wet roads on the Bucklebury circuit I flatted and sealant didn't save me, the tyre went right down and I DNF'd and had to be rescued. I repaired the tyre this evening.

Here's the cut on the deflated tyre. It's a sidewall slash, the kind of damage that has been terminal on countless tyres.

Image

The bead was a bit reluctant to come over the rim but not too bad. Here's what that cut looks like from the inside, too big for Stan's sealant to fill. You can see the muckiness of the existing sealant.

Image

I repaired the cut with a conventional puncture patch. Adherence to the inside of the tyre was good and no need to dust the repair with chalk.

Image

Then replenished the dose of sealant, remounted and re-inflated the tyre with a track pump. This is the repair with the tyre at 100psi. It's bulging slightly but not too bad. I've had clincher tyres with this sort of repair and they were stable until I chucked them out for being worn. However it would be desirable to use a repair patch with a bit of mechanical strength. I notice you can get tubeless-specific patches, I might get some of those.

Image

This repair was easy with home facilities. It would be do-able at the roadside, I think, possibly with the help of a CO2 canister for re-inflation.

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AndreLM
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by AndreLM

Thank you for the info. Just one comment regarding inflating tubeless tires with CO2.

I received my new wheels a few days ago (Pacenti SL23 rims, with Stan's rim tape and valve). I did not have the track pump or sealant, but I wanted to see how the tires (Schwalbe One 23mm tubeless) would seat in the rim. Hand pump did not work (obviously), but I had some CO2's around. I inflated them with CO2, but they lost pressure quickly... They were flat after 5 minutes (both).

I then found a track pump a few days later, and managed to inflate them with air. They held pressure much better: still losing pressure, but at "latex tube" rate.

My point is: do not count on CO2 only (without sealant) on the roadside. Maybe a tire with some remaining sealant would hold pressure better, but it is always better to count on a spare tube.


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Miller
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by Miller

I have found air pressure loss when using sealant is very low, like a butyl tube. I feel that sealant is an important part of the tubeless equation.

Geoff
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by Geoff

+1. I have been running a couple of sets of tubeless wheels as part of a long-term test. I would definitely second the notion that sealant is an important part of the benefit of the system. I don't believe in sealant for any system involving tubes, but it sure makes sense in tubeless.

In my personal experience, I do not believe that I could complete a repair like that on the side of the road. I think that the likelihood of me getting that tire off the rim and back on and getting it inflated again is low, as I had enough trouble doing that while indoors with a compressor. If that was me, I'd be on-the-phone, for sure. In fact, I am so confident that I could not do that, I would recommend a tube in your back pocket if you were going out of cell range...

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FIJIGabe
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by FIJIGabe

Having done several tubeless tire repairs, I've got to say that this is a pretty good write-up. In my experience, this repair will outlast the life of the tire, and there should be no negative effects. Now, as for the ability to repair on the roadside in this manner, I'm highly dubious. For one thing, if the leak is big enough, you'll have difficulty getting a temporary patch to hold, especially with sealant-covered fingers and sidewalls. On the side of the road, your best bet is still going to be a tube (and boot, if the damage is big enough), and leave the patching until you've gotten to your workshop.

With regard to the issue of having CO2 seal your tire, I've said it before and I'll say it again: CO2 should ONLY be used to get the tire to initially inflate onto the bead. CO2 has different properties than regular air, and shouldn't be your only source for inflation. CO2 will also leak faster than air, so naturally, you will have deflation issues. In your home workshop, make sure the valve isn't holding the tire from sealing, then hit the tire with a big blast from the cannister, and finish the job up to 120psi with the floor pump. Personally, I will inflate it to 120 to make sure the tire is completely seated, then I let most of the air out (to clear as much of that CO2 as possible), then I reinflate the tire to 120psi and leave it overnight.

Stoo
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by Stoo

Agree on the 'roadside repair'

Took me an age and a whole lot of swearing at home!!!

I always carry tube now.
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efeballi
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by efeballi

Geoff wrote:+1. I have been running a couple of sets of tubeless wheels as part of a long-term test. I would definitely second the notion that sealant is an important part of the benefit of the system. I don't believe in sealant for any system involving tubes, but it sure makes sense in tubeless.

In my personal experience, I do not believe that I could complete a repair like that on the side of the road. I think that the likelihood of me getting that tire off the rim and back on and getting it inflated again is low, as I had enough trouble doing that while indoors with a compressor. If that was me, I'd be on-the-phone, for sure. In fact, I am so confident that I could not do that, I would recommend a tube in your back pocket if you were going out of cell range...

Geoff,
I'm thinking about making the jump to tubeless. I have a Ultegra wheelset which Shimano says is incompatible w/sealant, due to corrosion issues. There was a thread with patches of rust on a DA tubeless wheelset due to sealant.
So, is going tubeless still worthwhile? I'd stick in a tube if there is a flat, and I'm just after better cornering/Crr, not indestructibility.
A little off topic I know, but didn't want to open a new thread.


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FIJIGabe
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by FIJIGabe

Shimano is really warning you to stay away from Stan's sealant (and actually, older Stan's sealant). The problem is that Stan's used ammonia in their formula, which are away at the aluminum material. If using Shimano wheels, I'd go with caffelatex, Orange seal or Bontrager's brew. Personally, I use a custom brew of 3pt Stan's/1pt Slime, but I'm using a carbon clincher, not aluminum.


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efeballi
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by efeballi

Great info. Tubeless goes into shopping list.


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Geoff
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by Geoff

Well, Stan definitely says that his sealant will not corrode your rim and that examples of corroded rims on the 'web' is not down to the use of the sealant, but from other environmental factors.

I can say that, from my own limited experience, I have seen no evidence of any corrosion on either of Campagnolo or Shimano rims. Now, I am also informed that both of the Campagnolo and Shimano offerings include a coating on the inside of the rim to deal with corrosion issues, so...

Anyway, I am running Stans in my test. I am running Specialized and Hutchison tires on sets of Dura-Ace and Shamals. Before anyone asks, the reason I am running those is that they are commonly-available, purpose-built factory offerings (as opposed to hand-built wheels on 'converted' rims), mot because I didn't pay for them. For tires, Hutchison was an early leader in the establishment of road tubeless. As for the Specialized, they have an interesting variable casing/tread size (25/23mm) and...ok, you know why I'm running this stuff.

So far, the tubeless system seems to be pretty stable. It seems to tick-off a lot of different boxes as a training tire system. Barring some big mishap this season (which I may have just jinxed, thanks for that), they seem to be a pretty good option.

mattr
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by mattr

That patch will (possibly) fail. As the mechanical strength of a patch is actually quite low.
Depending how much/many of the carcase structure/threads have been cut, I've tried repairs of about that size and ended up with patch poking out through the hole.
See if you can find some moleskin, it used to come in puncture repair kits to act as a glueable tyre boot. Can fix much bigger tyre damage with them. Alternatively cut some small pieces out of a worn out race tyre and use them.

Svetty
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by Svetty

Agree c Mattr - not sure I'd be confident that sidewall gape won't worsen. It's a bugger when newish tyres sustain terminal damage but sometimes you just have to suck it up. Might be worth trying a proper boot on the inside and then running it with a tube to get a few miles out of it but I'd get a new tyre if that was mine...

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FIJIGabe
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by FIJIGabe

Patches are pretty well regarded in the tubeless community. Most of the manufacturers actually recommend patching your tires, and even if it does fail down the road (literally and figuratively), you can just re-patch the tire. I've patched my tires countless times (I ride on some of the worst road conditions out there), and have yet to have a patch fail (even on sidewall patches).

With regard to the sealant and corrosion, I have seen, first hand, the results of Stan's and a Shimano DA7800 C-24-TL (tubeless). The corrosion does happen. The annodizing (that's the coating you are talking about) does help, but it isn't impenetrable. Personally, I'd stick to Caffelatex in those cases, since I know they've never used ammonia in their recipe (that's the problem).

defride
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by defride

I'd be wary of riding a sidewall repair as big as the one pictured on the front. I've no great problem in riding a repair of this nature, I have a repaired flint hole 1.5mm or so in Ultremo's and it's been ok so far. However, I had a similar sized sidewall tear on my MTB a while back, fixed it in the same fashion and it failed. The patch stuck no problem but the pressure blew through the patch with a very loud bang while descending at speed, that was at only 28psi.

tnc1970
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by tnc1970

system described work a treat, you can repair the tubeless thing ok. If you're not comfortable about the cuts (I'm not) you can use some shoegoo to fill and repair the outside.

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