Road Tubeless: Teach me please!

Equipment
1

I’m new to road tubeless and I need advice from someone experienced. The internet is stuffed with unhelpful polarized opinions and even my LBS can’t give me a decisive answer. Your help would be appreciated! Here it goes :

I managed to get a sub-millimeter puncture on the middle of sidewall of a 6 weeks old Zipp Tangente RT28 tubeless tire mounted on the new Zipp 303 Firecrest MY21 tubeless rims, after rolling on a 1 inch diameter rock with sharp edges. I’m using Stan’s NO TUBES regular latex-based scellant.

Upon impact, the tire completely deflated and the scellant did not provide protection. It’s unclear to me if the tire “burped” or if the air escaped from the puncture, but it was fast. I stopped, removed the wheel, held it horizontally with the puncture facing down, and shooke it slowly sideways so the scellant could do its job on the sidewall. I finally managed to reinflate the wheel (I was keeping it vertical when inflating) to an acceptable pressure using a 6 inch-long “ultra-mini” pump (I avoided using CO2 not to wreck the scellant), and rode 500 meters before having to stop again. I repeated the process, and this time I was able to make it back home (about 8 km).

The tire had deflated quite a bit upon arrival. Did the same process again, but this time with a track pump. Pressure held well, so I decided to give it hell to make sure it was safe by hopping with the bike 5-6 times. The scellant plug popped out. Did the process again, hopped about 10 times with the bike. This time, the puncture remained sealed and pressure held well.

I then went for a 120 km ride with the same tire. I left with 57 PSI and came back with 54 PSI. Zipp recommends 56 PSI for the front wheel for my weight.

But now I’m nervous : I have a 200 km gran fondo coming up in a week, and I’m scared to ride the same tire.

When reading about puncture protection provided by the tubeless system, my story does not correlate. I must have been doing something wrong. I thought about it a lot, and read everything I could find on the subject, and came up with a few hypothesis of what went wrong :

Hypothesis #1: Scellant could not coagulate due to lack of pressure drop

This is my main hypothesis. My mini-pump is ridiculously small and provides a microscopic volume of air for each stroke. I thought the mini-pump would do the job just fine since these tires have to be inflated at very low pressure so I could minimize what I carry. Is it possible that the scellant could not coagulate properly because air mainly escaped from the bead and did not produce any pressure drop where the puncture was? Additionally, when trying to re-inflate the tire, the ridiculously small pump I was using, although capable of bringing the pressure up in the tire, could not create the pressure drop & evaporation required for coagulation?

Hypothesis #2: Since the puncture is in the sidewall, I should have inflated the wheel while keeping it horizontally?

Not much else to comment on that, other than using the track pump seemed to have been more efficient at making the scellant do its job. However, this was also after spinning the wheel for 8 km. In any case, I’m looking for a method to get me out of the woods when I’m 4 hours away from my hotel room / home.

Is it safe now? Can I ride 200 km on the same tire or should the tire be retired?

Now that the sidewall puncture is plugged, and that the tire is holding its air, is it safe for the grand fondo? I do have a backup tire I could install, but then I’ll have no spare and I would be replacing an almost brand new tire that now seems to perform properly. I’ve read conflicting information about retiring tubeless tires once the sidewall is damaged. I’m not sure what to do anymore.

P.S. Yes, I do carry a tube and CO2 but that’s not what I want to discuss here.

Your input would be greatly appreciated!

2

You’ll always struggle with a sidewall puncture. Just like a car, they’re generally un-fixable.

Get a new tyre and move on.

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3

You can get rubber patches that you cement from the inside - hutchinson rep’air for example. These are way stronger and permanent than any plug or sealant.

I’d do that and ride it a couple times before trusting sealant alone on a big event.

Lots of people swear by dynaplugs as fixes that are good for the life of the tire on small punctures, but being a sidewall, I’d lean towards a full inside patch to be safe.

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Ps - you said sub-millimeter - do you mean sub-centimeter?

If you are close to a cm, probably a different answer… But if truly less than a mm, very surprising you have any problems at all!

5

If you had to plug it I’d replace it. The only time I’ve used a plug it was goo for circa 30miles at speed but it then started to fail often.

Edit: I’ve just remembered I use a plug on a mates TT disc and he was good for a 20min 10 but I don’t know if he replaced it after the race.

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Please don’t, I have thousands of miles on a tire that I patched after a significant sidewall puncture.

I agree the advice on this on the internet is pretty sketchy but this is an easy fix.

I carry a patch kit with my C02 cartridges and a small section of microfiber towel for roadside repairs and it has yet to fail me.

Follow these steps and save yourself the $50-$80 for a new tire.

  1. Identify the location of the cut/hole in the tire
  2. Use whatever technique you use to pop the tire off of one side of the bead at the location of the leak.
  3. Use the microfiber to wipe off the sealant around the area of the puncture on the inside of the tire. Don’t over think this, it’s easy and you can probably skip this step but I do it because it’s easy and it’s never failed me.
  4. Open the glue from the patch kit and smear some around the area slightly larger than the patch
  5. I wait 30 seconds and check to see if the glue is dry/tacky
  6. Peal off patch and place over the hole
  7. Air up the tire
  8. Ride as if you never had a puncture

Worked for me on this for another few thousand miles…

image
image1536×2048 731 KB

Here is the patch kit I use…

https://www.amazon.com/Park-Tool-Vulcanizing-Patch-Kit/dp/B01F9EG2E4/ref=sr_1_3?dchild=1&keywords=park+patch&qid=1600028721&sr=8-3

I do this on mountain and road and have patched a bunch of tires, never an issue.

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You put the patch on the outside of the tire? I thought they were supposed to go on the inside. Not arguing with you – I have zero knowledge of the issue – just trying to understand.

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No you place it on the inside.

That’s why you pop the bead on one side so you can access the area that is leaking. Wipe it dry, you can rough it with the sand paper that is included but I don’t usually on sidewalls, spread the glue, let it get tacky, put on the patch and pop the tire back on the rim.

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@hvvelo and @Stringwise, thanks for suggesting the inner patch method as a way to save the tire but also, as a roadside repair possibility. I always thought of this as a “shop-only” repair for some reasons.

The puncture I had on the sidewall is less than a millimetre (very small). Scellant might be capable of addressing it right now just because it’s so small, but as described above, it took a while to plug the hole. As @PTC mentioned, it seems valid to say that one’s can’t rely on sealant-only for sidewall punctures and this may be a reason for replacement.

I’m glad to know that with some structural reinforcement, such as using the patches, you can give the tire a second life. These tires are great but really expensive, so saving them makes sense money-wise.

The only reason I’m running the Zipp Tangente RT tires right now is that there isn’t many models out there that can be trusted and from which the manufacturers have confirmed compatibility with hook-less rims. I prefer playing it safe and using Zipp on Zipp for now. If anything does not go as advertised, Zipp should be capable of explaining why!

It’s becoming apparent that I should take the tire off before the event, install the spare brand new one, and fix the sidewall with a patch once the punctured tire has been cleaned-up. That sowed-up tire is going to become my new spare.

Does anyone have comments on the usage of the mini pump vs a track pump and pressure drop for sealant coagulation? Or is this a non-issue since the pressure drop/ instant coagulation should always happen when the thread is punctured while the wheel is spinning?

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See the picture attached.

@hvvelo I just re-read your reply. For very small puncture, are you saying it could be ok to trust the scellant?

sidewall
sidewall1512×2016 1.07 MB

11

I would totally patch that. Unless you are running super wide wheels and low pressure, I wouldn’t trust sealant with that one personally. Patch and it you will forget about it forever.

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100% agree with this. I sliced a Gravel King sidewall and used this method to seal an 8-10mm cut. Give the glue time to get tacky, slap the patch on it, and let the sealant do the rest. Mine has held up on long miles, mountain bike trails, pouriing rain, and all other sorts of brutal crap.

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Sorry, I meant that if it’s that small, you should be very well protected with a patch. If it was a cm-size cut, I’d be a bit more worried, but that tiny puncture should be great with a patch!

I also carry the patch kit on my bike and figured I could do it roadside in an emergency, but fortunately have never had to use it.

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I thought I had read on this forum that Stans sealant is not optimal for road tires due to the higher pressure?
I gave up on tubeless after too much faffing about🙄

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Best combo that I use and have absolutely no problems with is Stans Race Sealant and Dynaplugs if you need them. Tricks are shake the bottle and quickly invert into the tyre. Just pull a small part of the tyre of the rim and tip it in, don’t put it in the valve. Looking at that hole you have in the side wall it is nothing and should be fine with any sealant. My guess is that the sealant is not getting to it, so I would remove the rim from the bike, pump the tyre up then spin it on the horizontal a few times and leave it on the horizontal overnight or for a day or two…I am tubeless on road and would never go back. Yes there is an art to tubeless but once you know what you are doing, fixing punctures is a thing of the past.

Key items to have:

  • Good sealant - I recommend Stans Race, I have never had a puncture that it couldnt fix but it is a PITA to have to put it in the tyre. Remember just remove a small part of the tyre off the rim. the put it back on.
  • An awesome track pump or a bottle inflator - i use the Schwalbe Tyre Booster and it is a godsend rather than getting hot and sweaty and sealant everywhere.
  • A good plugging solution - Dynaplug Megapill for me.
  • Refresh your sealant every 8 - 10 months - once you get good at this it will take you 20 mins.

Just my views and I am sure that many people on the forum might have differing ones but this is what has worked for me…

Good luck, stick with it.

1 Like
16

As said above, if the sealant doesn’t patch the puncture sufficiently, you can patch the tyre from the inside. I just use normal tube patches, but let the dry on overnight at home, not sure if you could do that roadside (It might depend on the tyre too, the ‘glue’ solution might not vulcanize the tyre enough).

Also sometimes you just need to put more sealant in to make it seal, there might not be enough left after a new install.

It shouldn’t matter what type of pump you use, and co2 should be fine for getting home too (just not long term with some sealants).

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I think the only real potential problem with tubeless is the slightly higher chance of a failure you can’t sort at the roadside. A moderate puncture that the sealant doesn’t catch might be solvable with an inner tube and/or a patch, but there are some tubeless tyre/rim combos where getting the tyre off is an absolute nightmare (plus potentially re-seating it afterwards).

I suppose the trade off is more frequent punctures (with a tubed setup) but with the safety net of knowing you can fix anything but the most catastrophic rips/tears at the roadside. The longer the ride/the further I would be from home, the more likely it is I’d favour a tubed setup.

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Replace the tire and be done with it. Why mess around with subpar and stop gap solutions that are taking up your time.

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Gosh, where to start… because the solutions are neither “stopgap” nor “subpar”? To avoid wasting resources and littering up the planet more quickly? Because the cost of a new tire is a meaningful expense for some people? Simply to avoid wasting money?

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For me, $5 for a tire boot a 1/2 hour of my time vs $100+ for a new 5K TL (that’s how much they are here) and the same 1/2 hour to replace and will hold up as long as the tire lasts seems like a easy decision.

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