SlinkyWizard

I was riding , and suddenly, I heard a hissing / brushing sound from behind me, at first I thought a leaf had got caught in the spokes,

I decided to stop and take a look, and while slowing down, and glancing at the back wheel, I noticed fine sealant spray coming from the back tire, ( almost looked like aerosol spray ).

I immediately knew I had a puncture, coming to a stop, rotated the back wheel so the puncture was at the bottom, and a few seconds later, rotated the wheel to check that the sealant had done it's job, which it had. NO more sealant spraying from the tire. ( the sealant had managed to spray the back of my pants, and the seat post. )

At this point I wasn't sure what to do, should I ride home?, or wheel my bike back?, I wasn't very far from home, so decided to wheel my bike back for these reasons

1. I read to make sure you have tire pressure between recommended limits, and I was sure the tire was below the recommended 85psi minimum level

2. If I did ride the bike, would my weight have then blown out the seal the sealant created.

Tomorrow also brings it's own set of problems that I'm hoping someone here can help me with. I need to take my bike to the bike shop,

should I pump the tire up to 85psi? ( i'm scared the tire might pop where the puncture is )

Is the bike rideable in this condition?

Do i need a new tire or can I patch up the puncture?

Any thoughts or experiences would be of much appreciation.

indyfabz

The tire isn't going to "pop." Worst case scenario is that the puncture will re-open. I have had punctures that wouldn't stay sealed over 60 psi. The only way to tell if the tire is toast is to inflate it to your normal pressure. If it hold then it holds. If not, then it probably has to be replaced. Not sure why you didn't try this on the road.

mrFreel

Sounds like the tubeless system did its job perfectly. The question that needs to be answered is how big was the puncture? My guess is that it was small since it seems to have sealed quickly.
I wold suggest pumping the tire back up to pressure and seeing if it leaks. If it does not then take it for a ride around the neighborhood to test it and regain your confidence in the tubeless nature of the tire.

Assuming that it holds air then I would consider what would have happened if the tire had contained a tube. You would have patched the tube and taken a look at the tire to make sure there was not something in it to puncture the new tube. After that you would have ridden away to finish enjoying your ride. To put this into your situation, the sealant has patched the leak, kind of like putting in a new tube, and if all looks good then go on and enjoy your ride.

Koyote

"should I pump the tire up to 85psi? ( i'm scared the tire might pop where the puncture is )"


I'm new to tubeless, so someone correct me if I am wrong: isn't 85psi too high? I thought I had read that you really should keep tubeless tires under 60psi, lest the tire blow off the rim.

Also, at 85psi you are missing out on one of the advantages of tubeless, which is the softer ride and better traction of lower psi.

superpletch

I would inflate to usual pressure and inspect area that was leaking. If the puncture was large enough to hear and spray out sealant I would recommend either plugging with a tubeless plug or dismounting and installing a patch on inside. If the tire is gashed or torn I would replace tire.

It sounds like the tubeless system did it's job and sealed up while you were on your ride. I would have ridden it home. I had a drywall screw enter tread area and come back out through sidewall causing two holes. The hardest part was removing the screw from the tire, but sealant sealed both holes and I was able to rede home.

even though your tires are tubeless, you should still cary a tube for major punctures that wont seal, and a pump to inflate. Same as you would with a regular clincher tires with a tube. Odds are you will never use it, but it sure beats walking home.

Anyone who rides any distances regularly should learn how to dismount a tire and install a tube, it is quite simple and only takes a few minutes once it is learned.

jitteringjr

I am riding Mavic tubeless and they say the max pressure tubeless is 85# on my rims. I like to ride around 70#. I wonder if the OP is mixing up max and min pressures.

superpletch

it wont pop (probably). wear safety goggles if you want.

tire pressure in a tubeless tire depends on size of tire, and rider weight among other things. I will run my 700x25c tubeless tires anywhere from 60-100 psi depending on where I'm riding, my 700x35c tires I run from 35-85psi, again depending on riding conditions.

Koyote

What's the point of those higher pressures, given that they don't offer measurably less rolling resistance?

superpletch

my weight

Koyote

Okay, you got me there.

Metieval

heavier riders will see a better rolling resistance from a tire with a stiffer side wall. a touring tire.

bogydave

FYI
There are some tubeless tire repair kits out there for bikes.
Google or check with LBS
There is a thread here about tubeless bike repair, kits...., not sure the link ??
Can also carry a tube in case the puncture don't seal

SlinkyWizard

I'm running Gavia AC1 tubeless 700x28, and the psi recommended is 85 -115

so I pump up to 100psi before every ride.

I will pump up the tire to 100 today, and if all is well, will still take it to the LBS to get it checked out.

Thanks for all the advice,

jitteringjr

That seems unnecessarily high for a tire that wide. I wouldn’t go higher than 70# for a 28, more like 60# but I weigh 170ish

SlinkyWizard

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From what I've read about tubeless tires, they should be inflated between the recommended psi values?

jitteringjr

It doesn't help that Giant's website is completly useless in that they refuse to post any information regarding specifications on pretty much anything, but the manual for the wheels lists them as UST which is a Mavic standard.

https://www.giant-bicycles.com/_uplo...16-English.pdf

And the specs for my Mavic UST wheel shows the following specs for wheel pressure:

Max. Pressure tubeless: 25mm 6 bars - 87 PSI, 28mm 5 bars - 70 PSI. Max pressure tubetype: 25mm 7 bars - 102 PSI

https://shop.mavic.com/en-us/comete-...html#1028=3283

So Giant is claiming 85# minimum pressure on a tire specked to the same standard as Mavic's which is saying 70# max. So Giant's minimum pressure is 15# higher than Mavic's maximum.

I wonder if the 85-115 doesn't mean 85# max in tubeless and 115# max with tubes. That would put it more inline with Mavic's specks above.

Did you get any actual manuals with the bike or tires that either confirm this or counter this?

rollagain

I can't believe I'm seeing people arguing against manufacturer's recommendations.

pesty

@SlinkyWizard- Honestly, you'd probably be just fine running it at only 85lbs. I weigh about 215lbs and I don't inflate 25c tires past about 90 or 95psi when running tubeless. Probably subtract about 10psi from that for 28c, and you *should* be able to go lower if you weigh less. I have had 25c tires handle going below 60psi on me before, they may be squirmy, but they'll hold. The big worry below that is bottoming out and damaging the rim, or having the bead get unseated. I would be extremely surprised to see the latter of those happen at anything above 30-40psi. I'd just add maybe 1oz or so of sealant to it and treat it like nothing happened. Worst case scenario, the sealant doesn't hold and you get sprayed with sealant again. If it doesn't hold, try a plug, or take it off clean it really good, and glue a large rectangular tube patch over the hole from the inside.

That is definitely true on the pressure limits/recommendations for larger volume tires, like CX and MTB, but the sealant should still hold above that in road tires. I've had sealant hold at 100psi with no issues, it really depends on the size of the puncture. Generally, I subtract 20 or so psi for tubeless. For example, I'd typically run 25c around 110-120psi with a tube, so I run 90-95 without (as I mentioned, I'm about 215lbs, so I tend to run higher pressure). 80-85 should probably be just fine for a mid-weight rider on a road tire.

I'd put money down that Giant's recommendation is when using tubes. I personally wouldn't go any higher than 85psi with 28c tires running tubeless. As you are putting different stresses on the rim when running tubeless than when using tubes, and even more so with higher volume tires, I'd have concerns about putting 115psi into a 28c tire without using a tube.

jitteringjr

Its more arguing over what the recommendation actually is. Very often English translations from oriental languages is lacking. No where can I find the word 'minimum' is any of Giant's manuals here and even then the manuals are very generic on to which product and product line they actually apply too. In fact I would say Giant's documentation is the worse I have ever seen of any brand and I'm getting to the age where I have seen most brands.

asmac

I've been riding Schwalbe Almotion 700/38 tubeless for about a year using much lower pressures than before. Though I qualify as a superclyde and often carry touring loads I now ride at about 60lb in rear and 50 in front. The tires are rated at 80lb max but 60 gives a very nice, easy ride without any problems. In the past I would pump it to the max plus some. Tubeless means no pinch flats and good tires means low rolling resistance at lower pressures.

SlinkyWizard

No manuals came with the bike, I would ask the local Giant dealer here, but I'm not too sure they would know either.

Btw, I did check the tire for anything stuck in there, couldn't see anything, pumped up the tire to 100psi, and heard a dreaded hissing sound, and saw sealant and air leaking from the tire. I took the bike to my LBS, the guy carefully looked at the puncture, and found a tiny piece of glass, after removing it, he added more sealant, pumped the tire to 100psi, and the sealant did it's job. I have ridden 50km? since then, the rear tire is holding up well.

After reading this thread, I am confused as to what pressure to run these tires, I will lower the psi to around 90, and hope I can confirmation on what pressures are the right ones.

asmac

There is no exact technical answer re tire pressure. Within reasonable limits, it depends on tire size, weight carried, road/trail surface and rider preferences. As I said, tubeless permits lower pressure due to the (almost) impossibility of pinch flats. Try different pressures and see what works for your circumstances.
Also, with tubeless it's not a big deal to leave something in the tire such as a bit of glass. It becomes part of the seal and there's no tube to poke.

SlinkyWizard

After much checking on the internet to look for tire pressure with tubeless tires, I found this video from Giant,


4.50 mark explains allowed tire pressures.

b88

You can inflate the Gavia AC1 to within the recommended range. As per Giants manual, inflating the tire to near it maximum recommended pressure gives the lowest rolling resistance but produces the harshest ride. Go out and purchase a dynaplug kit.

IRideWhenICan

Hello,

I am new using tubeless.
I started using a new Mavic Comete Tubeless Wheelset and in my 4th ride, I did hit a rock on the road and the Mavic Yksion tire that came with the wheels got a tear on the side wall.
When I inflate past 60psi, air and sealant come from that area on the side wall...
The tire is useless, Right?