[Closed] Sweaty tyres (tubeless)

I'm currently running a brand new Specialized Fast Trak on the rear of my XC bike. Its been sweating and bubbling for the past month. It has sealed properly so it isn't losing air (at least not quickly) so not sure what is going on. I've found that its much worse if I leave it out in the cold garage.

I had a Purgatory Control tyre that did the same thing for a week but eventually sealed. I'm hoping this one does the same.

Yeah i get that, i thought it was condensation on them until this thread.

Being new to tubeless this sounds interesting!

Posting to keep an eye on the thread. 😉

My conti der baron projekt does until it has managed to sweat out all the sealant and then it goes down pretty quickly. Bloody useless thing. About to be replaced with a Maxxis DHR II as the shorty on the front has been perfect. But re the warmth thing.....bizarrely the baron stayed up fine during the summer but during the cold winter months it sweats. Bike is in the shed.

My conti der baron projekt does until it has managed to sweat out all the sealant and then it goes down pretty quickly. Bloody useless thing. About to be replaced with a Maxxis DHR II as the shorty on the front has been perfect. But re the warmth thing.....bizarrely the baron stayed up fine during the summer but during the cold winter months it sweats. Bike is in the shed.

I have a friend who gave up running tubeless on his Conti Xkings because they did the same thing.

The Conti website says to clean the tyre with isopropyl alcohol and then brush sealant on the tyre before mounting. Might have something to do with the release compound they use on the tyre moulds?

I have Conti mountain kings on both ends; front one is fine; back one sweats a bit but as long as I pump it up now and again it's copable with.

My conti's have generally deflated gradually if left for a few weeks, but seem to be holding these days.

Spesh purgatory on the back of one bike has been grazed a bit, but always sweats, clear looking fluid, but it sweats, and doesn't lose much air from what I can tell.

I've had a few tyres that did this - some Conti Race Kings were the worst, also some spesh Ground Control.

I think it depends on the sealant. I didn't used to get it with Stans, but I was forced to buy some emergency Bontrager stuff and, with the same tyres (Schwalbe), it dribbles loads. Greasy marks on the floor.

No difference in performance, but I'll switch back to Stans next time to avoid puddles.

core - Member 
but always sweats, clear looking fluid, but it sweats

Yeah, same clear liquid, slightly sticky. Stans on the inside remains the milky looking latex.

Hmm, interesting. Especially Conti's being common here 😀

WTB Trail Boss and Bee Line here, both get a wipe down periodically, don't see it as a major issue and no air is leaking.

Interesting. My seepage was definitely white so must have been just sealant. That was with café latex which I've never had issues with before. As above the conti mountain king I bought at the same time never had any issues until I ripped a hole in it.

I'm currently running a brand new Specialized Fast Trak on the rear of my XC bike. Its been sweating and bubbling for the past month. It has sealed properly so it isn't losing air (at least not quickly) so not sure what is going on. I've found that its much worse if I leave it out in the cold garage.

Replace Fast Trak with X-King and I have exactly the same - suspect we only notice it more in the cold because it doesn't evaporate off so easily.
Its not the cleaning the tyre thing as it started doing it after about 18 months on the bike. Doesn't seem to be doing any harm so i'm not too worried.

Happens to me too. Maxxis Advantage noticeably - and that's despite being kept in a (attached) garage. Stans fluid but the weepage isn't milky.

I'll email a pal who works at the Rubber and Plastics Research Institute and ask him what's going on.

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Check the sweatyness.

I have some 2.8 rocket ron doing this at almost every knob. Clear liquid sweat.

Spesh Slaughter Control. Grrrr. Major incontinance. (Not my real name)

I've got a sweaty Ralph, using Stans sealant. I'm thinking some component of the sealant attacks the rubber over time?

My pal at RAPRA (Rubber And Plastics Research Association) says:

"I do not know what rubber type is used for tubeless cycle tyres but it is common with a lot of rubber types to have some sort of oil extender or plasticiser to give the material more flexibility or maintain flexibility when cold – it is possible that it is the oil extender that is sweating out, rather than the latex. Remember that the latex is present to give a seal between the tyre and the rim and this should set to a flexible rubber itself (not remain liquid) – if the latex was sweating out, it would be sticky and should go solid. No idea whether this is the explanation but sounds reasonable to me!"

it is possible that it is the oil extender that is sweating out, rather than the latex.

But as he says, sweating latex would bead then solidify into granules on the surface, wouldn't it? It would also be opaque not transparent as you've observed. This guy is a PhD in polymer science!

The stuff I see is clear, though is slightly sticky or rather oily.

I had a customer in Nigeria who was moulding shoes out of recycled PVC and he was using ordinary engine oil as an extender and softener. Boy did they stink!

Stans say this;

Unlike other tire sealants, Stan's Tire Sealant is a very thin, low viscosity liquid that coats the inside of the tire and carries with it specially formulated sealing crystals

I still reckon it's this "carrier" fluid (or that something in the tyre is reacting to it) or it would common on non-tubeless tyres too.

My Maxxis High Rollers also sweated when they first had sealant put in, now the sealant seems to have 'soaked in' to the tyre and sealed it, they sweat less.

A simple Google found this about high aromatic oils:

"HA oils are not chemically bound to the rubber. They tend to leach from the mixture and migrate into the surrounding environment."

The stuff I see is clear, though is slightly sticky or rather oily.

I get this, I suspect it is the carrier fluid and the latex particles have been left behind.

Given that it is weeping out of the rim joint I'm pretty sure it's not coming from the tyre, but rather the sealant (Stans).

Yes, maxxis hr2 both set up exactly the same. Front is fine, rear weeps constantly despite top ups with stans. I just assumed it was possessed

mark90 - Member 
Given that it is weeping out of the rim joint I'm pretty sure it's not coming from the tyre, but rather the sealant (Stans).

I get from both the bead and some on the sidewalls too. Sometimes tiny foam spots but then just leaves wet patches when they dissapear. The tread also has various spots although seems to be at the base and I think maybe the stuff has dripped down and collected at the base.

Anyway, interesting stuff this. Thought I just had a unique weird thing going on. 😀

I get from both. Some along the bead but some on the sidewalls

In my case it's not the bead, but the actual pinned rim joint (yeh I know sealant shouldn't get there if the rim is well taped).

So in this case it can't be the rubber extender.

If it was a filler coming out of the rubber itself, you’d see a change in the rubber’s characteristics over time and that’s not consistent with my experience of sweaty tyres. I think there’s a much more mundane reason – it’s the liquid element of the sealant working its way through the imperfections of the tyre and all the little punctures that it seals but you don’t notice.

Most of my tubeless ready tyres don’t sweat at all when they’re new and get progressively worse as with use, reflecting the accumulated damage from punctures, but also minor separation of elements of the carcass (bear in mind the tyre is a composite of fabric and rubber layers) – some minor separation is going to occur through deformation under normal use.

Pure latex without adulteration is about 60% water and we all know it dries out over time. How do you think it dries out? It has to go somewhere and it leaves through the tyre.

It’s slightly oily because there are additives like a bit of glycol to help with freeze resistance.

IME glycol based sealants are notably worse for sweating, but how much a tyre sweats depends on the method and quality of its manufacture and how much of a hard life it gets. I don’t think it’s coincidental that my rear tyres sweat a great deal more than my front tyres

Could you collect enough of the "sweat" to identify it as water?

Been seeing this for ages (using various Maxxis TL and non TL tyres) and seems to appear after tyre been used a while. My bikes live indoors so wondered if nice warm centrally-heated environment encourages the fluid migration through sidewalls.

The only tyres not currently oozing jiz is OO ChunkyMonkeys and Smorgs.

Well, the partial pressure of water vapour will be greater with higher temperatures - it's the reason your clothes dry quicker when they're on the radiator. I don't know whether that transcribes through to greater mosture transfer through the tyre, but I would have thought so.

Tyre rubber will be slightly less dense at 21c than at 3c won't it?

I frequent Cycle Chat, which is more roadie and a few on there are going tubeless so I'll ask if anybody has seen this with road tyres.

I was worried about my sweatfest rear Nobby Nic and happened across this thread...... Think I will just stick with it now 😆

My tyres have been sweating like a bastard, much like me in this weather...

Never had this until I set up a Chronicle tubeless.

It's odd that fluid can leak out but air pressure doesn't drop.

^^^ yes, I find that odd too, air molecules are smaller than fluid, so if the fluid gets out.....

Glad it's a common problem though !