95 degree heat boom goes the tire

[clyde the point]

I love GK and have used them tubeless for several years now. Have been watching this rear tire for a couple of weeks deciding if it's time to replace. Well yesterday after the ride I rinsed it off and was letting it sun dry. Sounded like the worlds biggest pneumatic nailer when it decided to commit suicide off the rim. It has been quite hot here in Greenville and this thing was sitting directly in the sun. This was a regular GK not the tubeless version that only seems to be available in 32mm. Sealant was Orange, and there was plenty of it inside the tire when it popped. Just an FYI no real statement from me here about this, though I likely should have replaced this tire prior to today! The tire is less than a year old and has several thousand miles on it, however I am not too light. I run 90 in front 95psi in the rear.
https://live.staticflickr.com/65535/50132978136_391fdd64e2_b.jpg (https://flic.kr/p/2jo5BN1)IMG_1989 (https://flic.kr/p/2jo5BN1) by Clyde the Pointer (https://www.flickr.com/photos/148750154@N02/), on Flickr

[SlowPokePete]

Never been a fan of tubeless at high pressure...

SPP

[R3awak3n]

I would not say automatically high pressure. 32mm tires some can run at under 60psi. I run my 35mm at about that and they have been just fine. I agree though I probably would not do tubeless if I have to go much more than 70psi.

Its strange this happened, never heard of a correlation btw heat and tubeless blowing out of the rim. Did you just fill the tires up before putting the bike outside?

[Wattvagen]

This was a regular GK not the tubeless version

this was the problem, ultimately i would say.

[nalax]

this was the problem, ultimately i would say.
Yes and considering that even the 700/32 GK TLC has a recommended maximum of 60psi running tubeless, going at 90/95 was likely a bit of a stretch for the tires. Nice Road Logic!

[slambers3]

X

[2metalhips]

Using a non tubeless tire tubeless at 95 psi is an accident waiting to happen.

[MikeD]

Using a non tubeless tire tubeless at 95 psi is an accident waiting to happen.


Next thing that'll happen is the OP will tell us he's using them on hookless rims.

[R3awak3n]

I did not even read that... 90psi, even on a tubeless tire is an accident waiting to happen.

I know that 65psi is the max recommended by a lot of brands, I know some go up to 80ish but not 90, thats too high. I am not the lightest either and why I don't run tubeless on anything under a 35mm. At 35mm I can get away with 60-ish PSI.


And yes, that is a nice road logic.

[kppolich]

User error here. The sidewall says max tire pressure for tubeless and tubed. 90PSI!!! Yikes

[ColonelJLloyd]

Pushing the envelope, my friend!

Maybe the TL version with ~65-70psi next go round. ;)

[yinzerniner]

User error here. The sidewall says max tire pressure for tubeless and tubed. 90PSI!!! Yikes

Using a non tubeless tire tubeless at 95 psi is an accident waiting to happen.

Can't reiterate the above enough. Using a non-tubeless tire as tubeless while exceeding max pressure, you're lucky nothing happened while you were on a ride. It looks like the tire was a 28c, and there's plenty of different options at that size which are tubeless rated which could replicate or even exceed the ride quality of a GK.

Consider this blowoff a warning shot, and for gods sake run appropriate pressure and tires when going tubeless.

Here's a few resources to dial in your fit.
https://info.silca.cc/silca-professional-pressure-calculator
https://www.enve.com/en/tirepressure/

[clyde the point]

Next thing that'll happen is the OP will tell us he's using them on hookless rims.

https://www.panaracer.com/lineup/gravel.html
105psi is max for tubed 28's

https://www.hplusson.com/products
this indicated the Hydra is a tubeless compatible rim.

This post was for information only. I have run this combo for 3-4 years and maybe I have just been lucky. I am returning to tubes as the risks are too high for me to continue. This is a bike website and lots of people post stuff about bikes, and that's what I am doing. I took the risk when setting my tires up this way however I have had thousands of trouble free miles prior to yesterday.

I do appreciate the comments for the most part, and maybe this will dissuade others from attempting the same. Or at least give some data to the road tubeless discussion.

[ColonelJLloyd]

Running stuff out of spec and posting blame on a manufacturer with an indignant attitude is one thing, but this is not the case with the OP. He's sharing info that someone will find useful so I see no need for torches and pitchforks.

[Wattvagen]

I am returning to tubes as the risks are too high for me to continue.

i think it used to be pretty common to attempt "ghetto tubeless" set-ups a few years ago before tubeless ready/compatible tires were widely available. some configurations worked out OK, some were pretty dangerous.

today though, tubeless has really caught on, and there are many more choices for both tires are rims in tubeless ready compatibility.

i think the OP should potentially re-consider and try and real tubeless tire on those rims before giving up on tubeless, but of course, that's up to him.

[yinzerniner]

Running stuff out of spec and posting blame on a manufacturer with an indignant attitude is one thing, but this is not the case with the OP. He's sharing info that someone will find useful so I see no need for torches and pitchforks.

I kind of read it differently, where the OP knowingly used a non-compatible system and thinks that the tubeless rim is all that's needed for high-pressure tubeless compatibility, at least on the later reply where they reference the max tire pressure (tubed) and then the tubeless rim.

It's great that the OP was lucky enough to have the system run without catastrophe for years, but putting out a warning for the tire when they installed it out of spec is not that useful IMO. It shifting blame and putting out a false alarm.

Not here to string the OP up, but it would be really useful if the gist of the original post was "always use tubeless tires with tubeless rims, otherwise THIS could happen" instead of "look what happened when I tried tubeless(in a non-compatible setup that doesn't meet setup guidelines or specs), guess I'm off the tubeless train"

[ColonelJLloyd]

Oh. Well, I inferred based on OP running tubeless for years and liking those advantages that he just resigned himself to using a tubed setup for this particular bike because it will not fit 32mm tires, the narrowest size GK slick (which the OP likes) that is tubeless compatible. Not that he's now anti-tubeless because of this incident. More of a "I cheated the tubeless gods for years, but I flew too close to the sun (it was hot that day, my friends)" episode.

[yinzerniner]

More of a "I cheated the tubeless gods for years, but I flew too close to the sun (it was hot that day, my friends)" episode.

Icarus's wings were definitely ghetto tubeless. :banana:

But for real, I'm happy the OP didn't have to deal with the blowout while on a fast descent, or on a busy blacktop otherwise the results would have been much, much worse. And the newest generation road tubeless is a huge step forward in the sizing, install and comfort columns.

[shoota]

OP lucky he didn't die

[old_fat_and_slow]

Per the "Ideal Gas Law" pressure increases proportionately to temperature. So if yah aired up your tires indoors at a comfy 68 or 70 degrees Fahrenheit. If you go out to ride and the temps get up to 95 or 100. You can expect a 25 - 30 psi change in your tire pressure when the air in your tires heats up to 95 or 100 degrees (assuming the volume in your tires doesn't change appreciably). So if you aired up your tires to 90 psi inside in an air conditioned environment. If you ride into the middle of the day when the temps are 95 - 100. You can expect your pressure in your tires to go up to 115 or 120 psi due to the higher temperatures.

So keep that in mind if you want to run your tires at a high pressure.

[MikeD]

OP lucky he didn't die


Darwin didn't prevail in this instance.

[Spdntrxi]

definitely user error

[mj_michigan]

To calculate pressure increase, need the temperature in degrees Rankine, add 460, or Kelvin, add 270, if in Celsius.

Regarding the OP issue, I have done some sketchy bike things over the years. Almost paid a price once when my only slightly cracked seat post actually snapped during a ride (the ride back home was interesting, but I was only a few miles away). Nowadays, I am always following manufacturers recommendations on anything remotely safety related.

[muz]

Per the "Ideal Gas Law" pressure increases proportionately to temperature. So if yah aired up your tires indoors at a comfy 68 or 70 degrees Fahrenheit. If you go out to ride and the temps get up to 95 or 100. You can expect a 25 - 30 psi change in your tire pressure when the air in your tires heats up to 95 or 100 degrees (assuming the volume in your tires doesn't change appreciably). So if you aired up your tires to 90 psi inside in an air conditioned environment. If you ride into the middle of the day when the temps are 95 - 100. You can expect your pressure in your tires to go up to 115 or 120 psi due to the higher temperatures.

Not quite. You got the idea right, but the temperatures have to be absolute (Kelvin, not Fahrenheit). Otherwise you would predict 2x increase in pressure going from 1F to 2F. I'll do the math: 72F is 295K, 100F is 311K, so the percentage increase in pressure is 5.4% (i.e. negligible).

[HTupolev]

This was a regular GK not the tubeless version that only seems to be available in 32mm.
I run 90 in front 95psi in the rear.
Running a fat non-tubeless road tire at 95PSI, not exactly surprising that it would blow off. You're lucky it didn't happen while you were riding.

[nublar]

Wow that's crazy - I have 700x35 GK slicks and I run them at 40 psi tubeless

[old_fat_and_slow]

Not quite. You got the idea right, but the temperatures have to be absolute (Kelvin, not Fahrenheit). Otherwise you would predict 2x increase in pressure going from 1F to 2F. I'll do the math: 72F is 295K, 100F is 311K, so the percentage increase in pressure is 5.4% (i.e. negligible).

Whoops, thanks for correcting my error. At my age I'm surprised I could remember the Ideal Gas Law at all.

[Mark McM]

Not quite. You got the idea right, but the temperatures have to be absolute (Kelvin, not Fahrenheit). Otherwise you would predict 2x increase in pressure going from 1F to 2F. I'll do the math: 72F is 295K, 100F is 311K, so the percentage increase in pressure is 5.4% (i.e. negligible).

It used to be though that tires blew off under the heat of braking primarily due to pressure increases. But a little bit of testing showed that the pressure increases under braking aren't particularly large, and probably not enough to cause a blowout by itself.

http://pardo.net/bike/pic/fail-037/000.html

Instead, it is now believed that pressure increase is a secondary cause. The primary cause is more likely changes in mechanical properties of the tire bead and the casing under high temperature. The bead can become softer and more pliable at high temperature, as can the casing material. (Is it not a common technique for tight fitting tires to heat them up first, making them more pliable and easier to mount?) Also, not only does latex rubber get softer with temperatures, but at very high temperatures, it can become a bit slippery.

A black tire sitting in the sun on a hot day can get very hot indeed. That might have softened up the tire enough that it became pliable enough to slip out of the rim sidewalls. And the excess inflation pressure just provided that much more force to push the tire off

[muz]

It used to be though that tires blew off under the heat of braking primarily due to pressure increases. But a little bit of testing showed that the pressure increases under braking aren't particularly large, and probably not enough to cause a blowout by itself.


Not applicable to the OP's case, but I have had braking related blow-offs caused by inner tube failure. Inner tube contacts the alloy rim along the brake track, in between the tire and the rim strip. When the rim heats up, it can cause over expansion of the inner tube and a sudden loss of air, causing all sorts of mayhem. Been there, done that!

[bikinchris]

Never been a fan of tubeless at high pressure...

SPP

Yeah, at 95psi, you might be better off with tubes.

[bikinchris]

Not applicable to the OP's case, but I have had braking related blow-offs caused by inner tube failure. Inner tube contacts the alloy rim along the brake track, in between the tire and the rim strip. When the rim heats up, it can cause over expansion of the inner tube and a sudden loss of air, causing all sorts of mayhem. Been there, done that!

Conventional tube type Continental tires were tested to 435psi without a blowoff. They might have gone higher, but the rim split. The air pressure increase from sitting in the sun is nothing.

The newest version of tubeless doesn't have the hook and bead design that holds the tire on the rim.

[charliedid]

OP lucky he didn't die

Should probably just hang it all up and sit on the couch.

LOL seriously

[Hellgate]

Should probably just hang it all up and sit on the couch.



LOL seriouslyDon't forget the bon-bons.

I've no idea how long I've survived 100+ in Texas all these years.

[muz]

Should probably just hang it all up and sit on the couch.

LOL seriously

You laugh, but I take this tire stuff very seriously. Just this afternoon, I turned back after riding a few miles, when I realized my front tire was wobbly. It wasn't seated properly on the rim, and I couldn't fix it roadside. I crashed last year when my front tire lost air during a high speed descent, and I have been hyper vigilant since.

[rustychisel]

You laugh, but I take this tire stuff very seriously. Just this afternoon, I turned back after riding a few miles, when I realized my front tire was wobbly. It wasn't seated properly on the rim, and I couldn't fix it roadside. I crashed last year when my front tire lost air during a high speed descent, and I have been hyper vigilant since.

I take the view that tyres are one of the single most important aspects of a bicycle, and THE single most underrated.

Expected to work flawlessly in vastly differing operating ranges, offering a critical interface, and to flex and rebound without failure for literally millions of cycles or rotations.

That's a pretty tall engineering order.

[charliedid]

You laugh, but I take this tire stuff very seriously. Just this afternoon, I turned back after riding a few miles, when I realized my front tire was wobbly. It wasn't seated properly on the rim, and I couldn't fix it roadside. I crashed last year when my front tire lost air during a high speed descent, and I have been hyper vigilant since.

We all have our own level of comfort and risk. Some people are so afraid, they will not even ride a bike. Or ever learn how...

Life