Tubeless issue - tyre blew off the wheel!

[Bill]

I suspect it's user error but I was setting my bike up as tubeless, the rear had gone on absolutely fine. Although it was a bit of a struggle to get one side off to remove the inner tube and again to get it back on the rim.

The front was much easier to demount and get back on again and didn't seal quite as well initially but blew up ok. So I kept pumping... Not sure why but I was curious as I mostly MTB but wondered what a solidly inflated road(Ish) tyre would be like.

You know what they say about curiosity and cats!

Anyway at about 80psi there was an almighty bang that had me running out of the garage and halfway down the drive, and blew the tyre clean off the wheel.

And then Mrs Bill came outside ranting that eldest son is a lazy arse who won't revise so I got distracted and haven't had a proper look at it.

Brand new DT Swiss wheel and Vee tyre Rail in 700c X 40...

The big question is: Is it probably buggered???

Edited by Bill on Saturday 4th November 15:06

[bobbo89]

I did that first time setting up tubeless using co2 carts, tyre was fine to use again but my ears were ringing for a while and my shin stung like a bh where the tyre had slapped it as it flew off

[Bill]

At least it's not just me! Just spotted the maximum pressure of 85psi on the side wall. The domestic situation has eased so I got it all mounted ok.

[ChrisCJL]

In my experience, 80psi is probably too high for a tubeless road tyre. In theory, you run them at a lower pressure to clinchers. Hooked or hookless rims?

[edit] - just saw your reply Bill!

[BoRED S2upid]

You’re braver than me for even trying to fit them yourself both mine are tubeless and even the mechanic doesn’t get them perfect t first time round.

[mie1972]

Ha, I did same with a 38mm gravelking. Bang, latex sealant all over the kitchen.
Ears ringing. Wife was not happy about the mess.

Tyre was fine. Re pumped and holding air no problem 👍

[Bill]

Just been for a 15 mile shake down and the front which is the one I'd blown up seemed (mostly*) fine. The rear is losing a bit of air and needed reinflating a few times, and I discovered my pump is a bit knackered.


*Until the last few hundred yards when it burped the last of the air out having clearly dropped a bit up to then.

[ecs]

80psi sounds high. The max tyre pressure becomes irrelevant with tubeless, you need to see what the rims are rated to for your given tyre size.

The manufacturer will usually give you some info on this or a calculator on their website.

[irc]

700x40? Tyre pressure should reduce as tyre volume increases. Rider weight matters as well. More weight needs more pressure. I ride 700x35s on road (with tubes) at 65-70PSI and I'm 16 stone.

Lighter rider?, wider tyre, tubeless, 45PSI?

Try this calculator for a starting point for pressure.


https://www.renehersecycles.com/tire-pressure-calc...

[mikecassie]

A lot of tubeless wheels recommend 5 bar, 72.5psi max pressure for tubeless tyres. Was it hookless beads? I run my 25mm tyres at 60/65psi.
As an aside, maybe your gauge was faulty? I've been caught out with an old pump before which read very low.

[Bill]

Hmmm... The front tyre that I over inflated is holding pressure, but the rear has had a row of leaks develop along the seam. Do you reckon this is a defect or down to me riding it a bit too long on low pressure when it wasn't fully holding?

https://youtube.com/shorts/Fm3SBRnd9qk?si=Jf6O7i9t...

[bobbo89]

What sealant are you running?

[budgie smuggler]

Bill said:

Hmmm... The front tyre that I over inflated is holding pressure, but the rear has had a row of leaks develop along the seam. Do you reckon this is a defect or down to me riding it a bit too long on low pressure when it wasn't fully holding?

https://youtube.com/shorts/Fm3SBRnd9qk?si=Jf6O7i9t...

If its the one you blew off the rim, then you've probably damaged the sidewall. I've done the same so I know your pain (and mine was inside my house, you can imagine how loud the bang was in an enclosed space...not to mention the tubeless jizz everywhere!)

[Bill]

budgie smuggler said:

If its the one you blew off the rim,

It's not.

Using Muc Off sealant FWIW.

It's possibly a bit better since I left it lying on its side for a couple of days. Slightly concerned it'll start leaking again due to flex when I ride it.

[bobbo89]

Hmmm, Stans is good but quite thin so using something like Muc-Off or Peatys might help it seal.

Whenever I fit a new tyre I always UD the bike and spin the wheel for a good few minutes to get the sealant circulating.

[Hugo Stiglitz]

Soapy water all round the bead AND rim first.

[MelbourneWoody]

Bill said:

It's not.

Using Muc Off sealant FWIW.

It's possibly a bit better since I left it lying on its side for a couple of days. Slightly concerned it'll start leaking again due to flex when I ride it.

That right there is your issue. Honestly, the Muc off stuff just doesn't work. Stans, Orange Seal or Silca is really the only trusted stuff I've found. This has also been confirmed by just about every rider I know.

I've blown the same tire off a rim but this was a user error going over 70 PSI on my Zipps 303's. After installing tubeless on any wheels, you will need to go for a first ride to really bed in sealant. After that, you shouldn't really lose any pressure. If you continue to lose pressure, it's normally the sealant or tape to blame.

I run Orange seal on my 38mm gravel tires. 35PSI rear and 30PSI front. I have around 80ml of Sealant in each tire. On my road bike, I run 55 PSI rear and 50 psi front with around 50ml of Sealant in each tire. I might have to pump up a tire with a few PSI once every fornight.

[Bill]

I've been perfectly happy with muc off in my hardtail after repeatedly having to pump it up while using Stan's.

[bobbo89]

Opinions on tyre sealant are all over the place and having used Stans, Orange, Peatys, WTB and Muc-Off my opinion is that there is very little difference between them.

A 50:50 mix of Stans and Muc-Off sealed a stubborn front tyre that wouldn't hold air for me recently, I think due to the difference in viscosity.