Dumb Tubeless question(s) of the day…..

[berty bassett]

On a bit of a tangent - why not put sealant in the inner tube ? Would this allow low pressure riding ?seems logical unless I am missing something

 

[Jody]

On a bit of a tangent - why not put sealant in the inner tube ? Would this allow low pressure riding ?seems logical unless I am missing something

Low pressures with inner tubes invite pinch punctures. Also, why carry the weight of an inner tube with sealant when you can do away with the tube?

It's one of the big advantages of tubeless, lower pressures, better grip and more comfort

 

[berty bassett]

Low pressures with inner tubes invite pinch punctures. Also, why carry the weight of an inner tube with sealant when you can do away with the tube?

It's one of the big advantages of tubeless, lower pressures, better grip and more comfort

But surely you don’t know you have a pinch puncture as it would seal itself ! Also keep on adding sealer and doesn’t the weight add up over time ? Plus mountain bikes are heavier anyway ? And if you are just using them for downhill trails the weight would help ?
It’s a minefield 😁

 

[T4tomo]

It’s a minefield 😁

Even with tubeless tyres I'd avoid those, more than the sealant could cope with.

But surely you don’t know you have a pinch puncture as it would seal itself !

on a more sensible tangent, its the sealant reacting with the air that causes it to seal to hole, therefore if you filed a tube with sealant it wouldnt seal properly as the "outside" of the hole is inside the tyre so it wont react with the air properly.

This is also why the system fails sometimes with road tyres, as the higher pressure (vs fat off road tyres) for the the sealant out too quickly to seal.

 

[Jody]

But surely you don’t know you have a pinch puncture as it would seal itself ! Also keep on adding sealer and doesn’t the weight add up over time ? Plus mountain bikes are heavier anyway ? And if you are just using them for downhill trails the weight would help ?
It’s a minefield 😁

It isn't going to fix a ripped inner tube

You add sealant as the liquid and urea/liquid element evaporates off leaving just the latex. Latex can be pealed out if you really want to save some weight

Tubeless is used across the board and tends not to be for DH. They run even lower pressures and internal sponge type cores to protect the rim from strikes. Heavier bikes and especially wheels make accelerating harder. Otherwise they would all be running 50/60/70lb bikes

It's really not a minefield

 

[T4tomo]

Tubeless is used across the board and tends not to be for DH.

What about DH across the boards?

 

[Jody]

The picture is a trail bike

 

[Alex321]

On a bit of a tangent - why not put sealant in the inner tube ? Would this allow low pressure riding ?seems logical unless I am missing something

That is what the "slime" inner tubes do.

But no, they don't really allow low pressure riding very well, because pitch punctures tend to be bigger holes than the slime can self-seal.

With tubless, you don't get pinch punctures at all.

 

[Alex321]

This is also why the system fails sometimes with road tyres, as the higher pressure (vs fat off road tyres) for the the sealant out too quickly to seal.

Yep. That is the issue I had. Tried tubeless using Hutchison Fusion tubeless tyres, but even though tubeless, they had a minimum pressure (according to the sidewall) of 75psi. Which is too high for plugs to stay in when you get a puncture too big to self-seal.

When I tried, I found the plugs popping out at about 60-65psi.

 

[Sallar55]

Ok, missed that. The tyre has to come off anyway to get the tube out and fit a valve, so worth checking. If you’re going tubeless (which I have on all my MTBs) you’ll need a way of seating the tyres on the rims. If you’re lucky you can do it with a track pump and a lot of fast action but having managed that once I have failed on all subsequent attempts and now have an accumulator type pump which works every time.

My method: lube tyre beads with soapy water, mount on rims, remove valve core, blast tyres onto rims and then keep pumping until the beads seat ALL the way around (you’ll get a couple of loud pops), deflate and remove valve core, syringe sealant into tyre, replace valve core, inflate to preferred pressure, go ride. Check pressure regularly, it may take a few rides to stabilise.

Don't remove the tyre ,just break the bead on on side and remove the tube and fit a tubeless valve.With any luck it will be easier to pop the bead back on and hold air.

 

[figbat]

Don't remove the tyre ,just break the bead on on side and remove the tube and fit a tubeless valve.With any luck it will be easier to pop the bead back on and hold air.

With luck, if the rim is already taped then this would be a good solution.

 

[Mr Celine]

Thankyou (All) 😎🙏

Sorry. Pitch-black in the garage. Photo is best i can do. Looks to be 48mm long, it’s a Presta Valve and has a smooth shaft.

When I deflated the tyre: the sidewalls felt wafer thin. And like they were literally glued to the rim. I didn’t easily manage to break the seal anywhere. But was unsure what I was up against - so didn’t force anything. But I’ve been messing with bike / car / motorbike tyres for 35 years - and I’m not sure I've ever known a ‘normal’ bike tyre stick to a rim like this 🤷‍♂️ When the tyre was deflated I could move the valve / push it In and out like any normal tubed valve…..

I'd a similar recent experience. See this thread -

https://www.cyclechat.net/threads/how-do-i-carry-my-bench-vice-on-my-new-mountain-bike.290051/

 

[fossyant]

The picture is a trail bike

Possibly Enduro if 150mm and above ... wink wink.

 

[CXRAndy]

I've put sealant inside inner tubes with great reliability. I do like tubeless setup.

The valve stem doesn't a nut which holds the valve tight against the inside rim

 

[sevenfourate]

So thanks for all your thoughts.

And firstly - these turned out not to be a tubeless set-up at all. Just a non-wired sidewall tyre with a bead ‘stuck’ to the rim like i’ve never seen before. So I really had no experience of what I was seeing !

I was taking in to to have the brakes tweaked anyway - so in the end got them to change the tubes over for me at the same time. So although I’ve still not done myself - I do know it’s just a standard tyre / tube set-up.

Going forward: what makes this sidewall to wheel rim connection so limpet-like ?

And is this down to the tyre or rim design or both ?