Tubeless Sealant Viscosity - Thick versus Thin

[Bolt]

I'm struggling to understand why bike specific sealants are thinner than those for general automotive applications.  Surely a thicker sealant would form a semi permanent coating on the inside of the tyre and remove the need for periodic refilling due to evaporation?  The only consideration that I can think of is of valve clogging with a thicker sealant but this would be offset by the advantage that the need for inflation would be reduced due to the ability of the thicker sealant to seal the natural porosity of the tyre?

[dim]

I'm also new to tubeless and tyring to figure things out...

what I have read is that when you park /store your bike overnight (or for longer), it's good practise to ensure that the valves are not on the bottom of the wheel where the sealnt can clog the valves (I read it on a forum, only seen it mentioned once, so it could be bollocks but I do that just in case ... so perhaps you have a point with thinner vs thicker sealants

I've also read that some sealants are crap, and some are good (for bike tubeless tyres) .... the one that gets most praise/good reviews is the Orange sealant

I've also read that CO2 is not recomended for some sealants ....

and what I experienced on a puncture is that a lot of seaant and air escaped before my puncture sealed (so does the sealant work better on lower pressures?)

[Torslanda]

From a layman's POV, with some experience of sealants in automotive applications, I have misgivings about tubeless bicycle tyres.

The sealant is forced out through the hole by the air pressure and congeals to seal the tyre - I get that. Where it falls down IMHO is there is not sufficient volume of air in the tyre for the sealant to be effective before the tyre has deflated to the point where it's useless anyway. A car tyre generally runs a much lower pressure but the volume of air is huge by comparison. Car tyres also get hot, which must help the sealing process. 

Then there's the faff involved in getting the buggers on in the first place. Where, by the side of the road on a Winter's day with a deflated tyre that's rolled off the rim, are you going to get sufficient volume and pressure to simultaneously reseat and reinflate the tyre. You can't. So you have to put a tube in to get you home. So why bother?

It's a total mystery - to me at any rate.

ETA And a pump is FECKIN' HOW MUCH!?  WTF...

[Ben T]

You can however simply empty a cartridge into a punctured tyre without taking it off or anything and that will provide the necessary pressure to make the sealant effective without having to do anything else.

[dim]

From a layman's POV, with some experience of sealants in automotive applications, I have misgivings about tubeless bicycle tyres.

The sealant is forced out through the hole by the air pressure and congeals to seal the tyre - I get that. Where it falls down IMHO is there is not sufficient volume of air in the tyre for the sealant to be effective before the tyre has deflated to the point where it's useless anyway. A car tyre generally runs a much lower pressure but the volume of air is huge by comparison. Car tyres also get hot, which must help the sealing process. 

Then there's the faff involved in getting the buggers on in the first place. Where, by the side of the road on a Winter's day with a deflated tyre that's rolled off the rim, are you going to get sufficient volume and pressure to simultaneously reseat and reinflate the tyre. You can't. So you have to put a tube in to get you home. So why bother?

It's a total mystery - to me at any rate.

ETA And a pump is FECKIN' HOW MUCH!?  WTF...

Lezyne Micro Floor Drive HP ABS Pump with Gauge:
http://www.wiggle.co.uk/lezyne-micro-floor-drive-hp-abs-pump-with-gauge?sku=5360458180&source=igodigital



Includes Composite Matrix frame pump mount
Length: 300mm
Weight: 194g
Max: 160psi, 11bar

[Hot Flatus]

From a layman's POV, with some experience of sealants in automotive applications, I have misgivings about tubeless bicycle tyres.

The sealant is forced out through the hole by the air pressure and congeals to seal the tyre - I get that. Where it falls down IMHO is there is not sufficient volume of air in the tyre for the sealant to be effective before the tyre has deflated to the point where it's useless anyway. A car tyre generally runs a much lower pressure but the volume of air is huge by comparison. Car tyres also get hot, which must help the sealing process. 

Then there's the faff involved in getting the buggers on in the first place. Where, by the side of the road on a Winter's day with a deflated tyre that's rolled off the rim, are you going to get sufficient volume and pressure to simultaneously reseat and reinflate the tyre. You can't. So you have to put a tube in to get you home. So why bother?

It's a total mystery - to me at any rate.

ETA And a pump is FECKIN' HOW MUCH!?  WTF...

Never happened to me.

2 years use. No issues. Easy to fit provided you follow the protocol.

Overall, much less hassle than tubes and tyres. No inconvenient punctures, all maintenance done at a time and place of my choosing.

End of, really.

[dme]

Lezyne Micro Floor Drive HP ABS Pump with Gauge:
http://www.wiggle.co.uk/lezyne-micro-floor-drive-hp-abs-pump-with-gauge?sku=5360458180&source=igodigital

I have one of these, but stopped using it. It screws on to the valve rather than using a pressure attachment, and all too frequently it would remove the valve core rather than unscrewing from the valve during removal. It drove me mad.

[Aushiker]

2 years use. No issues. Easy to fit provided you follow the protocol.

Overall, much less hassle than tubes and tyres. No inconvenient punctures, all maintenance done at a time and place of my choosing.

End of, really.

+1  and then of course is all those mountain bikers running tubeless. Oh BTW my roadie and my fatbike are now both tubeless.

[chrisbainbridge]

[quote2 years use. No issues. Easy to fit provided you follow the protocol.

Overall, much less hassle than tubes and tyres. No inconvenient punctures, all maintenance done at a time and place of my choosing.

End of, really.[/quote]

+1

[Bolt]

So, referring back to my OP I think I have found the answer to my question   Today I attempted to fit a Clement USH 700x32 tyre on a Stans Radler rim using OKO Off Road Sealant which is about the consistency of custard.  Using about 50ml of the sealant the inflated tyre failed to seal effectively, losing small amounts of air around the entire circumference of the beads.  Despite every attempt to distribute the sealant by spinning and flipping the wheel, the situation didn't improve.  I then added about 50ml of water into the tyre, spun and flipped the wheel as before and re-inflated and bingo the tyre pressure held first time.

By way of comparison I had previously used Stans sealant to fit the other tyre on the front wheel.  Using exactly the same procedure the tyre would lose pressure from 50psi before settling at around 20psi over a period of around 6 hours. It took several spin, flip and re-inflate cycles before the tyre finally sealed properly. 

So, it's my conclusion that bike specific sealants are purposefully thin to seal the bead to the rim on fitting of the tyre, and I'm surmising that a thicker sealant that is able to cling to the inside of the tyre will be more effective against punctures.  So hopefully, starting with a thick sealant and adding just enough water to achieve a rim seal will produce good results.

[zigzag]

water may not be the optimal liquid to pour inside a tyre, considering that the winter is just around the corner

[dim]

So, referring back to my OP I think I have found the answer to my question   Today I attempted to fit a Clement USH 700x32 tyre on a Stans Radler rim using OKO Off Road Sealant which is about the consistency of custard.  Using about 50ml of the sealant the inflated tyre failed to seal effectively, losing small amounts of air around the entire circumference of the beads.  Despite every attempt to distribute the sealant by spinning and flipping the wheel, the situation didn't improve.  I then added about 50ml of water into the tyre, spun and flipped the wheel as before and re-inflated and bingo the tyre pressure held first time.

By way of comparison I had previously used Stans sealant to fit the other tyre on the front wheel.  Using exactly the same procedure the tyre would lose pressure from 50psi before settling at around 20psi over a period of around 6 hours. It took several spin, flip and re-inflate cycles before the tyre finally sealed properly. 

So, it's my conclusion that bike specific sealants are purposefully thin to seal the bead to the rim on fitting of the tyre, and I'm surmising that a thicker sealant that is able to cling to the inside of the tyre will be more effective against punctures.  So hopefully, starting with a thick sealant and adding just enough water to achieve a rim seal will produce good results.

tyres are good .... rims are good .... I assume that the rims have enough tape?

my only suggestion is that the sealant that you used may be crap .... after a google search, the OKO off road sealant comes up with this suggestion:

• Uses include trailers, wheelbarrows, golf buggies, ride-on mowers, mobility scooters and wheelchairs, small agricultural machines, fork lifts .....

(bicycles are not mentioned)

The Orange sealant that I use  gets good reviews

[Bolt]

water may not be the optimal liquid to pour inside a tyre, considering that the winter is just around the corner

  Good point, OKO off-road is rating down to -15c and appears to contain ethylene glycol as an antifreeze.  Hopefully diluting 1:1 should still provide adequate protection for the typical UK winter.

[Bolt]

tyres are good .... rims are good .... I assume that the rims have enough tape?

my only suggestion is that the sealant that you used may be crap .... after a google search, the OKO off road sealant comes up with this suggestion:

• Uses include trailers, wheelbarrows, golf buggies, ride-on mowers, mobility scooters and wheelchairs, small agricultural machines, fork lifts .....

(bicycles are not mentioned)

The Orange sealant that I use  gets good reviews

The use of non-bike specific sealant was deliberate as I want to try and understand what makes bike specific sealant "special" and hugely more expensive.  From my experiments so far I've confirmed that the sealant does need to be thin to the seal the bead when fitting and the diluted OKO was far more effective than Stans in achieving a good seal first time. 

[inappropriate_bike]

The use of non-bike specific sealant was deliberate as I want to try and understand what makes bike specific sealant "special" and hugely more expensive.  From my experiments so far I've confirmed that the sealant does need to be thin to the seal the bead when fitting and the diluted OKO was far more effective than Stans in achieving a good seal first time.

My experience with Schwalbe tyres (One Pro/G One) is that they have inflated and stayed up without needing any sealant at all. So they could be good candidates for thick(er) sealant.

[Aushiker]

My experience with Schwalbe tyres (One Pro/G One) is that they have inflated and stayed up without needing any sealant at all. So they could be good candidates for thick(er) sealant.

All that says is you haven't puncture them yet and that you have a tyre that matches with the rim just fine. I wouldn't be reading any more into myself.

Oh BTW I have a Giant tyre on the rear without sealant as I am waiting a wider tyre. I do not assume at all that I am protected by some puncture god ... My risk of deflation is the same as if I was running a tube ... not fantastic.

[PhilO]

The risk is still lower with tubeless. A thorn, drawing pin, etc in the tyre will plug it's own hole until pulled out. It doesn't work the same way with the inner tube.

One other thing in favour of tubeless that's not often mentioned is that even if it fails deflation tends to be slower than with.a tube, giving time to stop under control. Something I've had reason to be glad of after hitting a rock at speed on the MTB.

[zigzag]

The risk is still lower with tubeless. A thorn, drawing pin, etc in the tyre will plug it's own hole until pulled out. It doesn't work the same way with the inner tube.

One other thing in favour of tubeless that's not often mentioned is that even if it fails deflation tends to be slower than with.a tube, giving time to stop under control. Something I've had reason to be glad of after hitting a rock at speed on the MTB.

this is different from my experience - of all the punctures i've had on tubed tyres none of them deflated suddenly. there was a feeling that the tyre got mushy, and after looking down to check there was enough time to stop (even after sidewall cuts). tubless tyres work great at sealing pin hole type punctures from wire or thorns and not very well with the usual culprits - pieces of glass and flint.

[PhilO]

Tbf, ime sudden deflation tends to be pinch rather than penetration induced (as per my example) so it does depend a lot on what's typical for the individual. Similarly, I don't ride much in cities or chalky parts of the country so glass and flints count as less-common in my experience than thorns.

Although admittedly, I did once make the last few miles of a ride with 9 thorns in my tubed tyres. There was a huge sigh of relief when the car park came into sight!