Nobby Nic Sealant leak?.

[Itchy99]

I have a schwalbe Nobby Nic on the rear of my Cube Hybrid Race. I converted it to tubeless shortly after getting the bike about six months ago.
Recently I have getting a lot of oily patches on the tyre carcass (particularly the tread and to a lesser extent the sidewall). The only thing I can think of is that the tyre sealant is leaching through. The tyre holds pressure OK but these patches are increasing on an almost weekly basis. Anybody any ideas why this is happening?.

Ta
Rich

 

[iainc]

Normal for Schwalbe to seep a bit, it’s just the carrier fluid for the sealant. If you want to reduce it you could swop to a thick sealant, like Stans Race, but I tend just to live with it.

 

[gelfy666]

I had some Maxxis that also used to bleed, I changed to a different make of sealent, Finishline I think and they were better.

 

[Itchy99]

Cheers! I'll just live with it as tyre performance seems unaffected...and still got a lot of 'normal' stan's sealant left.

 

[steve_sordy]

I agree that it is the sealant leaking out before it hardens off. It is a handy way of keeping count of how many punctures you've had and how many flats you have avoided by going tubeless with sealant. My record is over two dozen punctures on each tyre and no flats.

The thing to do is to measure your tyre pressure before each ride and correct to your required psi. After months of putting 0-2psi in depending upon when you last rode the bike, you will start to see the pressure drop increasing. This is advance warning that you need to add more sealant!

 

[iainc]

^^^^ yes, but not necessarily indicative of punctures, many tyres, esp Schwalbe are slightly porous from the factory...

 

[steve_sordy]

^^^^ yes, but not necessarily indicative of punctures, many tyres, esp Schwalbe are slightly porous from the factory...

It depends upon what is meant by porous.What I consider porous is a tyre carcass that has a relatively uniform porosity that will not hold air. You can check this by pumping up the tyre (tubeless) and brushing over the tyre sidewall with soapy liquid. If the surface is porous you will get thousands of tiny eruptions of foam. If you get several large ones that is a manufacturing defect. The uniform porosity can be dealt with by using a latex sealant. Latex is much better at sealing porosity than non latex. I believe that the non-latex sealants are better at sealing the larger punctures.

 

[Itchy99]

I might just dunk wheel in some water to see what happens out of interest. I can't see that these are all punctures, although I do seem to be a lot heavier on the rear wheel on the ebike compared to my 'normal' mtb. I've also just changed to flatties instead of clipless pedals so I am tending to load the pedals a lot more.

 

[Itchy99]

Also of interest is why it took several months before these leaks/punctures were noticeable?

 

[steve_sordy]

Also of interest is why it took several months before these leaks/punctures were noticeable?

Maybe you have ridden somewhere different that has more brambles, or maybe you have ridden over some cleared brambles, or past a hedge that has been recently flailed. Could be all sorts of reasons for your sudden rash of punctures. I doubt that the tyre is deteriorating.

 

[Itchy99]

The main thing is that my tyre still works! Although to be on the safe side I am going to bung some more sealant in tomorrow..

 

[steve_sordy]

The main thing is that my tyre still works! Although to be on the safe side I am going to bung some more sealant in tomorrow..

I would not bother, unless the tyre is losing pressure to a degree that it will affect the ride. I know that some tubeless tyres just seem to hold the air pressure for weeks and weeks, mine never have. Which is why I check the air pressure before every ride. I use a digital pressure gauge the Topeak D2, brilliant bit of kit! I don't add sealant until I see the pressure loss increasing.
Topeak Smarthead Digital Gauge D2

 

[jerry]

I've just ditched my Minion DHR for the same reason. After a year of use, they started seeping sealant (I'm using Stans'). Technically, it still could be good for another winter, but cosmetically, it just looks messy

 

[Gary]

@iainc has given the correct answer here. Anything else is just anectotal waffle and pedantry.
Maxxis do exactly what the OPs tyre has too. For exactly the reasons Iain gave.
it's nothing to worry about

 

[steve_sordy]

I've just ditched my Minion DHR for the same reason. After a year of use, they started seeping sealant (I'm using Stans'). Technically, it still could be good for another winter, but cosmetically, it just looks messy

It only looks messy until you have ridden the first 100 yards off road, then the dark patches are gone.

 

[Itchy99]

Thanks for the replies fellas.
Spent Friday at BikeParkWales and the bike got a fair old hammering. Result is that the 'damp patches' (ooer missus) have increased exponentially. At this rate the spare room is going to fill up with Stan's sealant fairly soon.
Tyre still holding pressure...