Stans seeping through tires

I've noticed small spots on tires where Stans has seeped through and create a wet spot on the tread of the tire. This has shown upon a number of tires.  

- Bontrager R3 road (32mm for light duty dirt roads)

- Panaracer GK SS and SK

- Continental 5000 TL 

 

But not on Maxxis Ramblers.  The family MTB's all run Orange Seal.

 

The spots are small (1/4" ish) and I'm not concerned with failures nor of the fluid causing a slick spot, but it is interesting and I'm curious if others have observed this.  FWIW the tires hold air just fine and the spots only show up if the tire/wheel has been sitting for days.

 

In the past I used Orange Seal for the family gravel bikes and I never noticed spots.

 

TIA

I've had this problem with all my Continental tires but haven't noticed it causes any real issues other than annoyance.  So far, the Vittorias on the gravel bike haven't had this issue.  I run Stan's on the MTB and gravel bikes.  Once my Conti's are ready to be replaced on the MTB, I may go with some Vittorias on there as well.  I did try the Orange Seal for a bit too but can't remember if it leaked on the Conti's or not.

The Maxxis Ramblers on my gravel bike seep Stan's through the sidewalls all the time. So do the Schwalbe Rocket Rons on my hardtail. It apparently depends on the quality of the rubber coating on the inside of the tires, which apparently varies with TLR tires.

The only tyres I’ve had this problem with is the ultralight Rene Herse tyres…and they wouldn’t even stay up overnight tubeless!  Great tyres with tubes, rubbish tubeless.

I've used Stans for years and it’s very good and usually the best price, although it does dry up over 6 months and needs to be replenished. I think I’ll try Orange Seal again next just to see how long it stays liquid in the tyre. 

Have run Pirelli's (Cinturato Gravel H and Gravel M) as well as Vittoria Terreno Dry's with Stan's for several years and no seepage here. 

I have seen spot Stan's leak for years with specific tires too (the worst with Terrene Elwoods) , but have never had a significant loss of air or had the tire integrity be affected in any way.    I have never seen it with multiple sets of Panaracer gk-sk's and Maxxis Ramblers.   I have recently changed to Muc-off on some of my bikes and have not seen it with this product.  

Ive had mixed results, and ended up with three different sealants over 5 bikes and a dozen wheelsets I use.

Rene Herse tires tires I used regular Orange seal…I need to top off or replace pretty every three months.   Some tiny sidewall leakage on my Fleecer Ridge 55c tires when they sit for a bit, but will hold air for weeks, absolutely no leakage on my set of Manostash Ridge 44c tires, which makes me think the RH has been tinkering with the newer tire designs.  I also use it one my gravel wheelsets,  which currently consist also of Cont terra speed, Terrelo Dry, Pirelli Cinturato in H and M.  The orange seal regular seals as good than Stan’s race, but last longer, and regular Stan’s will seal eventually but takes too long IMHO.

Conti GP5000 I have on both my road and my old fun and touring bike, and I use only Silca, which seals like none other, but I can see it not turn into a giant booger in 9-12 weeks, so I often remove the tire entirely, clean, and replace sealant…I have not had much luck with extender fluid.  On side note, I have a new rear tire that has been leaking sidewall horrendously and doesn’t hold air overnight.  I like silca with road tires because it seals quickly which is nice because of the higher pressures and I lose less sealant.  We have lots of glass on the roads of broken car windows, broken bear bottles, and i get more road cuts than on the gravel.

With any bike tires I don’t ride a lot, like the endurance bike thats sitting on my indoor trainer, I use regular Stans, which last forever…seriously, I can get 6 months in some cases for adding some…that goes on maybe a set of wheels that I use only in the winter…I find it works ok…

I’ll never go back to tubes…I use to burn at least 3 a month…and nothing worse than changing a flat at 530am on the way to work.

I'm curious to know if these spots you're noticing are on brand new, never ridden tires, or well ridden ones? I do occasionally see small wet spots if there are very small punctures that the sealant has plugged in my tires, and my gf's tires (which were Maxxis Ramblers until I replaced them last week). I think Stans has a tendency to separate as it sits, which allows some of the more fluid parts of the mix weep through tires. The pinhole issue is typically on sidewalls in my experience, and on the treads usually means it's tiny, sealed punctures.

 

The biggest issue I've encountered in terms of sealant & tires are setting up new WTB's. I have a set of WTB Vulpine's in 700x36 that I rode last year. I was setting them up with Cushcore's in DT Swiss wheels. The sidewall seepage was so persistent that I had to remove the Cushcores, and lay the wheels on their sides overnight, using a bucket to get them level to allow the sealant to plug all the sidewall pinholes. Before doing that I was getting massive air loss overnight - dead-flat in a few instances. I believe the inserts were rubbing the sidewalls and removing the beneficial sealant build-up. I could probably run them now since the tires have stretched a bit. Maybe I'll try that this week.

 

Once I got the initial pinholes plugged, I never had an issue after that, and the tires held air like a champ. I believe that mfg'ing processes can have an effect on different batches of the same model. Some folks I know have had zero issues with the sidewall pinholes, others have had similar issues. YMMV I suppose?

It happens on both new and used tires.

A couple years ago, Maxxis replaced 3 Ramblers I had with weeping sealant.  None of the replacement tires showed any sealant coming through the sidewall.  A few times I've seen this happen on newly mounted tires, but the sealant itself seems to quickly seal the inner walls and the seeping sealant stops within 24 hours.  Several WTB tires did this.  the weepy Ramblers did not self seal after several days the the amount of sealant coming through the sidewall was 10x as much as I've seem from other tires. 

 

So I say give a new tire 24 hours to seal.  If you're still seeing seepage on day 2, replace it.