Is there any truth in the claims I have seen that Stans sealant degrades the rubber on the inside of the tire?
Stans sealant degrades tires???
- Thread starter afroboy
- Start date
There have been issues with some Kenda tires for sure, but it's not just Stan's. I was using homemade latex funk when mine died.
It is not an isssue of tires degrading. It is an issue of trying to use a non air tight, cheap ass fabric side wall tire for a tubeless application.
The sealant is pushed through the porous sidewall untill it hits the air. When it hits the air, it hardens and forms a skin on the outermost part of the tire. Now the air pressure within the tire continues to push outward thouth the fabric and ends up blistering and seperating the rubber/fabric layers in the sidewalls of the tires.
I have used stans in many different tires without any problems at all for the past three years. If youare going to use Kenda tires, just use the DH tires, the XC tires have VERY poor/thin sidewalls
The sealant is pushed through the porous sidewall untill it hits the air. When it hits the air, it hardens and forms a skin on the outermost part of the tire. Now the air pressure within the tire continues to push outward thouth the fabric and ends up blistering and seperating the rubber/fabric layers in the sidewalls of the tires.
I have used stans in many different tires without any problems at all for the past three years. If youare going to use Kenda tires, just use the DH tires, the XC tires have VERY poor/thin sidewalls
After puncturing a brand new Continental Vertical Pro UST tire, I decided to give Stan's a try. After running the tire for 2 seasons, the inside of the tire looks fine... no degrading from what I could see.
As davep said, it was only the Kenda tires. So, either don't use Kenda, or use the heavy duty Kenda tires with the sealant.
I've been through a couple sets of Michelins with the sealant and they all look fine when I'm done.
I've been through a couple sets of Michelins with the sealant and they all look fine when I'm done.
Excellent. daveP's explanation makes quite a bit of sense to me. I intend on using UST approved tires, as I have so far (Michelins), so I ought not to have trouble. Out of curiosity, have any of you used Stan's rims? I am used to the quality level of Mavic's 521/721s, and switched to the 819 form XC last season, but found it too narrow to keep my tires on the rim when I executed jump turns on the trails etc. I see they have a Freeride rim available; any reports? I am thinking it might be best to just go back to my 521s and install my own rim strip to seal them, so as to save dough, and use stuff I already have. Any thoughts?
Here we go again. Our sealant does not degrade tires! davep's explanation is not quite correct either but close. The blistering/bubbling that some have experienced can happen with standard and UST tires of all brands. The problem results from less than perfect vulcanization of the layers within a tire. The layers within the tire can separate, particularly when subjected to sharp impacts and is more prevalent at higher pressures. When a small area of the rubber begins to pull away from the nylon casing, it is possible for small amounts of air to enter through the pores in the rubber and the spot will grow. I have the bubbles/blisters in a controlled setting with UST tires and standard tires used with a tube.
The same mechanism that leads to knobs being torn from the casing is what is going on basically. When the knobs flex and twist under load they put a lot of stress on a small area of the casing. That small area finally gives and the knob which is part of the outermost tire layer pulls free from the nylon. Sealant or know sealant in the case of UST tire, leave it inflated and the bubble will stay inflated. A standard or UST tire with sealant, slice open the bubble, let the sealant seal the open pore on the inside if it hasn't already, and keep riding the tire.
In the tire biz, not just bicycle tires, it is difficult to make the rubber adhere well to the nylon and some companies are better at it than others. I produced a lengthy report on the matter, and could have gone even further with it, that was presented to Kenda and their engineers in Taiwan and the engineers agreed completely with our findings, sealant is not to blame. The myth/rumor continues to spread but since we got them to stop blaming sealant, it has died down a bit. Tire manufacturers that blame sealant for tire problems and refuse to warranty a UST tire are just plain irresponsible. I have no problem with them refusing to warranty a standard tire that is used tubeless however since that was not the original design intent.
I may publish the report on the website one day but I've not felt the need to just yet and I'm not sure how many people would even believe the results anyway.
davep - if you're the same Dave I think you are, thanks and I owe you one
The same mechanism that leads to knobs being torn from the casing is what is going on basically. When the knobs flex and twist under load they put a lot of stress on a small area of the casing. That small area finally gives and the knob which is part of the outermost tire layer pulls free from the nylon. Sealant or know sealant in the case of UST tire, leave it inflated and the bubble will stay inflated. A standard or UST tire with sealant, slice open the bubble, let the sealant seal the open pore on the inside if it hasn't already, and keep riding the tire.
In the tire biz, not just bicycle tires, it is difficult to make the rubber adhere well to the nylon and some companies are better at it than others. I produced a lengthy report on the matter, and could have gone even further with it, that was presented to Kenda and their engineers in Taiwan and the engineers agreed completely with our findings, sealant is not to blame. The myth/rumor continues to spread but since we got them to stop blaming sealant, it has died down a bit. Tire manufacturers that blame sealant for tire problems and refuse to warranty a UST tire are just plain irresponsible. I have no problem with them refusing to warranty a standard tire that is used tubeless however since that was not the original design intent.
I may publish the report on the website one day but I've not felt the need to just yet and I'm not sure how many people would even believe the results anyway.
davep - if you're the same Dave I think you are, thanks and I owe you one
Right on Mike B, thanks for giving us the skinny. I am always sceptical about reports like the ones I encountered about your sealant, so I figured I would put out the feelers and see what others thought. Its always nice to get it from the horses mouth.
Beer = Good!! Thanks for the swap! All is working well with the wheels.
I would be very interested in your tire info/findings. Thanks for the better explination. I was going write (my un proven thoughts) about vulcanization, but I am lazy, and tech jargon just leads to more questions... it is a never ending cycle..sometimes I feel like participating..other times not..
I often find myself in the same position. Your explanation was much closer than most people ever come including some "know it all tire sales types" that either don't ride at all or have never done any testing. I plan to do some more tire testing in the future on our tire/rim torture device but I've got too many irons in the fire at the moment.
US mags aren't in to the tech/testing stuff much but I would like to invite some out to see the testing in action to 'spread the word.'