Originally Posted by
Vince Canepa
I have been running Dura-Ace 7850 tubeless wheels for about 2 years. I started having leakage problems after 9-10 months. I found that the sealant had severely corroded my rims. There were tiny holes in the rims semi-plugged with corrosion and sealant. Eventually I had to replace the rims on my nickel because Shimano would not warrant them because sealant had been used. Since I had a shop mount and maintain the wheels I could not say for sure what sealant was used, but they told me they use only Stan's or Caffelatex and the only thing I see on the shelf in the service area is Caffelatex. I now run them without sealant and carry a spare tube. I'll pry the tire off and install the tube on the road if I have to.
BTW, the sealant dries up after 6 months for sure.
The upside to all this? While my wheels were down awaiting parts I ran Shimano RS-20s with Vittoria Open Corsa Evo CX tires. The difference in ride when I went back to the tubeless (Hutchinson Fusion 3s) was quite remarkable. I rode tubulars exclusively for over 30 years and can say that the tubeless system comes really close in feel. FYI, I run 90 psi front and 100 rear.
For me the tubeless has a distinct advantage in ride and handling but it also has some downsides. I'll see how it goes without the sealant.
I'd like to ride without sealant as well but my front tire leaks air from the valve stem. Stan says that perhaps air is trapped somewhere in the tape and is migrating to the stem, hence the leak. Others in response to one of my earlier post don't quite understand why one would do so. As others above have stated, there really isn't much weight saving once above and beyond a light tire such as a Conti GP 4000 with light tube. The two ounces of sealant does weigh 60 grams so I'd like to do without that addtional weight if possible. The roads are in pretty good shape where I ride so carrying a tube in the rare event of a flat is no biggie (I haven't flatted with tubed tires in over 3 years). I had to use a tire lever on my back Hutchinson Fusion 3 tire but not on the front. I was surprised how easily it went on. I got them both to seal with just a floor pump and without using soapy water. Thus far, I haven't ridden on the wheels (Stans Alpha 340) as I am currently riding on some Williams System 30's and will wait until Spring when I start to do more climbing; so I really can't attest to ride qualities at this point.
As for the corrosion, Stans says their sealant absolutely does not cause it. I don't know, perhaps something in it is interacting with something inherent in the metal of the Dura Ace wheel. Something is obviously causing it as I have read others talk about the same thing.