Now I'm the first to admit that I have pretty much zero experience driving in the snow, it's 3-1/2 hours away so I don't get up there much especially in the winter. I never had a vehicle I wanted to drive in the snow anyway, but I have the Touareg now and driving in the snow is one of the reasons I bought it.
About two years ago I purchased the Thule XL Summit chains and did a test fit at home... 2 years ago so they sat there until a couple of days ago when I decided I wanted to leave at 3am and drive to Yosemite to photograph the tunnel view at sunrise. Made it there no problem, actually even though there were signs saying chains required I never used mine (I intended too though). There seemed to be people without snow tires driving around as well as snow tires and people driving with chains. I was the one without chains and my newish all weather tires and really had no issues. But I had the chains with me so I wanted to put them on and see how it went.
According to the instructions, for my size tires and the particular model I bought I don't need to remove any of the adjuster bolts, so I didn't. I drove down the road for about a mile and pulled over to take in another view and thought something was weird.. No chains. Both fell off about 10 feet from where I started. Lucky for me traffic was super light and my expensive chains were pretty much both at the same spot in the middle of the road.
Messed around with them to make sure there were installed correctly and yes it seems they were according to the instructions. Tried again and sure another again one flew off, but I was watching this time and was able to retrieve it.
Yesterday I took all of the adjusters off and started from scratch when I got home. Drove up to a spot near home where I could test them out. To me, it seems like I needed two adjusters on each tire, not the 4 the instructions tell me to have. I used two and drove the heck out of it around the parking lot and up and down the street at up to 30mph for a few miles and they didn't come off. So.. I don't know. They seem to be adjusted right, I have two less adjusters than the instructions say I should have for my tire size and they seem to be staying on through turns, acceleration, stops and straight line driving.
Not sure I fully trust them though, but I don't drive in the snow enough to justify buying snow tires and rims. So, I guess I'll just need to see what happens next time...
Here's a picture of one installed before it flew off for the first time.