I've only used it on a small two-person hand cart that was having trouble getting up a small grade and it worked fine. It does have to be re-applied very few months depending on how much I run it, but it hasn't dried up in the bottle in over a year. I do think there's technique to applying it and letting it dry completely.
Worst case scenario is generally that it doesn't work; you're out a few bucks; and you have to scrape it off - not that difficult with a Dremel and small wire wheel.
