Never heard that term for them before, but I'm pretty sure my revo came with those on it and it was an original 2.5R revo. Never really had any issues with it. Only cautioned on the forums and in the manual to not tighten then back off like we do with springs due to once you flatten out the washers, they don't do their job anymore. I'd just tighten it until it was snug, then tighten 1/4 turn or so. Would require adjustment later, but I never took it apart after it was set and only adjusted it at all when I'd change engines or gear ratios.