Depends on the frame, a horst-link frame actually gets shorter when the suspension compresses.ShivaSteve said:As far as I know, on most full suspension bikes (e.g. other than old URT designs) the effective chainstay length is elongated under load on the rear suspension. That's why your chain has snapped. I don't think you can ride this kind of bike as a single speed other than in an emergency. Your chain will always either be too lose (and derail) or too tight (and snap). There is no middle ground.