that is actually, i think, a positive attribute, and the main reason i'm debating on purchasing a set rollers. i get so bored on my cycleops trainer. it's just not engaging enough - and for that reason - it really doesn't require concentration of any sort. being inside and stationary is bad enough. being supported makes it feel so artificial. if i could concentrate, as i do while i'm on the road, i think i'd have no problem going for upwards of 40 minutes, whereas with my trainer, i'll usually go 20.