I am looking into buying a Schwinn Airdyne, but I don't want to spend a lot by buying new. I have seen them in classifieds for a decent prices, but are older and the consoles look different than the newer ones that they have at my gym. The ones at my gym are the AD4 and have the newer display that is digital and black/gray colors. On the older ones, I have seen 2 other types that are either really old looking and a large black box type, or a slightly smaller white/cream colored one which is digital. What exact changes have been made over the years and what would I need to look out for when buying used and wanting to update to the newer console? Also, I saw an older airdyne comp, is this a better/more sturdy version?

Cycling - Schwinn - Original Airdyne