Up your resistance when you're slaving away in the basement with the Kreitler Flywheel. This handy wheel runs off of a belt connected to your rear roller, bringing a heavy mass into the mix to up the difficulty and momentum for a road-like feel. It maintains the roller's momentum when you stop pedaling so the training station simulates a real road ride more, not slowing down as much as the rollers do when the fly wheel isn't attached. For added resistance, you can add both a left and right flywheel to make your workout really count.