TC Idler = Smooooooth
This is the "premium" version of their idler wheel. They also offer an aluminum cog "sport" version for a bit less money. Before I get into the reasons I installed this, I will say that on nearly all of my recumbents I have installed Terracycle idlers. I feel that in every case they have added a level of smoothness and quiet to the drivetrain.
On the B1, the results were equal to those on my other bikes. Immediately I noticed a much quieter drivetrain through the idler section. The OEM ICE idler is not a piece of junk, mind you, but even after only 300 or so miles it had started to show obvious wear grooves. Nor was it very quiet. The Terracycle idler really made an improvement in this area.
A bit of functional bling goes a long way to creating a quieter ride.
Another thing that was immediately noticeable was a much smoother flow of the chain. Since the idler is a gear - as opposed to just a rubber roller - the drivetrain flows much smoother. Why? Well the chain just goes easier over a gear as opposed to chewing into a flat rubber surface under tension. Some may debate this, but after seeing the wear that results on flat surface OEM idlers on my bikes in the past (a LOT) versus the wear on my older Terracycle idlers (little if any I can notice) I am sold.
Terracycle sells idler kits for a lot of recumbent bike and trike makes. I highly recommend them. For the B1, there was no specific kit, but ordering up the proper size idler for a direct swap replacement was simple and always an option.