Here is roughly where it's supposed to go on the exercise bike. The 65 tooth chainring will go on the right side. But the challenge still exists of running two chains on the single speed, fixed gear flywheel. I have been working with a local bike shop, Bici Mundo, which deals with a lot of used and older bikes. One of the mechanics had the thought of attaching a 5-speed freewheel to my flywheel where there is only one cog currently. As I said earlier (link above) I'm looking to run a 28 tooth chainring on the exercise bike forward to a 28 tooth cog on the flywheel. Then another chain would run from a 14 tooth cog on the flywheel up to the 65 tooth on the shredder. Well, this 5-speed flywheel's smallest cog is a 14 and largest is a 28. So it should work, if there is enough room.
The usable width of any hub is referred to as the Over Locknut Dimension (OLD). The question is whether 5 cogs stacked next to each other will be too wide for this 120mm OLD frame. For reference, standard a mountain bike rear hub is 135mm. If nothing else, I could have the dropouts welded onto the frame with wider spacing, but this will be a last-ditch effort if necessary.
Gearing is one crucial thing to figure out but I will also need to mount this 30 pound shredder up on the front of the bike so it's operable by the rider. It also needs to be adjustable up and down to adjust chain tension. That all should be accomplished pretty easily with a bracket or two.
The hopper should arrive tomorrow and I am planning on displaying this at the Flagstaff Community Market this Sunday with the Azulita Project. If you are in Flagstaff, stop by to see it!