Hello again guys.
My rowing bike will use a hanger instead of a solid axle. Unless you guys think I’m wrong. I respect bicycle mechanics. So I’m all ears. I used to be friends with a guy named MONKEY who was the mechanic for Mert Lawill and Shawn Palmer. I respect you guys dearly.
Since it’s a rowing bike, I will be selling probably 5 a month only, so I don’t mind buying 5 rear derailleurs on eBay. What I want to clarify from you geniuses is that 7 speeds is more forgiving than 8 and 9 speed cogs for a rear cassette. Remember that my chain travels backwards in the return stroke of the row. So I don’t want the chain to jam on the derailleur cage. The rowing bike needs very very minimal gear-up ratio . 90% of the time you are rowing on the 11-tooth cog. Having said that, which short cage rear derailleur has high tension and uses a derailleur hanger and can be used with 7 speeds? If it makes no difference in alignment forgiveness, I can go up to 9 speeds.

Thanks