jorgemartin
Senior Member
There's this pulley/wheel thingy. You can see it on this picture under the seat just in front of the rear shock. http://www.onbikex.de/images/bikTifID_25295_2000_2000.jpg
Okay, I get now how the ratio duplication works. My only concern is: will a 39t chainring improve the steep uphill business over a 46t? Probably so but I guess the only way to know is to do it. On the other hand, because the derailleur's capacity is 37t (53-39+34-11=37), I couldn't possibly use a smaller chainring, so 39 is my only choice.
I've checked SRAM's website and it says this about the X9 9 speed rear derailleur: "Aluminum long/medium-cage/composit short cage" ... So I guess that means that the X9 is a short cage after all and the teeth capacity will be reduced. This information doesn't appear in the 2010 technical manual document...
I was referring to the cage of the X9 rear derailleur... How would I use this Alfine chain tensioner? By the way, are there any recumbent specific features (such as an idler or the length of the chain, which is around 3.8 metres) that influence this whole cassette teeth capacity?
An idler is a pulley or roller that does not produce any mechanical advantage, nor transmit power to a shaft. Idlers are used to lead a chain around a bend (as in short wheelbase recumbents), or to take up slack in a drive chain