Instruction: Given a question and its related document, determine if the question is answerable by analyzing the information in the document. Output yes if the document addresses the question, or no otherwise.

Input:
Question: Will this work with a 21 speed Schwinn Ranger mountain bike?
Document: Bought this as part of upgrade for an old 1980's Schwinn. Had some generic replacement derailleur on the bike that was barely functional, did not work as well as the original. This derailleur works great (better than the original), very precise and smooth shifting. Highly recommend - can't beat the price.
The Shimano Tourney TX55 6/7 Speed Rear Derailleur is being used as a chain tensioner. The bike is a single speed but too wide to put a cassette of gears on rear. So I put a triple chain wheel on the front. This rear derailleur holds the chain with enough tension to work with the front 22/32/42 chain wheels on front.
I needed a new rear d&eacute;railleur for my Next Amplifier mountain bike (6 speed freewheelx3 speed crankset). I bought the bike 4 months ago and have put almost 1000 miles on it already, so I just wore out the P.O.S. d&eacute;railleur that came with the 'Wally World' bike.I got the TX55 instead of the TX35 because it looked a little more heavy duty, and I'm not disappointed.
Used this to replace derailleur that broke when I didn't adjust it after replacing the rear inner tube. Perfect fit for my Conway 21-speed.
i finally install this Derailler on my bike last night i took it for a ride this morning work great now i need to replace the cable for the Derailler will buy again from this seller thank you
I bought this for an old mountain bike found at a yard sale. installation was easy and a perfect fit.
I can't figure out how to apply this unit to my bike. I purchased for a 6 speed, but don't know to apply to the frame.
Needed to replace original derailleur on 1973 Peugeot 10-speed and it installed and fit perfectly. Bike shifts smoothly and runs quiet once again. :-)
So my son crashed his bike and bent the old Derailleur. This one was marked as being compatible and it was. Fit great and the install instructions were great too. As a kid I would tear apart my Schwinn Stingray every week with my buddies, but we never touched Derailleurs so I was a little scared to do this install. Now, I cant wait to do another.. but no crashes this time. :-)
This d&eacute;railleur shifts smoothly, a great improvement over the "clunk!" sound my old d&eacute;railleur used to make. It's made mostly out of aluminum (some plastic) and feels like it can handle the long miles I put on a bike. I live in South Florida where it's completely flat, but I think this derailleur could handle some serious mountain trails and stand up to the challenge.For $15 and free shipping this d&eacute;railleur cant be beat!
Answer: yes