Probable derailleur problems

[jljack13]

Hello, I recently purchased a western flyer freestyle 10 speed road bike for super cheap ($5) off the internet but now Im fixing it up to make it road ready and keep running into problems. The one i am particularly having trouble with is the rear derailleur, which is a Shimano positron II. It seems like the derailleur does not have to pull to pull the chain back into riding (have not actually ridden it due to safety concerns but moved the petals) resulting in extra slack. also only one of the pulleys actually touches the chain. Can I fix this or do i need to purchase a new one if so which one I am wanting to keep cost as low as possible just looking to be able to travel ~10 miles on roads at a decent speed. Would this one work: http://www.nashbar.com/bikes/Product_10053_10052_533510_-1___202435

[1FJEF]

(10-04-2013, 01:27 AM)jljack13 Wrote:  Shimano positron II. It seems like the derailleur does not have to pull to pull the chain back into riding (have not actually ridden it due to safety concerns but moved the petals) resulting in extra slack. also only one of the pulleys actually touches the chain.

You have typing or translation errors, so I don't understand the questions, but it sounds like the chain is routed incorrectly. Also that is not a cheap rear derailleur (RD), you can find them for half that, but we need a clear picture of the RD & RD hanger so we can tell what will fit, & if a short cage is OK.

[nfmisso]

This one will work:
http://www.amazon.com/Shimano-Tourney-TX35-Derailleur-Speed/dp/B003ZMH69S/

But; you may need different shifters.

[DaveM]

(10-04-2013, 12:30 PM)nfmisso Wrote:  But; you may need different shifters.

If it's a "Positron" system, you'll definitely need a new cable, maybe shifters. The positron systems don't rely as much on the back pull of the spring in the derailleur to pull it in to higher gears. You "push" the derailleur with the shifter which is why they use a solid, wire like gear cable instead of a normal one. I've never tried a positron shifter with a normal der, but it might work.