Somebody replaced the 6 speed cassette on an 18 speed mtn bike?

Question

They put a single gear [freewheeler?] in its place. Then they sold it to me. How do I install a new cassette?

Answer 1

Unless you have the tools or want to buy them, it'll be much cheaper to have a shop do the work for you.   You'll need the correct freewheel remover for the singlespeed freewheel, and then you'll need to buy a new 6-spd freewheel to thread onto the hub...and the correct remover for it if you ever want to remove it again.  

If the previous owner did the conversion correctly, then there's a good chance they respaced the hub and wheel dish in order to get the proper chainline between the front and rear gears.  If so, then you'll definitely want a bike shop's help in returning that to normal.....if that's been done, you probably won't even be able to get the rear wheel (with the new 6-spd freewheel) into the frame until things are corrected.

A freewheel should cost you between $10 and $25 and the rest is just labor unless you need shifters or derailleurs, cables, etc.  

Hope this helps some.  If you want to learn how to do things yourself or just understand what's involved, check out the "repair help" section at http://www.parktool.com ....great photos and instructions.   Good luck!    :o)

Answer 2

With the prices of components coming down, but labour charges going up, I'd say it'll be far easier and cheaper to buy an off the peg rear wheel package with cassette included and just stick it straight in, but I imagine you'll need the shifter and rear mech too? A good bike shop'll do a good bulk deal!

May be worth mentioning I just upgraded my g-f's bike from 6 to 8 spd. A new mavic/deore wheel, shifter and rear mech combo cost equiv of $150 U.S fitted. Hope this helps

Answer 3

That is a tough question without more info. Are the shifters and derailleurs still installed? If not, you might be better of re-selling it as a single speed and buying a new bike.

If everything is still there and all you need to do is replace the cassette, then you need a "chain whip" and a lockring removal tool.

See parktool.com for excellent, detailed instructions.