What's the difference

[Wizard9956]

Hi all , could someone tell me what the difference is between a Shimano 6speed 14-28 freewheel cassette ( the one on my bike at the moment ) , and a Acera 8speed 11-32 freewheel cassette , this one Shimano Acera 8 SPD Mountain Bike Cassette 11/32 CSHG30 on eBay, also Cassettes Sprockets, Bike Parts, Cycling, Sporting Goods (end time 02-Mar-08 15:55:54 GMT) , ie are the overall dimentions the same .
I have emailed the seller , and the reply is it won't fit , just wondered why not .

Thanks Wizard

 

[mk1]

The type you have, the whole assembly screws on to the hub, whereas the 8speed Acera cassette slides on to a separate Freehub, which is not compatible with your hub.

Martin

 

[mk1]

This page might explain it better Shimano Cassettes & Freehubs, by Sheldon Brown

Martin

 

[flecc]

You can get a freewheel with similar sprockets that's suitable, the Shimano HG50 freewheel. It's a seven speed Megarange. There's six sprockets from 11 tooth to 24 tooth, then a seventh sprocket with 34 teeth, basically an emergency low gear. With a low gear sprocket larger than your present 28 tooth, you may need a new rear mechanism to allow for the extra span of movement.
Shimano's Acera Smart Cage rear mechanism is suitable and megarange compatible, reasonably priced too, £14.99 at Wiggle
.

 

[Wizard9956]

Thanks for the replys , it's starting to make a lot more sence now , and thanks for the links that gives me all the info i need and where to buy .
atb
Wizard