Chain slipping on cassette cogset

[wcgreen3]

I am new here. Found this forum while trying to find a solution to this problem and really hope someone can help me. I had to replace the rear wheel of my Next mountain bike and found a used one that looked like new. After putting the tire on it and mounting it on the bike, I tried to ride it but the chain slipped on the outside two cogs. So I removed the wheel and examined the cogset [cassette type] and noticed the outer two cogs were slightly loose. So I attempted to tighten the cog retainer but it was already as tight as it could go and still those two outer cogs were loose. It appears to me that the chain is slipping because those cogs are loose and that something is missing.... perhaps a washer that would snug those two cogs. BTW, the inner five cogs are a single unit.

I have no experience with these cassette cogsets so I have no idea how to service them.

As I mentioned, otherwise the wheel is like new. The cassette mechanism appears to be perfect, and the chain only slips on the outer/smallest cogs.

Ironically and adding to the mystery, I came across another wheel that has the exact same problem. It is older and has signs of age but it also has the same problem with the outer two cogs being loose. I have tried swapping out the cogsets between the two with no success. So I have two wheels but can't use either of them.

Any help would be GREATLY appreciated!

[wcgreen3]

BTW, the cluster I am having the problem with has 7 cogs. I am thinking the cassette is intended for 8 cogs and this could be my problem. I came across a 4mm cassette spacer on ebay that is intended to fill the gap for a 7-cog cluster on an 8-cog cassette. Would this be the solution to my problem? And if so, wouldn't a common washer large enough to fit on the cassette work just as well?

[Bill]

(07-09-2012, 07:30 PM)wcgreen3 Wrote:  BTW, the cluster I am having the problem with has 7 cogs. I am thinking the cassette is intended for 8 cogs and this could be my problem. I came across a 4mm cassette spacer on ebay that is intended to fill the gap for a 7-cog cluster on an 8-cog cassette. Would this be the solution to my problem? And if so, wouldn't a common washer large enough to fit on the cassette work just as well?

Ok to assist us with this is there anyway you can upload pictures of the one your having problem with and the one you are replacing? In my experience of restoring a Next they only had 7 cogs. Is this a Power Climber?

[nfmisso]

(07-09-2012, 07:30 PM)wcgreen3 Wrote:  .....Would this be the solution to my problem? And if so, wouldn't a common washer large enough to fit on the cassette work just as well?

Maybe

No !!! the spacer has to be the correct thickness, and to a much tighter tolerances than common washers.

As Bill said - pictures please.