Compatability question?

[fatandforty]

Why doesn't the new 7 speed Shimano cassette I bought fit where my old one was?

It seems to be that the last ring with the lock won't snug down enough leaving the other sprockets loose.

What are the possible issues?

 

[Inigo Montoya]

Why doesn't the new 7 speed Shimano cassette I bought fit where my old one was?

It seems to be that the last ring with the lock won't snug down enough leaving the other sprockets loose.

What are the possible issues?

its - most likely - a compact cassette with a 11t cog. that cog is designed for a special compact freehub. this is needed because the freehub's diameter is to large for the 11t cog.
one way to use it on a normal shimano freehub is to add a spacer on the inside of the freehub. changes the chainline though.
another possible solution is to use a 12t cog from a normal cassette.

 

[legrandefromage]

You need a spacer between the cassette free hub and the cassette - put the spacer on first, then cassette, then tighten.

check on the back of your original cassette as it might still be stuck on there

 

[fatandforty]

Yep it's 11-28.

I had the spacer but I think I may have put it in the wrong place.

Will try again tonight.

Cassette to freehub grease or no grease?

I always thought grease but I just swapped one on a fairly high end DH bike and it was dry.

 

[legrandefromage]

Yep it's 11-28.

I had the spacer but I think I may have put it in the wrong place.

Will try again tonight.

Cassette to freehub grease or no grease?

I always thought grease but I just swapped one on a fairly high end DH bike and it was dry.

I use just enough so it keeps out moisture to stop surface rust on the freehub.

Once the cassette is in place, it should sit slightly proud of the frehub body so the lock ring can bite on the surface of the last ring.

Not sure what Inigo is on about - lock rings are different sizes but thats about it

 

[Inigo Montoya]

Not sure what Inigo is on about - lock rings are different sizes but thats about it

http://www.sheldonbrown.com/gloss_ho-z.html#hyperdrivec

 

[legrandefromage]

Not sure what Inigo is on about - lock rings are different sizes but thats about it

http://www.sheldonbrown.com/gloss_ho-z.html#hyperdrivec

oooh....

You know, I've never come across that issue in, well, 20 years of bodging.

stone me....

 

[Inigo Montoya]

oooh....

You know, I've never come across that issue in, well, 20 years of bodging.

stone me....

lucky you! the first cassette i bought ~1 year ago was compact! drove me crazy until i found out whats going on thanks to sheldon (R.I.P.).

 

[fatandforty]

sorted thanks

Had a slight issue with the lock ring not engaging but this was solved by removing some burrs that had devolped on the old spacer.