Bicycle Mechanics - 7 speed cassette on 8/9 speed hub

Hey, I've read how to do this by installing a 4.5mm spacer first, then the cassette itself....seems straight forward. On harris cyclery it says "you will need to remove the bolts holding the cassette together" right after it mentions how to adapt a 7 speed cassette to the 8/9 speed hub.

Do you really need to take the casette apart to do this? I don't get this....

Basically I have an 8 speed on there now, but can get the same range with a 7 speed and use my indexing on my downtube shifters this way.

Thanks,

There are some very small headed bolts or sometimes rivets that hold the cog stack together. The heads will interfere with the spacer placed on the inside of the cassette so Sheldon recommended removing the bolts/rivets. I guess you could machine clearances into the spacer if taking the bolts out concerns you.

The only reason you have to remove the bolts is that their heads inside the largest cog keep the spacer from seating flush. There are two cures:

1. File clearance notches in the spacer to let the bolt heads recess into the spacer
2. Install the spacer outside the cassette between the smallest cog and the lockring.

I've done it the second way and it works fine.

Ok, I will probably try the second method first. If that doesn't work I have a little file in my toolbox.


Thanks,

The only reason you have to remove the bolts is that their heads inside the largest cog keep the spacer from seating flush. There are two cures:

1. File clearance notches in the spacer to let the bolt heads recess into the spacer
2. Install the spacer outside the cassette between the smallest cog and the lockring.

I've done it the second way and it works fine.

Just a word of caution doing it the second way, I tried this not to long ago and found I had given myself a 'neutral' gear. If I threw the shifter really hard I could get it to jump off the last cog and rest on the spacer. Now, this usually wasn't a problem, but it didn't do me any good either (and I tried to think of a legitimate use). Then one day, I was sprinting from a traffic light, threw a hard shift and POW right into neutral.

ate it pretty bad when the cranks suddenly offered no resistance. Although with indexed you will probably be ok.

Wouldn't that only happen with your high limit stop too loose? No criticism meant, just honest curiosity.

What about the ridges in the lockring which are meant to mesh with the ridges in the smallest cog? In time the lockring may loosen....(?)

Removing those rivets/bolts holding the 7sp cluster together is not that bad - and it makes it much easier to clean the cassette if necessary :-)

If they are bolts it's super easy. If they are rivets, it's more of a pain but doable.. grind the "heads" off and drive them out with a hammer and punch

the bolts in a cassette are a 1.5mm hex, btw. I usually take mine out and pitch them anyway....so I can clean the cassette more easily.

just a word of caution doing it the second way [as mentioned by hillrider], i tried this not to long ago and found i had given myself a 'neutral' gear. If i threw the shifter really hard i could get it to jump off the last cog and rest on the spacer. Now, this usually wasn't a problem, but it didn't do me any good either (and i tried to think of a legitimate use). Then one day, i was sprinting from a traffic light, threw a hard shift and pow right into neutral.
Ate it pretty bad when the cranks suddenly offered no resistance. Although with indexed you will probably be ok.

wouldn't that only happen with your high limit stop too loose? No criticism meant, just honest curiosity.
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