8 Speed cassete on a 7 speed freehub

[hamster]

7 and 8 aren't quite matched (8s has a 4.8mm spacing, 7s has 5.0mm). However you can usually get a good-enough setting if you set it up to run true on the middle of the cassette not from the highest gear. In my experience it always runs a bit rattly and gets tetchy with dirt, but it's worth a try I suppose.
Alternatively, fit an 8s freehub body to your 7s hub and re-dish. It's only about 1/4-1/2 turn off the drive side spokes to adjust the dish.

 

[Tootyred]

You can also often swap around the spindle spacers to lessen the need to re-dish. Often the cassette hub can be shifted towards the frame without causing chain issues a few mm.

Swapping the freehub over simply needs a chain whip and a 10mm allen key... use the cassette to hold the freehub still with the chainwhip holding the cassette, then insert the 10mm key into the freehub.....this obviously after you have removed the spindle!

 

[joglo]

it's already mentioned above, if you are very keen on having 8 speeds, but just a freewheel for fitting 7speed cassettes, you can use a 9speed cassette but remove one cog from it and run the remaining 8 speeds with a 9speed shifter where the last gear should be blocked by limiting the derailleur swing with H and L screws.

 

[voteforpedro]

You can also often swap around the spindle spacers to lessen the need to re-dish. Often the cassette hub can be shifted towards the frame without causing chain issues a few mm.

Swapping the freehub over simply needs a chain whip and a 10mm allen key... use the cassette to hold the freehub still with the chainwhip holding the cassette, then insert the 10mm key into the freehub.....this obviously after you have removed the spindle!

I could probably do that myself, I´ve got all the tools needed. I´m not even going to try to make an 8 speed shifter work with a 7 speed cassete, I hate when shifting doesnt work properly for all the gears, not worth it.
Now onto the mission to find a 8 speed freehub.

 

[Tootyred]

Just go to a bike charity and see if they have a knackered hub. The freehub may be fine.

 

[voteforpedro]

How can you tell if it´s a 8 or 7 speed freehub if I manage to find something without a cassete?

 

[Imlach]

This may be of use from a member on bike forums

 

[voteforpedro]

This may be of use from a member on bike forums

View attachment 735808

Nice! Very usefull.
Thanks dude!

 

[Takingabreak]

I could probably do that myself, I´ve got all the tools needed. I´m not even going to try to make an 8 speed shifter work with a 7 speed cassete, I hate when shifting doesnt work properly for all the gears, not worth it.
Now onto the mission to find a 8 speed freehub.

If you already have an 8 speed shifter and a 7 speed wheel with a 7 speed cassette, it won't cost you anything to set them up and see how well the indexing works.

 

[legrandefromage]

8 of a 9spd cassette will fit quite happily onto a 7spd freehub body but then you will need a 9spd shifter

8spd shifters work well with 5 and 6 spd blocks, I currently have 8spd RSX running a 1980's 600 5spd freewheel