cassette hub body interchangeability?

"Song" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Hi,

Wondering if it's possible to switch an 8-speed shimano freehub body onto

a

Quoted message said:

7-speed (126mm) freehub, and if it is, what's the best way to correct the spacing. Thanks in
advance.

Sheldon Brown has an excellent article:

sheldonbrown.comk7.htmlOpen ↗

Thanks for the link. Now that I know it's doable [as a replacement option], anyone out there know if
I can grind down the inner end of a 7-spd body to make the splined section wide enough for 8-speed?
It seems like a 7spd has a wider 'flange' at the end that could possibly be milled away to make room
for an 8th cog.

TIA, Song

"bfd" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

"Song" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

Hi,

Wondering if it's possible to switch an 8-speed shimano freehub body onto

a

Quoted message said:

7-speed (126mm) freehub, and if it is, what's the best way to correct the spacing. Thanks in
advance.

Sheldon Brown has an excellent article:

sheldonbrown.comk7.htmlOpen ↗

Agreed- I did this two weeks ago. Piece of cake.

What spacing are you wanting to "correct"? No matter what you do, the wheel will be stronger with
less dish. I'd recommend that you replace the axle with one that's longer (141 or 146mm) and convert
the hub to 135mm over-locknut with more spacing on the left side.

You can only do this if you're willing to bend the frame to the new spacing. This is easy with steel
frames, harder with welded aluminum and titanium frames, and impossible with bonded aluminum and
composite frames.

Jeff

Song said:

Hi,

Wondering if it's possible to switch an 8-speed shimano freehub body onto a 7-speed (126mm)
freehub, and if it is, what's the best way to correct the spacing. Thanks in advance.

Song

Don't forget Sheldons 8 from 9 on 7 trick. Take 8 sprockets & 7 spacers from a 9 speed cassette, a 9
speed shifter and a 9 speed chain. These can be fitted on a 7 speed freehub body with 126mm drop out
spacing. I have tested it and nearly gathered all the parts I need to do it on two of my bikes. The
frame does not need bending and the wheel does not need re-dishing yet I still get 8 speed.

--
The Reply & From email addresses are checked rarely. mseries.freeserve.co.ukmseries.freeserve.co.ukOpen ↗

Song said:

Wondering if it's possible to switch an 8-speed shimano freehub body onto a 7-speed (126mm)
freehub, and if it is, what's the best way to correct the spacing. Thanks in advance.

Remove the axle by undoing the left cone and locknut . Unscrew the cassette body retaining bolt with
a 10mm key held in a vise. Unscrew the wheel from it.

Take note of any spacers or seals between the cassette body and hub. You may use the ones from the
original hub, from the new body, a combination or none to avoid drag of a seal or the body against
the hubshell. (There are several variants of body, seal and spacer. I have never seen a hub/cs body
combination that would not work but the spacers and seals vary a lot)

Clean all bearing areas thoroughly, rebuild with new 1/4" balls, grade 25, nine on each side. You
usually can respace the axle, removing spacers as required. Note the portion of axle protruding
beyond the locknut serves only to help center the wheel in the frame end - it is not a load bearing
part. So you can use a hub with just a couple of threads beyond the locknut without difficulty.

--
Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971

Thanks to all for the advice. To clarify: I have a 130mm frame on my homebrew campus fixie, and
a recently salvaged 8spd STI [so I'd like to use an 8spd cassette], but a random spare 7spd
126mm wheel. The basic idea is being able to switch the bike into a tourer if necessary, once or
twice a year.

So I guess if I can't (or shouldn't) modify the old 7spd body, I should just replace it with an 8spd
as per Sheldon Brown's article and advice posted here. Alternative is: anyone know a good way to rig
an 8spd shifter to run on a 7-spd cassette?

Just curious: So if the part of the axle beyond the locknut isn't weight-bearing (cf. Andrew Muzi),
what bears the weight then? The skewer? The frictional force at the skewer nuts?

regards Song

Song said:

So I guess if I can't (or shouldn't) modify the old 7spd body, I should just replace it with an
8spd as per Sheldon Brown's article and advice posted here. Alternative is: anyone know a good way
to rig an 8spd shifter to run on a 7-spd cassette?

You could fit as many sprockets with 8 speed spacings in as you can, maybe you'll only get 7, maybe
eight. Your STis will still work but you may not have 8 speed.

--
The Reply & From email addresses are checked rarely. mseries.freeserve.co.ukmseries.freeserve.co.ukOpen ↗

Song said:

Thanks to all for the advice. To clarify: I have a 130mm frame on my homebrew campus fixie, and
a recently salvaged 8spd STI [so I'd like to use an 8spd cassette], but a random spare 7spd
126mm wheel. The basic idea is being able to switch the bike into a tourer if necessary, once or
twice a year.

Quoted message said:

So I guess if I can't (or shouldn't) modify the old 7spd body, I should just replace it with an
8spd as per Sheldon Brown's article and advice posted here. Alternative is: anyone know a good way
to rig an 8spd shifter to run on a 7-spd cassette?

An 8spd STI shifter will shift a 7 speed cassette using a normal Shimano derailleur without any
modification. The cog spacing is nearly identical (4.8mm vs 5mm).

You can add a couple of washers to the wheel to make it fit into the 130mm spacing more precisely,
although this isn't strictly necessary.