Shimano 7/8 speed.

[anderson]

Is it possible to use a shimano 8 speed cassette on a shimano (600)
7 speed hub? I'm assuming that the 8 speed spacers are thinner than
the 7 speed ones.

Thanks.

 

[Zog The Undeniable]

anderson wrote:

> Is it possible to use a shimano 8 speed cassette on a shimano (600)
> 7 speed hub? I'm assuming that the 8 speed spacers are thinner than
> the 7 speed ones.

You have to replace the freehub, redish the wheel and respace the frame
to 130mm (shame it's not a mountain bike - the spacing for them changed
with 7 speed).

Given the hassle, you might as well go to 9 speed.

 

[Sheldon Brown]

anderson wrote:
>
>> Is it possible to use a shimano 8 speed cassette on a shimano (600) 7
>> speed hub? I'm assuming that the 8 speed spacers are thinner than
>> the 7 speed ones.
>
Zog The Undeniable wrote:
>
> You have to replace the freehub,

No, he or she does not need to replace the whole Freehub, just the
Freehub _body_.

See: http://sheldonbrown.com/k7.html#transplant

> redish the wheel and respace the frame
> to 130mm (shame it's not a mountain bike - the spacing for them changed
> with 7 speed).

That's correct.

See also http://sheldonbrown.com/frame-spacing

Sheldon "Ugrades" Brown
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[juicemouse]

I have an older Trek 730 hybrid that's been slowly evolving into more
of a touring/cross/all-rounder kind of bike. It's got a Shimano Alivio
7 speed setup on it now, and I'd like to go to 8 speed. If the OLD
spacing is already 135mm, would I have to do any spacer swapping on the
hub or re-dishing of the wheel if I swapped out the freehub body? I'm
probably going to spring for new hubs eventually anyway, but I was
thinking about just doing this in the mean time if it isn't too much of
a hassle.

 

[JeffWills]

juicemouse wrote:
> I have an older Trek 730 hybrid that's been slowly evolving into more
> of a touring/cross/all-rounder kind of bike. It's got a Shimano
Alivio
> 7 speed setup on it now, and I'd like to go to 8 speed. If the OLD
> spacing is already 135mm, would I have to do any spacer swapping on
the
> hub or re-dishing of the wheel if I swapped out the freehub body?
I'm
> probably going to spring for new hubs eventually anyway, but I was
> thinking about just doing this in the mean time if it isn't too much
of
> a hassle.

Yes, you'll have to play with spacers in order to get everything right.
The 8-speed body is wider than the 7-speed, but I can't recall if that
means there's fewer spacers on the left or more spacers on the right.

You'll definitely have to redish the wheel.

Jeff

 

[James Thomson]

"juicemouse" <[email protected]> wrote:

> I have an older Trek 730 hybrid that's been slowly evolving into
> more of a touring/cross/all-rounder kind of bike. It's got a
> Shimano Alivio 7 speed setup on it now, and I'd like to go
> to 8 speed. If the OLD spacing is already 135mm, would I
> have to do any spacer swapping on the hub or re-dishing
> of the wheel if I swapped out the freehub body?

Yes, you'll need to re-dish, and you'll lose a spacer from the left end of
the axle. That may mean leaving off the hub's external rubber seal.

> I'm probably going to spring for new hubs eventually anyway,
> but I was thinking about just doing this in the mean time if it
> isn't too much of a hassle.

In that case, consider running eight nine-speed sprockets on your current
wheel, as described here ('8 Of 9 On 7'):

http://www.sheldonbrown.com/k7.html#up7

When you replace your rear wheel, you can go to a full 9-speed system.

James Thomson

 

[Zog The Undeniable]

Sheldon Brown wrote:

> No, he or she does not need to replace the whole Freehub, just the
> Freehub _body_.

Excuse my shorthand. If I'd meant the whole freehub I would have said
"hub".

 

[Tomek Li]

"anderson" <[email protected]> wrote in message
news:[email protected]...
>
> Is it possible to use a shimano 8 speed cassette on a shimano (600)
> 7 speed hub? I'm assuming that the 8 speed spacers are thinner than
> the 7 speed ones.

The simple way to accomplish your task:

1. Replace the 7 sp. freehub body with a new, 8 sp one
2. Redish a wheel, as it will now shift some 2,5-3 mm to the left
3. Fit an 8 sp casette (I myself would rather go for 9 sp)
4. Fit 8 sp RH Shimano shifter (once again,I myself would rather go for 9
sp)
5. Adjust shifting and enjoy

Cheers,

Tomek Li