7 speed cassette onto 9 speed hub?

[Fab Foodie]

Both Shimano.
Is this possible with spacers?

The rear rim on my 7spd wheels has started to split around a spoke. I have currently 2 spare pairs of wheels I could use.
As this is on DT shifters I could fit an 8 speed cassette possibly.

What are the options and where to get the bits?
Cheers
FF

 

[BSRU]

I used to have a deore hub with a 7 speed cassette, you just need the right spacer.
SJS are good for those sorts of bits.

 

[Steve Malkin]

The 7 speed wheels will be 126mm OLN, so presumably that is the dropout spacing of the bike they are fitted to?
A 9 speed hub will be 130mm OLN so you will need to spread the rear dropouts to accommodate the wider hub. If it's a steel frame you can probably achieve that by just 'springing' the arms apart when fitting the wheel, but it should really be cold set.
If it's using non-indexed downtube shifters then once the wider hub is in the frame there would be no reason not to just stick an 8 or 9 speed cassette on there, why would you want to bother with a 7 speed one?

 

[Fab Foodie]

The 7 speed wheels will be 126mm OLN, so presumably that is the dropout spacing of the bike they are fitted to?
A 9 speed hub will be 130mm OLN so you will need to spread the rear dropouts to accommodate the wider hub. If it's a steel frame you can probably achieve that by just 'springing' the arms apart when fitting the wheel, but it should really be cold set.
If it's using non-indexed downtube shifters then once the wider hub is in the frame there would be no reason not to just stick an 8 or 9 speed cassette on there, why would you want to bother with a 7 speed one?

The 9 speed Ultegra wheel off my Giant TCR1 fits a treat and seems (quick test run) to be OK, but has max rear sprocket of 25T whereas the 7 speed has 28T, all in all not such a big issue but with a 40T smallest front ring I need all the help I can get for the Whitstable ride on Friday!

 

[Steve Malkin]

Ah, I see.
In that case, your 7 speed cassette can be made to fit, but you'll need a 4.5mm spacer behind the largest sprocket.

 

[Fab Foodie]

You would be fine with 40 x 25.

.... Damn that's my excuse for walking the hills gone then ....