[QUOTE 4997918, member: 9609"]I have an older bike with 126mm between the rear dropouts.
For a while I have wanted a spare rear just for emergencies
I have found two rear wheels in a skip the night . . . 130mm dropouts, 8 speed as opposed to my 7 speed.
So to my question, can I convert these so as they fit without bending my frame ?
Is it possible to get a spacer for the freehub so as a 7 speed cassette will fit onto an 8 speed freehub ?
In the picture you can see a chrome coloured washer/spacer between the locking nut and the cone that is 5mm wide; could I simply replace that with a 1mm washer then grind 4mm off the threaded axle ? thus giving me a 126mm wheel.[/QUOTE]
IMO it'd be worth trying to discover if there was a functional reason for the wheels being skipped (as opposed to just surplus to requirement).
From the image these are low grade wheels so the effort to convert them to 126mm OLN (which you need to keep because your wheels in use are 126 (these are just to have a spare)) is probably disproportionate.
Yes, you can get a spacer to allow a 7sp cassette to 'fit' onto an 8sp freehub.
But if you replace the 5mm spacer nut on the axle with a 1mm one, that will shift the centre line of the wheel rim (as
@Sharky has said) and when you try to remediate that by redishing, the extreme spoke angles will mean the wheel is unacceptably weak.
If your frame is steel, I reckon
@User 's advice is best. If I were you I'd find a 126mm freewheel wheel second or third hand, which would be good enough to serve as a spare.