I love them, have 3 or 4 old SPOX pairs on the go, and some more modern 26" Xyclones, QR with discs.
The spokes are pretty tough, and are rarely the problem. The rims do wear like any rim, (although some are ceramic coated), usual downfall is bearings and freehub, but they are serviceable.
I think he old rims are re-badged Sun Metals CR-18s, but you'd need a 24 spoke one for that pair. Not unknown, but pretty rare. Later models switched to 28/32 spokes.
I've salvaged replacement rims from surviving front wheels in the past. Several Mavic and Velocity rims are a similar profile, so could be substituted. The spokes do have a decent adjustable range if the rim's slightly different height.
The
Spinergy company are still going, but not so much profile in the bike world these days.
They still use the same thickness spokes on their wheelchair wheels, where our 26"/559mm size is still popular (but logically known as 25"
). I have a small stock of spokes.
My old company, Draft Wheelchairs, in Cambridgeshire also had stock of spokes and I think they are still available from them, or Spinergy direct. Spinergy's new wheels adjust at the rim now, but they are the same spokes.
Length is measured overall, end-to-end. This was the 2018 offering with part numbers:
They are more fiddly than standard spokes and nipples since the spoke needs to be held firm at the hub against twisting while the nipple is turned. OK for just truing, but a PITA for building up with a new rim.
The details of the nipples, and required spoke keys varied a little over the years, but I certainly have these to lend if you need, and duplicates of most. Most commonly, you'll need one small spline key and a hex spanner, or on older wheels, two spline keys (one large, one small spline).
All the best,