If I do need to get 597 size (26") rims, any idea where I could source them?
Nobody seems to make them, so you're going to be searching in the second hand market. Check the tyre markings to see if the 26×1¼ has suffix EA1 (597) or EA3 (590)
Thanks for the help. One of the tyres is very worn and hard to read the other says 32-597 so clearly is that size. I'll just have to call them and see if they'd be happy with the 590 size from sjs but also having to get new tyres. Guess there will be an issue with brake caliper reach.
Nobody seems to make them, so you're going to be searching in the second hand market. Check the tyre markings to see if the 26×1¼ has suffix EA1 (597) or EA3 (590)