As far as I can judge, measuring across with a tape, 41mm each. The pads are 112mm long (point to point) and 45mm wide at the centre.
That's interesting about an 88 CRX having ABS, thought the first were the EF8 Vtec's. I had a 89 EF7 parts car that didn't have it, still got the ZC engine&box out'a that. (Pic of the inside of the cambox & valve cover)
http://i898.photobucket.com/albums/a...en2pics009.jpg
The CA Accord that these twinpots came off was an '86 with the first of the B20A's (auto) in it. It was fitted with ABS as well. Massive great gadget with pipes and hoses, an electric hydraulic pump, and it's own computer that rivalled the EFI one in size. Bought it after it had hit a lamp post, thought I could straighten out the bent and kinked left chassis rail by the old chain around a post and driving the car backward. Yeah. Found out how strong those rails actually were. Wrecked it instead.