Can't find any replacement original chainrings (SG A-52-42-30) . What can I use instead? I have an early 2000's Giant OCR 2 roadbike (3x8 speed) with worn out chain rings on the Shimano Sora FC-3303 triple crankset. The original rings are the SG A-type, 5 bolt, 130 mm BCD in 52T-42T-30T sizes. All I can find are used ones, and I'd prefer not to change the crankset. Can I just drop the A-type originals and go with new ones in the same bolt pattern and BCD that are close (ie 53T-39T-30T)? Thanks
Yes, you don't have to use actual Shimano chainrings, you can use 'third party' brands.

There are a few manufacturers that produce replacement chainrings in a wide range of BCD measurements and tooth counts, so you be able to get exact matches.

If you do decide to change gearing, derailleur position and chain length will need to be changed, but you should probably be replacing the chain at the same time as as rings anyway, and also checking at the cassette for wear and replacing that if necessary.