OK, this is turning into another bad day. I have an old 6-spd that I wanted to replace the freewheel for a higher T one. While I was on the road, I ordered a cheap Sun Race 13-30T 7-spd cassette(this is being edited, I meant freewheel). It wasn't until I got home home that I looked to see the RD is a 'short-cage'. It's a Shimano 600 SIS and I've got a bad feeling that it's not going to reach a 30T. Let me down gentle.