Bicycle Mechanics - Freewheel & derailleur compatibility question

Need some help on this. Currently have a bike that is equipped with Campag 980 with a 52-42 crank and 13-24 freewheel. I wanted to get a slightly lower gear and I was looking at installing a 13-28 freewheel and going to 7 speed. The mechanic at my LBS said it should be able to handle a 28 tooth max. Also I've been made a sweet deal on NOS Suntour Sprint 9000 derailleurs and shifters. Would either of the rear mechs be ok with the 28 tooth on the rear? I would imagine I just have to stay off the large ring in front when on the larger two cogs in back.

Campy has a differnt cog spacing than Shimano so if you are putting a Shimano compatible freewheel on the back you will need to replace the Campy rear mech or switch your shifters to friction only. I wouldn't mix Campy and Shimano drive train components, you are asking for headaches. AS far as the tooth size is concerened are you worried about the rear mech chain tensioner being stretched too far? It is very possible, but if you stay off the large front and large back at the same time you should be ok. DOn't let anyone else ride the bike without telling them about this gear "quirk" though.

I wouldn't mix Campy and Shimano drive train components, you are asking for headaches.

I agree but the OP did not say anything about using Shimano or indexing.

Need some help on this. Currently have a bike that is equipped with Campag 980 with a 52-42 crank and 13-24 freewheel. I wanted to get a slightly lower gear and I was looking at installing a 13-28 freewheel and going to 7 speed. The mechanic at my LBS said it should be able to handle a 28 tooth max. Also I've been made a sweet deal on NOS Suntour Sprint 9000 derailleurs and shifters. Would either of the rear mechs be ok with the 28 tooth on the rear? I would imagine I just have to stay off the large ring in front when on the larger two cogs in back.
According to Sutherland's the 980 should be able to handle a 28T freewheel and 26T total capacity (difference between small and large freewheel cogs + difference between smallest and largest chainrings). Your proposed total capacity is (28-13)+(52-42)=25 so you should be ok. Large-large and small-small combinations should be avoided in any case.

Campy has a differnt cog spacing than Shimano so if you are putting a Shimano compatible freewheel on the back you will need to replace the Campy rear mech or switch your shifters to friction only.
The 980 isn't an indexed derailleur so this concern is moot...

The 34 tooth freewheel gives me a bit of pause, it wouldn't surprise me is neither derailer could take it. Maybe your better off with something a little smaller like a 30.

Thanks guys. I figured I should be ok. It's friction, no indexing, regardless if I change to the Suntour parts and/or 7 speed. I ask about going to a 28 tooth max as I haven't seen any freewheels with a 26, er, at least any that are worth it.

The 34 tooth freewheel gives me a bit of pause,

???