I'm retiring the 5-speed freewheel on my late-70s Chris Kvale bike and switching to a Suntour Ultra 6-speed Winner freewheel. I got a SRAM PC-68 chain with it. The chain instuctions refer to a proprietary chain tool for the PC-68. Do I really need that? I tried removing a link with the standard chain tool I have used for my five-speed chains, and it seemed to have pinched the remaining link in the process -- it pivots stiffly now. Any advice?