The chains I use are 6 and 7 speed compatible.I changed to a slightly thinner one and that seemed to help a little.The problem may better be described as a sticky or gritty feel while pedaling and I'm going to try to see if it goes away if I do some miles as the cassette was unused and maybe not oiled enough as Tuc did point out.There is no problem in the front by the way.Also the shifting is friction shifting only.
Last edited by trek330; 05-13-12 at 02:30 PM.