Joined: Oct 2018
Posts: 2,191
Likes: 1,054
From: Columbus, OH
Bikes: Pake C'Mute Touring/Commuter Build, 1989 Kona Cinder Cone, 1995 Trek 5200, 1973 Raleigh Super Course FG, 1969 Raleigh Superbe, 1986 Miyata Nine : 1960/61 Montgomery Ward Hawthorne "thrift" 3 speed, by Hercules (sold), 1966 Schwinn Deluxe Racer (sold)
This is fine, don't sweat it. The 2mm deviation you're describing likely won't cause the rails to become permanently deformed. If you have a friendly lbs or co op nearby, they probably have a collection of clamps you can sort through to find a better fit (if this is a seat pin clamp, and not a modern integrated clamp).