One top seat collor is the Thomson Seatpost Clamp. Great looks, great clamping, long life and no squeaking. The perfect addition to your Thomson Cockpit. There is also the Salsa Lip-Lock Seat Collar. The Salsa Seatpost Clamp Lip Lock Model has a threaded seat collar as well as a pivoting stainless steel threaded insert which reduces bowing and fatiguing of the pinch bolt. Consider the Woodman Deathgrip Seat Clamp, Item #: SE295F04. Woodman's popular Deathgrip seat clamp is a strong and lite seat clamp that gets the job done. Hope Seat Collar - Quick Release - For those riders who prefer to have a quick release on their saddle, Hope offers this 2014 CNC machined aluminum clamp. Kalloy Xtb-N QR Seatpost Clamp - Item #: QR295B02 - The Kalloy XTB-N is a strong 2D forged clamp that features a quick-release lever. Syntace Superlock Seat Clamp. High-end 7050 aluminum construction with a shot-peened and anodized finish. Thomson seatposts and stems only require 25 inch pounds of pressure to hold your post securely. 15mm tall and very quiet. Average weight of only 27 grams. Thomson's Seatpost Collar gives you lightweight, squeak-free, forget-it's-there performance. Float on both sides of the collar ensure even distribution of clamping force, and Thomson's legendary precision machining provides good looks and super-tight tolerances. Product Features - Material: aluminum - Diameter: many to choose from - Quick-Release: no - Weight: 26 g - Recommended Use: road or mountain - Manufacturer Warranty: limited lifetime. Shimmy Shimmy is a term for a harmonic shaking of the bicycle, which usually occurs at a fairly high speed. Shimmy can be very scary, and can lead to loss of control. All bicycles are subject to shimmy under the right (wrong) circumstances, but it is more pronounced in some bike parts and under some conditions than in others. The rider feels shimmy mainly through the handlebars, so it is often assumed that the cause relates to the front wheel or the headset. Serious shimmy is also frequently caused by floppy, poorly supported luggage on top of a rear luggage rack. Replacing your bike seat collar may be related. The front end of the bicycle, on the other hand, is symmetrical, so the steering action works alternately in both directions, right and left. Shimmy is very much like the way a fish's tail drives the fish through the water, only backwards in two ways -- front-to-rear and in terms of energy transfer: the side-to-side motion of the fish's tail moves the fish forward -- but the forward motion of the bicycle feeds the side-to-side motion of the front wheel. The steering angle of the front wheel converts the forward motion of the bicycle into sideways motion at the bottom of the wheel, twisting the frame. The center of mass of the steered parts -- front wheel, fork, handlebars, baggage -- is ahead of the steering axis -- and so the resulting tilt of the head tube steers the front wheel back to the other side. Many bike owner have 30.0 mm seatpost clamps as Surly is a big, big market here, so if you offer a 30.0 mm that's a good fit. A shim for their 31.8mm seatpost clamp to provide a solution for 30mm seat tube Surlys. With a pitlock seatpost skewer and it looks to be working fine (based on a quick around-the-block shakedown ride.) It is available in the clamp-size dropdown after you select the color.