Check the listing for details. Wolf Tooth 38.6mm Aluminum Seatpost Clamp - Precision Self-Aligning,. Condition: New. Listed at 25.82 USD. The precision-engineered Wolf Tooth Seatpost Clamp secures your seatpost and looks good doing it. At the heart of this seatpost collar is our custom self-aligning bolt and anchor. The M5 bolt includes a spherical washer and mates with a cylindrical anchor barrel. This means that threads are always perfectly aligned, preventing binding and ensuring consistent clamping force. Machined from 6061 aluminum in our Minneapolis facility, the Wolf Tooth Seatpost Clamp is available in seven sizes. Compatibility Clamping Diameter:. 28.6mm/29mm 29.8mm/30mm 31.8mm/32mm 34.9mm/35mm 36.4mm/36mm 38.6mm/39mm 39.7mm/40mm Frames may vary slightly from the nominal diameters due to tolerances and paint thickness. Clamps will fit on frames that are within +/- 0.5mm of specified size. For example, a 34.9mm clamp.