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Questions & Answers (3) Q & A
KCNC's Twin Clamp is designed to solve the annoying slipping seat post! It does happen - and this clamp is designed to prevent posts slipping down inside the frame by having 2 clamps joined together - one clamps the seat tube as normal but the top clamp grips the seat post itself to provide an extra clamping force without over stressing the seat tube clamp or the seat tube and seat post itself!

Comes in 4 combinations of seat tube / seat post sizes;
- 30.7-27.2mm (23g)
- 31.8-27.2mm (25g)
- 34.9-30.9mm (27g)
- 34.9-31.6mm (28g)

- CNC machined with two Ti bolts make it light
- Machined from 7075-T6 AL alloy
- Twin titanium bolts, gold nut bars
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Questions & Answers (3)
Can you tell me the height of this clamp please?
09 Apr 2018
Hi there,

The height is 24mm

Seatpost clamp
16 Nov 2017
Hi guys, which side double seat post clamp would i need? My stump jumper has a 30.9 dia now... I'm not sure which diameter this refers to and i don't have a set of verniers to hand.


That would be your actually seatpost diameter, so it is likely that the 34.9 & 30.9mm size should be the correct one, however we have no way of knowing the frame size specification of your Specialized frame to be able to say for definite if it will fit or not.

My bike has a 31.8 seat clamp but slips.
29 Aug 2017
It is the correct size. I now want to try a twin bolt KNC seat clamp but am not sure what size as you offer four options. My guess is 34.9-31.6?

The measurements would be the diameter of the seat tube and the diameter of the seat post.