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KCNC SC13 Twin Seat Post Clamp

Customer Reviews (5)
2.6 / 5| Write your review
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£24.99 Please note this product has selling restrictions to your country. was
Manufacturer : 
SJS Cycles part number : 
Manufacturer part number : 
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
Product Reviews (5)
Questions & Answers (4) Q & A
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Product Reviews (5)
Overall Product Rating 2.6 / 5
Like the clamp
By Big E
09 Dec 2020
2 / 5
Like other reviewers...the bolts suck! Head snapped on bottom bolt during installation, and lost barrel nut. Can't find parts anywhere. Not spending the money for another. Superglue and an $10 clamp will do
By Michal Kreft
05 May 2020
1 / 5
Consbolt should be made from steal or titanium
Proslight, nice looking
I've had 2 these clamps
in both the bolts broken
using 6kN and 7kN
despite manufacturer claim
maximum strength is 10kN
did the trick
By Alan s
13 May 2019
4 / 5
I recommend this product
Prosdid exactly what it was supposed to do
after struggling for months with any number of other solutions the seat post is now fixed and doesn't slip any more - a blessed relief
Good clamp with swiss cheese bolts
By Steven Laycock
13 Jun 2018
1 / 5
The clamps works well. I needed a 27.2/31.6. Unfortunately the head of one bolt snapped off at installation despite using a torque wrench.

The second, larger bolt rounded off and had to be drilled out.

The bolts have a strangely narrow head which site in a circular hole so its not easy to find steel replacements.

If you can find steel bolts that will fit this clamp works exceedinglu well. But good luck with that.
Solved my slipping seat post problem
By Anonymous
26 May 2018
5 / 5
I recommend this product
I couldn't stop the carbon seatpost on my new TI Boardman from slipping down until I bought this clamp.
Bought the black to match the original design, and torqued it up to 4Nm on the top and 6 Nm on the bottom.
Problem solved. If I lost a couple of stones in weight, I might be able to go back to the original Boardman clamp.
Questions & Answers (4)
Do you know when you’ll be getting stock of 34.9 / 30.9 in Black. Thanks.
22 Dec 2020
We won't be as they are now discontinued.

JK 22.12.20
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.