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Seatpost Clamps


The 3bDouble Clamp, the Mad4One unicycle seatpost clamp

an innovative solution to securely lock the seatpost and frame together




We often make the mistake to speak of “the diameter of the seatpost”. In fact the seatpost clamp works on the frame that holds the seatpost.
The equivalence "seatpost diameter - outside frame diameter" is not always the same, because the thickness of the frame changes if we use different materials.
Anyhow here the equivalence seatpost - frame we most commonly find on the market:
Seat post  22 - frame 25.4
Seatpost 25.4 - frame 28.6
Seatpost 27.2 - frame 31.8


However, we find some exceptions on the market:
  • The QX frames in Aluminum use a 25.4 seatpost  and a 31.8  seat post clamp.
  • Up to 2016 the Nimbus Eclipse and the Equinox frames were using a 25.4 seatpost and a 30.8 seat post clamp. Starting from 2017 they mount a 25.4 seatpost and a 31.8 seat post clamp.
  • The QuAx RGB frames mount a different measure and are not compatible with other products. Here we have a 31.6 seatpost and a 34.9 seatpost clamp.

The types of seatpost clamp available on the market




The quick release clamp ►  is the most easy one for the fast changing of the seat height, but for example, in basket or hockey, the quick release is considered dangerous because the lever that sticks out can hurt you in case of falls.

When you are performing advanced tricks the quick release can be uncomfortable and even annoying.

Sometimes the single quick release is not sufficient, for this reason, we propose to mount a double quick release. 


The 1-bolt clamp ►  is the lightest and if you use it with "mechanical intelligence" it should not give big problems. Some 1-bolt clamps are so light that they show limits in stiffness.


The 2-bolts clamp  ► is the one that should guarantee the best tightness, but it is not always sufficient.




The 3b Double Clamp of Mad4One ► is an innovative product developed by Mad4One in 2017. The 3b-DoubleClamp is a One-Piece CNC machined Aluminum clamp. A new solution that securely locks the seatpost and frame together.    
Take care, not to over tighten the screws with this clamp. You no longer have to sacrifice your frame to ensure a tight seat. 

A short video made by Pierre Sturny on the Mad4One 3B Clamp:  Pierre Sturny. 


Pay attention when tightening the bolts. Please do it gradually, slowly almost gently. The steel bolt may easily damage the fillet of the Alu-Clamp.

All clamps you find in our shop are made of Aluminum. The Mad4One seat post clamp are anodized in Italy in 14 different colors.




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