Seatpost Clamp Question

[milwaukeehaze]

I want to put a QR seatpost clamp on my Giant NRS Comp 2 and I have a 27.2 Thomson Seatpost right now. Short of taking the existing bolt-on clamp off to measure it, would I use a 28.6 or 30.0 mm clamp diameter?

Thanks!

 

[nerdag]

I want to put a QR seatpost clamp on my Giant NRS Comp 2 and I have a 27.2 Thomson Seatpost right now. Short of taking the existing bolt-on clamp off to measure it, would I use a 28.6 or 30.0 mm clamp diameter?

Thanks!

If its 27.2 post, then chances are its a 31.8mm clamp.

HTH,

nerdag.

 

[milwaukeehaze]

If its 27.2 post, then chances are its a 31.8mm clamp.

HTH,

nerdag.

Thanks for the response. Yeah, I think you are correct. My frame is carbon and by the looks of the thickness of the edges of the seatpost hole (that the current seatpost collar surrounds) it is about 2 mm thick, so adding 4 mm to the 27.2 post, the diameter would be 31.2 and adding in some play, 31.8 would be right.

 

[gclark8]

Do not use a Quick Release clamp on a carbon frame. Use only the clamp supplied and tighten only with a torque wrench to the specified tension!!

 

[milwaukeehaze]

Do not use a Quick Release clamp on a carbon frame. Use only the clamp supplied and tighten only with a torque wrench to the specified tension!!

Do you know what the reason is to not use a QR clamp? I normally don't use one, but occasionally I want to transport my bike inside the back of my SUV using a floor-mounted fork mount, but the seat needs to be lowered to fit. I just the thought the QR would be the easiest way.

 

[nerdag]

Do you know what the reason is to not use a QR clamp? I normally don't use one, but occasionally I want to transport my bike inside the back of my SUV using a floor-mounted fork mount, but the seat needs to be lowered to fit. I just the thought the QR would be the easiest way.

George is right.

It's too hard to control the amount of torque you should use, making it easy to crush top of the carbon seat tube.

Not sure of any solutions to your dilemma.