700 seat post.. not a quick release clamp?

[tlippy]

My seat post dia is 31.45mm, the O.D.of the clamp needs to be38mm . what size do I buy?

 

[Nova Haibike]

Not sure I understand what you mean by the O.D. of the clamp. Do you not mean the I.D. of the clamp?

If you want to buy a different clamp, remove the old one and measure the O.D. of the frame's seat tube. That will be the size you need.

 

[tlippy]

I removed the lever on the O.E. clamp, kept the barrel nut and concave washer and used the O.E. bolt which I tightened the seat with an allen wrench that came with my 700. A 38.5 was difficult to get. All's well. Thanks for commenting