Hello

I currently have a 34/50 double chainring on my six-speed Brompton, and would like to add a derailleur so I don't have to stop and move the chain by hand.

Someone used one of the following clamps to do just that on a Dahon:

• LitePro Braze-On K-Series Front Derailleur Clamp Adapter For Dahon K Frame
• LitePro P-Series Braze-On Front Derailleur Clamp Adapter For Dahon P Frame

Any idea what the difference is between the K and P Series, and which one is more likely to fit a Brompton, whose seattube measures 38,55mm?

Thank you.