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It depends on models, currently only HDC300 is not adjustable. But there is "WS" version for short reach if it's not adjustable.

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The length of center bolt to mount on fork for front and frame for rear is different. Also the forward of brake pad is opposited.

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No! Due to the different actions within the shifters, the road lever can not use it with mountain bike front derailleur.

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Yes, part number P423.11 is a special compound replacement brake pad specifically designed for use on carbon rims.