저두 궁금했는데요 아시는분 부탁해요..프레임교환해야하거든요..

M5가 더 가볍고 강하다고 합니다. 돈 따지지 않는 비싼 자전거에만 쓴다고 하네요 -_-;
전에는 S-Work에 M4가 쓰였었네요. 아래는 스페셜 홈페이지에서 긁어왔습니다.

<< M5 >>
M5 has exceptionally high tensile strength so less material can be used without sacrificing strength requirements.
M5 retains substantially more of its strength (hardness) after welding than other alloys, again enabling less material use while maintaining high strength.
Where it's found:
M5 is utilized in our S-Works hardtail and S-Works FSRxc models where cost is no object and ultimate performance is.

<< M4® >>
Specialized's brand new aluminum alloy process used for frame construction. M-4's advantage over other materials is it's ability to be shaped much more extensively than 6061 aluminum, M2, Titanium, or steel.
M4 is our proprietary aluminum alloy, which means we've taken aluminum and alloyed it with 1.2% Silicon (Si), 1.0% Copper (Cu), 1.6% Magnesium (Mg), and 0.3% Vanadium (V). M4 has almost twice the elongation (16%)of M2 and allows for much more creativity in manipulating the tubing resulting in a frame that is lighter, stiffer and stronger than just about anything out there.

가격 차이는 많아도 별 차이 없는걸로 알고있습니다 하드테일로요 .. 그래두 5가 좋긴 좋을거 같은