Replacing a rim brake fork with a disc brake one?

[jamesofyorkshire]

I have a 2016 Trek FX7.7................which is actually a Domane 4 with flat bars. It has rim brakes. I'd like a disc brake on the front. If the dimensions of the headset bearings etc. are the same, is there any reason I should not put a fork with disc brake on the frame? Is the frame/headset designed differently to take discs?
I can't think of any reason why it's not feasable but I wanted to throw it out there for more knowledgeable people to comment on. Maybe the torque pull or something might mean it's not a good idea.

Why do I want a front disc? I spend a LOT of time in Europe doing the famous climbs. I'm only an old fa** that grinds up the hills, and am quite timid coming down. That usually means being on the brakes a lot and I always keep stopping to let the front rim cool down as I don't want the front tyre blowing off! I figured a mechanical disk on the front is the answer. I'm happy enough with the bike otherwise and don't want to waste money on another one.

[crazydave789]

straight swap over, shouldn't be a problem just make sure you have a long enough stem.

[andrew_s]

a) The loads on the frame are the same, provided that you are decelerating at the same rate.
b) You want to check the fork rake is the same, as well as the headset dimensions. If it's different, the handling of the bike will change, which may be something you would get used to after a few days, or it may not.
c) Disc brakes overheat too, even mechanical ones, as there's less mass of metal to absorb the heat. The best way to avoid the issue is plummet and stop braking, which means more of the energy is going into wind resistance, and also means managing the extra speed during the plummet phase.

[jamesofyorkshire]

" just make sure you have a long enough stem". ???

Plummet??? I don't think so......lol