HerrKaLeun

I don't think a redundant rim brake up front will work since with disc brakes you likely have rims not made for rim brake. Also that adds weight, if that matters to you. You could just carry an additional mech. brake and carry with you.

I recently upgraded my front and rear mech. disc brake to hydraulic and never would go back. I don't think reliability is an issue with hydraulic brakes. and if, you still have the rear brake. If you only have one brake (even if you mount the rear to front) you should not really ride at all or only cautiously since that brake also could fail. If you ride cautiously and slow, it doesn't matter where the brake is.

If overheating front brake is a concerns, use larger rotor and possibly a more expensive brake with cooling fins. Sounds like you plan to have lot of luggage and on long descents I see your concern.

Maybe once you installed your front brake and shortened the lines yourself and bleed the air you gain more confidence. They are far better. You have two opposing pistons moving (mech brakes mostly only move one), no cable stretch, larger advantage etc.

You also could use a rear hydraulic brake and as long as you can move the hydraulic line without having to bleed. Then you just roll the (too long for front brake) brake line around your handlebar for that time.

When I upgraded my brakes I planned to keep the rear mech. brake because I'm cheap and assume it is not used often. but once I had my front brake and saw how easy it is to adjust and set up I went for the hydraulic rear brake. Sounds like you buy all new hardware, I would not waste time on mech. brakes when hydraulic brakes are so cheap these days.

If your hydraulic brakes are properly sized (front rotor!), of good quality and properly maintained I don't see danger of failure. and that is what the second brake is for anyway. You probably have 100 drive train failures and 1000 flats before you have one brake failure.

Edit: you could carry a bleeder kit on your tour if you really want to swap brakes