Originally Posted by Hocam
Horizontal dropouts are only more functional with a rear brake so you never have to re-adjust the pads when changing chain tension.
Rear brake adjustment, if you ever want to run full fenders without hassle, versatility.
Track ends are only really useful if you want to jam the rear wheel 1/8" from the seat tube.
How does a RD put more force on the axle? Because of the mechanical advantage of the gearing? I don't follow if that's why
It's not the RD, it's the gearing that puts force on the chain/axle. Lower gears=more torque/force.
A weak 110# person spinning in a granny gear will generate more torque/force on the chain and on the qr/axle than any world champion track rider. This is why QRs can be used on fixed rear wheels- they are under way higher loads on geared bikes. Same thing with chains- they are under way higher stresses on geared bikes than on any fixed bike.