The first Fusin geared hubs I saw used philips heads, but later versions used allen heads.
The main disadvantage of philips is it's really easy to strip out the head if you use the wrong size driver and/or it's too tight (or siezed), and really hard to then get the screw out with normal tools you'd have laying around. (I happen to have a stripped-screw remover for computer case stuff that worked when one of my Fusin's screws did that, but most people won't).
An allen head is not as easy to damage, and if you *do* happen to do so, you can usually still grip the outside of the head and turn it with pliers, if space permits where the screw is located.
As Motomech notes, if you have to use allens that are tiny, the wrench can't apply sufficent torque without twisting, though that would have to be pretty small.
FWIW, the philips stuff on the FUsins didn't use lockwashers, but the allens did use a split-washer. But they were large enough heads that I never had teh problem Motomech dexcribes; I think they were at least a 2mm wrench (maybe 2.5?) cant remember anymore.
At present I have an HSR3548 hub on teh right wheel of SB Cruiser, and even when it was on CrazyBIke2 it's always had this wierd problem where it's cover screws loosen and fall out if I don't regularly check them, even with loctite. So it's got a mishmash of screws with at least 4 or 5 different head types, from standard hex-head bolt to allen to philips to some security-bit type with a slot, to regular flat head, and I forget what else. None of them are any better at staying in than any other, but some are a lot easier to tighten and loosen.
The main disadvantage of philips is it's really easy to strip out the head if you use the wrong size driver and/or it's too tight (or siezed), and really hard to then get the screw out with normal tools you'd have laying around. (I happen to have a stripped-screw remover for computer case stuff that worked when one of my Fusin's screws did that, but most people won't).
An allen head is not as easy to damage, and if you *do* happen to do so, you can usually still grip the outside of the head and turn it with pliers, if space permits where the screw is located.
As Motomech notes, if you have to use allens that are tiny, the wrench can't apply sufficent torque without twisting, though that would have to be pretty small.
FWIW, the philips stuff on the FUsins didn't use lockwashers, but the allens did use a split-washer. But they were large enough heads that I never had teh problem Motomech dexcribes; I think they were at least a 2mm wrench (maybe 2.5?) cant remember anymore.
At present I have an HSR3548 hub on teh right wheel of SB Cruiser, and even when it was on CrazyBIke2 it's always had this wierd problem where it's cover screws loosen and fall out if I don't regularly check them, even with loctite. So it's got a mishmash of screws with at least 4 or 5 different head types, from standard hex-head bolt to allen to philips to some security-bit type with a slot, to regular flat head, and I forget what else. None of them are any better at staying in than any other, but some are a lot easier to tighten and loosen.