[sometimerider]

then there will be less clearance between the front of your toes and the tire. Thus, by 'bending' the fork, it puts the wheel further forward allowing for more clearance.

I don't think so. Straight forks, at least all those I've seen on road bikes, aren't really straight. They have a bend right below the head tube:

View attachment 179608

Thus they can have exactly the same trail as a curved fork. See this for a description of fork trail.

IMO, a curved fork, given otherwise similar geometry and materials, is less likely to break (the bend point of a straight fork is a high stress point) and provides better suspension.

Other things being equal, a curved fork is better.

 

[sometimerider]

I see. That would seem to make sense- in other words, a curved fork provides tighter handling because you are essentially steering directly under the wheel vs. out in front of your wheel, yes?

The quickness of the handling is largely determined by the head tube angle and the amount of trail (less trail implies quicker steering). Since straight and curved forks can be identical in those measures, they could be exactly the same with respect to quickness.

(Of course, quicker steering implies twitchier handling - so it's a trade-off.)

 

[sometimerider]

This is a case of "it depends".

Doesn't it always.

I think what you're saying matches (and in a few spots, exceeds) my understanding of the issues at play (hey, I've had some physics and engineering classes).

With a curved fork, the stresses endured when an impulse tries to compress the fork are distributed over the curved portion. In a straight fork, they are concentrated right at the bend below the head tube. I think the latter is harder to deal with and less likely to be both strong enough and able to behave elastically.

Thanks, Bent.

 

[sometimerider]

Yep... but with a curved fork, you get the same stress at the bottom of the head tube. The shape of the fork doesn't matter to the crown. All it knows is someone is bending the crap out of it, and if the rake is the same, the moment is the same.

I'm not sure that's true if one fork can better act as a spring than another. And I think a curved fork does. If the fork's design can absorb impulses, the crown will see less stress.

A straight (but angled) fork can also act as a spring, but most of the bending stresses are concentrated at one point.

 

[sometimerider]

Maybe we are thinking of different affects... I am merely talking about the load from my fat arse sitting on the bike. I think you may be considering hitting something from the front. In that case, you may get higher loads in the straight fork... Ill have to think about that one...

You're right, I haven't been talking about static loads. That shouldn't be a significant design issue. It's the dynamic loads, such as when you hit a pothole, that can break a fork. And how the fork responds to them contributes to ride comfort (a very important issue to me and my arthritic wrists).