Marzocchi went there once, with a single-crown Shiver:
Originally Posted by chelboed
I think it flamed out quickly because of irresolvable flex issues. Seems they designed it around 30mm stanchions though, so the results were predictable.
From the PB article:
Originally Posted by Daspydyr
"The old argument of inverted forks having [more] torsional flex needs to be thrown out the window as it is far less relevant than most believe. Keeping in mind that the fork is well into its travel when being ridden, which stiffens the inverted chassis up greatly, the cliche test of pinching the front wheel between your legs and twisting really has no bearing in real world applications. It is also interesting to note that many forms of motorized sport actually build in a degree of lateral flex to allow the wheel to follow the smoothest line through a section - especially when leaned over in a corner - which allows it to track better in the rough."
Also of note: In the moto world, superbikes have all gone to inverted forks because of needing to offset not only fore-and-aft flex forces but the lateral forces of braking/cornering, especially as displacements (and thus weights) have increased.