That misnomer - Sliding Pillar...
The trad Mog front suspension does have some advantages - it is simple, easy to maintain and keeps the tyre surface in road contact at a constant.
So, it doesn't have a great deal of travel, big deal. It can be set up to give more movement early in compression, by slightly shorter main springs, so that both main and rebound are not pressing on the stub axle (that's the moving bit BTW, not the pillar) concurrently. Though it seems counter-intuitive, having both springs in compression acting on the stub axle increases the spring rate. So, in standard form (until the new generation, shorter, rising rate springs appear) the Trad has falling rate suspension for the initial suspension travel.
There is an excellent article in an edition of Uncle Melvyn's magazine, The Morgan World, by Peter Ballard. Bit of a suspension guru is Peter. Riding in his 4/4 CVH is competely different to my unmodified '76 4/4 (with its falling rate setup).
Cheers,
