Brett, I suppose that your question is related to another post, riding the Great Divide on a mountain bike. If this is a bike with front suspension, then I would like to point out that all front racks that are connected to the wheel axis or the lower fork legs are bad from a mechanical point of view. A front suspension fork is designed to enable a relatively low mass (wheel + lower fork legs, say 2.5-3 kg) to move rapidly in adapting to surface roughnesses. Adding a significant load of rack with panniers to this unsprung mass would severely affect the operation of the fork.
With front suspension, the only sound design is one that is mounted on the fork crown or steering tube, such as the Tubus Swinghttp://www.tubus.com/product.php?xn=65
Unfortunately I saw that Tubus has stopped the production, but you may still find one in bike shops or on eBay.
I had bought a Tubus Swing for my GD ride, but in the end decided to go without front panniers and use a small frame bag for storing a few heavy tools. This worked fine, but next time I will take a bigger handlebar bag to get a better weight balance between front and rear.
Naively, I had mounted a bottle holder on the fork leg with zip ties. Just a few miles after leaving Banff on a mildly rough trail, the bottle + cage suddenly catapulted into the banks of the Spray river. Luckily I could retrieve the bottle. The zip ties had snapped. It shows that any mass connected to the fork legs is subjected to high accelaration forces, caused by the almost instantaneous movements over a few inches. It could easily have lead to collateral damage. See a current topic on http://www.bikepacking.net/forum/index.php/topic,6135.0.html