You raise a good point. In the world of street runners, most shoes are pretty well marked as best for cushioning, stability, or motion control. In the trail-running world those distinctions are a little less clear. Thats largely because you really cant build a cushioned" trail-runnerthe terrain considerations make that nearly impossible. So, most trail runners feel much more firm than a road running shoe. And that makes them inherently stable, so motion control is less of an issue, and why do I feel like Im talking in a circle?
Anyway, my point is that a firm shoe, such as a trail-runner, is inherently stable. That means theres less need for all the wedges/bi-density materials/shaped outsoles that define motion-control shoes built on fairly soft, road-oriented midsoles. That said, Id suggest you look at the following three shoes that may give you trail-running capability with a bit more motion control than others.
Montrails Continental Divide ($105; www.montrail.com) is a very tough shoe with a wide base for stability and a good mix of cushioning and ruggedness. It has a medial posta wedge of firm material along the inboard side of the shoeto help control pronation.
As a reformed marathoner (meaning, I quit), I always found that Asics shoes were exceedingly stable (like you, I over-pronate). So I think youd like the Asics Gel Eagle Trail V ($100; www.asics.com). This is a motion-control shoe, with a medial post similar to the Montrail and what Asics calls an Impact Guidance System" that prevents your foot from rolling inward in that classic over-pronation funky chicken deal.
The Salomon XA Pro 3D XCR ($125; www.salomonsports.com) isnt a true motion-control shoe, but its super stable and very tough, which should work well for you. It also has a Gore-Tex liner in the event youre on wet terrain quite a bit. I also like the rubber toe bumpers, which protect your digits from rocks and roots.
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