Crawlers generaly have:
70-80 degrees of flex
Longer wheelbase - ~16-17"
Higher center clearance - ~4-5"
Single motor for shafties and dual motors for Clods
- Gear reduction for shafties with down to ~140:1 gear ratio
- 8/9 tooth pinions for Clods; gear reductions are more rare
Soft, sticky, tall and narrow tires w/ low air-pressure
Brushed motors as brushless is just unnecessarily expensive
As low a center of gravity as possible
4wd w/ locked diffs and as little hanging off the diffs as possible, (so the tires contact the rocks before anything else)
And here's a gratuitous shot of mine [sm=cool.gif]:
