Is it traction that is the problem" Or is it that the narrow tires keep deflecting off gravel and stones?
I would bet its the latter. If so, then its not aggressive tread you need, its wider tires. Unless you are climbing up and over rough terrain or trying to find friction in slippery mud, then tread will do little for you.
Put some fatties on that thing.
jim
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Cross Check Nexus7, IRO Mark V, Trek 620 Nexus7, Karate Monkey half fat, IRO Model 19 fixed, Amp Research B3, Surly 1x1 half fat fixed, and more...
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SB forever