Keep the paint on your pedals for longer "150mm" crank arms

[Thewootts]

Miranda Bike Parts


At a good price as well might i add.

 

[Mabman]

Or you could just learn to time your pedal stroke while keeping the TA active and use 170's as normal.

It's pretty easy to do and in fact I bet 90% of the people that have much time on a regular mtb have already been doing for years. Use a slight amount of pressure on your rear brake which allows you to keep pressure on the pedals, thus keeping the TA active, while moving the cranks at a slow rate to avoid strikes.