Remove the front shock. Jack up the front tire till you hit the bump stop or bury your tire into the wheel well. You should hit a bump stop! Measure down where the shock goes and record that number, now jack the frame up till the wheel stops drooping. Measure that length. Now do the same with one side on the rear end. Give those numbers to a good off road place and they can match a good fox, ADS, King, or a good quality mfg of shock for your type of off roading. Bigger tires, or an axle upgrade changes your load rating then that means changing the valving. You really do get what you pay for here.