Better belt bite, less slipping, and better performance.  Our green secondary spring is stiffer than the factory spring with the white stripe.  We use this spring on 27″ tires to 30″ tires.  Check out our red spring for 30″ tires and larger tires.  The red spring can be used with 27″ tires to 30″ tires for very aggressive drivers combined with our JBS clutch weights.