Main Idler

The main idler is the silver idler on the Pro-Turn 600 deck and is designed to maintain constant tension on the primary deck belt around the left and center spindles. The idler ensures up to 50% belt wrap is maintained on the left spindle.

The main idler is mounted to an idler bracket, which has constant tension (non-adjustable) from the tensioner spring. This is part of the AriensCo. Constant Belt Tension Deck System (CBT Deck System).

Idler Pulley

The Pro-Turn 600 XFactor3 deck has one stand-alone pulley placed to the left of the center spindle. This is to allow for more belt wrap around the center spindle as the belt routes back to the PTO Clutch pulley. The pulley is also in place to allow for added tension on the belt.

Belt

The majority of Gravely commercial decks are designed with a two-belt system to ensure optimal performance. The belt on the left is a V-belt, also known as a cut-edge belt. This is a more aggressive belt that will reduce slippage when engaging your PTO Clutch. The secondary belt is often a cogged style belt, which will allow for more forgiveness around a smaller pulley.

Tech Tip: Look at your belt. There should be a certain amount of glaze or shininess after some wear, which is caused by running in the pulleys or a minimal amount of slip. However, if your entire belt is glazed or shiny, that is when you will begin to see differences in the RPMs and therefore excessive slip.

Spindles

Gravely spindles are designed with forged aluminum to help withstand excessive heat. If you have a customer that complains of poor quality of cut, especially with the Mohawk effect where you see uncut grass between your spindles, then you should be assessing spindle speed. Or when you see belts snapping with a clean cut, that could indicate a bad bearing on a spindle or multiple spindles causing excessive drag (spindle speed loss).

Your deck and spindles are designed to run at full throttle when mowing. Therefore, when cutting the spindle speeds should be at approximately 3500 RPMs. They will change from deck to deck because of pulley size and blade size.

Further Information

Blades

The best type of blade is dependent on the conditions and environment in which you are cutting in. If you have problems with cut quality, four easy checks can be done even before deck troubleshooting:

1. Level your deck.
2. Balance your blades.
3. Sharpen your blades.
4. Clean the mower deck of any grass or debris after each use.