Pro-Line Rear-Tine Tiller Rear
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Honda-equipped rear tine garden tiller with 16-inch tilling width, cast-iron transmission, and excellent maneuverability

If you have a large garden, you need an impressive tiller. The Troy-Bilt 21A-665B766 boasts a powerful Honda engine with enough torque to really chew through compact soil. Forward-rotating tines cut a 16-inch width and can get as deep as 7 inches, so you can cover more ground in less time. A strong transmission and features like the Just One Hand operation increase the tiller’s maneuverability, which is good considering rear-tine tillers have a reputation for being harder to navigate.

Honda GX 160cc engine

The Honda engine on the Troy-Bilt is a 4-cycle 160cc engine. 4-cycle engines are more durable, fuel-efficient, and quieter than 2-cycle engines, so you can rest assured that the Troy Bilt is a reliable tiller. The engine makes the tiller ideal for bigger gardening projects up to 1500 sq. ft. and has sufficient torque to break through hard dirt.

Forward-rotating tines

The tines on this tiller rotate forward, which makes them easier to maneuver and safer. Their width is about 16 inches with a 17-inch tine shield for added protection. You can adjust the depth up to 7 inches deep, which is pretty standard for tillers of this kind.

13-inch tires

Good tires help keep tillers stable and balanced even on rockier, uneven ground. The 13-inch tires on the Troy-Bilt 21A-665B766 are agricultural-quality, which means they have excellent tread and are able to handle rough, even muddy ground.


Good transmission

The cast-iron transmission is very durable and has a bronze gear drive. It is well-equipped to handle hard jobs and is able to go both backwards and forwards. This adds versatility to the tilling process and ensures the Troy-Bilt will stay in good shape for a long time.


The Just One Hand operation on the tiller also aids with maneuverability. It makes it easy to just guide the tiller with one hand so you can maintain control and have more flexibility. In general, forward-rotating tines are also more maneuverable, so the smooth operation enhances that quality.

Bumper guard

To protect the engine, the tiller has a bumper guard installed in front of it so dirt, rocks, and roots don’t get tossed into the motor and cause damage.


Forward tines not as effective on really tough dirt

Forward tines are not as effective as counter-rotating tines when it comes to working through really tough dirt, like ground that’s never been tilled. However, the forward tines are safer, since the machine jumps forward when it hits a rock, and it is easier to control. It’s a trade-off, and you’ll have to decide if it’s a good one.

Overall Review

The Troy-Bilt 21A-665B766 Pro-Line Rear-Tine Garden Tiller is a good choice if you have a large garden with tough soil. You can use it on untilled ground, though you should know that the forward-rotating tines on this unit are not as effective as counter-rotating ones. They are still powerful though, and have a good tilling width and depth. A bumper guard and superior transmission help keep the engine protected and performing its best for as long as possible.