Dethatcher with Achilles wheel

Couple years back a friend told me a "dethatcher" might be good to use on the lawn once in a while.

My tractor's a Husqvarna. They offer two different dethatcher models: front-mounted, and rear-mounted, made by Agri-Fab. The rear mount didn't make sense to me as I figured I'd dethatch and mow and bag the clippings all in one operation. The bagger occupies the rear, so the dethatcher has to go in front.

Image from the Agri-Fab Owners Manual

So that was my plan. But it turns out the front-mount dethatcher costs about $200 more than the rear-mount one. Nice, huh? Well, you know I struggled with that decision, then went ahead and spent the extra money for the front mount model. I got the thing during the winter so I'd be all ready for Spring.

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Spring came at last. I used the thing once, for maybe an hour. Hit a soft spot in the lawn. The wheel and the dethatcher tines sunk in the mud, and before I could stop the tractor, it rolled up on top of the dethatcher. The cheap plastic wheel couldn't take the tractor weight. Bent the wheel so bad it had to be replaced.

To buy a new one was $40 -- for a plastic wheel that's practically worthless. I so I spent the rest of dethatcher season shopping for a 7-inch wheel.

The 7-inch wheel is a common size. But this one takes a 5/8" axle, unusually large for a 7" wheel. And apparently the only one manufactured, in this solar system, is the $40 one. Eventually I broke down and bought the damn wheel. I installed it and put the dethatcher away, ready for Spring.

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Spring came again this year. I put the dethatcher on and set to work. I have to say, the bagger catches a nice mix of dead grass and powdery soil, and I love adding that to my compost pile. It'll give me some impressive volume, too, if I can ever get the whole yard done.

But it is slow going, because I don't want to buy another flimsy $40 wheel.

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Well, it was good for maybe an hour before the thing got stuck in mud and the tractor climbed on top of it again. And I was crawling slow. Damn tractor only has to go a few inches after the dethatcher gets stuck, and that's all she wrote. This time, though, I had an idea.

Images from the Agri-Fab Owners Manual

With the 7" wheel installed on the funny bent axle, I had a little over half an inch clearance above the wheel. So an 8-inch wheel should fit. I went to Harbor Freight and looked a their 8 in. Solid Rubber Tire with Polyethylene Hub (item#61706). That's the one that says its maximum working load is 1100 lbs. It's an eight-dollar wheel. The first time I saw that "1100 lbs" I thought it was a typo for 100 or 110 lbs. Even so, if it can support 100 lbs, that's better than the original wheel without a doubt. And $8 instead of $40.

The wheel measures 7³∕₄" diameter at the tread face. Just under 8": a little forgiveness there; I may need it. It's a rubber tire on a plastic rim, but the rim is thick plastic, not paper-thin like the original wheel. I bought two.

Harbor Freight #61706

The original wheel used about 1¹∕₂" of the axle. The new wheel is about 2", 2¹∕₈" wide at the axle. The axle doesn't provide that much room to fit the wheel on.

However... As you can see in the picture, surrounding the axle bore hole the hub is inset about ³∕₈", which means the wheel occupies less axle space. There's an inset like that on both sides of the wheel, so the wheel only uses about 1¹∕₄" of the axle. It'll work!

I put one of the original washers back on the axle, far as it would go. Then I put the Harbor Freight wheel on, far as it would go. It was stopped by the washer. I had about half an inch of axle sticking out past the inset.

The axle didn't come out past the wheel enough to install the hitch pin that keeps the wheel on. However... There was enough axle sticking out that I could get an axle cap nut on it. The brim of the axle cap is smaller than the inset diameter, so the cap nut goes on okay. And you should have seen how pleased I was with myself then!

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I used the dethatcher the same day I fixed it. No problem. And I used it longer that day than all the time I had used it before. And the wheel is still good. And I was gaining confidence and going faster, so that dethatching my lawn may be a less endless task than I thought.