This is a bit of an odd thing to print, I admit.
A while back I changed my garden tractor's tires from turf tires to lug tires.
At first I simply installed the new tires on the original rims but was not all that impressed with them to be honest.
So then I decided that I needed a wider wheel base for more stability.
I tried to find spacers commercially but there was nothing that was direct fit, and things that could maybe be adapted were far too expensive and not locally available.
Then I thought about machining some out of aluminum plate or fabricating weldments (I have access to machine tools).
But I decided I would try printing something first.
A few caveats-
First, it is specific to AYP/Craftsman style garden tractors and others using the typical 4.5" bolt circle 5 bolt mount as shown.
And it must use the same center hub diameter as the AYP/Craftsman tractors do.
This is because the hub centers the wheel, not the bolts.
Second, you should print the test ring first in order to check for material shrinkage and scaling against the hub diameter of the tractor axle.
Change the scale in your slicer accordingly to achieve about a 0.010" diameter gap against your hub.
Then use that scale for the actual spacer prints of course.
Third, fair warning, this is a very lengthy print.
It will take 4-6 hours to print one or even longer depending upon your particular printer.
Do NOT skimp on the fill percentage to speed it up, the final parts need to be as close to 100% solid as you can manage.
How to print and use them-
Print the test ring to get the proper size as mentioned.
This will save you having to adjust the bore or nose post-print, which could be a problem.
Then print the spacers using the scale you determined with the test ring.
Print with the highest percentage of fill your printer can handle.
Clean up the support material in the side holes and ream out the bolt holes if necessary using a drill.
For the spacer as it is designed the wheels are moved outwards by 2", so the original lug bolts will not work.
You will need to purchase 7/16"-14 x 2-1/2" long bolts and hardened steel washers.
Note that I only had longer ones on hand, so they show a lot of thread in the photos.
If you scale the spacer thickness differently, adjust the length of the bolts accordingly.
Mount the spacer and wheel to the axle using the new bolts with the washers between the bolt heads and the wheel.
Tighten in a star pattern using several passes.
Don't torque the bolts like crazy as you might be tempted to do if the spacer was made with metal.
After a few hours re-torque them again using a star pattern and making several passes.
Check them after a few uses and then again after a few weeks.
I can tell you that they make a huge difference in the "feel" of the tractor.
It rides over bumps much more comfortably now because there is less side-to-side jostling.
Also, the tractor is now more stable when traveling across hill sides and slopes due to the wider wheel base.
So far I have had no problems with the pair I made (and they did stabilize so that I haven't had to re-tighten them recently).
I hope you will enjoy them as well.
Please pardon the grass clippings in the lug tire photos, our tractor gets used a lot......
Doesn't matter PLA
The color doesn't matter (see post-printing notes)
My choice of PLA was mainly because it is more rigid than other materials like ABS.
For this reason it should compress less and settle into its final shape quicker.
They will compress to some extent over time so you may have to re-tighten the lug bolts a few times before they stabilize.
It must be said that these spacers are in no way intended for any usage other than on a garden tractor.
No go karts, no dune buggies, no ATVs, and of course absolutely nothing that goes onto the public roads.
They will not hold up to that sort of usage and would be unsafe in those applications.
Please do not even try to use them that way.
They have however held up nicely on our garden tractor for an entire mowing season with only two re-tightenings.
How long will they last?
I don't know.
But so far so good. :-)
To answer a question I was asked-
The reason it is designed as five spacers and a centering ring rather than a continuous tube is because if you examine the way the wheels mount from the factory, the hubs only contact the wheels at the five bolt points, at least on my tractor.
So there was no point in making continuous rings at the bolt circle.
The side holes are intended to save material and also to prevent any accumulation of moisture or debris and are circular rather than rectangular to reduce stress points.
Remove the support material in the openings and clean off any rough edges.
Ream out the bolt holes as necessary to clear the bolts but don't go overboard.
It is best to paint PLA because it will not hold up well in sunlight otherwise.