The originals may not have been rated for 500 lbs. Think about it: 4 x 500lbs = 2000 lb load holding capacity is what you created with those wheels, i.e. way too much. I betcha the old ones were in the 100 pound range instead of 500.....

I'm looking for some replacement wheels for my Wico Pinball Dolly...

I found myself looking at Harbor Freight at the casters...and of course one can't simply put on new casters...

The wheels themselves are removable and replaceable...which is GREAT...and not so great.
The casters at Harbor Freight have the wheels permanently attached....so, I could grind them...but it would be better to just get some decent wheels with bearings in them and call it a day.

A nice narrow wheel (like from an inline skate) with some spacers would be great, I think.

I think that a wheel rated at 125 pounds per (if you ended up with the full weight of the pin resting on two wheels, you'd still be ok) would work.
They look like 3 inch wheels that are 1 1/4 or 1 3/8 wide...the problem is I can't find any that aren't outrageously priced...

Has anyone replaced their Wico wheels without cutting, grinding and drilling ?

I put skateboard wheels on mine, works great. Get the newer harder wheels and it rolls better than new.

Got a link?

Casters and wheels for commercial products won't be found at HF. These carts are designed to move coffins. If you try to skimp, you'll just end up frustrated and without good wheels.

Here is where you will find replacements

https://www.mcmaster.com/standard-casters

Is it really "commercial" if it is just the pin mover in your house?
And again, you can't simply bolt on a new caster and wheel to these carts without cutting the old ones off.
Seems like a much smarter thing to do is simply remove the axle bolt and replace the wheel itself.
Maybe a quick evaporust soak on the original bolts and a toothbrush...just to clean them up.
These things must be every bit of 40 years old...probably closer to 60...
It also seems silly to order the entire caster and wheel assembly if your intention is to simply put the wheel on the cart and toss the caster...

The Grainger site is just as full as McMaster-Carr is of wheels in casters that cost $25 each...

And if you get a wheel that is rated to take the weight of a 250-300 pound machine... (so minimum 75# per wheel) it should be more than adequate. Right?

A couple of guys on facebook's Pinball Enthusiasts page used these:

https://www.harborfreight.com/3-in-polyurethane-light-duty-swivel-caster-69848.html

...and they seem to be attached with bolts instead of a permanently attached pin.
So that's a pretty low-cost way to get this done. Original spec is 275# per caster.

The guy said that he needed to enlarge the hole to make everything work but didn't specify what he drilled, the wheel or the cart.
Presumably he drilled the wheel.
His Wico is of a newer type than mine...mine is the old school one with the pedal and no handle.
He could remove casters but chose not to.
Mine has the originals welded on permanently and has not been altered.
He said that the wheel dimensions are the same. (which begs the question, "why did you need to drill anything?")
Presumably, drilling is going to reduce the rated load limit, of course. (And the wheel is from China, so there is a real concern about it performing to spec.

I dunno, it would be kinda cool to pimp out the cart and put on some really colorful/obnoxious in line skate wheels or skate board wheels...

these might be much better for only an additional $2 each over the HF choice...

https://www.amazon.com/casters-poliolefina-rodamiento-capacidad-250-lbs/dp/B00426CIJ4