Razor Ground Force Electric Go-kart to harbor freight 10" tire adapters

thingiverse

So what is this thing? Well the Razor ground force electric go-kart is a small electric gokart with some seriously awful, tiny, hard wheels. Fine on perfectly smooth pavement but seriously sucks when going on asphalt put down more than 5 years ago. Obviously pneumatic tires are the answer here. And the 10" harbor freight tires seem to fit the bill perfectly. You'll find them as the following sku's. 30900, 69385, 62409, 62388. Check the sidewalls aren't bulged or anything. Don't worry about the awful bearings they come with, you won't be needing them for this project. This should also fit the 13" tires also sold at harbor freight, but cost an extra $8 per corner. No promises on clearance but at max steering angles it will clear. The internal hub might not. So during optical (looking at the thing) research for this I also noticed that while the entire rear axle spins, only the right rear wheel actually has power. So this mod can also convert your kart to solid rear axle and increase traction. If you still want single wheel drive, use a front hub file for the left rear. The bearing ID is different, but the OD is the same. Teardown is pretty simple, take all the stock wheels off. Pull the bearings out (we use them again). And don't loose the key for the right rear, we also use that. Mods suggested for the front tires, split the rim apart and drill a new valve stem hole in the side with the axle tube. Put it back together "backwards" so the old "front" of the tire faces the inside of the kart. This keeps axle stress with the bearings directly in line with the new tire and minimizes angular stress. I don't know if this actually does anything, but I'm not about to test it. Also yeet the rubber covers, they get in the way slightly. Rear tires install normally, everything is friction fit. (use a hammer and block of wood for all this) Though if you have a good drill bit and some aim, I do suggest drilling a pin hole through the left rear axle and putting a screw or coathanger pin through. It might start spinning like a bushing sometime in the future. Or use glue, that could work too. It's only a 10mm shaft so a hole might weaken it too much. Your call, I'm gonna try glue and friction. While you have everything apart, lube everything related to steering and tighten up the tolerances with the pivot pin area. My kart was second hand off craigslist and was not maintained. Possibly ridden by kids a bit too heavy. This project dedicated to my little sister. Can't wait for her to open this awesome kart on Christmas.