We Need To Talk About Front Tires

 The tires I want to use are 20" fat tires. I also have 16" rear tires from a lawnmower, but they don't have brake mounts. Weight is one of my biggest concerns. The fat tires are about 18lbs each. The lawnmower wheels weigh 5lbs more each. 

The CV joints that I got have 21 splines. I can't find axle hubs that fit. Everything I found uses 23 or more splines. And the axle hubs would add more weight. Ideally, I'd like to mount the wheel/brake directly to the CV shaft, if I can.

I removed the axle bolt from one of the 20in Fat tires to see how it's constructed.

It looks solid. The center hole is 12mm and the inside of the flange is 25mm. If I turned down the spline on the CV axles, the diameter of the CV axle would be around 20mm. I think the 12mm hole could be widened to 20mm.

I'm waiting on an aluminum front wheel hub that I want to study. It would be great if I could modify an existing hub to fit on the CV shaft. Maybe I could turn a custom wheel hub for the fat tires on the lathe? 

Rudy February 11, 2023

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A New Idea For The Front Axle Hub

I've reimagined the front axle hub, keeping our machine shop captain's advice to run the axle directly into the hub of the front tire. Instead of one, solid machined piece, the bracket is now 5 plates welded together. The bearing that supports the CV would be pressed into the outer plate. The outer plate includes mounting holes for brake calipers. An eye bolt is positioned at the necessary pivot point.

The bracket would sit on head bearings (from bicycle necks) and secured to the wheel frame.

I added rabbits to the mating parts so that everything self-aligns when it's clamped together for welding. Here it is with the tire on:

Mounting the tire hub still needs more research. I need to see if the hub has enough material to cut splines into, which would mate to the CV joint's spline shaft.

If all that can work, it'll still need a long bolt to clamp everything together. That would need to be turned on the lathe.

Rudy February 06, 2023

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