Axle/Wheel Nut Tightness

[Spaceman]

I still need to drill my axles for the cotter pins, but I can't tell if I've tightened the axle nuts the correct amount. The plans say "tighten nut until bearings are snug and a light drag is felt while spinning the wheel." Is there any way to quantify that? Do you just tighten until there's no side-to-side play and then maybe a little bit more? That's about where I'm at but wanted to check.

Thanks!

[n307tw]

You should be able to turn the wheel and it stops relatively quickly (within a full revolution). If you spin the wheel and it keeps turning it’s probably too loose. That’s probably the best way I used to quantify what Sonex was trying to explain.

[mike.smith]

I have had to use large diameter washers (ID of the axle/OD of the bearings) of varying thicknesses to get the friction right. Since even small turns of the large nut covers a fair bit of distance when locating the large cotter pin, it's tough to get the right friction without some trial and error with washers. Note, I have also needed these washers on the inside face of the wheel to keep the wheel away from the Sonex hydraulic brake assembly, so the wheels don't scrape the hydraulic brake body.

[DCASonex]

Just a reminder, but as been mentioned here before, make 100% sure your bearing seats are fully seated in the wheels, or they will soon loosen, the wheels wobble, and the seats may need to be further seated to the extent that your nicely drilled cotter pin holes are now too far out on the axle.

David A.

[radfordc]

My Dad taught me how on my 53 Ford sedan. Tighten the nut until the wheel won't turn...this ensures the bearings are fully seated. Then loosen the castle nut until the wheel just starts to turn freely. Find the nearest position of the nut that allows the cotter pin to fit.

[Scott Todd]

I was also taught to gently snug it down and then back it off. DON'T crank hard on it. I was told you could flat spot the bearings. But as a retired engineer, I now know it would take quite a bit to flat spot a hardened steel bearing, roller or ball. But still, snug it down and then back off until cotter key lines up :)

[Spaceman]

Awesome thanks guys!

[Bryan Cotton]

Just a reminder, but as been mentioned here before, make 100% sure your bearing seats are fully seated in the wheels, or they will soon loosen, the wheels wobble, and the seats may need to be further seated to the extent that your nicely drilled cotter pin holes are now too far out on the axle.

David A.

Here's another tip - check them after an hour or two of flight. My aerobrakes were acting up, and I found the wheels were both loose.