rear axle nut

[paintdude96]

Rear axle nut that hold the rear brake drums on and axle striped what size is the axle and nut. It is a 2004 ezgo txt. Can i rethread it to a little smaller size and get a different nut ?

[scottyb]

That's hardened steel I don't think you can cut threads in it? Maybe time to get a fresh axle and nut. Remember nut torque spec is 90-140 ft pounds

[geoffarias]

Scotty-curious as to why its so critical to get 90lb? Is that so there isn't play in the hub on the axle? Trying to understand the physics and why its important. Ive seen the 90lb minimum emphasized with passion on this forum and when swapping out to HD hubs last weekend and telling my mechanically inclined and detailed father in law the importance of this I couldnt really explain why

[rib33024]

Originally Posted by geoffarias

Scotty-curious as to why its so critical to get 90lb? Is that so there isn't play in the hub on the axle? Trying to understand the physics and why its important. Ive seen the 90lb minimum emphasized with passion on this forum and when swapping out to HD hubs last weekend and telling my mechanically inclined and detailed father in law the importance of this I couldnt really explain why

Any thing less and the brake hub splines will strip out. 120/130 is best

[scottyb]

90-140 ft pounds is no more than you would put on a car lug nut. The lateral pressure applied reduces the reliance (stress) on the fine axle splines to drive the wheels without stripping out the softer hub material.

[JohnnieB]

The amount of torque that is available at the Axle/Hub interface (splines) is ludicrous.

It may be a bit confusing to those not familiar with gear ratios and the like, but every circular object such as tires, gears, sprockets, axles, Etc. has a gear ratio. If the radius (lever arm length) of the circle is 1 foot, every ft/lb of torque applied to its center point will equal 1 ft/lb of torque at the circumference. If the radius is less than a foot, the it is a torque multiplier.

The stock height tire is 18", so it has a radius of 9", or 0.75 feet and 1/0.75 is 1.33333, so a stock height tire has a gear ratio of 1.33:1 and is a torque multiplier.

The stock differential gears are 12.44:1, for every 10ft/lb of torque the motor puts out 124.4 ft/lb of torque is applied to the axle. Toss in the 1.33:1 gear ratio of the 18" tall tires and there is 169.5 ft/lb of force applied to the ground where rubber meets road.

Here comes the tricky part.

The axle is only 25/32" in diameter, which works out to a radius of 0.033 feet, or a 30.72:1 gear ratio. With 10 ft/lb of torque at the motor, there is 124.4 ft/lb of torque at the axle and 3821.6 ft/lb of torque at the splines.

With nearly 2 tons of force trying to strip the soft steel splines in the hubs for each 10 ft/lb of torque the motor puts out, it ought to be fairly easy to understand why to axle's castle nut needs to be tightened sufficiently.

[jclark138]

Originally Posted by JohnnieB

The amount of torque that is available at the Axle/Hub interface (splines) is ludicrous.

It may be a bit confusing to those not familiar with gear ratios and the like, but every circular object such as tires, gears, sprockets, axles, Etc. has a gear ratio. If the radius (lever arm length) of the circle is 1 foot, every ft/lb of torque applied to its center point will equal 1 ft/lb of torque at the circumference. If the radius is less than a foot, the it is a torque multiplier.

The stock height tire is 18", so it has a radius of 9", or 0.75 feet and 1/0.75 is 1.33333, so a stock height tire has a gear ratio of 1.33:1 and is a torque multiplier.

The stock differential gears are 12.44:1, for every 10ft/lb of torque the motor puts out 124.4 ft/lb of torque is applied to the axle. Toss in the 1.33:1 gear ratio of the 18" tall tires and there is 169.5 ft/lb of force applied to the ground where rubber meets road.

Here comes the tricky part.

The axle is only 25/32" in diameter, which works out to a radius of 0.033 feet, or a 30.72:1 gear ratio. With 10 ft/lb of torque at the motor, there is 124.4 ft/lb of torque at the axle and 3821.6 ft/lb of torque at the splines.

With nearly 2 tons of force trying to strip the soft steel splines in the hubs for each 10 ft/lb of torque the motor puts out, it ought to be fairly easy to understand why to axle's castle nut needs to be tightened sufficiently.

Best explanation EVER!

And you didn’t have any friends as a child, did you?

Im just jealous . . .

[swb713]

Dang ... Now THAT is an Explanation!!!

Well done Sir.

Sent from my SM-G930T using Tapatalk

[Buggieman18]

If his math brain is like mine, adding 8+5 requires the use of fingers! Ha!

[Sir Nuke]

AND if that doesn't do it......here is some other math to consider....if you DON'T properly torque the nuts, you WILL, sooner or later digging into your wallet and buying new drums, or axels, or castle nuts, or a combination of those parts... that's the WALLET MATH....its easy to understand! lol