Cart keeps stripping Left Rear Hubs

br549

My left rear hub keeps stripping out - I use my cart for hunting and the terrain does have some steep hills and some ruts but for the most part the paths are decent - it have replaced it twice in the last 3 months and each time I have noticed a couple of popping noises just before it strips - details about my cart: 2003 TXT - 6" lift - 23x10x14's wheels/tires - 48 volt converted with a stock 36/48 motor - SR48500 controller - any hints or tips are appreciated!

BGW

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swm63

Scottyb has heavy duty hubs.

br549

Thanks swm63 - I plan on ordering one for sure but my concern is that it may be something that I am overlooking that is attributing to my issue such as an improperly seated axle or an improperly torqued axle nut?

scottyb

Stock hubs are weak. Be sure to torque the Axle nut to 90 -140 ft pounds.
I suggest a pair of HD hubs. Once you FIX one side the other side becomes the weak link unless they match.

Golf cart guy

Change the axle too.

Stock hubs will work- the key is the correct torque on the axle nut. My customers never have an issue.
If you want overkill, buy the HD hubs

scottyb

Good point, if the axle has had 3 hubs disintegrate on it then it most likely is damaged as well. New axle, stock hub, bearing and seal, with the torque posted above may fix the issue... but the Aucso HD hubs cost little more than OEM hubs. Your call.

JohnnieB

The strength of the splines in the stock EZGO brake hubs are most definitely the weakest link in the mechanical chain between the motor and where rubber meets road.

What most people are unaware of, which apparently included the EZGO engineers, is how much force exists at the axle splines.

The effective gear ratio of a circular object such as a tire or an axle is 1 foot divided by the radius of the circle in feet and the effective gear ration of a stock tire (18") is 1.33:1 and with a 12.44:1 gear ratio in the differential, you get an effective gear ratio of 16.59:1 between motor and terra firma, so 16.59 pounds of force is applied to the tire tread - road interface for each ft/lb of torque produced by the motor.

With 23" tall tires are installed (1.04:1 ratio) the effective overall ratio is 12.98:1 and only 12.98 pounds of force is available at the tire's tread surface for each ft/lb of torque produced by motor, or 78.2% of the force available with a stock height tire. In other words, an effective loss of 21.8% of torque due to increased tire height.

The axle diameter stays the same regardless of tire height and I understand the typical EZGO axle is 25/32" in diameter, so the radius in feet is 0.032552" and that makes the gear ratio for the axle alone as 30.72:1 and when coupled with the 12.44:1 differential gears the effective gear ratio at the axle splines is 382.16:1. That means for every ft/lb of torque produced by the motor, 382.16 pound of force is applied to the hub splines.

In other words, when the is accelerating from a standstill or climbing a hill or any other condition that will cause the motor to put out 50ft/lb of torque, there is upward of five tons of force trying to strip the splines in the hub.
(19,107.8 pounds actually)

In a nutshell, considering the tremendous amount of force available, I'm amazed more hubs aren't being stripped.

yurtle

I'm not sure the engineers were paid to design them to survive us crazy people who use them for several decades, with larger tires, beefier motors, souped up rear ends, lotsa weight, etc. After all, they still had to be cost competitive.

Probably the worst thing to hit them would be small diameter mud tires, going downhill as fast as the non-stock motor can handle, then slamming on the brakes. Small tires = high delta RPMs at the hubs. 35 MPH to 0 MPH "feels" like more Gs than slamming the go pedal to the floor. At least with DC motors.

BobBoyce

Especially considering how many put 23" tires on their carts, then wonder why problems occur.

yurtle

Paraphrasing JohnnyB, it's a wonder so many have survived. Failure rate is statistically pretty darned low, empirically speaking.