Trailer hubs
 

I have a 1999 triple axle trailer w/6 lug wheels the had the 16.5” steel rims on it till last spring when I switched to 16” aluminum wheels after the first month I broke 4 of 6 lugs off 1 hub, so I replaced all 6 studs. Then at the end of summer I broke 4 of 6 studs off another hub. To get my trailer in the barn I have to make a right turn on cement dragging the tires which I know isn’t good, but never had any problems with the steel wheels. The guy at the Trailer place told me I’m breaking the studs because the aluminum wheels have 5/8” holes and the studs are 1/2” so they eventually start to loosen the lugnuts. Anybody have any ideas how to fix this before I buy steel wheels?

Are the lug holes in the wheel tapered and are you using lug nuts that are tapered?

Most wheel holes for studs are oversized, and use the tapered nut face to align the wheel.

Even on hub centered wheel/hub systems.

Even dragging the tires sideways under rated load should not break wheel studs like that.

You never had an issue with the 16.5 steel wheels doing the same thing?

Are you re-torquing the alum wheels after install and a few heat cycles?

Wheel studs should be Grade 8 or better. Gr 8 is 150k psi tensile strength. 60% of that in shear.

Something is likely impacting the studs and shock loading.

The new alloy wheels are the anomaly and new part to the system.

Once in a blue moon, I break a 1-1/8" wheel stud on my Mack front axle. Just shears off. I replace the broken one and the one on either side of it. Torque to 550ft lbs.

Mack dealership never could figure it out...so we just do a preventative replacement on them.

^
Great information!

Lug centric wheels HAVE to have a tapered nut...are you using the ones that came with the wheels? As Tartilla notes, the ONLY thing that has changed is the wheels, so Objective Evidence indicates that is where the problem lies. That needs to be the focus of your corrective action.

I am wondering if the new wheel nuts are longer due to the Aluminum wheels. I am guessing they are "mag style" rather than an open stud through lug? Are the hubs that are breaking also without brakes compared to the ones that do? If so, the Longer lugs could be bottoming out prior to them getting the wheel completely tightened up, thus creating the "wobbly effect" and breaking them off. I experienced this on a brand new trailer that they changed the steel wheels to aluminum a the dealership for delivery. They went back afterword's and changed the hubs to shorter studs and problem disappeared.

I would check the bolt circle on the hub and the aluminum rim...... to make sure they match
if the 1/2" studs are not dead center in the 5/8th holes in the rim that could be your problem

LuckyCat,

And I would not use oval-holed, "multi"- BC wheels.

Thanks. Brad.

Thanks all for the awesome responses, I do not have unilug wheels and they are the correct bolt pattern. I did not retighten them after driving a few miles 🤦. I went out and took some measurements after reading the above and the old studs stick out 1” from the brake drum and the new studs stick out about 1 1/4”. The aluminum wheels are about 1/2” thick plus the taper so maybe that is the problem, only 1/2-5/8” into the lug nuts?
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I would bet $100 that the top of the lug nut is bottoming out before the wheel tightens all the way down. Exactly what we ran into with the trailer I had issues with. Change to a mag wheel lug that is a longer shaft/shank (?), so it will screw all the way tight to the bottom of the wheel.

Open lugs will fix that problem as well