wheel studs

one of my customers has a 08 sterling bullet (dodge 5500). I swapped out his steel wheels for aluminum and now he's breaking wheel studs. he uses the truck to haul trash. its set up as a small roll off truck. he does back up and jam the brakes when he dumps the cans at the landfill, but he never had trouble with the steel wheels for the first 200k miles and has broken 4 studs in the last 10k miles. have you guys ever run into this?:Banghead

What kind of wheels are you using? hub piloted or budd.

hub piloted

Are the studs long enough for aluminum wheels? There should be at least 3-4 full threads visible after the nuts are tight - if not they need to be replaced with longer. Did the studs look like they had been cracked or broken for awhile or fresh breaks with clean metal all the way through? My first thought is either wrong studs(too short) or they were over-tightened. Got any pics of the broken studs?

no pics. when I put the aluminum wheels on I got longer studs for it so none of the studs have more than 10k miles on them. haven't had trouble with the rears, just the front. I torqued the wheels to 140 ft lbs cause that's what the lugnuts have stamped on them

Jerking the load off shouldn't have a bearing on what's happening here. When he does that as you describe he's actually unloading weight from the front axle, there's no reason that should cause the studs to break. Is he checking the lug nut torque on occasion? Loose wheels will break studs and aluminum wheels need to be retorqued more often.

Inferior wheel studs? There are a lot of fake parts on the market. Your supplier may have received some studs with inferior metallurgy without even knowing it.

Back in my drag racing days one of the guys we ran with had a '68 Cuda that would break the rear wheel studs. No fun.

One other thing you can check is the contact patch where the wheels contact the hubs and look for 'witness marks' that show the contact patch between the two components. If there isn't enough contact between the two components under heavy braking the wheel can 'work' the studs in spite of the correct torque. The wheel/hub interface needs enough of a 'friction pad' in that area to make the torque on the studs function. If the wheels are putting a sideways force on the studs they'll break them off as they're not designed for those kinds of loads.

Could there be a difference in PCD between the truck hubs and the new ally wheels? - such as inch PCD on the truck hubs, whilst the new ally wheels are metric PCD?
We have cases here in Australia where there's a difference in PCD of 1mm between inch hub PCD and metric hub PCD. Put a metric wheel on an inch hub with 1mm difference in PCD and it bends the wheelstuds.

Joispoi has a good point. It's not the first time Chinese-made parts don't meet specifications, because the Chinese company indulged in "quality fade" by reducing the steel quality or heat treatment specifications.