Aluminum wheel torque specs - PSA

[CityHick]

Hey All. As some know I recently took delivery of a set of US Mags Indy U101 wheels in 17x9, and had new 37" tires installed onto them. The other day while lowering the tire pressures from the 40psi set by the shop who did the installation, I discovered that there were some cracks/bulges forming on the inside surface of the hub bore. Concerned by this, I reported the problem to the Amazon seller who I got the wheels from, and he pursued the issue with the manufacturer.

Long story short, I caused this problem by torquing the lug nuts to 100 ft-lbs as I'd always done with my previous steel wheels and with most/all OEM wheels on my other vehicles.

As stated the Amazon seller took my concern to the US Mags company, who agreed to cover the wheels, despite their stance that this was my mistake under their warranty. This was a relief, and the vendor then told me that I cannot follow OEM specs with these wheels, and that they should be torqued only to 60 ft-lbs max. Maybe I'm the only dumbass who did not know this, but in case I'm not... learn from my mistake!

I have since learned that OEM aluminum wheels (and some aftermarket aluminum wheels) have steel inserts in the lug holes which allow the higher OEM torque spec. "cheaper" wheels without said reinforcement will crush under that much force.

I am glad that I noticed this problem before it resulted in a catastrophic failure on the road. Having already experienced a high speed wheel bearing failure, I am a little sensitive to the idea of losing a wheel at speed... in both of these situations I feel that someone was looking out for me.

[crawlin68]

Wow! I had no idea about this either. I would have done exactly what you did and torqued them to 100 ft. lbs. Learn something new every day. I'm happy to hear that they are going to get you a new wheel though. That was really nice of them and great customer service. Did it only happen to one wheel?

[CityHick]

Wow! I had no idea about this either. I would have done exactly what you did and torqued them to 100 ft. lbs. Learn something new every day. I'm happy to hear that they are going to get you a new wheel though. That was really nice of them and great customer service. Did it only happen to one wheel?

It happened to all 4 wheels. They are replacing all of them for me. I expected that I'd be buying new wheels due to my mistake. They do not publish this information anywhere that I've been able to find. Sometime soon I'll have 4 new wheels to swap tires onto, and then I'll have to ship the damaged wheels back with prepaid labels.

[1968u15]

It's good on the manufacturer to cover the damage. Realistically, how would you or anyone else know the torque spec was different than the oem spec.? I believe the manufacturer is responsible to supply any information on installing their products in oem locations where the specs are different. So many things can be different. Right down to the alloy used. There are many products provided by aftermarket companies that include revised spec.s for that very reason. And since we as Bronco owners are willing to change just about everything it's definitely something to keep in mind. I'm glad they stepped up and took some responsibility by replacing your wheels. I'll bet they start providing documentation for future buyers.

[CityHick]

I agree it was good on the manufacturer to step in and help here. I do not see the torque spec listed anywhere online for these wheels. Yesterday when I took the wheels and tires down to have the tires moved onto the new wheels, I explained the situation to a few people at the tire shop, and none of them had ever heard of lowering the torque value for any wheel at any time. Their opinion was that the OEM spec should always be followed. I am going to try to get in touch with the manufacturer soon about this. Their website does state that all questions etc are handled by their vendors, but I am going to try to step around that and get guidance from them directly. I agree that there are a lot of variables present that dictate this specification.

While different, in my profession (software engineering/support/services) we sell both direct and through vendors and in theory the vendors are capable of answering questions and addressing some issues, but most often those requests come directly to us, as the source. So... I will see what I can do. The tire shop said they'd be uncomfortable letting a vehicle leave the shop with less than OEM torque specs and advised that I not go any lower than 85 ft-lbs for safety's sake. So we shall see where this leads.

[Efibroncoman]

This is the first I’ve heard of aluminum wheels cracking around lug holes. I’ve been in the automotive/truck industry for over 20 years. I’ve had 3 Ram trucks with aluminum wheels(no inserts) where lug nut torque is 140 ft.lbs. I also work on big trucks that have all aluminum wheels with no inserts where lug nuts are supposed to be torqued from 450-500 ft.lbs, however nobody actually torques them. They just run them down until the 1” impact stops moving. Those guns are often rated for 2000-3000 ft.lbs. I think US Mags here should definitely do something to prevent this issue. Maybe they’re using softer aluminum that most?? I don’t know, but I’ve always torqued 5-6 lug wheels with 1/2” or 9/16” studs to 100 ft.lbs. Never seen this issue. Unless they included a label insisting on 60 ft.lbs, you did nothing wrong.

[70 Steed]

You would think that U.S. Mags would be having this issue frequently as most tire shops would be torquing their wheel to 100 ft. lbs.

[CityHick]

I don't know what to think about this really. I have them torqued to 70 ft-lbs at the moment and I am keeping an eye on them for now. I agree this seems like it would be a very common issue if they really cannot handle 100 ft-lbs. I have been doubting myself about this for a while now, like perhaps I mistakenly torqued them to something much higher but I really don't think so. I am fairly convinced that what I experienced was the result of a manufacturing defect, and I am a little nervous that what I have now could have the same defect. I don't know... so far so good. I am hoping that the manufacturer responds to my request; they have not yet.
For what it is worth, I've reached out to someone else who has the same wheels; he said that he torqued his to 100 ft-lbs and hasn't noticed any signs of damage like what I had happen. Granted that's a small sample size but it's a data point none the less.

[Efibroncoman]

If you went much higher than 100 ft.lbs you’d likely come close to breaking 1/2” studs. After a closer look at the picture, I think they made the center hole too big leaving the wall thickness at each hole too thin. I’m gonna stand by my previous statement, not your fault!

[crawlin68]

My first thought was that I bet these wheels are made Chineesium aluminum and just super soft. But who knows?

[Lars]

I have a copy of the 1970 Ford factory service manual for my Bronco. It lists the wheel torque as being 70 - 115 ft-lb. So 100 should be just fine.

I am the one that Tony reached out to about this, having the same wheels. I am pretty sure (as in, not 100%) that I torqued mine to 100 ft-lb since that's what I've been doing for decades. But I haven't had time to confirm it. My wheels have not deformed, and I've hammered them pretty hard already. Go figure. I need to check mine before my situation can be used as a data point, but I can confirm that the wheels are made from Chinesium alloy.

I find it astounding that the manufacturer would insist on such a low torque after the fact, while not bothering to publish that in an easy-to-find place, such as in large font bold print all over the shipping box.

[CityHick]

I updated my first post since a couple of points may not have been clear.

It was the vendor, an Amazon seller, who gave me the guidance on torque specs, not the manufacturer. This was verbal guidance given to me over the phone.
I reached out to the manufacturer through their email web form and have not yet heard back from them, though if their wheels truly cannot accept the 100 ft-lb spec this needs to be stated very clearly for all to see. I still feel it is possible that I unwittingly set the torque too high the first time around, but I really don't think I'd have done that, since 100 ft-lb is more or less habit for me when it comes to tightening lug nuts.

I too have the service manual and also found the 70-115 ft-lbs guidance which is part of what made me set them to 70 ft-lbs. I'd rather be at the bottom of the spec, than below it. I have visually examined my wheels several times since installing them and all appears to be good. I have several days of errands and back roads driving on these wheels now and have checked the torque a few times. All seems okay. For a wheel that is very clearly stamped as a DOT wheel, its odd to me that the OEM spec is too high, but I guess we'll see.

As someone who's been trying to regain confidence in his rig for a while now, this was a setback... but that's my battle to overcome.

[CityHick]

Another update - US Mags got back to me. They advised to follow the manufacturer's torque spec and that 100 ft-lbs is what they have on record for a 1970 Bronco. So... perhaps this thread is one that should be deleted.

I don't have an explanation for what happened, though with the mfg saying they should be okay at 100 ft-lbs, I have to believe that what I experienced was a fluke and hopefully it's not something that will happen to me again.

I further conclude that the vendor was being overly cautious in their guidance.

Thanks to those who commented here.