Be careful when installing aftermarket wheels, count the threads.

[K_W]

I made a mistake that could have been very expensive.

In December I purchased aftermarket MB Icon wheels and WS80 winter tires to share between our '13 Corolla and '01 Camry. I installed them on her Camry with some Dorman spline drive nuts and she was using them until this weekend. I put the same wheel & nut combo on the Corolla for the 600 mile road trip this weekend, based upon a prediction of freezing rain that never happened.

We got back today and while taking them off I noticed how quickly the nuts came off. I counted the turns on the rest and found the wheels were held on with only 7 1/2 threads on the rear and ONLY 6 1/4 THREADS on the front... 12 threads is safe minimum (I do not know how much engagement the Camry had, I will check when the proper nuts arrive.)

Fortunately, nothing happened during the trip, the nuts where still tight, and the originals went on smoothy so I didn't do any damage with my oversight... but I got lucky.

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If you buy aftermarket wheels, especially for your Toyota, you may need "ET" lug nuts (extra threads in shank below seat) to get enough thread engagement. Rule of thumb is to have 1.5x as much thread engagement as the stud is wide.

For taper seat wheels, ET taper seat lug nuts come with .25 to around .5 inch (6 to 13mm) length shanks. Your needs will vary by wheel and vehicle.

Formula; Divide stud diameter by thread pitch to get minimum thread engagement...

Minimum
12mm ÷ 1.25mm x 1.5 = 14 1/2 threads
12mm ÷ 1.50mm x 1.5 = 12 threads
14mm ÷ 1.50mm x 1.5 = 14 threads

 

[femurphy77]

So who initially installed the wheels and didn't pay attention to what they were doing?

 

[SEIndSAM]

You learn something new on INGO every day....thanks for posting...

 

[ljk]

That's why hub centric is better than lug centric, better support from the hub, less stress on the lugs.

 

[K_W]

So who initially installed the wheels and didn't pay attention to what they were doing?

Me... in a rush to get the car ready on time. I knew better too.

 

[easy]

Minimum thread engagement should be 1.5x minor thread diameter.

 

[Leo]

Good post. I have heard of that before. That is why people use lug nuts without an end cap to make it quicker to pass tech inspection for racing.

 

[K_W]

Minimum thread engagement should be 1.5x minor thread diameter.

Thanks, I used major diameter for the above calculations (which will yield more recommended thread engagement) and will delete the 1x minimums.

 

[russc2542]

That's why hub centric is better than lug centric, better support from the hub, less stress on the lugs.

I do like hub-centric setups better but for this particular thread it doesn't matter much. Thread engagement is a big deal for fastener tension much more than shear-loading. Whether the wheels are hub- or lug-centric doesn't affect the tension on the studs.