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I have a 2005 Diesel Mazda Bounty UTE, which is also called a B2500. Similar to a ford courier / ranger.

I inspected my disc brakes, then put my tyre back on. I have since realised I need to torque my lug nuts.

My manual says this about the lug nuts,

Steel Wheel (16x6JJ) - 117.6 - 147.0 (87 - 108)
Except steel wheel (16x6JJ) - 88.2 - 117.6 (65 - 87)

Where the first values are Nm and in the brackets are ft lb.

What is steel wheel, vs except steel wheel. How can I tell which applies to me? In any case my torque wrench only goes up to 108 Nm.

Any tips?

  • What car year, make and model? If in doubt, I always aim for 80lb/ft - but will go with the car's factory service manual value if I can find the info. – PeteCon May 14 '18 at 2:39
  • How long is the handle of your 1/2” breaker bar? How much do you weight? Hint: torque = force applied over a distance ( the distance from the socket to your hand). A rough approximation of force is half to a third of your body weight when pushing down. Pretend you got a flat tire on the side of the road. – zipzit May 14 '18 at 3:08
  • @zipzit you can apply more force by pulling up on the breaker bar and using leg muscles ie straightening your legs... – Solar Mike May 14 '18 at 4:21
  • Haha. Yeah I weigh quite a bit, over 100 kg. So I might have tightened them too much. I will take them off and redo it. At least I should be able to get them off. 100kg on, 100kg off. – peter May 14 '18 at 23:13
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Steel wheels tend to be plainer, and simply pressed out of steel. Alloy wheels are more decorative. The attached photo shows common wheels on the Toyota B2500 and variants.

Torque values are often supplied with a +- value (10% is not uncommon), so just get them up as best you can with your torque wrench, and put a higher capacity one on your shopping list. The value for wheel nuts is given so that the monkey at the local tire shop doesn't run them down with a pneumatic torque wrench to 300lbs or so..

Alloy vs Steel wheels

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    OK. Mine are definitely steel then. Exactly like the ones on the right. Thanks. – peter May 15 '18 at 6:30
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Alloy wheels need to be tightened with less force than steel wheels, due to alloy being a but softer and more prone to deformation under high stresses. In this case it seems that "except steel wheel" is a bit of a haphazard translation for an alloy wheel.

Alloy is usually aluminium, but could in theory also be magnesium. You can determine the difference between alloy and steel by look, weight, or by trying to stick a magnet to it. Steel is magnetic, aluminium is not

If you have steel wheels on your Mazda, your torque wrench is a bit too light to properly tighten the lug nuts.

  • Don’t you need bigger nuts for alloy wheels .... – Solar Mike May 14 '18 at 11:58
  • I don't entirely agree, at least for Toyota the torques are the same: blobs.continental-tires.com/www8/servlet/blob/1080706/… – juhist May 14 '18 at 12:51
  • @juhist i was under the impression that generally alloy wheels needed to be tightened to about 120nm and steel to 140nm, unless specified otherwise by the manufacturer. Your list proves otherwise. There seem to be only a few italian manufacturers that list different forces for alloy wheels and even then the force needs to be higher for alloys, not lower. I stand corrected. – MadMarky May 14 '18 at 15:12
  • Excuse my ignorance, how can I tell the difference between steel wheels and alloy wheels? Is the difference subtle, or pretty obvious? I expect alloy means aluminium, so the difference will be based on the metal colour? – peter May 14 '18 at 23:11
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    @peter alloy is usually aluminium, but could in theory also be magnesium. You can determine the difference between alloy and steel by look, weight, or by trying to stick a magnet to it. Steel is magnetic, aluminium is not. – MadMarky May 15 '18 at 7:42

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