Justify Torque

[Platinum White]

I have a  Ford 2017 Ford Edge Titanium. Page 332 of the owners manual has a torque value of 162 lb.ft. for the lug nuts. WHYIs the torque so High when the torque for an F-150 is 100 lb.ft.?

To keep the wheels on is not an acceptable answer.

[IWRBB]

Torque values are determined by how much torque it takes to stretch a bolt or stud the correct amount needed to provide the proper clamp load.  It's that simple for every single fastener on the entire vehicle.  If you don't torque it enough, there's not enough stretch and not enough clamp load.  

 

Torque values will vary based on the type of steel used and the diameter of the bolt/stud.  So the lugs on the Edge are likely a larger diameter, a stronger steel (or both) compared to the F150 you have.    I'd bet the F150 you have has 12mm studs, where as the Edge has 14 mm studs.  F150s from 2009+ have 14 mm and call for 150 ft-lbs. 

 

As to why 150 ft-lbs is good enough for the 14mm truck lugs but the Edge calls for 162 ft-lbs, it does seem odd since they are the same diameter and thread pitch lugs.  However the F150 has 6 lugs vs the Edge's 5 lugs.  You'd have to go to 180 ft-lbs on 5 lugs to get the same total clamp load as 150 ft-lbs on 6 lugs.  That'd likely put the lug close to plastic deformation, IE failure, so they took it as high as possible without getting too close to the limit.   So the Edge has less total clamp force than recent F150s, as you would expect, even with it's higher lug nut torque rating.  

 

As to why the current F150s and the newer Edges have such a higher clamp load than the older 12mm lug Ford vehicles- I'm not sure, but I'd guess it has to do with NVH, braking and crash testing.  Total guess- a Ford engineer would have to tell you that.  

[akirby]

I think the larger studs and higher torque values are due to the larger wheel sizes.  My F-150 only has 18” wheels.  Edge can go up to 22”.

[IWRBB]

12 hours ago, akirby said:

I think the larger studs and higher torque values are due to the larger wheel sizes.  My F-150 only has 18” wheels.  Edge can go up to 22”.

 

There are F150s that come with 22 inch wheels as well.  

 

The 12mm lugs have not been on a F150 for nearly 20 years now.  They switched in 2000 to the 14 mm studs.  

[akirby]

1 hour ago, IWRBB said:

 

There are F150s that come with 22 inch wheels as well.  

 

The 12mm lugs have not been on a F150 for nearly 20 years now.  They switched in 2000 to the 14 mm studs.  

 

Just checked and it's 150 lb/ft on F150 regardless of wheel size.  So it's stud size not wheel size, but maybe they went to larger studs to support the larger wheels (20"-22").

[Platinum White]

Good luck getting the lug nut loose on a roadside  with the provided tire tool.

 

I strain using a 24 inch breaker bar.

[JacobZ06]

On 7/17/2019 at 1:54 PM, IWRBB said:

Torque values are determined by how much torque it takes to stretch a bolt or stud the correct amount needed to provide the proper clamp load.  It's that simple for every single fastener on the entire vehicle.  If you don't torque it enough, there's not enough stretch and not enough clamp load.  

 

Torque values will vary based on the type of steel used and the diameter of the bolt/stud.  So the lugs on the Edge are likely a larger diameter, a stronger steel (or both) compared to the F150 you have.    I'd bet the F150 you have has 12mm studs, where as the Edge has 14 mm studs.  F150s from 2009+ have 14 mm and call for 150 ft-lbs. 

 

As to why 150 ft-lbs is good enough for the 14mm truck lugs but the Edge calls for 162 ft-lbs, it does seem odd since they are the same diameter and thread pitch lugs.  However the F150 has 6 lugs vs the Edge's 5 lugs.  You'd have to go to 180 ft-lbs on 5 lugs to get the same total clamp load as 150 ft-lbs on 6 lugs.  That'd likely put the lug close to plastic deformation, IE failure, so they took it as high as possible without getting too close to the limit.   So the Edge has less total clamp force than recent F150s, as you would expect, even with it's higher lug nut torque rating.  

 

As to why the current F150s and the newer Edges have such a higher clamp load than the older 12mm lug Ford vehicles- I'm not sure, but I'd guess it has to do with NVH, braking and crash testing.  Total guess- a Ford engineer would have to tell you that.  

That is the most coherent answer I have seen on the topic.  Thank you.

[omar302]

Today I went to one of our "professional" wheel shops and asked them to toque the wheel lug nuts to 220 NM (162 lb-ft), and all the workshop guys were surprised. They were afraid it would strip the studs and only went to 200 NM, gradually. So my question is how many here actually torqued their wheel lugs to 162 lb-ft and for how long? Also, did they have to remove the wheels later on for any reason, confirming out of actual trial that there is no reason for concern torquing them as specified?

[IWRBB]

I've removed lug nuts that were WAY over 162 ft-lbs on smaller diameter 1/2" studs and they didn't break or stretch.   By the way, I'm talking about YOU Tire Discounters.  We bought a used Fusion that the dealer had new tires put on at TD before we bought it.  Tire Discounters just ran em down with an impact it seemed like.  They were crazy tight, and made all kinds of tinking noises as they loosened up.  Lugs were still fine though.  

 

Every 15+ F150 has had the same lug size and threads as the 15+ Edges, and the the F150s are specified at 150 Ft-Lbs.  Nobody seems to think that's too high.  The Edge has one less lug, so I can understand why Ford upped it slightly over the F150.  I don't see another 12 ft-lbs causing the lugs to strip/stretch/break, especially if Ford is telling you it's the required torque value.   I'm kind of shocked a tire shop would send out a vehicle with it's lug nuts torqued to less than factory specifications.  Seems like a lot of liability on their end for no reason.