Lug nut torque

After removing and lifting into my Explorer (one side at a time) the rear end of the Tiger I am amazed how tiny the wheel lugs are.

I eat pasta bigger in circumference than these lugs.

V-8 + top loader + Dana/Salisbury and then these pencil size (yellow number 2) lugs..............do any of you with bigger horse power ever snap these things?

Mike

Lugs.

I think the problem is when people over tighten the nuts such as with an air gun and weaken the studs . I will be changing mine for larger type when I do a brake upgrade . I will let you know which studs I use .

Little Lugs vs Mega HP ??

Well, never had a problem with the tiny critters as long as they were snugged to torque. Floppy or over stretched will snap one or tear a wheel in quick fashion. The average engineered "shear" of that particular alloy in 7/16" is well over 11,000 X 4. Your fully beefed SBF ain't ever gonna get there, Dude. We did build a steroid 289 some 35 years back that tore out the U-joint, but, the little lugs and their baby pinion flange kin held on just fine.

Restoration: Somewhere between the surge of novel inspiration and the final day of test drive, my brand new grandkids grew grey & bald.

The ultimate conclusion above is very comforting. However, if I am understanding the shear number for the wheel stud itself, doesn't that 11,000 number equate to a 7/16 Grade 5 bolt? If so, I would have thought it would be closer to a Grade 8 or better bolt. Just curious.

Gene

Stretch that bolt

OK Gene: Lug bolts are generally 9 Mark on up to 12 Mark. The issue of "shear" strength is only partly related to "tensile" (aka mark) strength. In practical applications like building construction, "shear" is measured using formulars forcing on a 1" sq area. Whereas measuring that almost invisable dimension where the lug bolt pokes thru the hub is a whole other brain cramping set of barnyard math. amen

Randy, I am agreeable to all you have said. It's just that since you used the term "shear" and the number 11000, I went looking to better understand the numbers.
I am in the process of putting in 1/2 inch studs in all my wheel hubs. I have become concerned that the stresses from R compound tires in autocrossing might be too much for the stock studs.
Your info gave me a point of departure to see where I am starting from to how much better is where I am going. While I expect cornerning forces to be more like elongation forces than shear forces, understanding the relative strength on a shear basis might still be somewhat informative. On the website www.rockcrawler.com/techreports/fasteners/index.asp I found a chart that showed a 7/16 bolt in a grade 5 had a shear capabilty of 11270. I compared that to your shear number of 11000 and thought I would ask. As they say a little bit of knowledge can be a dangerous thing. Good night, may we all sleep well. Gene

Shooting your own foot.

Anyone know of an actual failure of the stock studs?

I have heard of stock wheels failing.

Tiger's have been autocrossing and running track events with the stock studs and big gummy tires for over 40 years. I have for over 20 years.

The only stud incident I recall was at a recent Tiger's United involved upgraded studs which were threaded/not pressed into the hub from the backside. Apparently when a couple of the acorn nuts went on they caught the threads of the stud?s? and screwed them back into the hub. Only a couple threads were actually into the lug nut. The nuts could not hold on but as I recall the wheel got loose but it did not exit stage left. Close call.

That is one reason racers do not use acorn nuts. You can not see that there are enough threads inside that nut.

Rick

keepin' it simple

Thank Rick, fer bringin' it all back to earth. Now, if I can get the pontoons on the roto-tiller and get the garden going . . . . . . . . . . randy

For any who remain interested, you might find Owain Lloyd's recount of his 2009 Casablanca Rally in his 1965 Tiger worth reading from this and many other great perspectives. Specifically to this stud topic, he recounts shearing 4 studs on Day 9. He is not explicit that they were stock studs however. Check out www.casablancachallenge.com for a thoroughly enjoyable experience recount if you have not seen it already.

And my apologies to all for asking for clarification of seemingly contradictive facts put forth in support of an expert's pronouncement. I did not realize a respectful inquiry tendered in good faith placed the topic in need of being brought back to earth.

Gene

That might have been at Big Bear...my wife and I were walking to some of the antique shops when we spotted what appreared to be a Tiger lug nut in the dirt on the side of the road. When I asked around that night, sure enough, it belonged to one of the Tigers- and it wasn't the only one he lost!

Launch that expert

Never wuzz, never will be. Just a lifetime of surviving some of the most embarrassing screw ups one can imagine . . . . . . . .

0neoffive said:

Launch that expert

Never wuzz, never will be. Just a lifetime of surviving some of the most embarrassing screw ups one can imagine . . . . . . . .

Click to expand...

black66 said:

Lugs.

I think the problem is when people over tighten the nuts such as with an air gun and weaken the studs . I will be changing mine for larger type when I do a brake upgrade . I will let you know which studs I use .

Click to expand...

The workshop manual mentions a torque of 48 foot pounds for ‘road wheel nuts’ am I reading this correctly as the lug nuts which standard ones are 7/16 should only be 48 foot pounds ? I was expecting more like 75 pounds Any suggestions since there are many comments not to over torque the nuts