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-   -   wheel bolts torqued 5 lbs below spec. is that ok? (http://www.peachparts.com/shopforum/tech-help/25913-wheel-bolts-torqued-5-lbs-below-spec-ok.html)

rickjordan 11-05-2001 01:07 AM

wheel bolts torqued 5 lbs below spec. is that ok?
 
Ever time I remove a wheel, I make sure to torque it back on. Unfortunately my torque wrench only goes up to 75 ft lbs and I believe the spec. is 80. Will this 5 lbs. make a difference? I don't see me going out to buy another torque wrench just for 5 lbs. A couple of months ago I had my wheels rotated and balanced. The place I took it to cranked the living daylights out of the wheel bolts. I had to use a half inch drive breaker bar and my full weight to get the bolts loose. I knew there was no way in hell I was going to be able to get them loose while on the side of the road with tire iron. I discovered this while trying to remove a wheel to look at my front rotors.

LarryBible 11-05-2001 06:40 AM

Personally I would not feel safe with my lug bolts under torqued.

There are two reasons that you torque the lug bolts, one is so that you ensure that they are tight enough that the wheel won't come off, not a good thing.

Secondly, you torque them evenly in a star pattern to prevent brake rotor warpage.

In the early eighties I started just "torquing" my lug bolts with the factory lug wrench. I tighten them in the five pointed star sequence, by leaning on the handle an equal amount in sequence. I have never warped a rotor or lost a wheel with this method.

First snug them in sequence, then put the wrench on each bolt, in sequence, in a position roughly parallel to the ground, then put your upper body weight on it. After using your torque wrench to 75 pounds, you should have a bit of a feel for how much weight it takes on your wrench.

Good luck,

1991 560 SEC 11-05-2001 06:49 AM

I agree with Larry. You should always torque to the spec, regardless of where the bolt is.
You can get a good torque wrench at Sears. I bought one that goes up to 250 FT/ LB`s for about $69.00 , it has FT/ LB`s and Newton Meters. Also with any torque wrench realese the pressure when your done.

John

Herr Leber 11-05-2001 08:57 AM

For Accuracy - Get a Snap-On Torque Wrench
 
If you want accurancy, get a good torque wrench. The cheap ones can vary wildly.

I dont work for SnapOn , but their stuff is great.

300EE320 11-05-2001 12:03 PM

If you're a member of the Craftsman club, all of their torque wrenches are on sale this week for $53! (regular $69).

jsmith 11-05-2001 02:53 PM

the Sears/Craftsman ones are very nice. i picked one up on sale and was very impressed with the click stops and twist lock mechanisms. my two smaller torque wrenches don't have either of these features. i found it interesting though that the Craftsman literature made no mention of releasing the tension nor storing at the lowest setting...

-fad 11-05-2001 03:55 PM

...wondering, how uneven torque around the lugs would yield rotor warpage....

I've followed the criss cross torqueing pattern without a torque wrench, and in 20 years, not had a single rotor warp on 10 MBs...

help educate me ont his one..I'm apparently missing something

tks-fad

1991 560 SEC 11-05-2001 04:15 PM

You either very lucky or very good!!!!
What happens when wheels are not torqued correctly is uneven take up on the hub and rotor. This inessence creates a run out condition that warps the rotor and sometimes the wheel!!
It`s uneven pressure at the matting surfaces.
John

sbourg 11-05-2001 05:57 PM

"...wondering, how uneven torque around the lugs would yield rotor warpage...."

Even if minutely, the metal of the rotor deforms under pressure, causing distorting of the shape over time. This is compounded by uneven heat distribution due to uneven pad contact and uneven heat conductivity through the studs.

This effect should be slight if an effort is made to torque the bolts evenly by hand, and is much more pronounced if the bolts are torqued fairly evenly, but much too tightly.

Steve

LarryBible 11-05-2001 06:16 PM

Uneven torque can definitely cause warped rotors. How much tolerance do you have before it becomes enough uneven torque, I don't know.

If I were to use my hand torque method on a race car that were driven to the point of red rotors, I wouldn't want to use my method. But for my moderately driven 123 car it's worked great. I guess I now have to do some testing to see just how even I'm torquing them with my method. I expect that I'm torquing them within 5 or 10 pounds of each other.

Proposing my hand torque metod is not in any way a statement saying that you shouldn't torque them carefully with a torque wrench. That is obviously the safest method. I'm just relating my experience regarding what has worked well for me.

Have a great day,

-fad 11-06-2001 11:40 AM

Thanks so much for sharing this critical information with an anal retentive vehicle enthusiast!

I now have another weekend asap project (my wife already thinks that I should move my bed into the garage and cancel the cable subscription since so much of my time is spent with the cars!!!)

-fad

mplafleur 11-06-2001 12:36 PM

I have never, nor have never known anybody to ever use a torque wrench on wheel nuts.

The first (and only) time I saw one used was in a Sears advertisement for one of their torque wrenches. I thought it was only a selling point.

Now I've been given something to think about.

300EE320 11-06-2001 01:15 PM

Consientious shops torque lug nuts. I has some tires replaced once and the shop had a process that I just loved!

The tire guy went around each wheel and torqued all of the lug nuts, then signed the invoice. He handed the torque wrench to a second employee who checked the adjustment on the wrench and then double-checked every lug nut. Then he signed the invoice! They must have had a wheel come off at some point to go overboard like that, but it sure made me feel good to see it.

I always torque the lug nuts and check the air pressure anytime someone else has the wheels off (Costco for tires, etc.). The lug nuts are usually overtightened (some of them), and the air pressure usually varies +/- 10 psi.

1991 560 SEC 11-06-2001 01:29 PM

Wow!!!!
Never let them put your wheels on with an impact wrench!!!!!
Another thing, when you put your wheels on you should;
1. Put anti- siez on the lug bolts so you can get an accurate reading and get them off the next time

2. Put anti- siez on the front hub where it mates with the wheel. Dissimilar metals. Doing this will assure that you get the wheel off the next time.

John

normwm 11-06-2001 08:15 PM

I had a Craftsman click type torque wrench that was so inaccurate that I broke two head bolts before I borrowed a snap-on torque wrench a realized what was going on. It was overtightening by 20 pounds. I recommend one with a dial.


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