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Torque wrenches are accurate to 100% of scale; it's the bottom 20% that they're not accurate. You're fine to torque a 140 lb lug with a 150 lb wrench. The first few times you take the wheels on/off you'll find lugs that take a little more torque if you check after you drive. This is from the studs seating in the hub flange, stretching a little, and the wheel nut flange wearing in a little. My process:
1. With car in air install wheel and thread on 1 lug to keep wheel in position. Install other 4 lugs using socket and snug by hand.
2. Take 1/2" ratchet and tighten in star pattern; gutentite is 85-90 ft/lbs generally.
3. Lower car enough to have tread hit ground and create enough friction to stop wheel from turning.
4. Torque in 3 star passes - 100, 120, 140
5. Lower car all the way; roll it back and forth a few feet (harder to do w/ C8 as it has to be running) check again at 140.
6. Drive the car around the block; check again at 140
Only check torque when everything is cold; never after a drive. For trackdays I do them first thing in the AM and don't touch the rest of the day.
What You Need To Know About Accuracy... For All Mechanical Click-Type Wrenches. The ANSI Standard allows 4% of reading error between 20% and 100% of wrench capacity. Below 20% ANSI allows an error in reading equal to 0.8% of wrench capacity. What Does This Mean To You? Using a wrench at 5% of its full scale may result in up to 16% error in reading. How can you be sure you are anywhere near the fastener torque specification? Use Caution When Buying Torque Wrenches Rated Below 20% of Full Scale. Torque wrenches that are scaled below 20% of full scale may not be accurate and may lead users to operate them below their useful range. Select a torque wrench so your working range falls near the mid point of its capacity
Last edited by RapidC84B; Nov 30, 2020 at 03:16 PM.
Thanks to all that replied to my original post. I figure the cheap Harbor Freight torque wrench for 10 bucks will work fine for what I need. Just want to check torque values after I put a few miles on as I have read on here some lug nuts were quite loose. I don't think I will ever be taking the wheels off myself that I can imagine. A lot of good info I have learned about torque wrenches. It's too bad sometimes whatever they use in Bowling Green or at the dealers doesn't seem to be as accurate as a $10 Harbor Freight torque wrench...
Thanks to all that replied to my original post. I figure the cheap Harbor Freight torque wrench for 10 bucks will work fine for what I need. Just want to check torque values after I put a few miles on as I have read on here some lug nuts were quite loose. I don't think I will ever be taking the wheels off myself that I can imagine. A lot of good info I have learned about torque wrenches. It's too bad sometimes whatever they use in Bowling Green or at the dealers doesn't seem to be as accurate as a $10 Harbor Freight torque wrench...
Torque machine at BG is accurate, but first few torque cycles seat the studs sometimes.
.... It's too bad sometimes whatever they use in Bowling Green or at the dealers doesn't seem to be as accurate as a $10 Harbor Freight torque wrench...
GM could be "dead on ***** accurate" as Marissa Tomei noted was the Craftsman Signature Series wrench she used! As she also notes, "It's an industry term!"
But as soon as the new car is driven that torque setting on some lugs will be less! That is why it says to retorque after 150 miles. Especially needed for brand new parts! The lugs and seats will mate in time and the torque value will remain!
Thanks to all that replied to my original post. I figure the cheap Harbor Freight torque wrench for 10 bucks will work fine for what I need. Just want to check torque values after I put a few miles on as I have read on here some lug nuts were quite loose. I don't think I will ever be taking the wheels off myself that I can imagine. A lot of good info I have learned about torque wrenches. It's too bad sometimes whatever they use in Bowling Green or at the dealers doesn't seem to be as accurate as a $10 Harbor Freight torque wrench...
You may not take them off but anytime I have tires/wheels done at a commercial place I always loosen then retorque the lug nuts because commercial places may not torque them, may use an air gun and could tighten them much more or significantly less than the spec.
I would not be surprised if Chevy dealers torqued C8 lug nuts to 100 lb-ft like every other Corvette. A number of Chevy dealers changed the oil on the first dry sump LS7s and only drained one plug then put in 6 quarts of oil "because they all take that".
I think everyone over thinks this. Jesus. Use a good torque wrench, do it in a correct fashion, it's not rocket science. As an old professional tech, you'd be shocked how may people still use torque sticks. The world has not ended. It's mental stimulation for most of us.
I torque and torque check when cold. If you are just checking the torque, DO NOT loosen then torque. Just pop the wrench on and tighten till you hear the click.
If you are removing the wheels for a rotate or brakes, get yourself a nice battery impact that way you can get a good clamp on the wheel with the nuts when installing and then finish with the torque wrench to 140ft.lbs.
Originally Posted by AzDave47
You may not take them off but anytime I have tires/wheels done at a commercial place I always loosen then retorque the lug nuts because commercial places may not torque them, may use an air gun and could tighten them much more or significantly less than the spec.
I would not be surprised if Chevy dealers torqued C8 lug nuts to 100 lb-ft like every other Corvette. A number of Chevy dealers changed the oil on the first dry sump LS7s and only drained one plug then put in 6 quarts of oil "because they all take that".
So to just check torque, should you are should you not loosen then retorque
I won't be doing much if any mechanical work on my C8 but I am going to buy one of the cheap Harbor Freight half inch torque wrenches. So what is the proper procedure to check for correct torque. Do I loosen each lug nut first and then re tighten to 140 lb? Can I use the Harbor Freight torque wrench as a tool to loosen especially if originally nut was over torqued? Does it matter if Hub is hot or cold and I did read never to put any lubricants on the studs.
Thanks in advance!
Where did you read that you should not lubricate the threads?
Where did you read that you should not lubricate the threads?
Every place you look IF you try to understand the implications of adding lubricate or even anti-seize! Quoting just one I found:
"For everyone that thinks using anti-seize on wheel studs is a great idea, you might want to think about it more. Sure it will torque up and clamp the living do-do up really tight, but at the same time it is also can stretch the stud beyond the yield point to the point they could just snap. Dry, clean wheels studs, and a good torque wrench is the correct way. Here are a couple of pages from my training manual, which has examples of the what the effect of putting lube on the studs, which can DOUBLE the clamping force, which turn into tons of force. Proper clamping force is the key to keeping the wheels attached to your vehicle. Also, excessive clamping forces will probably distort, and damage the lug nut seats on the wheel, and brake rotor. And who knows what damage there is to the actual threads on the nut/stud."
Just one of many if you search. Yep that 140 ft-lbs on a lubed stud could be like using twice the load on the stud or the equivalent of using 280 ft-lbs! Same with all bolts in any situation. Yep could break the stud!
PS: Perhaps this graph will help explain why when in says the lug nut and wheel stud should be clean and dry when torqued to the specified value:
So to just check torque, should you are should you not loosen then retorque
If you torqued the lug nuts yourself, then no need to loosen. If a shop did it, I do loosen them some and then torque to spec. The reason I would do this is if the shop used an impact wrench on a C8 for example, they could have done some lug nuts to 160 or more. What you are looking for to avoid problems is uniform torque on all lugs. If you just check to see if they are tight to 140, you could have two to 140 another to 160 and two at some higher number.
When one of my C8 buddies was at coffee one morning, I checked his lug nuts for him and just made sure they were all at least 140.
So to just check torque, should you are should you not loosen then retorque
Unless you know the torque on the lugs in below spec, always loosen and re-tighten. If someone else torqued them last, they could be torqued too high, and the torque wrench won't tell you that.
Also, don't use the torque wrench to loosen the lugs. Only to tighten.
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Originally Posted by Broken Halo
Just picked up this Craftsman at Lowes. Regular $90 on sale for $50. Has tighter tolerance then the ICON, is 3" longer for better leverage (27"), and came with calibration certificate. https://www.lowes.com/pd/CRAFTSMAN-1...-lb/1000772366
Not a bad buy. Unfortunately they are out of stock at our local Lowes.
Not a bad buy. Unfortunately they are out of stock at our local Lowes.
Did you physically go into the store, or did you just check availability on their website? My Lowes said out of stock on their website, but when I called to check they had 2 in stock.
Made this summary pic showing what is needed; including CAUTION to NEVER use any Lubricant, WD40, or Anti-Seize:
