skeet

After installing my new Bilsteins and removing my wheels I did the correct procedure, upon installing the wheels, of first torqueing the lugs to 80 ft/lbs in a star pattern and then going around and increasing the torque to 98 ft/lbs. I drove the car about 100 miles and when I re-torqued them to the same 98 ft/lbs some of the lugs pulled tighter.
I know the manuel says torque to 100 ft/lbs but I think 98 ft/lbs will be OK. Anyone disagree?
Anyway my point is that aluminum wheels need to be re-torqued after the first 50 miles.

86Moon

Hmm...was that before or after you sent your wife into a total PANIC :lolg: :lolg: :lolg:

C4SMAJ

Im sure it will be ok...Im just curious why you want to torque them at 98 and not 100.....when I torque mine I go 40-70-100......
:seeya

skeet

I know the service manual says 100 but I read in one of the Corvette mags that 98 was a better idea.It was a long time ago and i forgot the reason. Also, it is easy for torque wrenches to be off 1 or 2% and I would rather be slightly under than over.
Does anyone know what effect temperature has on torque ratings? It you torque lugs in Phoenix at 100 ft/lbs when the temperature is 115 degrees is that still going to be 100 ft/lbs in Fargo, ND. when it is say 30 degrees?
I will try the 30-70-98 next time.

CentralCoaster

I don't think it matters... but the lugs will tighten up in colder weather. I don't even measure mine... just put em on as damn tight as I can get em. They might have 140 ft-lbs on them for all I know, but they're sure as hell not coming off, sometimes don't even when I'm trying to!

Mr Mojo

I read somewhere that aluminum wheels should be retorqued after the first 25 miles, then after that you should be fine.

There are times where I don't fell 100 lbs/ft is enough, I tighten by hand and finish with the torque wrench and it doesn't take much to get to 100.

Corvette Kid

I don't think temps per se would have much effect but I wouldn't torque them when thw rotors are real hot.

Kizmo

Well aluminum does experience allot of expansion and contraction! I have also understood that you should re-torque to 100ft. lbs. after 25 miles. This is plenty time for the wheels to heat up. The key is to re-torque at 100 ft. lbs. after the wheels have cooled. This was told to me by a friend who has a tire and wheel store.

As far as the 100 ft. lbs. I don't think I would second guess GM engineering on this subject. Also properly torqued wheels are suposed to help reduce rotor warpage.
:seeya





[Modified by Kizmo, 9:58 PM 3/10/2004]

xs650

Between the tolerances on torque wrenches and the big variations you get on actual bolt tension depending on coefficient of friction of the nut, stud and wheel, you don't know within 15% how tight your wheel actually is, so a 2% differance means nothing. The only useful information that 98 lb ft recomendation gave you is that you shouldn't pay any attention to whoever wrote it.

Aluminum expands/contracts at about three times the rate of steel, so you wheel will probably be a tad looser at 30 deg F and get tighter at higher temps.

Steve85

In working with both Land Rover and GM engineers and while schooling for my Automotive Science degree did I ever hear once that a wheel needs to be heat cycled. If this was necessary, every new car with aluminum wheels would have at least 25 miles on it in the showroom. And they are not putting the wheels on torqueing them, putting the car in an oven, letting it cool and resetting torque.

Even during a recent GM brake class where they introduced us to using shims between the rotor and the hub to eliminate on car lateral runout for the sole purpose of preventing BRAKING VIBRATION caused by warped rotors, was the need to torque, heat, cool, retorque the wheel mentioned. It was specifically mentioned that when torquing the wheel, we not grab the torque stick (a calibrated extension with a set torque rating) to ensure an accurate result. If you heat and cool then retorque and tell me it changed I want to see wheel temp readings and your torque wrench calibration.

I understand you want to be safe and do it right, but you don't need a Tomahawk missile to kill a fly. :cheers:

Kizmo

I do know that many new car dealerships have a pre-delivery requirement where they check and re-torque the wheels. Maybe that is just a liability issue on their part. I have personally re-torqued my wheels after a heat up and cool down and have found that it was needed but I'm not an engineer, I'm just going by what the torque wrench told me. Click! click!

(To the above reply) I guess you dont need to follow any pattern or any specific torque rating either, correct?

Modified by Kizmo, 7:02 PM 3/10/2004]


[Modified by Kizmo, 7:09 PM 3/10/2004]

Steve85

"I do know that many new car dealerships have a pre-delivery requirement where they check and re-torque the wheels. Maybe that is just a liability issue on their part."

Yes, torque is checked aong with 75 other things. The vehicle has hardly been driven, perhaps out of the plant, onto the truck, off the truck to the lot. 99% of the vehicles I have PDI'ed have less than 10 miles.

"I have personally re-torqued my wheels after a heat up and cool down and have found that it was needed but I'm not an engineer, I'm just going by what the torque wrench told me. Click! click!"

What were the wheel temps before and after (determines amount of expansion/contraction), exactly the same? Now, was the torque correct the first or the second time? Since you did not measure the torque, then take the lug nuts loose before retorquing, you've done nothing for accuracy. To get an accurate torque setting you SHOULD NOT start with the bolt within a few pounds of the setting desired.
If you feel better retorquing, in all seriousness, back them off a 1/2 to full turn and make a single smooth sweep of at least 1/4 turn to the "CLICK"


"(To the above reply) I guess you dont need to follow any pattern or any specific torque rating either, correct?"

Sorry I did not get into the pattern. No, I even stated that you must be careful to operate your tools properly to ensure an accurate setting.

Modified by Kizmo, 7:02 PM 3/10/2004]

I really was not trying to be a dick, just letting you know that it's really not necessary and showing examples to make a point. Hence the fly joke at the end. I had visions of hudreds of forum members taking their rides in for tire rotations and telling the mechanic to drive the car 25 miles and then retorque, otherwise my wheel will fall off. Get my drift...

It's not personal, just an observation w/examples from years of experience to the contrary of what was stated.
:cheers:


[Modified by Ski2Tee, 3:41 PM 3/10/2004]


[Modified by Ski2Tee, 3:44 PM 3/10/2004]

xs650

[QUOTEI really was not trying to be a dick, just letting you know that it's really not necessary and showing examples to make a point. Hence the fly joke at the end. I had visions of hudreds of forum members taking their rides in for tire rotations and telling the mechanic to drive the car 25 miles and then retorque, otherwise my wheel will fall off. Get my drift...

It's not personal, just an observation w/examples from years of experience to the contrary of what was stated.
:cheers:
[/QUOTE]

Well, I am a Dick.

I pretty much agree with what you said, but maybe not for the same reasons. The factiry torque ratings take a bit of loosening into account.

What does happen in a joint where the contact surfaces are less than perfectly lapped together, is that some of the surface irregularities between the nut or screw head and mating surface wear away giving up a bit of fastener tension. Also between the wheel and hub to a lessor extent.

You can really see the effects of this when you drive a couple of hundred miles on unpaved roads with freshly torqued wheels or wheels that have only been run on pavement since torqued.

But to get back to reality, If I ever drive my Corvette on several hundred miles of gravel road, I will be sure to recheck lug nut torques :eek: :eek:
Right before I have somone shoot me and put me out of my misery.

In the interest of science, I just rechecked the torque on the lugnuts I tightened about 500 miles ago. Two of the moved the slightest amount. The others didn't budge.

Dick


[Modified by xs650, 1:46 PM 3/10/2004]

Kizmo

Thanks Richard! :lolg: :lolg: :lolg: My reply was based on things that I have heard from other people. Be it wrong or right it can't hurt. Also I am glad you checked your lug nut tightness "in the interest of science" We will all be able to sleep better tonight. :sleep:


[Modified by Kizmo, 10:05 PM 3/10/2004]

Powerdrive

Just grab a four way and crank till tight :D

Kizmo

I'm one of those guy's that just has to keep beatin a dead horse.

I don't have my Vette owners manual because my car is at my buddies shop, but I do have my 2001 Silverado manual in front of me and it clearly states in the section about wheels:

NOTICE:

Improperly tightened wheel nuts can lead to brake pulsation and rotor damage. To avoid expensive brake repairs, evenly tighten the wheel nuts in the proper sequence and to the proper torque specification.

I wonder why the GM engineers would write such a thing if it dosent apply.
:confused: I guess they don't know better.

I can't wait to check my Vette owners manual, because I think this horse is still kickin! :yesnod:

Signed Richard

Unriced

Go with the factory recommendation, after all they designed and built the damn thing, right?

I had some morons at a tire shop overtorque my original locks and they wrecked them.

Let alone should you ever need to replace a flat, overtightening could make a 10 min stop

turn into 10 hours.... Go with the spec....