GM/McGard Wheel Locks Out of Balance
03-30-2006, 10:07 AM
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St. Jude Donor '13
GM/McGard Wheel Locks Out of Balance
My salesman gave me a set of the GM wheel locks for the C6, they are made by McGard but have GM packaging and GM part #12498078. This is verified as the correct part for a C6.
The back of the package says "Precision weight matched to maintain wheel balance".
But when I took one out, they felt heavier than a normal C6 nut. So I got out the scale-
Locking wheel nut= 947 grains
Standard wheel nut= 771 grains
Difference= 176 grains. That's about the same additional weight as a Quarter plus two Dimes.
Of course the out-of-balance weight is fairly close to the center of the axle (about 2 1/4"), so it's less serious than if on the rim
(about 7 3/4"). If you use the ratios, it's about the same as 52 grains out on the rim where the balance weights are located. Similar to taking 1 and 1/2 dimes and glueing them alongside your balance weights. Can anyone say if that difference would be noticeable?
There may be better wheel locks, and you can argue that no wheel lock is very effective. Other threads have beaten that subject to death, let's just look at the balance problem. Thanks.
The back of the package says "Precision weight matched to maintain wheel balance".
But when I took one out, they felt heavier than a normal C6 nut. So I got out the scale-
Locking wheel nut= 947 grains
Standard wheel nut= 771 grains
Difference= 176 grains. That's about the same additional weight as a Quarter plus two Dimes.
Of course the out-of-balance weight is fairly close to the center of the axle (about 2 1/4"), so it's less serious than if on the rim
(about 7 3/4"). If you use the ratios, it's about the same as 52 grains out on the rim where the balance weights are located. Similar to taking 1 and 1/2 dimes and glueing them alongside your balance weights. Can anyone say if that difference would be noticeable?
There may be better wheel locks, and you can argue that no wheel lock is very effective. Other threads have beaten that subject to death, let's just look at the balance problem. Thanks.
03-30-2006, 10:21 AM
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Meaning of Precision Balanced missunderstood
I think they mean that each replacement lug nut is the same weight, so that the new lug nuts won't throw your wheels out of balance. Precision weight matched means that all of the lugs in the package are the same weight as each other. It does not imply they are the same weight as your OEM lug nuts.
03-30-2006, 10:29 AM
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St. Jude Donor '13
Unlike some companies, the GM/McGard locks come in a set of 4 for the car. That means one per wheel, so the locks need to be the same weight as a standard wheel nut.
If they sold a set of 20 for the car, then your idea would be correct. Unfortunately, they don't do it that way.
If they sold a set of 20 for the car, then your idea would be correct. Unfortunately, they don't do it that way.
Last edited by Gearhead Jim; 03-30-2006 at 02:46 PM.
03-30-2006, 10:36 AM
#4
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I have wheel locks that came with the car (dealer installed I assume, but he didn't change extra... ) they are obviously bigger, so I assume heavier, than the stock lugs. I haven't noticed any out of balance feel at speeds ranging from 5 to 100. I doubt that little bit of weight would make much difference.
03-30-2006, 11:08 AM
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It sounds to me like McGard should lay off empty marketing bilge.
My past experience in rotating equipment says a lug nut will have virtually no affect on wheel balance. As you said, the location is too close to the center of the wheel. In fact, I haven't tried it, but I have a hunch you could leave a lug nut completely off, and it would have little effect on wheel balance. Whatever happened to GGWoody?...he'd try anything.
My past experience in rotating equipment says a lug nut will have virtually no affect on wheel balance. As you said, the location is too close to the center of the wheel. In fact, I haven't tried it, but I have a hunch you could leave a lug nut completely off, and it would have little effect on wheel balance. Whatever happened to GGWoody?...he'd try anything.
03-30-2006, 02:53 PM
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St. Jude Donor '13
Originally Posted by LS1LT1
Your C6s didn't come standard with wheel locks though right?
Mine doesn't have them.
Mine doesn't have them.
We need someone who works balancing tires to tell us how a 52 grain imbalance at the rim would feel. To make it easier for him, perhaps someone can convert 52 grains to whatever unit they use for the weights, probably grams.
Or someone with well-balanced tires could go run at 120 mph on a smooth road to feel what it's like, then glue a 52 grain weight to the rim and make another run. Post the results here, I'll buy you a beer (OK, two beers) if we meet.
03-30-2006, 03:14 PM
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Originally Posted by Gearhead Jim
To make it easier for him, perhaps someone can convert 52 grains to whatever unit they use for the weights, probably grams.
For this small mass to make any difference, even at full OD of the wheel, balance weights would have to be denominations of 0.1 ounce. To the best of my recollection, the smallest denomination of the old clamp on style weights was 0.25 ounces. Anyone know the mass of one of those stick-on weight segments?
Last edited by JmpnJckFlsh; 03-30-2006 at 03:19 PM.
03-30-2006, 05:50 PM
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St. Jude Donor '08-'09-'10-'11
Originally Posted by Gearhead Jim
My salesman gave me a set of the GM wheel locks for the C6, they are made by McGard but have GM packaging and GM part #12498078. This is verified as the correct part for a C6.
The back of the package says "Precision weight matched to maintain wheel balance".
But when I took one out, they felt heavier than a normal C6 nut. So I got out the scale-
Locking wheel nut= 947 grains
Standard wheel nut= 771 grains
Difference= 176 grains. That's about the same additional weight as a Quarter plus two Dimes.
Of course the out-of-balance weight is fairly close to the center of the axle (about 2 1/4"), so it's less serious than if on the rim
(about 7 3/4"). If you use the ratios, it's about the same as 52 grains out on the rim where the balance weights are located. Similar to taking 1 and 1/2 dimes and glueing them alongside your balance weights. Can anyone say if that difference would be noticeable?
There may be better wheel locks, and you can argue that no wheel lock is very effective. Other threads have beaten that subject to death, let's just look at the balance problem. Thanks.
The back of the package says "Precision weight matched to maintain wheel balance".
But when I took one out, they felt heavier than a normal C6 nut. So I got out the scale-
Locking wheel nut= 947 grains
Standard wheel nut= 771 grains
Difference= 176 grains. That's about the same additional weight as a Quarter plus two Dimes.
Of course the out-of-balance weight is fairly close to the center of the axle (about 2 1/4"), so it's less serious than if on the rim
(about 7 3/4"). If you use the ratios, it's about the same as 52 grains out on the rim where the balance weights are located. Similar to taking 1 and 1/2 dimes and glueing them alongside your balance weights. Can anyone say if that difference would be noticeable?
There may be better wheel locks, and you can argue that no wheel lock is very effective. Other threads have beaten that subject to death, let's just look at the balance problem. Thanks.
03-30-2006, 06:08 PM
#11
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Gearhead Jim,
I won't even pretend to know what you are describing. Its too techy for me. However, when wheels are balanced, they are, of course, balanced without the lugs. If they are that close to the center of the hub, would it matter much? Or would a "proper" balance include the lugs? Or are the wheels balanced based on the assumption that all the lugs will weigh the same? Sorry, just trying to participate here.
martin
I won't even pretend to know what you are describing. Its too techy for me. However, when wheels are balanced, they are, of course, balanced without the lugs. If they are that close to the center of the hub, would it matter much? Or would a "proper" balance include the lugs? Or are the wheels balanced based on the assumption that all the lugs will weigh the same? Sorry, just trying to participate here.
martin
03-30-2006, 06:19 PM
#12
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Originally Posted by BigJoe
I have wheel locks that came with the car (dealer installed I assume, but he didn't change extra... ) they are obviously bigger, so I assume heavier, than the stock lugs. I haven't noticed any out of balance feel at speeds ranging from 5 to 100. I doubt that little bit of weight would make much difference.
03-31-2006, 04:36 PM
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St. Jude Donor '13
I took a close look at the factory stick-on weights on my 2006 Coupe, they are stamped:
.25 Fe
Would than mean .25 gram? .25 oz?
BKNIMKR-
Yes, the wheels are usually balanced without the nuts, they assume that each nut has the same weight. Usually that's true, but not for this case. And as discussed, "x" amount of imbalance near the hub is less important than the same amount out on the rim. I'm just trying to figure out if it's significant here.
ZeusC6-
Haven't checked the C6, but on my C5 the factory wheels had a slightly thicker spoke opposite the sensors, presumably to get the balance about right. Of course the balance weights do the final adjustment.
.25 Fe
Would than mean .25 gram? .25 oz?
BKNIMKR-
Yes, the wheels are usually balanced without the nuts, they assume that each nut has the same weight. Usually that's true, but not for this case. And as discussed, "x" amount of imbalance near the hub is less important than the same amount out on the rim. I'm just trying to figure out if it's significant here.
ZeusC6-
Haven't checked the C6, but on my C5 the factory wheels had a slightly thicker spoke opposite the sensors, presumably to get the balance about right. Of course the balance weights do the final adjustment.
04-01-2006, 05:13 PM
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Originally Posted by Gearhead Jim
I took a close look at the factory stick-on weights on my 2006 Coupe, they are stamped:
.25 Fe
Would than mean .25 gram? .25 oz?
.25 Fe
Would than mean .25 gram? .25 oz?
What month was your car built? I was Rejexing my wheels today and noted that the balance weights on my wheels were marked "0.25 FG". Since my car was built 9/17/05, "F" could be the year, and "G" could be the month.
Typically, in GM's date coding system, "E" = May, and "G" = July; July manufacture of the balance weights would make sense for my car. However, if "F" is the year, then the year sequence would had to have to started in 1999 (=A), which is not an obvious choice. Note that date codes are always based on the calender year...not the model year.
04-01-2006, 06:08 PM
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Originally Posted by BKNIMKR
Gearhead Jim,
I won't even pretend to know what you are describing. Its too techy for me. However, when wheels are balanced, they are, of course, balanced without the lugs. If they are that close to the center of the hub, would it matter much? Or would a "proper" balance include the lugs? Or are the wheels balanced based on the assumption that all the lugs will weigh the same? Sorry, just trying to participate here.
martin
I won't even pretend to know what you are describing. Its too techy for me. However, when wheels are balanced, they are, of course, balanced without the lugs. If they are that close to the center of the hub, would it matter much? Or would a "proper" balance include the lugs? Or are the wheels balanced based on the assumption that all the lugs will weigh the same? Sorry, just trying to participate here.
martin
I do also remember reading the manual on a 1988 Mustang GT that came with factory wheel locks saying something to the same effect that the wheel lock must be placed in a certain position in order to balance properly. Now some 18 years it is coming up again? who really pays attention to this stuff anymore...if we had to have everything in such a way we would need to take alot more Prozac, Zoloft, and
pills if we worried about every little thing 
04-01-2006, 09:15 PM
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St. Jude Donor '13
My car was built 02-06-06, and I have a set of polished take-off wheels from a C6 that was supposed to have been built in 01-06. Both have the Fe code on the weights, although in some light it looks like Fg (but it IS Fe).
It would seem strange for them to date code the weights, but I've seen stranger things.
Dang it, I may have to just install the wheel locks and see if I get a vibration. The problem is that there is always SOME vibration, less is better. Hoping that someone can give an answer from the weight/distance numbers.
It would seem strange for them to date code the weights, but I've seen stranger things.
Dang it, I may have to just install the wheel locks and see if I get a vibration. The problem is that there is always SOME vibration, less is better. Hoping that someone can give an answer from the weight/distance numbers.
04-02-2006, 03:16 PM
#18
Originally Posted by Gearhead Jim
Unlike some companies, the GM/McGard locks come in a set of 4 for the car. That means one per wheel, so the locks need to be the same weight as a standard wheel nut.
If they sold a set of 20 for the car, then your idea would be correct. Unfortunately, they don't do it that way.
If they sold a set of 20 for the car, then your idea would be correct. Unfortunately, they don't do it that way.
04-02-2006, 05:21 PM
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St. Jude Donor '13
routesixtysix-
Did you notice any vibration after installing the locks, with the GM nuts still on the other 4 studs? That's the big issue, I don't give a hoot about exactly what things weigh if they work OK. It just seems that the weight difference could be enough to cause problems. $45.99 for the set of 4 locks and 16 nuts sounds like a great deal, my local dealer charges over $7.00 retail for just one regular nut. Even if you can get the GM nuts for $5.00 each that comes to $100 for all 20 nuts and you don't get any locks.
On the other hand, if the McGard locks are not weighted properly to equal the GM nuts, I wonder if they weight-match the McGard nuts. The McGard nuts would need to be 176 grains HEAVIER each, that's a lot. 176 grains is about the weight of a complete 9mm cartridge.
cortnjeff-
I wondered about that Fe symbol also, but I can't believe they make the weights out of iron. They could coat them but no coating lasts forever. The customers will not be happy when their polished or chromed wheels start to get rust stains some day.
Did you notice any vibration after installing the locks, with the GM nuts still on the other 4 studs? That's the big issue, I don't give a hoot about exactly what things weigh if they work OK. It just seems that the weight difference could be enough to cause problems. $45.99 for the set of 4 locks and 16 nuts sounds like a great deal, my local dealer charges over $7.00 retail for just one regular nut. Even if you can get the GM nuts for $5.00 each that comes to $100 for all 20 nuts and you don't get any locks.
On the other hand, if the McGard locks are not weighted properly to equal the GM nuts, I wonder if they weight-match the McGard nuts. The McGard nuts would need to be 176 grains HEAVIER each, that's a lot. 176 grains is about the weight of a complete 9mm cartridge.
cortnjeff-
I wondered about that Fe symbol also, but I can't believe they make the weights out of iron. They could coat them but no coating lasts forever. The customers will not be happy when their polished or chromed wheels start to get rust stains some day.
04-03-2006, 02:00 PM
#20
Originally Posted by Gearhead Jim
routesixtysix-
Did you notice any vibration after installing the locks, with the GM nuts still on the other 4 studs? That's the big issue, I don't give a hoot about exactly what things weigh if they work OK. It just seems that the weight difference could be enough to cause problems. $45.99 for the set of 4 locks and 16 nuts sounds like a great deal, my local dealer charges over $7.00 retail for just one regular nut. Even if you can get the GM nuts for $5.00 each that comes to $100 for all 20 nuts and you don't get any locks.
On the other hand, if the McGard locks are not weighted properly to equal the GM nuts, I wonder if they weight-match the McGard nuts. The McGard nuts would need to be 176 grains HEAVIER each, that's a lot. 176 grains is about the weight of a complete 9mm cartridge.
Did you notice any vibration after installing the locks, with the GM nuts still on the other 4 studs? That's the big issue, I don't give a hoot about exactly what things weigh if they work OK. It just seems that the weight difference could be enough to cause problems. $45.99 for the set of 4 locks and 16 nuts sounds like a great deal, my local dealer charges over $7.00 retail for just one regular nut. Even if you can get the GM nuts for $5.00 each that comes to $100 for all 20 nuts and you don't get any locks.
On the other hand, if the McGard locks are not weighted properly to equal the GM nuts, I wonder if they weight-match the McGard nuts. The McGard nuts would need to be 176 grains HEAVIER each, that's a lot. 176 grains is about the weight of a complete 9mm cartridge.