So grease.... a topic near and dear to a mechanical engineer's heart!
You apparently already have the Magnalube G. It looks like very good stuff from the mnfr's info and datasheet:
https://www.magnalube.com/g-product-infohttps://13003da1-0d4f-0427-f0b8-57bfb235dd1b.filesusr.com/ugd/381112_65d2eebce0ee6c9b2e612273f514771f.pdfIt's got an NLGI consistency of grade #2 - which is the usual for auto wheel bearing grease.
The thickener is polyurea/PTFE, which is fine if ALL the old grease is cleaned off everything - as anybody when doing any brake job / bearing re-pack. Most wheel bearing greases (including the old grease in yours in all likelihood) are lithium complex thickeners and generally not compatible for mixing with polyurea.
The base oil is mineral oil (not synthetic). Base oil viscosity is:
800 SSU at 100°F
76 SSU at 210°F
The Magnalube G is good for very high temperature service - partly attributable to the PTFE (Teflon) in the base I'd assume..
For comparison, the grease I like for wheel bearings is Penzoil 707L "red" - datasheet below:
https://torqueking.com/content/lubricants/specsheets/Pennzoil%20707L.pdfIt's a lithium complex thickener.
The base oil is mineral oil (not synthetic). Base oil viscosity is "about" (converting from CentiStokes to SSU):
1070 SSU at 100°F
80 SSU at 210°F
So the oil in the grease is pretty close to the same viscosity in the two greases
In short, I would not buy the Magnalube G specifically for wheel bearings since I'm a creature of habit and have used the Pennzoil 707L many times, and it's easy to get. But since you have enough Magnalube G to do your bearings, I'm sure its fine (or possibly "better") to use. I'm guessing it's expensive? You can pretty much be sure that whatever grease you use - as long as it's intended for bearing service - is going to out-live the brake components.
Maybe it's obvious, but when I do front wheel bearings, I pack both bearings 100% (slathering the outside of bearing with grease is nowhere near a 100% pack) and fill the void between the two bearings about 50%.
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