-
Hey Guest!
British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!**Upgrade Now**
(PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
but were afraid to ask: 
STOP!! Never post your email address in open forums. Bots can "harvest" your email! If you must share your email use a Private Message or use the 
smilie in place of the real @
Pretty Please - add it to our Events forum(s) and add to the calendar! >> 
Impact wrench question
- Thread starter tdskip
- Start date
Share this page
Offline
Good question. Never seen torque specs. I was told some fifty years ago to stop when a moderate blow wouldn't move the nut (spinner). Obviously before the days of precision and before hex center nuts. You can extrapolate torques by size but I don't think for knock offs. I don't see any problem with an impact but could only guess at a torque number.
Tom
Tom
Offline
Removal? Maybe! Installation? NEVER! 
TR3driver
Great Pumpkin - R.I.P
Offline
The actual torque delivered by an impact wrench will vary greatly depending on how solid the connection is. This is the main reason that "impact" sockets are so much heavier than standard sockets; the standard sockets will flex enough to loose a good deal of torque. Getting a connection to a knockoff that is both solid and reliably repeatable is difficult even with the hex knockoffs; impossible with the eared ones.
Personally, I don't like using an impact wrench to tighten even ordinary lug nuts, because of the repeatability issue. I have seen too many professionals that get them either way over tight, or not tight enough; sometimes on the same wheel! If the impact is handy, I'll use it to initially run the nuts up; but final tightening is best done on the ground, with a hand wrench (or better yet, a torque wrench).
The factory engineers clearly knew what a torque wrench was, and revised the procedure for tightening the knockoffs several times. I have no doubt that, if they felt a particular torque was the right way to go, they would have specified it that way. Witness the service bulletin about the special nuts for the splined adapters, which calls not only for a specific torque, but driving the car and then rechecking the nuts.
Personally, I don't like using an impact wrench to tighten even ordinary lug nuts, because of the repeatability issue. I have seen too many professionals that get them either way over tight, or not tight enough; sometimes on the same wheel! If the impact is handy, I'll use it to initially run the nuts up; but final tightening is best done on the ground, with a hand wrench (or better yet, a torque wrench).
The factory engineers clearly knew what a torque wrench was, and revised the procedure for tightening the knockoffs several times. I have no doubt that, if they felt a particular torque was the right way to go, they would have specified it that way. Witness the service bulletin about the special nuts for the splined adapters, which calls not only for a specific torque, but driving the car and then rechecking the nuts.
Offline
I've struggled too many times with wheels and wheel-related bits put on far too tight with impact wrenches. I don't have all that much experience with the wire wheel adapters and such, but I seem to recall it's tough enough to find a socket that you can use on them, let alone a proper impact socket. And for the relatively few times one might need to R&R a wire wheel hub, I don't feel I'm saving all that much valuable time by grabbing the impact wrench! :laugh:TomMull said:
Geo Hahn
Yoda
Offline
My head hurts.
I think this conversation may be going 2 ways at once.
The question of impact or no impact I took to be referring to the bevel nuts that secure the splined hub adaptors. Those I snug down with my wimpy HF electric imapct and finish off with a torque wrench.
The eared (or hex) knock-offs that secure the wire road wheel are usually tightened with modest mechanical means -- I use a 3 lb dead-blow hammer hitting a length of 1x1 oak.
I think this conversation may be going 2 ways at once.
The question of impact or no impact I took to be referring to the bevel nuts that secure the splined hub adaptors. Those I snug down with my wimpy HF electric imapct and finish off with a torque wrench.
The eared (or hex) knock-offs that secure the wire road wheel are usually tightened with modest mechanical means -- I use a 3 lb dead-blow hammer hitting a length of 1x1 oak.
M
Member 10617
Guest
Guest
Offline
George,
You are right. The conversation seemed to be branching.
You are right. The conversation seemed to be branching.
TR3driver
Great Pumpkin - R.I.P
Offline
Considering that I've seen those nuts come loose twice now, with nearly disastrous results both times, I would not only use a torque wrench but follow the factory advice to recheck after 10 miles, and again after 500 miles.
Hardly seems worth picking up the impact gun just to spin them down, but maybe that's just me.
Hardly seems worth picking up the impact gun just to spin them down, but maybe that's just me.