Should wheel bolts be fully tightened by air or by hand?

[gazza285]

Mave said:

I don't think I've ever had a car with a flanged interface - every one of them has taken all the loads through the clamped joint!

I presume he meant the hub spigot, which is there to reduce the sheer load on the bolts.

[Mr-B]

I needed to remove the rears on my e46 BMW and they just would not budge, jumping on the wheel brace wasn't enough, gave up in the end. (Garage had tightened them with a gun when they changed the tyres) Being that tight can't be right can it? Good job I hadn't got a puncture at the side of the road.

[Mave]

gazza285 said:

Mave said:

I don't think I've ever had a car with a flanged interface - every one of them has taken all the loads through the clamped joint!

I presume he meant the hub spigot, which is there to reduce the sheer load on the bolts.

I think the hub spigots are there to centralise the wheel, rather than carry shear load.

[Mave]

Mr-B said:

I needed to remove the rears on my e46 BMW and they just would not budge, jumping on the wheel brace wasn't enough, gave up in the end. (Garage had tightened them with a gun when they changed the tyres) Being that tight can't be right can it? Good job I hadn't got a puncture at the side of the road.

I guess it depends on the wheel brace and how much load you can actually apply to it. IMHO the standard wheel braces you normally get aren't really up to the job of undoing a correctly torqued bolt - Whereas an extendable one is about right.

[motco]

Mave said:

John Laverick said:

Whilst we're on the subject don't forget that the wheel/hub is designed with a flanged interface so large amounts of shear force due to the mass of the vehicle is transmitted directly from wheel to hub and not via the bolts.

I don't think I've ever had a car with a flanged interface - every one of them has taken all the loads through the clamped joint!

With or without a flange the driving and braking torque is transmitted through the clamped joint, and it seems to me that greasing the face passes this torque (and other shear forces in a non-flanged set-up) more to the studs than happens with a dry face. The more I think about it the more I suspect greasing is a bad idea.

[InitialDave]

It's fine, don't worry about it. You only really need a light smear on the spigot to stop the worst of it in my experience. Whether you choose to or not, though, getting all the existing corrosion off everything with a wire brush is well worth it.

Here is a bulletin Jaguar issued instructing that light greasing on wheel fitment should be carried out to prevent corrosion problems:
http://workshop-manuals.com/jaguar/s-type_(x200)/v...

[SlimJim16v]

Mr-B said:

I needed to remove the rears on my e46 BMW and they just would not budge, jumping on the wheel brace wasn't enough, gave up in the end. (Garage had tightened them with a gun when they changed the tyres) Being that tight can't be right can it? Good job I hadn't got a puncture at the side of the road.

The usual M12 or 1/2" nuts/bolts are about 70 - 80 lb while our new MINI uses M14 to 103 lb.

bds did them so tight I had to jump on an 18" breaker bar to get the ordinary bolts off. The dealer/garage had to pay a specialist £80/bolt to get the lock nuts off.

I tested them after. Torqued to 103lb and could get them off OK with the std wheel brace, though not ideal. So whoever did yours is a .

[Ganglandboss]

[jimmy the hat]

motco said:

I was at a track day a year or so ago when an MG Midget with non-standard fat wheels shod with semi-slicks was running on the the circuit. Suddenly it was a three wheel wagon because one of its pathetically puny four-skinny-studs-per-hub studs snapped and the remainder came rapidly unzipped under the strain.

Indeed. "Loads of fat"?

motco said:

Quite what this means for greasing hub faces and studs I don't know, but car designers have to build in sufficient safety margin to allow for anything from dry rusty faces and studs, to thoroughly lubricated ones with the nuts given the half-Nelson with a long wheel brace.

No, they really don't, The torque they're done up to in the factory will be one thing, being virgin parts. The 'Service Torque' in your owner's manual will likely be higher to account for non-virgin, maybe a bit rusty, parts. Both will be tested. "thoroughly lubricated ones with the nuts given the half-Nelson with a long wheel brace" will almost certainly not be. The factor of safety is provided by the fact that the testing represents the worst possible loads the car/component will see spread over an entire lifetime so unless you do this and drive every mile like it's a Royal Mail van*, you'll probably be alright even if you do it a bit wrong. Excess performance will be seen by the budget car manufacturer as an opportunity to remove material and save money just as it would be by the premium manufacturer as a guarantee of quality.

• Incidentally, Royal Mail vans had an issue with wheel studs breaking off at one point. It was because they were copper-slipping wheel studs and torquing to a dry torque spec. They do a lot of miles so have a lot of servicing/tyre changes so sooner or later the repeatedly overtightened studs fatigued and broke.

My C2 was a bugger for the rear wheels sticking on. I know this, so every time they come off, wheels and hubs get a good wire-brushing. They're now fine. If you absolutely insist on copper-slipping, then put a small amount on the spigot interface, not on the hub/wheel face.

Here endeth the sermon. I'm all for people taking the advice of the manufacturer under advisement, if they actually understand the advice, why it is advisable, how what they're doing is actually going to affect the performance of whatever and whatever else it relates to and whether they're going to experience any undersirable results. Copper-slipping your wheel studs and stamping on the breaker bar, because you've always done it and it must be OK because the nuts have never come undone, is not this.

Sorry, here endeth the sermon.

Cheers, Jim

[Mr-B]

SlimJim16v said:

The usual M12 or 1/2" nuts/bolts are about 70 - 80 lb while our new MINI uses M14 to 103 lb.

bds did them so tight I had to jump on an 18" breaker bar to get the ordinary bolts off. The dealer/garage had to pay a specialist £80/bolt to get the lock nuts off.

I tested them after. Torqued to 103lb and could get them off OK with the std wheel brace, though not ideal. So whoever did yours is a .

Yes I agree, they were bds!

Saw the guy in the garage today get them undone using a 1 meter plus long bar!! He said they were a bit tight! Guess I will have to invest in one of those in case of punctures.

[GC8]

Patrick Bateman said:

My Boxster manual says lubricated, all the other cars I've had (mainly BMW's) are meant to be dry.

At the end of the day, read the manual because it can obviously vary.

I was about to give this very example. Porsche even sell a lube for the threads, although they've never actually assembled new cars using it.

[jimmy the hat]

GC8 said:

Patrick Bateman said:

My Boxster manual says lubricated, all the other cars I've had (mainly BMW's) are meant to be dry.

At the end of the day, read the manual because it can obviously vary.

I was about to give this very example. Porsche even sell a lube for the threads, although they've never actually assembled new cars using it.

Not necessarily you two but a few posts on this thread have given me the impression that there is a bit of if it's good enough for Porsche/Jag etc going on in some people's heads. Point being, as has been said, this will have been tested by Porche/Jag etc and the Torque Spec they're giving you is relative to the use of the provided lube. On another forum, where I've had this argument, I've even had it cited that often cylinder head bolts are supplied with lube, as if you'd want your wheel studs to be single-use because they yield every time you torque them up.

Also, it has occurred that some think that the problem with lubricating threads is that it might make the nuts/bolts all slippery and likely to come undone. This is not the problem. Therefore, just because you've always done it and your wheelnuts haven't come undone, it doesn't mean you've never had a problem. It means that you haven't yet been made aware of whether of not you've had the problem.

This is the problem:

ashleyman said:

JamesRF said:

Had this one yet?

Discovery crash on the M4:

https://www.youtube.com/watch?v=n6h19yeKvbw

Looks like a failure on the car of some kind, pretty scary crash!

One of the commenters says it was his wife driving (she's fine) and as far as they know it was down to over-tightened wheel bolts.

Anyway, I'll leave it there. If anyone is genuinely interested in whether or not they should do it and why if not, feel free to ask. Anybody else obviously knows much better and will carry on doing what they want regardless of how stupid and dangerous they don't know that it may be.

Cheers, Jim

[cuprabob]

GC8 said:

Patrick Bateman said:

My Boxster manual says lubricated, all the other cars I've had (mainly BMW's) are meant to be dry.

At the end of the day, read the manual because it can obviously vary.

Porsche even sell a lube...

Sure it's not for the owners

[InitialDave]

jimmy the hat said:

Not necessarily you two but a few posts on this thread have given me the impression that there is a bit of if it's good enough for Porsche/Jag etc going on in some people's heads.

I will point out that my Jaguar example is for using grease on the wheel to hub interface. It specifically says not to lubricate the threads.

I agree that people do suffer from a little knowledge being a dangerous thing in this area, especially when combined with "well I've been doing it for X years".

[SonicShadow]

My wheels come off frequently enough that seizing / corrosion has never been a problem!

I use a torque wrench most of the time, but I can get it pretty much spot on by feel with the stock Toyota bar. Still check later with a torque wrench though.