Rear wheel refit question

[AndyW]

I noticed the first signs of slight corrosion on the unpainted surfaces of the wheel hub - interestingly on removing the wheel, as I loosened the wheel bolts a small amount of water seeped out from behind the hub (the bike had been washed a day or two previous and not used since).
Personally I would always apply a light smear of grease to surfaces like this but I see that the RepRom manual specifically says not to!?
"Check that the wheel centering spigot and contact surfaces of the wheel hub are free of grease"

What harm could a little grease (or ACF50) be? I'm tempted to ignore what the manual says......what d'ya reckon?

 

[Owen Snell]

......What harm could a little grease (or ACF50) be? I'm tempted to ignore what the manual says......what d'ya reckon?.....

The friction on the interface will be providing resistance to the torque loadings between the wheel and the mounting. If the manual say not to grease the surfaces, that will be why, so don't grease them.

No reason not to ACF50 after assembly though.

 

[John Armstrong]

The friction on the interface will be providing resistance to the torque loadings between the wheel and the mounting. If the manual say not to grease the surfaces, that will be why, so don't grease them.

Eh, that has got me confused

 

[Deleted account 211025001]

I can't think of a reason why not to Andy

Can't see it being to do with torque values as 60Nm times 5 nuts is hell of a lot of force for a wee bit of grease to make a meaningful diference to

Andres

 

[Owen Snell]

I can't think of a reason why not to Andy

Can't see it being to do with torque values as 60Nm times 5 nuts is hell of a lot of force for a wee bit of grease to make a meaningful diference to

Andres

The nuts provide the clamping force which creates the friction grip between the 2 surfaces. This will have been taken account of in the design of the wheel mounting. BMW tell you not to lubricate these surfaces for a reason, so why do something against that advice?

 

[THE DOCTOR]

Would any grease residue be thrown off at speed onto the brake disc?

 

[Deleted account 211025001]

Would any grease residue be thrown off at speed onto the brake disc?

That did cross my mind but as long as you were judicious with the amount you put on it ought not to be a problem.

Still can't see it being a torque thing Owen Snell as the spindle/boss is not a tight fit with the wheel so I still can't see grease here making any difference

Andres

 

[AndyW]

Thanks Owen Snell/Outtomunch

Still can't see it being a torque thing Owen Snell as the spindle/boss is not a tight fit with the wheel ....

Maybe no grease on the mating surfaces of the hub/carrier but a little on the spindle/boss in view of the above comment.

Still full of cold snivvling, sneezing and coughing so prolly not going to put the wheels back on today.......pair new tyres BT020/021 combo.

 

[Our Gee]

Can,t see any reason why a thin greasing of the mounting surfaces would be a problem. BMW advise against "Oiling or Greasing" wheel studs, ie the threaded Screws. Oiling or Greasing threads dramatically alters the applied Torque and "will" lead to overtightened Screws.

 

[mpdouglas]

As an educated guess, I suspect that the official guidance it is to ensure that hydraulic action of trapped grease doesn't prevent the wheel from seating properly on the hub as you torque up the wheel bolts. Accordingly, a light smear of anti-seize, ACF50 or a light grease shouldn't be a problem.

 

[Owen Snell]

Thanks Owen Snell/Outtomunch


Maybe no grease on the mating surfaces of the hub/carrier but a little on the spindle/boss in view of the above comment.

Still full of cold snivvling, sneezing and coughing so prolly not going to put the wheels back on today.......pair new tyres BT020/021 combo.

There is a good reason for keeping the mating surfaces grease free, which is why BMW specify that you do so. Equally, there is no reason not to protect the surounding surfaces, which will be easiest done once the wheel is replaced to make sure the mounting faces stay clean.

It is irresponsible to advise otherwise either as an "educated guess" or as a "can't see why not" without having a good justification for going against the manufacturer's recommendation. I would be interested to hear a proper engineering explanation of why BMW are wrong in this case.

 

[Our Gee]

Perhaps someone can direct me as to where the Riders Manual says not to Grease the "Mating Surfaces" ie Hub Carrier and Wheel.
Thanks

 

[Owen Snell]

Perhaps someone can direct me as to where the Riders Manual says not to Grease the "Mating Surfaces" ie Hub Carrier and Wheel.
Thanks

Rep-ROM, as per 1st post.

 

[bmwrich58]

As an educated guess, I suspect that the official guidance it is to ensure that hydraulic action of trapped grease doesn't prevent the wheel from seating properly on the hub as you torque up the wheel bolts. Accordingly, a light smear of anti-seize, ACF50 or a light grease shouldn't be a problem.

On all my "alloyed cast wheeled vehicles" ie: bike,truck,car...this corrosion problem is controlled by applying a touch of "anti-seize" at the face of the mounting surfaces. Two different metals touching each other are the culprit.
First a good wire brushing to remove the corrosion then apply a dab smeared just enough to coat the surface.
Common sence will tell you that an over abundence use "too much" of this "anti-seize" product, will exit from these attached surfaces.
This action caused by centrifical force action and will most likely contaminate surrounding surfaces. Ie: brake rotors etc.
Other than that,...Works great, never a problem!
Definately leave the 'lugs/bolts" dry for fastening.

 

[Jon P]

All BMWs (single sided swingers + rear disc brake) do this. A good wipe with WD40 to clean it up and then a small smear of copper slip.

 

[GSmonkey]

Just don't lube the studs with coppaslip or anything else.

 

[AndyW]

There is a good reason for keeping the mating surfaces grease free, which is why BMW specify that you do so. Equally, there is no reason not to protect the surounding surfaces, which will be easiest done once the wheel is replaced to make sure the mounting faces stay clean.

It is irresponsible to advise otherwise either as an "educated guess" or as a "can't see why not" without having a good justification for going against the manufacturer's recommendation. I would be interested to hear a proper engineering explanation of why BMW are wrong in this case.

I prefer to play safe (go with what the manual says) when in doubt

 

[D6]

been puttin a small amount of copperslip on all my shaft drives, never a problem