Copper grease use.

So, just a quick question.

Having applied copper grease or slip onto a bolt, nut and washer thread and contact surface area . Do I reduce the torque specification by 15% or is there another calculation?

Thanks in advance.

I was advised by a mechanic friend not to torque bolts if you grease them. Not heard the 15% thing before?

Is the original torque for a dry thread? I have a program on computer at work that has the friction coefficients for most makes/types of grease. I'll try logging into it when I go back onshift tonight. I have about 0.12 or 0.13 in my head.

When I was rebuilding engines (cars) it was always advised to clean and lubricate threads to stop the dry friction interfering with the torque figures

Interesting thread, be good to see the further comments. I wasn't aware of any reduction due to lubricated/dry threads, it does make sense if you are working to very tight tolerances tho, maybe in precision engineering circles etc.

95inches said:

I was advised by a mechanic friend not to torque bolts if you grease them. Not heard the 15% thing before?

Click to expand...

Find that a bit strange 95.. I use a light touch of Coppaslip on my Caliper bolts, it wouldn't sit right with me not setting to a specific torque, think this is a common application for high temp grease.


Stuart

Torque Settings

I've never bothered using it on my bikes (road or race) and prefer just torquing bolts to specification and using Loctite as directed in the service manual. Whilst not applicable to race bikes I'm fairly certain BMW may have issue with not using correct torque settings if you then had a problem resulting in a warranty claim and that was found to be the cause.

I marked the rear axle nut position, (manufactures original position when new) then removed the wheel.

On installing wheel I applied copper grease to the nut surface area and thread.

I noticed that if I torqued it up to 100Nm the bolt would go past the marked position and be over tightened. So I just left it at the original marked position.

I could check the torque tension but I'm sure when copper slip is used you can take off 10-15%

Would be good to have the program Kennybush, if you could let me know how to get it and where?

Thanks.

J

Torque Setting

I've lost count of how many times I've changed wheels on my bike. Providing you are using a good quality torque wrench you are highly unlikely to over-tighten the rear axle bolt.

stuartb said:

Find that a bit strange 95.. I use a light touch of Coppaslip on my Caliper bolts, it wouldn't sit right with me not setting to a specific torque, think this is a common application for high temp grease.


Stuart

Click to expand...

It was advice given while I was changing the front wheel and tightening the front calliper bolts. He said if you don't ride it all weathers keep the bolt dry and torque to spec. If you ride all year then add some grease but don't torque them as you will easily over-tighten the bolts. The 10-15% less makes sense in this context.

HPlogger said:

I marked the rear axle nut position, (manufactures original position when new) then removed the wheel.

On installing wheel I applied copper grease to the nut surface area and thread.

I noticed that if I torqued it up to 100Nm the bolt would go past the marked position and be over tightened. So I just left it at the original marked position.

I could check the torque tension but I'm sure when copper slip is used you can take off 10-15%

Would be good to have the program Kennybush, if you could let me know how to get it and where?

Thanks.

J

Click to expand...

I would get all the grease off the rear nut and axle thread and tighten to the manufacturers setting. The rear nut uses a mechanical thread system so interfereing with it could be bad.

I know of a number of track riders who don't use the oe nut because if removed and retightened a lot it eventually fails to hold the correct torque and damages the axle thread. Not a problem for road users and occasional track days but worth considering if you are changing the rear a lot.

I changed my nut to a Gilles one to avoid this potential problem. It's also significantly lighter than the original, so I can eat more pies .

I've had the copper grease on for 3000 miles now and nothing has changed. Im curious as to how the copper can affect the mechanical working of simple the threads axle, washer and nut. The only load on the thread is the tension of the nut. The wheel runs on the bearings inside seals on the axle.

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Am I correct in my understanding that you have been riding for 3000 miles without knowing what torque you have set for the rear axle nut?

soofsayer said:

Am I correct in my understanding that you have been riding for 3000 miles without knowing what torque you have set for the rear axle nut?

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Hahah are you kidding me? No, I know I set the torque to exactly the same place as it was set to when brand new. If you paint the nut and a fixed point on the swing arm with a very fine brush, you can turn the nut to the exact same place being the correct torque. I do have a professionally celebrated torque wrench done this year, so I know the nut is tight enough with the copper slip on. I just wondered if any tech heads knew what they are talking about regards using copper slip totally fine on the axle nuts by the way.

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HPlogger said:

I noticed that if I torqued it up to 100Nm the bolt would go past the marked position and be over tightened. So I just left it at the original marked position.

I could check the torque tension but I'm sure when copper slip is used you can take off 10-15%

Click to expand...

I misunderstood you from this post, I read it as you didn't know, good the hear otherwise, . what torque do you set the nut at with the grease applied?

I do have a professionally celebrated torque wrench done this year, so I know the nut is tight enough with th.......


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Lol what does a celebrated torque wrench look like... hahaha brilliant

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stuartb said:

I do have a professionally celebrated torque wrench done this year, so I know the nut is tight enough with th.......


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Click to expand...

Lol what does a celebrated torque wrench look like... hahaha brilliant

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Haha that's hilarious, I mean calibrated

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So funny ! Lol

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HPlogger said:

Would be good to have the program Kennybush, if you could let me know how to get it and where?

Thanks.

J

Click to expand...

Just managed to get logged into the program. Its a program that we have for calculating tightening values for pipe flanges. Had a look to see if i could make any sense of what the % difference is, but there isn't an option for no grease. The friction coefficient for copper based greases varies between 0.09 for copperslip (not to be mixed up with copaslip which is 0.12) and copper ease which is 0.14. Just the difference between the different greases make a huge difference to the final torque of the bolt Approx 30 %.
To be able to work out what percentage to subtract from the original torque, you'd need to know what the original coefficient is, which i think varies depending on the thread size, contact area of the threads, and what the materials are of the 2 threads.

I'm far from an expert in it. Thats why we have a computer program to work it out for us

If riding all weathers I would be inclined to clean the bolt and nut, torque to the correct value then apply an anti corrosion like ACF50
that way you know the nut is torqued correctly.