Centerlock rotor installation/Disc newbie thread

I’m building up my first disc (road) bike myself and don’t yet know what works and doesn’t due to lack of first-hand experience.
Very reputable sources say not to grease splines or lockring threads for fear of system contamination, but going bone-dry on these interfaces makes me cringe.
Is a light layer of grease on splines/threads acceptable here to try to minimize galling, or will I fk myself before I even begin by not keeping these components grease free?

I’ve always put on a light coating of grease myself and never experienced any contamination.

I too was too concerned about what would happen if I exposed that interface to the great British winter without any grease.

N=1, but I’ve never greased the splines and never had a problem removing rotors.

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So you’ve greased lockring threads but not the splines?

No, neither…sorry I didn’t make that clearer!

Appreciate any and all advice on disc brake do’s/dont’s. I don’t want to mess this up, furthermore, I’d like to have it all turn out 100%, good brakes that feel good are a high priority.

Another question: Is it necessary to use a torque wrench to tighten the lock ring? 40 Nm would require a dedicated wrench for pretty much this one purpose.

Some grease carefully applied in right place. Use Crombie tool with moderate force to tighten. Done.

I’ve never used a torque wrench for cassettes, for example, which are similar torques to centerlock rotors. 40NM is about the same torque as applying 44 pounds of pressure to an 8 inch lever arm.

Depending on the type of lockring you’d also be using that wrench for threaded BB’s.

I’ve never greased rotor splines or lockring threads and never had a problem.

I’ve never used a torque wrench either. About as tight as I can get (without jumping/heaving/contorting) with a standard length adjustable spanner works well.

That said, I do think that 15 years of working on my own bikes have given me a reasonable sense of what’s the right kind of force in most situations (and I will always used a torque wrench where carbon is involved). If you don’t have that, and plan on doing more builds/extensive work in the future, a torque wrench that can have multiple head attachments and goes up to 50nm is probably a worthwhile investment.

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I always grease the splines (on the rotor, not on the hub to prevent grease from getting pushed between rotor and hub flange), and the thread of the lockring. Have been doing this for ever on all the wheels and bikes we sell. I use a thick, very sticky, waterproof grease to make sure that it a) doesn’t get anywhere else, and b) protects the parts even for those guys who ride through the winter and protect / service their bikes in a less then optimal way.

I live in a very wet climate (PNW) and I have never greased the splines on the hub or the rotor. I have never had an issue with corrosion at this interface. I do grease the threads on the lockring and torque with a torque wrench, and after the first ride I always re-torque.