S/S kits, ref. caliper bolts question

[carbold]

With regard to the relative tensile strengths of stainless steel fasteners.
Most stainless fasteners that are easily available are either A2 or A4/70. This means that the tensile strength is 700 Newtons/mm². This is equal to or greater than the tensile strength of any fastener that has NOT got 8.8 stamped or embossed on the head.
If you are replacing a fastener that has got 8.8 embossed/stamped on it go for A2 or A4/80. These fasteners have a tensile strength of 800 Newtons/mm² making them equal in tensile strength to an 8.8 fastener. A2/A4 80 fasteners are easily available from most nut and bolt stockists. The only fastener I've found on my 1150 Adventure (so far) of greater tensile strength is the Allen Bolt on the bottom end of the rear suspension strut which is a 10.9.
As far as the A2/A4 is concerned, this figure refers to the make up of the steel. A4 fasteners are used in the chemical and food industries as they have a greater resistance to chemical attack.

Problem is you've got to look at the yield strength not the tensile strength. Yield strength is the stress at which the material deforms plastically (no good). The tensile strength, sometimes called the ultimate strength, is the stress level where the material breaks.
A2-70 has a yield strength of 450 Newtons/mm² and a tensile strength of 700.
A2-80 has a yield strength of 600 Newtons/mm² and a tensile strength of 800.
8.6 steel has a yield strength of 480 and a tensile strength of 800.
8.8 steel has a yield strength of 640 and a tensile strength of 800.

Having said that, I wouldn't worry and in fact I used A2-70 to replace 8.8 (a2-80 is more difficult to find)

 

[ELIMINATOR]

Carbold, so what do you think about the torque settings then. 40Nm seems a lot when my Honda CB-1 400 manual reads 27Nm.

I just don't want to strip the threads, copperslip seems necessary as the ally & S/S have an incompatibility according to the coppersmith at work who used to work in the Dockyard.

Are you saying that you've put S/S bolts in your calipers?

 

[carbold]

Carbold, so what do you think about the torque settings then. 40Nm seems a lot when my Honda CB-1 400 manual reads 27Nm.

I just don't want to strip the threads, copperslip seems necessary as the ally & S/S have an incompatibility according to the coppersmith at work who used to work in the Dockyard.

Are you saying that you've put S/S bolts in your calipers?

Yes I have A2-70, not only the caliper bolts but also those bolts keeping the caliper halves together. And that was 20k miles ago...and always used 40 Nm