a2 stainless vs 8.8 steel, brake calliper fasteners

[barwel1992]

well i purchased some a2 stainless steel fasteners last night for my brake calipers but since then thought about it a bit more and it turns out that a2 does not have as much tensile strength as the 8.8 steel bolts, the problem is i just cant find any m10 x 35 1.25 pitch zink plated 8.8 bolts (socket cap or flanged nex preferd)

my question is will the a2 stainless ones be ok? or should i at least get a4 stainless bolts ?

(pro bolt dont state what stainless they use, only the grade titanium they use on there titanium bolts (grade 5))

[maviczap]

I doubt Pro Bolt aren't going to sell bolts that ain't up to the job, otherwise they'd not sell any

Ring them up an specify they're for calipers

I aint had any issues with my Pro Bolt caliper bolts.

[barwel1992]

^ will do, the bolts im looking for are under calliper mount bolts for the rsv mille 98-02 so they are defiantly for callipers it just dose not state what grade

Edit: its 316 grade so A4, looks like i need to get some as the one i got were a2

[Specialone]

A2 M10 are gonna be way stronger than you need imo, suzuki make theirs of cheese and they seem to do an ok job.

[maviczap]

The answers on the tin

[DarrenSV650S]

They'll be fine

[barwel1992]

so just stick with the ones i got ? (just as im about to click the pay now button lol)

[timwilky]

Well if you want steel flanged bolts m10*1.25*35 with a coating a search found these. (http://www.custom-fasteners.co.uk/acatalog/Metric_Domed_Head_Flange_Bolts.html) Cannot say anything about them, simply a google result

[barwel1992]

it doesn't say what they are made of, thanks though :) just says chrome

[philbut]

I personally would not use stainless bolts to mount my calipers. I use zinc coated hardened steel. My bolts are now a bit furry - but better than than one shearing. Go for titanium if you want them to look good, stainless should not be used in safety critical applications.

Chrome coating a bolt will reduce the properties of the original steel, which is why chromed caliper bolts are usually a larger size than you really need. Still better off going with a coated bolt rather than stainless though.

[Specialone]

I personally would not use stainless bolts to mount my calipers. I use zinc coated hardened steel. My bolts are now a bit furry - but better than than one shearing. Go for titanium if you want them to look good, stainless should not be used in safety critical applications.

Chrome coating a bolt will reduce the properties of the original steel, which is why chromed caliper bolts are usually a larger size than you really need. Still better off going with a coated bolt rather than stainless though.
Im not an expert on chroming so only know the basics and this is a genuine question, how can chroming affect the structual properties of a bolt?

[Whitehouse]

shouldnt you really be bothered about the shear stress of the bolt not the tensile strength?

[barwel1992]

the figures i found gave grade A4 stainless exactly the same strength as the 8.8 high tensile steel, at this moment in time i think im going to get the high tensile stainless ones

[embee]

8.8 isn't normally reckoned to be "high tensile", other than by folks trying to sell them and using technobabble. I would only call 10.9 and above "high tensile".

8.8 is a normal general purpose automotive grade, a good compromise of strength, toughness and cost.

Any electroplating process can potentially alter the material properties of a heat treated steel. Beware zinc plated capscrews with a 10.9 or similar stamping in the head, these will usually have been black oiled finish screws, which will have been 10.9, but then zinc plated as an afterthought by someone wanting plated screws. Always treat zinc plated (BZP) capscrews as 8.8 at best.

In reality bike brake caliper mountings are not going to require ultra strong fasteners (they are threaded into cast alum fork sliders after all), but I wouldn't personally ;) recommend using anything other than stock items (liability and all that).

[yorkie_chris]

Triumph use stainless caliper bolts. Would be interesting to pull test some.

[barwel1992]

ordered the 316 grade (A4) stainless ones from pro bolt

[philbut]

Im not an expert on chroming so only know the basics and this is a genuine question, how can chroming affect the structual properties of a bolt?

Think embee answered above. Essentially if you plate something, you heat it - microstructural changes can result if the correct heat / cool cycle is not adhered to, so particularly the materials at the surface will be modified.