A2 (304) stainless caliper bolts anyone used them???

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old git · #1 Post by **old git** » Tue Jun 08, 2010 6:53 am

Posted on technical section, anyone changed from the crap stds. to stainless for this part please??

anzacinexile · #2 Post by **anzacinexile** » Tue Jun 08, 2010 7:35 am

Oh yes - no problems

#3 Post by **mangocrazy** » Tue Jun 08, 2010 1:59 pm

No problem in finding SS bolts in the correct size for that application, but I've heard from a number of sources that SS bolts are NOT recommended for use in a high-stress application like that. You should really stick with Hight Tensile steel for caliper and disc bolts. Stainless is comparatively weak as metals go, and certainly not close to HT steel.

anzacinexile · #4 Post by **anzacinexile** » Tue Jun 08, 2010 4:19 pm

The standard bolt size in SS is more than adequate for the stress's involved. My only advice is to get decent quality SS bolts, not the cheep shit crap that go-faster bling merchants sell - very poor quality of steel

old git · #5 Post by **old git** » Tue Jun 08, 2010 5:31 pm

OK, thanks chaps for the replies.
Had already been noted that the tensile strength of SS is lower than high tensile OEM fittings, but after a bit of digging,

Metric Class Marks on Head Material Tensile Strength Yield Strength
N/mm2 psi N/mm2 psi
8.8 8.8 Steel 800 116,000 640 93,000
10.9 10.9 Steel 1040 151,000 940 136,000
12.9 12.9 Alloy Steel 1220 177,000 1100 160,000
A2-70 A2-70 302 Stainless 700 102,000 450 65,000
A4-80 A4-80 316 Stainless 800 116,000 600 87,000

So, standard A2/302 stainless is a little down on tensile strength against HT 8.8 but A4 / 316 has the same at 800N/mm2
In which case, it would seem that 316 should be OK for the application and would not old corroded 8.8 steel be down on strength anyway as it has oxidized/rusted.

Yeild seems to be where the components start to deform, rather than shear, again 316SS seems to be close enough as not to matter.

Know I am sad, but found this & the replies all most interesting.

Thanks,

Sorry, table don;t line up right when posted

D-Rider · #6 Post by **D-Rider** » Tue Jun 08, 2010 6:56 pm

The yield point is where it snaps under tension (after it has been stretched somewhat)

old git · #7 Post by **old git** » Tue Jun 08, 2010 7:33 pm

D-R, thanks, interesting what you can find once you get a start on something.....
looked at Tastynuts / Probolt websites, hiden under the questions & answers section they confirm their ss fixings are 316 which is as good or exceeds the 8.8 HT fixings used as OEM componenets.

MartDude · #8 Post by **MartDude** » Tue Jun 08, 2010 9:44 pm

Thanks for that OG, really useful post. I need to replace some of my fasteners - the plated bolts are pitting, rusting and definitely not as pretty as they should be.

Prompted me to do a bit of searching, & found this stockist - prices look reasonable, although the site doesn't say anything about a minimum order value
http://www.felixfastenersuk.com/A4.htm
http://www.felixfastenersuk.com/PDFs/webpricelist.pdf

Slight hijack - can someone tell me what the name is of those little caps with springy tabs that one pushes into the hex sockets of socket screws, in order to prettify them? Better still would be a supplier.

Also, where can I get grease nipples for my knees?

Aladinsaneuk · #9 Post by **Aladinsaneuk** » Tue Jun 08, 2010 9:46 pm

MartDude wrote:Also, where can I get grease nipples for my knees?

ask hanna

#10 Post by **mangocrazy** » Tue Jun 08, 2010 9:47 pm

In that case I stand corrected. I'd much rather use SS fasteners than steel, as they not only look better, but last way longer. And A4 (316) SS is even more corrosion resistant than A2/302; I believe its specified for use in marine and other harsh environments (like British roads in winter)....

If it was race or regular trackday use, I'd still prefer HT steel, though...

wayno · #11 Post by **wayno** » Tue Jun 08, 2010 9:48 pm

Probolt do stainless bolts that can be used in high stress areas i.e. caliper bolts, I think they have toi be 316 grade, not the cheaper 304. I try to replace as much as possible with stainless on my bikes, it helps next time you need to strip anything.

#12 Post by **Kwackerz** » Tue Jun 08, 2010 10:05 pm

MartDude wrote:Slight hijack - can someone tell me what the name is of those little caps with springy tabs that one pushes into the hex sockets of socket screws, in order to prettify them? Better still would be a supplier.

like these?

CLICKY

dunno... well, of a UK source anyways..

MartDude · #13 Post by **MartDude** » Wed Jun 09, 2010 1:21 am

Aye, them's the buggers. Ta.

old git · #14 Post by **old git** » Wed Jun 09, 2010 6:11 am

mangocrazy wrote:In that case I stand corrected. I'd much rather use SS fasteners than steel, as they not only look better, but last way longer. And A4 (316) SS is even more corrosion resistant than A2/302; I believe its specified for use in marine and other harsh environments (like British roads in winter)....

If it was race or regular trackday use, I'd still prefer HT steel, though...

Check out probolt, says they are 316 SS & can be used on track, spec equals or exceeds that of the standard 8.8 HT
Diff. is that now we know 316SS is good to go, can source from cheaper supplier not from robbers.
Looked at the SS front axle nut on their web, £25! guess who's talking to the engineering dept. at work later for their supplier!

Do note chaps that some of the bolts have the fine pitch thread, like the caliper mounting bolts & some are standard metric thread, so just double check before you go placing any orders on tinterweb suppliers.

Jadaris · #15 Post by **Jadaris** » Wed Jun 09, 2010 7:54 am

Aladinsaneuk wrote:
MartDude wrote:Also, where can I get grease nipples for my knees?
ask hanna

when you're dribbling too much?....

Cheeky sod