I’m fed up with bolts rusting up, mainly because I don’t dry my bike down after cleaning it after a ride.
I have in the past replaced the prone bolts with expensive ti (stem, steerer, bottle cage etc).
But recently was thinking – why don’t I use stainless steel bolts as a much cheaper alternative, is there a reason why bike companies don’t already spec stainless bolts on production bikes and components?

is there a reason why bike companies don’t already spec stainless bolts on production bikes and components?

Cost

The heads are little more prone to rounding, especially on cheap stainless bolts.

A bit like cheaper ti bolts then!

I can see cost being the main drive behind cheaper bikes, but we are litterally talking pence in difference here.

I don’t find the heads prone to rounding. I use stainless on my bikes

Found ti bolts to be useless (like cheese) stainless for me every time

Stainless and ti bolts are fine but always make sure the allen key you use is nice and sharp with no rounded corners. Find a local friendly engineer or mate who will grind flat the allen key and you’ll be problem free forever.

If what i`ve been told over the years is true Stainless steel screws going directly into aluminium components can fire up big time as a “battery effect” reaction can take place with the stainless steel winning and the Aluminium corroding around it.
Might be better with some good quality 12.9 steel fasteners. Apologies if i`m wrong.

Cost, mechanical performance, galling.

Galvanic corrosion – not a problem if you use coppaslip. I have been using stainless bolts in my old motorcycles and bikes for decades and not one has corroded in place unlike the mild steel ones.

smiththemainman – Member
If what i`ve been told over the years is true Stainless steel screws going directly into aluminium components can fire up big time as a “battery effect” reaction can take place with the stainless steel winning and the Aluminium corroding around it.
Might be better with some good quality 12.9 steel fasteners. Apologies if i`m wrong.

I was just about to say this. Stainless with aluminium has a higher potential difference than other steels, and the Aluminium will form the anode and therefore corrode away. I do have some stainless bolts in my alu commuter frame though, and nothing seems to have gone wrong yet (though I did make sure they were nice and greased up before fitting).

If what i`ve been told over the years is true Stainless steel screws going directly into aluminium components can fire up big time as a “battery effect” reaction can take place with the stainless steel winning and the Aluminium corroding around it.

The galvanic potential between aluminium and stainless is higher than between aluminium and mild steel, but not so much that it’d cause problems usually. Titanium/aluminium is worse than stainless.

Grease the bolts and they’re fine. The bigger problem with stainless is it can be prone to galling. Again, grease helps a lot with that.

bencooper (as usual) has it. We’re swapping out cad plated screws for stainless in work with no apparent ill-effects after some fairly strenuous testing

https://en.wikipedia.org/wiki/Galvanic_series

This is why we use Titanium bolts for carbon fibre and why putting aluminium in contact or bridgeable contact with carbon fibre is very bad and leads to debonding.

Good advise the grease and the coppaslip, the second one reminds me of an old fitter I worked with he used it by the barrel load, but boy was he the best fitter I ever saw , nothing he fixed ever broke again, he would strip brand new pumps straight from the factory and play hell they were not fit for purpose and balance and modify, they would literally run for ever, it was a joy to watch him, saying that I would not like to be the one paying his wages as he was so meticulous and took forever to finish jobs.

andyl – Member

Cost, mechanical performance, galling.

Galling only occurs between similar metals – so it shouldn’t be an issue when putting stainless fasteners on a bike as they will normally be going into alu components. I’ve never had a stainless fastener gall into aluminium (the aluminium is too soft for cold welding to occur) either at work or when bike tinkering.

Stainless into stainless will generally give you galling issues, although the risk can be reduced a bit if you use 304 (a2) fasteners into 316 for example. At work, we generally use Nitronic 60 inserts if we really have to use stainless fasteners into stainless components.
We used to use silver coated screws, but they were expensive and people in the field wouldn’t have them available so would replace them with normal a2-70 fasteners, which would then gall….

The galvanic corrosion stuff mentioned above might be more of a concern, but I’ve never had a problem personally.

Galling only occurs between similar metals

Indeed. It’s my standard answer for when people ask about replacing normal steel fasteners and components with stainless. It does have some application to bikes but less common. eg stainless bolt and nut/rivnuts/stand-offs, stainless frames, chainring bolts etc. Most of the time on a bike it will be into aluminium but not always.