epnnf

That is on brake levers, shifters or stem. I believe stainless steel is softer/weaker than alloy steel. Bout titanium? Please advise.

Koyote

I believe most such bolts are cro-moly steel, which is stronger.

Kimmo 

Stainless fasteners are a nice touch; they stay looking good unlike plated steel, and are pretty much always strong enough, unless maybe they're under-specced like Thomson's M3 stem bolts. Titanium is often not a great idea to replace steel bolts; the strength difference is a lot more than for SS. Aluminium definitely has its place, particularly in headset top caps where M5 in steel is total overkill and any non-stainless steel is going to look like crap with the rust.

mixteup

I would have no problem substituting SS, for most fasteners like that -
If you're under the impression that manufacturers use some kind of grade 8 fasteners for things like clamp screws, I have news - They don't.

I most always substitute SS fasteners for mounting racks, cages, etc. I'm pretty sure that SS would handle the torque values for most clamp screws on a bike.
You can buy really nice stainless button head capscrews from McMaster Carr, and others - I use them often, in various sizes.

The one thing with stainless steel, is that it should always be lubricated / anti-seized, or installed with loc-tite, because stainless can gall when threaded into itself, or seize from corrosion, when threaded into aluminum.

fietsbob

There are numerous alloys of both types of steels.. like there are a number of different aluminum and titanium alloys ,

hex headed bolts can be marked indicating the differences , such as 8.8*, vs common mild steel, un marked..

in addition there are a number of heat treatment options..

* I used those higher strength steel bolts, to mount the bottom of my touring bike's rear rack.
it was not stainless , so I painted it. ..







...

leob1

I'll use SS bolts if and when plated starts to rust. I don't worry about them being weaker or softer, they aren't under that much stress on a bicycle.

sweeks

I've been replacing a lot of random bolts with titanium over the years, mostly on my "winter" bike because titanium is immune to salt and corrosion in general. They look nice as well... I've replaced chainring hardware, brake shoe hardware and other miscellaneous fasteners and have had no problems with bolt stripping or breaking. According to this THIS web site,

"High quality Ti bolts can be used in the following areas:
-disk brake rotor bolts;
-caliper mounting bolts;
-seatpost saddle rail clamp bolts;
-frame/fork v-brake/cantilever brake bosses;
-stem clamp bolts; and
-any other areas where the strength of steel is needed."

dedhed

I'm pretty sure if I can use stainless for stuff like this it'll be plenty strong for a bicycle application.

86az135i

I only use wrought iron bolts.

Cycle Tourist

Where can I find allen headed bolts? I'd love to replace rather than repair badly rusted nuts and bolts but hate using hex headed bolts that are commonly available. They look so tacky. I only buy a couple here and there and don't need large quantities.

krecik

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fietsbob

Fishing Seaport , So Marine hardware & supply Store , has abundant stainless steel stuff..

Wisconsin is not on a salt water lake.. that's in Utah ..






...

Rick

There are standards for strength of screws and bolts. There are properties like malleability, tensile strength etc. The ANSI standards are what industry is supposed to adhere to. Counterfeit hardware has caused problems for aircraft and other industries. Although it is only a bicycle, I question manufactures about strength of a part. I am going to use the SYZR pedals with my custom bicycle shoes I ordered. I called Speedplay and asked which pedal axle material had more strength. They told me the SS was the strongest. I have snapped more than a handful of pedal axles over the years and double that of crank spindles. This stopped in 1980 when I made the decision not to stand on the pedals anymore.

Iride01 

I'd trust what the manufacturer put in them to be the proper strength. Unless you bought some really cheapo obscure POS's.

Some stainless steel is strong and other stainless is not. Stainless comes in all sorts of flavors.....alloys actually. In fact just about every metal in common use is an alloy because in a pure state, there is almost always something that any particular pure metal doesn't do well. Even gold. Depending on what other elements it was alloyed with and the percentages is what determines it's strength and other characteristics. Some stainless alloys are real expensive some are really cheap. Guess which the big box building supply stores sell.

A lot of bolts and nuts are sold as "ungraded" whether carbon steel or stainless steel or whatever. So you have little to no idea what the strength is. Learn how bolts are graded, use graded bolts and you'll know.

mixteup

Bolt Depot, for small quantities :
https://www.boltdepot.com/

I buy these from McMaster Carr, but they sell only larger quantities - In about any size or spec you'd need:
5mm, for bottle cages -
https://www.mcmaster.com/94500a298
6mm for some rack or fender mounts -
https://www.mcmaster.com/94500a315

HillRider

There are two major categories of "Stainless Steel" in common use:

The 300-series which are known generically as "18/8 chrome/nickel" and have a low carbon content. The most common grades are 303 and 304. These are non-magnetic or only weakly magnetic, not heat-treatable and very corrosion resistant. They are moderately strong and more than sufficient for any bicycle fastener. Nearly all stainless steel spokes are 304 stainless and their strength is obviously adequate.

The 400-series sometimes called "stainless tool steels". These have a lower chrome content, usually in the 12%-15% area, low to no nickel, fairly high carbon content and often other alloying elements like molybdenum. These steels are magnetic, heat treatable to high hardness and strength and are used for cutlery, machine tools, firearms bearing balls and other items where their hardness and strength are required. Their resistance to common corrosives is good but not in the same league as the 300-series. You will rarely find them used for bicycle components.

There are other classes of stainless alloys, e.g. the "Hastaloy" series, that are used for specialty purposes where extreme corrosion, high abrasion resistance or heat resistance are required but these are far too expensive and exotic to ever be used in bicycles.

WizardOfBoz

Yes, you can, but be aware that some of the more corrosion-resistant stainless varieties (e.g. 316) are VERY susceptible to what is called gall. The nut and the bolt surfaces stick and start to dig out material from each other when they rub together when tightened. You end up with a nut and bolt that are cold-welded together, and they are irrevocably ruined, with the only solution being to destroy both (sawing, drilling, EDM) to remove the remnants. Solutions are to use anti-gall compound before tightening, or to plate the SS surfaces (with silver, for example). Titanium also galls easily.

Given that one appeal of a bolt and nut (as opposed to a rivet or welding) is that you can make and unmake the joint, the galling issue is a point in disfavor of SS and Ti nuts and bolts.

Alloy steels are generally much less susceptible to galling, can be very strong, and are relatively cheap compared to SS or Ti.

If you have rusting or corrosion issues (e.g. you live by the ocean and often get salt mist in the air) SS or Ti might be desirable. Just make sure to use anti-gall BEFORE you make or unmake the joint, even under no load. If you are not having rust/corrosion issues, I'd avoid SS. If you are a racer or a weight weinie, Ti is more attractive. But again: use anti-gall!


Not uniformly so. Reynolds 953 is a type of stainless that has incredible strength. Roughly 50% stronger than 4340 Chrome-Moly steel. Properly made stainless bolts can be very strong. See here for a comparison.

So it depends. And even within one class or another, regular (carbon/alloy) and stainless steels come in many grades. You could choose mil-spec bolts made from 8630 or 4037 (there are non-stainless steels). But even a lot of good fasteners (for example in the 8.8 class) are made from good old medium carbon steel.

So, I suggest:
1) If you are making and unmaking the joint a lot, I'd avoid both SS and Ti.
2) Unless you race, or accept the fact that you are a gratuitous weight-weinie, I'd avoid Ti.
3) If you use your bike in a wet and/or corrosive atmosphere (near the ocean, or in downtown Beijing) and have had or expect to have rust/corrosion issues, consider SS or Ti. If you do use either, invest in very good anti-gall. And use it. Religiously.

dedhed

Reality is most of the stuff you're going to come across in SS fasteners from Ace, True Value, McMaster, Fastenal etc when you ask for SS fasteners is going to be 18-8 - 304. On the low end you might find 302, but not normally.
This is the real world of what people mean and use when they say "stainless fastener".

Anything else you want 316, 316L, 304L, 400 series, you're going to be special ordering and know what you want/require or specify based on the requirements of the application.

304 is 95 ksi Tensile, 42 ksi Yield, and 55% Elongation. More than adequate for ANY bicycle application of fasteners. Even the imported stuff (which most of it is) is fine.
I've sent SS fastener samples to the lab for element testing to verify composition and have yet to have a SS fastener, import or domestic, fail to meet ASTM requirements.