stainless steel bolts stronger/weaker than steel?

[tv_vt]

I'm thinking of replacing some corroded stem bolts with stainless steel bolts. Also thinking of replacing a seatpost bolt with stainless steel.

Question for those in the know: generally speaking, are stainless steel bolts stronger or weaker/more brittle than regular steel bolts? I know it's not a simple answer, depending on specific alloys and all, but would I be creating a possible failure point with the stainless over non-SS bolts?

Thanks!

[Lewis Moon]

I'm thinking of replacing some corroded stem bolts with stainless steel bolts. Also thinking of replacing a seatpost bolt with stainless steel.

Question for those in the know: generally speaking, are stainless steel bolts stronger or weaker/more brittle than regular steel bolts? I know it's not a simple answer, depending on specific alloys and all, but would I be creating a possible failure point with the stainless over non-SS bolts?

Thanks!

A good quality SS bolt is probably as strong or stronger than OEM.

At the torques you SHOULD be working at, you should have no problems.

IMHO, YMMV, ***.

[dave thompson]

Thom, as stated above, the torque values are nowhere even close to failure points on either the stainless or standard steel bolts. Use either one but the stainless bolts mean less maintenance for you.

[AngryScientist]

on most of my bikes now i've gone through and replaced any carbon steel bolts with stainless. these are mostly on the stem, especially the top cap bolt, which collects sweat and rain/debris. rust is the enemy on bikes. go stainless.

[Ralph]

I think plain steel is stronger than SS. Especially Ace hardware level of SS. Again as others have noted, bicycle use won't usually max either out.

Also....there is some engineering know how in the use of bolts....how many threads need to be exposed for max strength, how many threads need to be engaged, etc.

[Chance]

I'm thinking of replacing some corroded stem bolts with stainless steel bolts. Also thinking of replacing a seatpost bolt with stainless steel.

Question for those in the know: generally speaking, are stainless steel bolts stronger or weaker/more brittle than regular steel bolts? I know it's not a simple answer, depending on specific alloys and all, but would I be creating a possible failure point with the stainless over non-SS bolts?

Thanks!

Regarding the highlighted part above, "weaker" doesn't normally go with "more brittle". The opposite is more likely. The highest grades of steel or stainless steel are normally more brittle which means they don't flex or stretch much in the plastic range before they snap in two. Weaker steels are normally more ductile which means they'll flex or stretch more in the plastic range before breaking in two.

Although we've all seen some bolts fail, it's hard to get a good quality steel bolt to break when used on an aluminum stem. In my experience the aluminum stem threads will strip out before you can tighten the bolt enough to damage it. Over time it may fatigue to failure (probably the worse case scenario for cyclists) but any good quality bolt should be fine. Having said that, my personal preference is the highest grade available.

[rain dogs]

bolts are graded. get the right bolt for the job and it shouldn't matter if it's stainless or not

[soulspinner]

Not sure about seat binderbolts, I remember ham fist/breaking a seat collar bolt and the guy at the shop I worked at said its so you cant overtighten it and damage the collar or the seatpost. If stainless raises that threshold, you could theoretically damage something relatively expensive.....or maybe I drank way too much caffeine :rolleyes:

[EnginCycle]

Black oxide hardened bolts are the best for applications that require torque. Next is the zinc coated steel bolts for applying torque. Stainless bolts gall and often get stuck when not greased. 18-8 stainless is better than the stuff you will see at the local hardware store. That is often 306 which is very weak and will strip out easily on both the socket and the thread. Just make sure you always use grease since all torque specs are adding the lube to the threads so you get better movement.

All in all the steel bolts are better (first and second generation Thomson stuff came with black oxide steel bolts). As stated above as long as you get quality 18-8 stainless you will be more than good enough for the torque spec on most of the bicycle. I would avoid it on crank bolts and anything that is going over 20 newton meters.

-Drew

[sworcester]

Black oxide doesn't mean it's stronger, just that it has been put though the chemical process.
But on a bicycle, stainless vs non isn't a strength issue. Grade 8 would be the hardest and least likely to break, grade 5 less so, but for a bike, stainless is fine. There isn't a lot of torque on a bolt on a bicycle compared to a car or airplane.
Stainless just means it won't rust. Never-sieze on a steel bolt would do the same thing, or a titanium bolt, given proper torque off a torque wrench.
If you are having rust issues, never-sieze rocks.

[shovelhd]

Grade 5 is good enough for anything on a bike.