Keeping my bike rust free.

[Chz]

To be honest, if you have a decent bike that's fairly recent then all you're going to get is surface rust on the finish. Most, if not all, of the parts on a good bike are aluminium, cromoly alloy and whatnot and immune to rusting through.

 

[Sigmund Fraud]

cromoly alloy and whatnot and immune to rusting through.

Cromoly is steel and is by no means immune to corrosion.

 

[Crispy]

The only rust on my bike is in the hollow of the allen nut that holds the handle bars on Now, dirt on the other hand...

*peels tyre-flung roadkill off the bottom tube*

There's definitely some feathers stuck on there.

 

[Chz]

Cromoly is steel and is by no means immune to corrosion.

It's a steel alloy, much the same as stainless steel is. It's prone to surface corrosion but should never rust through.

 

[Sigmund Fraud]

It's a steel alloy, much the same as stainless steel is. It's prone to surface corrosion but should never rust through.

sorry but thats rubbish.


Its nothing like stainless steel at all. Stainless steel is a mix of steel and chromium. The chromium gets and extremely thin layer of corrosion built up on its surface but then corrodes no more - effectively the outer layer of corrosion seals it against future corrosion.

Cromoly steel is an alloyed steel ie its a mix of metals...just like almost every steel thing out there ie steel, chromium, molybendium, manganese mixed in various ratios. What is usually referred to as 'cromoly' ie 4130 grade Chromium / molybendium mix steel (sometimes referred to as Reynolds 501/520/521) is no different corrosion wise to other types of steel bicycle tubing such as Reynolds 531,653,753,853 and Columbus SL/SLX/Chromor/Ultrafoco steels.

And unlike stainless steel it does corrode - and will corrode all the way through and cause frame tubes to fail - just ask my mate whose racing bike seat tube collapsed on him as he went over a bump - the tube had been corroding from the inside for years before finally giving way.

Seeing as even 531 double butted frame tubes are only 0.8mm thick and ultralight steels such as Columbus Ultrafoco can go down to 0.22mm (thinner than a coke can) it pays not to let rust eat into steel bike tubes.

 

[Crispy]

And unlike stainless steel it does corrode - and will corrode all the way through and cause frame tubes to fail - just ask my mate whose racing bike seat tube collapsed on him as he went over a bump - the tube had been corroding from the inside for years before finally giving way.

*gaffer tapes steel plate to inside of seat to prevent rust-failure-induced-impalement*

 

[Sigmund Fraud]

*gaffer tapes steel plate to inside of seat to prevent rust-failure-induced-impalement*

mudguards will do

 

[Chz]

Chromoly

Alright, it's rust-resistant and not rust-proof; but the point stands that a well-maintained bike can be left outside for years and not rust out. The steel must have already suffered some form or trauma or cracking for a frame to fail like that.

As a pedantic point, stainless steel wiil rust through easily if abused or cracked, and it's *much* softer than 4130 alloy.

 

[Sigmund Fraud]

Alright, it's rust-resistant and not rust-proof; but the point stands that a well-maintained bike can be left outside for years and not rust out. The steel must have already suffered some form or trauma or cracking for a frame to fail like that..

it was a 4 year old Roberts build audax frame made from Columbus SL steel tubing. Its owner treated it with kid gloves but all the time it was slowly rusting through from the inside until there was only paint holding it together. Then it snapped.

If you think a steel framed bike is so rust proof why don't you fill your frame with seawater and ride around on it for a few weeks?

As a pedantic point, stainless steel wiil rust through easily if abused or cracked, and it's *much* softer than 4130 alloy.

As a pedantic reply, sorry but this is more absolute bollocks from you.

Stainless steel is an extremely *hard* steel - so much so that its very difficult to work with. If it was so soft, why don't people make bikes from it? Cos it don't rust, right?

Well they just have - just. Reynolds have after what they claim is a 15 year research period come up with Reynolds 953 Stainless steel bike tubing thats rust proof, as light as the lightest aluminium and stronger than titanium. Only drawback is that at present there are only two framebuilders in the world able to make a frame from it, its extremely *hard* so requires patient and meticulous working. And its likely to be nebulously expensive when it finally arrives.

certainly not softer than 4130 cromo as you claim...

 

[Reg in slippers]

calm down siggy!


if rust resistance from new is de-rigeur, then why not buy either a titanium or carbon frame?



*resists urge to post up more bicycle porn*

 

[Chz]

If you think a steel framed bike is so rust proof why don't you fill your frame with seawater and ride around on it for a few weeks?

Wouldn't exactly be a well-maintained bike, would it?

Your comments on stainless do point to the crux of the matter under discussion - there is no such thing as a "standard" stainless steel alloy. The closest thing is 18/8 (18% chromium, 8% nickel - commonly known as Type 304) which is what the vast majority of things marketed as "stainless" are. It is indeed *MUCH* softer than chromoly alloy (which is fairly standarised - Type 4130). There are some somewhat common stainless types that can be heat-hardened, but most at the expense of becoming brittle - not generally desirable in a bike frame.

Reynolds 953 would not be a typical stainless alloy. I don't know the composition of that one, as it's a relatively new mixture. I imagine they've worked long and hard to come up with it, so kudos if it works out well. Steel that's stainless, hard but not brittle, and easy to work with tends to be pretty rare and expensive.

Look, I know quite a bit about steel and not a lot about bikes beyond that I ride them, so my points are more generalised. It is true that well looked-after chromoly shouldn't rust through under normal circumstances - but it happens. It's equally true that good stainless can rust through in certain circumstances. I'm just saying that neither is *likey* under the common operating conditions of a bicycle.