Bicycle Mechanics - Shimano 550 Rims - spoke rust

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If they're the new R550 wheels, those have stainless spokes and I have a hard time believing they're rusting. Maybe they're just dirty?

The spokes are stainless steel.

Touch a magnet to 'em; stainless spokes are usually 304 alloy which is non-magnetic.

Thanks. The wheels are Shimano 550s and the spokes are not stainless steel unfortunately. Wish they were. I keep my bike very clean and I know rust and I know stainless when I see it.

Thanks J

I'm pretty sure Shimano never made any of their wheels with anything but stainless spokes. It's pretty much universal on anything but the very cheapest wheels. If these are your wheels, check out the specs here: http://tinyurl.com/bdwsu

Thanks. I tried the magnet test as suggested. The magnet grips the spokes on my R550s like they would any other steel.

Regards J
Wow, that's bizarre.

High quality bike modern bike wheel are NEVER built with plain steel spokes. Where did you get these wheels?

Stainless is just that. stains - less.

The stainless used in most modern production is fairly high carbon and will corrode under the right circumstances.

I have no specific knowledge of the Shimano wheels, but this holds true for items such as firearms, etc...

-Z

Stainless is just that. stains - less.

The stainless used in most modern production is fairly high carbon and will corrode under the right circumstances.

I have no specific knowledge of the Shimano wheels, but this holds true for items such as firearms, etc...

-Z

Well, sort of...

It's not the carbon content that allows corrosion, it's the iron.

The addition of chromium and nickle is what gives stainless its rust-resistance, and yes, sometimes it rusts anyway.

Also, some stainless alloys will attract a magnet, just to make things more confusing.

I would be very interested in hearing (reading) what the Shimano rep has to say!

I spoke to Shimano and took the WH -R550 wheels over to the local Shimano office/warehouse. As the wheels were still in warranty (12 months warranty) they were both replaced without question. The front wheel spoke corrosion was much more significant than on the rear wheel. It was hard to get much comment from the office but one rep told me that there had been a problem with a batch of wheels. I gathered that they had certainly seen this spoke corrosion problem before. I must say that Shimano were really excellent to deal with - new WH -R550 wheels with new skewers and new rim tape . Full credit to Shimano for standing by their product and warranty and for being so helpful in replacing the wheels for me so promptly. (This contrasts with the bike dealer who had no interest in helping). So I am very grateful to Shimano who have demonstrated that they will stand by their customers.
Glad to hear you got it worked out! Certainly an odd problem, too bad you didn't pry 'em for a little more information on how that happened :)

Well, I'll be picking up a bike tonight with black spokes, I'll be taking a magnet along.

Out of curiosity, I tried the magnet on my wheels. Yep, my spoke pull s the magnet, but not as strong as non-stainless steel. And yes, they are supposed to be stainless steel.

Erm, stainless and non-stainless are both magnetic. Stainless steels simply have 15-20% chromium in them. The other 80% is still, well, steel...

Erm, stainless and non-stainless are both magnetic. Stainless steels simply have 15-20% chromium in them. The other 80% is still, well, steel...
Magnetic properties of materials are very complex: just because 80% of a material is magnetic on its own doesn't mean that the whole thing has even remotely similar properties. The alloying of iron with other metals (even in very small quantities) can affect the crystal structure of the alloy, which upsets the conditions required for ferromagnetism.

If I recall correctly, stainless steels containing nickel, even just a few %, are non-magnetic because the nickel causes the iron to crystallize in a structure called Austenite that won't allow ferromagnetism. On the other hand, low-nickel stainless steels crystallize in the Ferrite structure similar to pure iron, and these ARE ferromagnetic.

There are tons of different stainless steel alloys, some are strongly ferromagnetic (= attracted to a bar magnet), some aren't. In any case, I have no idea what alloy is used for bike spokes. I am guessing that spoke materials are chosen for their corrosion-resistance, strength, and cost--rather than for magnetic properties :)

What moxfyre said.

I have various grade stainless here at home, some are slightly attracted, others not at all. The better quality is not. My quality kitchen cutlery is not attracted, the cheapos are. So a spoke attracted to a magnet is not the final test. But I'm happy to report the bike I picked up tonight spokes are not ferromagnetic.