[Closed] Steerer corrosion (Reba) - casued by grease?

Looks more like glavanic corrosion caused by steel crown race on aluminium steerer and trapped moisture.

Can't comment on risk of failure from corrosion though.

Looks like a chemical erosion to me, but would be impossible to be definite without someone clever doing something expensive with computers and stuff.

So, I'm going to go for that part of the steerer getting and staying a bit damp, coupled with the effects some chemical. That could indeed be in the grease you are using, or the a washing detergent, or road salt possibly.

is that a groove where the headset top race sits.... that worries me more than the corrosion if it is ....

Struggling to see why it would be an expensive repair, little bit of surface corrosion on a extremely strong part. Would you replace a steel frame for the same amount of corrosion?

thanks - I'm using a mucky nutz these days so hopefully there will be much less water getting in there from now on. Annoying anyway, replacement csu's are really expensive!

Can't say I'd give it a seconds thought.

[i]Struggling to see why it would be an expensive repair, little bit of surface corrosion on a extremely strong part. Would you replace a steel frame for the same amount of corrosion? [/i]

Steel bends, Aluminium snaps...

I've had the same, there was moisture condensing on the steerer. I always put a thin layer of grease on the steerer tube now.

Doesn't look bad to me, I certainly wouldn't replace it.

Yes that is a 'groove' from the headset top race (king) - but it is a polish more than anything... Have since replaced to a grip nut anyway.

I wouldn't replace a frame with those no but this feels a bit more important structurally no?

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Hmmmm... the oxidation goes quite deep, doesn't it?

Pretty deep cable groove on the crown there too.

Poor maintenance to blame surely?

hard for me to measure but if the metal is only 3-4mm thick some of the pits may be half way through.

robdob, yes I am sure it was - I'm just trying to find out what caused the corrosion to avoid my new forks going the same way...

Wow... now we have a close up I'd be a bit more thoughtful

Sent pics to manufacturer ?

^^ agree :/ I might strip mine down now and have a peek 😯

that is quite deep but it's one of those odd cases..

- If it were my fork I'd ride it and check it regularly
- If a customer came in and asked for advice I'd recommend replacement.

My forks got sent back to Fishers by Loco and they returned them with no action, saying it was just corrosion and fine. Was mildly annoyed, but they haven't got any worse.

this is what my revs looked like
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whats your headset and steerer made from.

further apart the more they rot.

how ever my landy is showing that the alu gets eaten pretty quick by the steel.

So perhaps fitting a headset with an alu crownrace such as a hope might be a good move to avoid the dissimilar metals - then the corrosion will take place between the replaceable crownrace and the steel bearing surface.

I doubt it is half way through as it will look deeper due to the metal expanding as it corrodes.

Corrosion pits are worrying as they will eventually lead to cracks. But steerers are pretty overbuiltu. Jst think of the deep gouges hammering a star nut in does at the top.

Worth emailing Sram as they may have had a dodgy batch of steerers with increased risk of corrosion. I suspect they will just send you back the price of a new CSU though.

The first pic I thought meh nothing wrong with that. The second really shows the defect up though, I'd be a bit concerned riding with that when the consequences of failure are extensive pain and dentistry...

It is probably galvanic corrosion related to the steel headset race (but could be other caused mentioned above). Depending on the grease used this could make it worse, some grease is ionic (and makes it worse), silicon based grease (i.e. fork grease) would avoid this being a contributing factor - bit isn't normally used for bearings (I don't know enough to know why this is the case).

Hope crown race is normally steel with a split.

Is that a step up crown race ie a tapered head tube? It might be worth fitting a normal 1.5" crown race and get the aluminium Hope step up adapter. Smear plenty of waterproof and if possible high particulate (eg teflon filled) grease on the steerer before fitting the adapter.

Hope crown races also have a nice rubber seal which can help keep moisture out but they can also trap it in if water is entering somewhere else so check the top of your headset for gaps or if water i getting into the frame somewhere else and running down to the head tube.

Worth emailing Sram as they may have had a dodgy batch of steerers with increased risk of corrosion. I suspect they will just send you back the price of a new CSU though.

Do you mean SRAm directly, or Fishers? Fishers certainly have quite a relaxed attitude about it anyway.

Yes it was used with a Chris King (Tapered) with he baseplate shown. I think the grease was Finnish Line Teflon.

Yes I was worried about loss of teeth so it hasn't been used for ages and has since been replaced - I can't imagine Sram/Fishers will care but you're right it might be worth a go!

"Hope crown race is normally steel with a split."

is that a new thing ? i have 4 or 5 all have alu split crown races.

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not a million miles from that - i thought i had one of each going right back to the old non replacable bearings ones

have emailed fisher - we'll see!

t-r - you're right. They are aluminium.

OP what is yours made from?

Blimey, deep marks there, interested to hear what Fisher say. Good luck!