Rivnut corrosion?

[Jad]

I was taking off my bottle cages and found this crusty corrosion coming from under the rivnut on the (Ti) downtube. I've looked for information--not quite clear on what I can do about it (galvanic corrosion, right?). Try to remove rivnut (hassle/undesirable)? Is this just cosmetic for the titanium?

I keep grease on the bottle cage bolts, which work fine. Thanks for any suggestions.

https://farm2.staticflickr.com/1844/44291553321_0ec806ff45_c.jpg

https://farm2.staticflickr.com/1848/44291555641_58bbe6d228_c.jpg

[duff_duffy]

I’ve had a few titanium bikes have similar issues with the rivets. I’d just cover with a cage and not worry about it. Just keep threads greased and don’t overtighten the bolt. I’ve replaced the seattube rivets on a few bikes and looks fine, unfortunately the downtube rivets may not have easy way out if you have to replace them.

[11.4]

It's normal. It's as likely to be perspiration salt as actual corrosion. If I have to replace rivnuts at any point I slather them with anti seize before installing. The tightness of the installation is what keeps them from rotating, and the anti seize just helps the rivnut last longer without corrosion and keeps salt out for a while. For the moment, I keep the rivnut itself well lubricated under the lip and am meticulous in hot climates about keeping the rivnuts clean and washed off.

There are good and bad rivnuts, by the way. I've had some that have gone years without any issues and others that crap out in a year. I wish I knew which were the good ones, but they are very inconsistent in quality. So don't hesitate to have them replaced if they are failing quickly.

[AngryScientist]

i think what i might do with this particular case is clean the ti of all corrosion well, then, with masking tape over the ti, expose only the raised; exposed portion of the rivnut and give it a good coat of rustoleum (after cleaning the surface). that might help keep it at bay for a bit.

this would be a quick task with some painters tape, an exacto knife and a small artist brush

[Jad]

Thanks a lot for the suggestions--I really like the idea of just putting the cage on and forgetting about it, but I don't know if I can handle that! It's an annoyance that I know would poke at me a bit...

I like AngryScientist's idea of cleaning and containing, and I happen to have some artists' brushes I just picked up for a painting job. I wonder how far under the rivnut lip I could get. Its fairly flush.

... So don't hesitate to have them replaced if they are failing quickly.

11.4, appreciate the reassurance. I have tightened rivnuts, but never replaced one. When you've had them replaced, has it been pretty simple?

[cmbicycles]

11.4, appreciate the reassurance. I have tightened rivnuts, but never replaced one. When you've had them replaced, has it been pretty simple?

It is usually as simple as drill off/out the old one, fish the innards out thru the BB or head tube, and install a new one.

[Jad]

^ Yeah, that's what I've read; I think if I knew the after-drilling part left in the tube was retrievable, I'd be more game for it. Maybe the holes from BB and HT to the downtube are larger than I remember though...
Eta: I'll be breaking it down soon, so will check it out.

[CSTRider]

Could also be a collecting point for sweat, electrolyte drink, and water bottle condensation. I'd just clean up threads with a lubed q-tip, reinsert water bottle cage nuts with anti-seize ... done.

[nicrump]

Drilling those out sounds easier than it really is. I mean if all goes well then great but when it goes sideways it can get ugly really fast.

If it is all there and tight then just clean the stink out of it and keep it greasy.

[rwsaunders]

^ Yeah, that's what I've read; I think if I knew the after-drilling part left in the tube was retrievable, I'd be more game for it. Maybe the holes from BB and HT to the downtube are larger than I remember though...
Eta: I'll be breaking it down soon, so will check it out.

Listen to nicrump...he's probably dealt with a few thousand of these puppies.

[Jad]

Drilling those out sounds easier than it really is. I mean if all goes well then great but when it goes sideways it can get ugly really fast.

If it is all there and tight then just clean the stink out of it and keep it greasy.

Fair enough, and thanks for the caution--it does make me nervous to think of approaching the frame with a spinning bit (or, according to a less refined method, a hacksaw). I'll apply some elbow and Phil Wood grease and see how it goes.