Simple corrosion question ...

Galvanic corrosion …. does any occur between titanium bolts and any attached stainless steel hardware ?

Passive 316L stainless should be fine, sensitised possibly not. However if you need to use titanium then the rest should be the same, the European and UIAA standards  and logic says so.

simple answer: yes
https://www.engineersedge.com/galvanic_capatability.htm

but really, there are no simple corrosion questions.

A friend of mine rebolted a route in Glenwood Canyon (limestone) a few (2?) years ago where the old (20 years +) bolts were SS (probably 304) with Ti hangers.  We were surprised that there was significant corrosion, and from the looks of it, it was galvanic.   I wish I could find the photos, I'm not sure I still have them.  

dave custer wrote: simple answer: yes
https://www.engineersedge.com/galvanic_capatability.htm

but really, there are no simple corrosion questions.

thanks for sharing this. Interesting resource. 

I was told you had to be careful about galvanic corrosion on titanium bike frames specifically with regards to aluminum bottom brackets,  So I am not surprised to here its and issue for bolts.

I'm idly curious:  what about the fixe PLX stuff, fine with regular stainless 304 or 316 bolts?  they claim it minimizes galvanic corrosion.  I wonder how that all works.  I dont see PLX bolts just plx hangers...

Zacks wrote: I was told you had to be careful about galvanic corrosion on titanium bike frames specifically with regards to aluminum bottom brackets,  So I am not surprised to here its and issue for bolts.

I'm idly curious:  what about the fixe PLX stuff, fine with regular stainless 304 or 316 bolts?  they claim it minimizes galvanic corrosion.  I wonder how that all works.  I dont see PLX bolts just plx hangers...

there are a number of threads on this. None are all that helpful, but the consensus seems to be that PLX is just a high corrosion resistant (HCR) stainless steel and not an issue when used with other stainless components. I thought Fixe was starting to make their bolts with PLX, but just looking, they are all still labeled as 304. 

Fixe make both wedge bolts and theTriplex in PLX.

Zacks wrote: I was told you had to be careful about galvanic corrosion on titanium bike frames specifically with regards to aluminum bottom brackets,  So I am not surprised to here its and issue for bolts.

I'm idly curious:  what about the fixe PLX stuff, fine with regular stainless 304 or 316 bolts?  they claim it minimizes galvanic corrosion.  I wonder how that all works.  I dont see PLX bolts just plx hangers...

I have a full suspension titanium bike and having galvanic corrosion where the titanium meets the stainless steel bolts holding the rear shock.  I complained to the manufacturer about this in may.   The corrosion makes removing the shock very difficult, generous application of a hammer was necessary.

John Byrnes wrote: A friend of mine rebolted a route in Glenwood Canyon (limestone) a few (2?) years ago where the old (20 years +) bolts were SS (probably 304) with Ti hangers.  We were surprised that there was significant corrosion, and from the looks of it, it was galvanic.   I wish I could find the photos, I'm not sure I still have them.  

20 years ago there were not that many people placing stainless bolts in the us. Would like to see these bolts.

climber pat wrote:

I have a full suspension titanium bike and having galvanic corrosion where the titanium meets the stainless steel bolts holding the rear shock.  I complained to the manufacturer about this in may.   The corrosion makes removing the shock very difficult, generous application of a hammer was necessary.

A bike component could easily be 400 series stainless which could corrode on it's own with salt from sweat. Would be good to know what grade stainless.

I know where a few 304 five piece with ti hangers are in NC. I will have a look.

Timothy Fisher wrote: I know where a few 304 five piece with ti hangers are in NC. I will have a look.

Likely, you will need to pull the bolts to really see anything.  As I remember, the hangers and outer stud looked fine, the galvanic "gaps" were behind the hanger on the shaft.  

climber pat wrote:

I have a full suspension titanium bike and having galvanic corrosion where the titanium meets the stainless steel bolts holding the rear shock.  I complained to the manufacturer about this in may.   The corrosion makes removing the shock very difficult, generous application of a hammer was necessary.

Aluminium to titanium is about as bad as it gets, 400 sensitised stainless fairly bad as is sensitised 304. Sensitised 316 better than 304 and passive 304/316 galvanically identical to titanium so not a problem. Bike frames it's more difficult to say, tests on the compatabilty of Grade 9 titanium are hard to find but the 3% aluminium would raise questions.

Every environment is different but here in the high desert I pulled a bunch of bolts that had TI hangers and SS hangers with carbon steel 5 piece bolts aged about 20 years.  There was not a noticeable difference in corrosion between TI hangers or SS hangers.