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drca

Tubeless valve and rim corrosion

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I have a 2013 Gas Gas TXT Pro Racing with the flanged rear tubeless rim.

I change my rear tire regularly but it seems that I am always in a hurry and never take the time to correctly inspect my rim when I do it.  Well I have been having a slow pressure leak in the rear recently that became worse yesterday so I took the rear wheel off the bike and hunted for air leak with my bottle of soapy water.

Turned out that there was some small rocks embedded between the rim and tire and most of the air was coming through there.  But there is also a very small leak at the valve level (at the interface rim / valve).

Is the tubeless valve on these rims the same as the automotive type or are they special trials rim version?

So I took the tire off the rim and decided to clean up the tire were it makes contact with the rim as well as the rim.  Well, I am sorry I didn't take photos of the rim before but after I cleaned it up with a wire wheel and sanding pad discs, here is what I had left:

5bb13c849a2c7_2018-09-3008_47.40(Custom).jpg.7486f92145959851db75a046a4bccd4c.jpg5bb13c85cf80a_2018-09-3008_47.53(Custom).jpg.724c382a70385b7b989f696c5eb2d900.jpg

There are some pretty bad corrosion with flakes of alloy coming off...  Is that common?  What can cause that?

Thanks.

DC

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28 minutes ago, drca said:

I have a 2013 Gas Gas TXT Pro Racing with the flanged rear tubeless rim.

I change my rear tire regularly but it seems that I am always in a hurry and never take the time to correctly inspect my rim when I do it.  Well I have been having a slow pressure leak in the rear recently that became worse yesterday so I took the rear wheel off the bike and hunted for air leak with my bottle of soapy water.

Turned out that there was some small rocks embedded between the rim and tire and most of the air was coming through there.  But there is also a very small leak at the valve level (at the interface rim / valve).

Is the tubeless valve on these rims the same as the automotive type or are they special trials rim version?

So I took the tire off the rim and decided to clean up the tire were it makes contact with the rim as well as the rim.  Well, I am sorry I didn't take photos of the rim before but after I cleaned it up with a wire wheel and sanding pad discs, here is what I had left:

5bb13c849a2c7_2018-09-3008_47.40(Custom).jpg.7486f92145959851db75a046a4bccd4c.jpg5bb13c85cf80a_2018-09-3008_47.53(Custom).jpg.724c382a70385b7b989f696c5eb2d900.jpg

There are some pretty bad corrosion with flakes of alloy coming off...  Is that common?  What can cause that?

Thanks.

DC

Yes it is common only way to prevent it would be to take your tyre off very often and wipe the rim clean on the inside .The valve is not special it is just a certain size ....just buy one at a trials dealer it will be the easiest way to obtain one. the corrosion is caused by water and oxygen in the air that you put in the tyre and also water in the lubricant that has been used to fit/remove the tyre........if you use washing up liquid as a lubricant to mount your tyres[ooer missus] this is quite acidic usually and so will only accelerate this corrosion https://youtu.be/q-RVJyNpfDk

Edited by oni nou

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Looks as though you have suffered some serious corrosion ( just stating the obvious). The materials used to make the tyre plus some water getting in between the tyre and rim have all reacted when the wheel rotates and static electricity is generated. This acts on the conductive surface of the wheel rim and eats away at the aluminium. Static electricity can be generated in most of the rotating components of an engine, you even get the crankshaft journals being attacked by this phenomenon and wheels are the worst offenders....travel sickness is put down to static build up. Water as moisture never goes well with aluminium if left to its own devices and add static and you have a cocktail waiting to cause trouble. If you replace that now dubious rim I would be coating the inside of the rim with a good quality paint, what you have suffered is quite common with some rims. The paint goescsome way to stop the reaction and when dried helps to seal the tyre bead to the rim, it does make removal a bit harder though.j

Edited by section swept
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8 hours ago, feetupfun said:

You can use WD40 to mount the tyre instead of a water-based lube

Luckily the product you mention does eventually dry up, but at least you won’t have the worry about suffectants attacking the rim. I use a bar of soap that’s going soft, acts just like proper tyre fitting soap.

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1 hour ago, section swept said:

 I use a bar of soap that’s going soft, acts just like proper tyre fitting soap.

Soap is by its very nature CAUSTIC.

Oxford dictionary defines soap as "a cleaning agent that is a compound of fatty acid", etc.

Proper tyre soap is NOT soap - more accurately tyre LUBE.

I am quite familiar with corrosion to rims - here's what I found on removing the rear tyre from my Bultaco Alpina long-term project :-

5bb1dd1f52cf4_Alpinar.wheel-rimcorrosion(3).thumb.jpg.6154c6f58d3883e75a0e28e564b6a9f7.jpg

Edited by lorenzo
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4 hours ago, section swept said:

Luckily the product you mention does eventually dry up, but at least you won’t have the worry about suffectants attacking the rim. I use a bar of soap that’s going soft, acts just like proper tyre fitting soap.

Yes the WD40 eventually dries and I find it continues to protect the rim from corrosion. As well as for seating tubeless tyres, it's good for protecting tube type rims that fill up with water when you ride a wet trial. I suspect that it wouldn't go well with a natural rubber tube, but I haven't seen one of those for about 40 years

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17 hours ago, section swept said:

..travel sickness is put down to static build up. 

Do you follow Scientology?

Edited by faussy
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What you have is galvanic corrosion which occurs when you have two dissimilar metals ,steel [valve] and aluminum [rim] in an environment that supports corrosion [water plus tyre lube] . Depending on where the metals appear on the Electrochemical Series, will determine which metal corrodes. In this case aluminum is higher on the list than steel and will therefore lose electrons[corrode] to the steel. Its the same theory that is used to chrome plate steel, only its done in a controlled manner. Galvanized steel is another example, Zinc is deposited onto the steel and will always lose electrons to the steel [even when in contact with water] as zinc is higher on the series than steel . I would guess that any product that is used to put the tyre on should be checked to see what they contain, any product with salt in it will only assist the corrosion. The problem seems to be worse when the rims are anodised [that is colouring the naturally occuring oxide layer on the aluminum rim]  The rims seem to corrode from the inside out which would indicate that the Anodised outer layer has a different electrochemical position than the rim itself.

Cheers Greg

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20 hours ago, feetupfun said:

Yes the WD40 eventually dries and I find it continues to protect the rim from corrosion. As well as for seating tubeless tyres, it's good for protecting tube type rims that fill up with water when you ride a wet trial. I suspect that it wouldn't go well with a natural rubber tube, but I haven't seen one of those for about 40 years

I have sealed the spoke nipples on the inside of the rear rim to keep water out...with a bit of luck...my rims are original Arkront and show no real signs of corrosion on the inside. Might be down to the silicon mix when the aluminium was cast, or possibly the rolling process to form the rim could have something to do with it. I won’t hold my breath as I can feel some comments coming my way saying that Arkront are rubbish and dissolve in water etc??⛲️?????

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43 minutes ago, section swept said:

I have sealed the spoke nipples on the inside of the rear rim to keep water out...with a bit of luck...my rims are original Arkront and show no real signs of corrosion on the inside. Might be down to the silicon mix when the aluminium was cast, or possibly the rolling process to form the rim could have something to do with it. I won’t hold my breath as I can feel some comments coming my way saying that Arkront are rubbish and dissolve in water etc??⛲️?????

I'm starting to get the idea that you are not being entirely serious. First you reckon static electricity causes car sickness :huh: and rim corrosion :wacko:and now you are saying that you have to waterproof your spoke nipples :blink:. Mind you it is a fairly entertaining :D discussion

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6 hours ago, sherpa325 said:

What you have is galvanic corrosion which occurs when you have two dissimilar metals ,steel [valve] and aluminum [rim] in an environment that supports corrosion [water plus tyre lube] . Depending on where the metals appear on the Electrochemical Series, will determine which metal corrodes. In this case aluminum is higher on the list than steel and will therefore lose electrons[corrode] to the steel. Its the same theory that is used to chrome plate steel, only its done in a controlled manner. Galvanized steel is another example, Zinc is deposited onto the steel and will always lose electrons to the steel [even when in contact with water] as zinc is higher on the series than steel . I would guess that any product that is used to put the tyre on should be checked to see what they contain, any product with salt in it will only assist the corrosion. The problem seems to be worse when the rims are anodised [that is colouring the naturally occuring oxide layer on the aluminum rim]  The rims seem to corrode from the inside out which would indicate that the Anodised outer layer has a different electrochemical position than the rim itself.

Cheers Greg

Not a boat owner are you, having to change anodes for different water conditions, ie aluminium for brackish water...river and sea mix or estuary. Zinc for sea water and magnesium for river water. All of these anodes have to be earthed and clean of antifouling and other applications before they can act as sacrificial anodes to protect props, rudders, steel hills etc. Zinc needs moisture to protect steel and aluminium not just on boats but for electricity pilons and other constructions that are  on the ground. Cathco based in Chesterfield is one of the largest companies specialising in catholic protection for all aspects of metal constructions through to ship building. In Lorenzo picture it looks as though the spoke nipples are unaffected by the corrosion and it is the alloy rim that has acted as an anode sacrificing itself as opposed to the nipples rotting away. There by hands a theory that you should consider the material from which the rim, spokes and nipples are made from including the valve assembly. In the case of the valve assembly for a tubeless tyre ensure that the fixing is NOT earthed by overtightening or not using sealing washers correctly, stainless spokes and stainless nipples is to some wheel builders a no no, preferring to use brass nipples instead. Had Lorenzos rim been painted on the inside the corrosion might have been far less, but he wouldn’t have known until taking the tyre off. 

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1 minute ago, feetupfun said:

I'm starting to get the idea that you are not being entirely serious. First you reckon static electricity causes car sickness :huh: and rim corrosion :wacko:and now you are saying that you have to waterproof your spoke nipples :blink:. Mind you it is a fairly entertaining :D discussion

Like to be entertaining, but informative too! Serious about the travel sickness, that’s why you can still obtain earth discharge straps that hang down off the rear of the chassis/body. What with nylon seat material, nylon content in tyres, etc etc the static that can build up is noticed by some people. You even get some car owners getting a static shock when they get out of their car and touch the door handle. Manufacturers either use non conducting materials for door handles or trust to the paint to provide insulation, but the first scratch on the handle and zap. Also serious about rim issues, anything that helps an owner to understand a problem or reason for something happening and hopefully provide a solution or remedy is what I’m about. I like to keep things light hearted to as this is a sport to be enjoyed?

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