Damaged rim

[ark]

So I broke the valve inner off in the valve stem whilst trying to top up my sealant. I bought a new valve and replaced it but when I pumped it up I heard air escaping through the rim somewhere. When I checked, the hole where you put the valve through was all cracked. Any idea how this happens ?

[V12man]

Looks like corrosion... time for a new rim - best you check the other rim too - fair chance it will have the same problem.

[droo]

A bad seal at the valve hole, causing sealant to leak through to where the valve hole was drilled and not anodised. The ammonia in the sealant attacks the aluminium and you end up with that.

 

Eish.

 

What rim is it?

[beachless]

Happened on a set of Mavics I have as well. To me it looks like the sealant corroded mine and in your case I think the same.

I am much more careful of the sealant brand I buy now and replace it more often as well.

[ark]

A Class Cervino tubeless

[kingalton]

• there was a post a little while back re someone using epoxy to seal the rim and then drill the hole again..

[BigBoy10]

Happened on a set of Mavics I have as well. To me it looks like the sealant corroded mine and in your case I think the same.

I am much more careful of the sealant brand I buy now and replace it more often as well.

sealant brand used now?

[DirtyFrank]

https://community.bikehub.co.za/topic/142843-mavic-wheel-fix-pratley-putty-to-the-rescue/

 

i had a similar problem , pm me if you need further explanation.

[ark]

sealant brand used now?

i have only used Stans

[DirtyFrank]

It may not be the Stans, remember that water and cleaner/degreaser can find its way into the rim void, this lies around in your wheel for some time and can also attack the rim at its weakest spot which is probably the valve stem hole as it is naturally susceptible to some surface damage due to removing and reinstalling valves/tubes, any corrosive liquid will attack the bare aluminium in this area over time and may cause the damage.

[Soufflé]

The lock nut should always be firmly tightened to prevent movement and leakage

[BigBoy10]

i have only used Stans

[LOOK695]

Can this also happen to carbon rims?

[JXV]

Severe corrosion. Has this wheel been in sea water? e.g. done the Imana Wild Ride?

Stainless Valve and alloy rim will result in galvanic corrosion if any moisture is present and especially if that moisture is conductive (salty). Most folks don't know it but dishwashing liquid has a lot of salt in it and should not be used for washing bikes.

Carbon will not corrode at all but its an expensive upgrade.

[Ryno.]

So stan's won't corrode the rims?

[Skylark]

The lock nut should always be firmly tightened to prevent movement and leakage

Firmly finger tight... Tighten with pliers and you'll be snapping valve stems regularly as there'll be no wiggle room for the stem to absorbed being bumped whilst pumped up etc.