Aluminium downtube corrosion?

T800

Prepping the bike for a forthcoming tour this afternoon, I spotted bubbles in the paintwork on the downtube, around the bottle cage bolts. Is this a bad sign, or worse, dangerous?

Do I need to get 'round to the LBS pronto to discuss safety and frame integrity, or is it something I can talk to them about after the trip?

I last cleaned the bike a couple of months ago, but it was dusk that evening, and I was very tired, so just because I didn't notice this problem at that time doesn't mean it wasn't there. Also, I noticed some very small blue flaky bits in the vicinity of bottle cage today, though I don't know what they're from or if they're of any significance.

The bike's a 2001 Cannondale T800 that is my commuter, shopper, tourer and general all-round primary mode of transport. It's parked under cover at home, but at work is left out in all weathers.

supersonic

Aluminium oxidises to form a protective surface. However if you have got something under the paint eating it away (ie road salt), it could cause some damage. How bad I do not know. The same happened to my GT under the stickers - once removed the surface was pitted and scarred, but seemed superficial and had no problems.

T800

Thanks for that. I'm going to pack some weight into the panniers tonight and go for a spin on the bike to see how confident I feel with it and see if there's any ominous creaking to be heard from the frame!

supersonic wrote:

Aluminium oxidises to form a protective surface. However if you have got something under the paint eating it away (ie road salt), it could cause some damage. How bad I do not know. The same happened to my GT under the stickers - once removed the surface was pitted and scarred, but seemed superficial and had no problems.