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Frame rust - how to identify(5 posts)

Frame rust - how to identifydan ida
Aug 21, 2002 1:09 PM
When buying a used frame, high quality 853, where do you most commonly find "inside of tubes" frame rust? And how do you see in there to check?

re: Frame rust - how to identifyMike Prince
Aug 21, 2002 1:30 PM
Easiest way I can think of is to pull the seat post out and wipe it off. The color of the residue on the rag should be a decent initial indicator. Additionally, put a rag around the end of a screw driver or broomstick and get down a bit further in the seat tube to check. Other than that you may be able to see inside of the head tube or BB shell, but not really anywhere else.

Hope this helps.
I put that in the same box with aluminum frame fatigue.Spoke Wrench
Aug 21, 2002 2:11 PM
I read lots and lots of posts about both, but I've personally never seen either. I'd have to assume that steel frame rust and aluminum frame fatigue are both so rare as to be non-issues. I've never had a frame that didn't last longer than I wanted it to.

Things I would look for:
1. Repainted bikes. There's always a story there, find out what it is.
2. Physical damage. Scratches and dents should match the story the guy tells you about the bike. Check the bottom of the top and down tubes just behind the head tube extra carefully. Rippled paint there means the head tube has been pushed back.
3. This one's hard until you've seen a couple. Welds blend from one tube to the other. If it looks like there is a hair at the base of a weld, you're seeing a hairline crack.
I put that in the same box with aluminum frame fatigue.Rusty Coggs
Aug 21, 2002 4:06 PM
Rust does happen. Maybe more so on older bikes that have sat outdoors or maybe never had the seatpost pulled to empty the water from BB shells with no drain hole.Climate and proximity to salt water may also have an influence.I rescued an old GT mtb that had such a rusted out BB that I would not ride it.Have also heard of fairly current quality steel forks failing at dropouts from rust, and A Colnago Master Light having rusted out at the BB in short order.Possibly poor care and feeding, but not to be dismissed as an imposibility.
re: Frame rust - how to identifyAndreas_Illesch
Aug 21, 2002 11:15 PM
high end steel frames from 853, columbus nivachrome or foco/ultrafoco are nearly rust resistent if kept right.
rust appears first inside on the joinings of tubes where there are corners where dirt and water can accumulate.
on cheaper frames there ist often a little oxidation (=> rust) on the welding points. for example on my GT frame inside the seat tube where the seat stays are touching. put out the fork and check the inside joinings of tubes whith the steer tube. there should be holes inside the steer tube where down and top tube touches. take a torch if necessary. next place to check is the joining of top and seat tube from inside. and then check inside all along the seat tube. whith a good torch you can look all down to the bottom bracket, if you manage to place the torch and your eye well.