I can't believe it's 531

[bonj2]

Have you sold and dodgy "531" frames on Ebay recently, Bonj?

no i've got a bike which has a 531 frame but i'm not selling it. and no it wasn't bought off ebay before you ask.

 

[Landslide]

Dunno how true this is, but I once heard that some 531 seat tubes have an internal diameter of 27.2mm at the seat end, and 26.8mm at the BB end. These tubes were sometimes brazed in upside-down, hence the variation in seatpost sizes.

 

[mearle]

ebay/paypal *always* acts in favour of the buyer

Not necessarily true. For example, the "shilling" up of bids by sellers is not uncommon, and has been made easier by anonymous bidding. "Bidder 2" on my purchase was very likely a shill account for the seller, as its bid history was exclusively for this seller. You can report it, but I hear nothing comes of it, presumably because the higher the final price, the more commission ebay makes.

 

[e-rider]

Well, if you're unhappy with eBay then stop buying stuff on there - simple.

Most of it is well overpriced anyway!

 

[tyred]

My 531 frame is 26.8mm. I had to butcher the original seat pin as it was stuck in the frame and I wanted to move it to suit me. I went to the LBS and bought a 27.2mm replacement as I thought that was what I needed. When it didn't fit, I took it back to the shop along with the frame to have it measured. The LBS owener said that in his experience, many 531 frames were 26.8mm, even when they were supposed to be 27.2mm.

You probably could dispute it with ebay and possibly get your money back but in this case I wouldn't unless there is something else wrong with the frame. It is probably a perfectly good frame anyway and you cannot prove it isn't 531 without a great deal of difficulty.

 

[samid]

To the original poster: FWIW I happen to have a 531 frame (55cm ctt) with forks and BB but nothing else installed - i.e. similar to what's on your photo. If you have a scale and can weigh your frame/fork, I could weigh mine and we could compare the weights - at least it would give you some point of reference (although of course there are different types of 531 as was already noted, your frame may be different size etc etc).