Frame Advice

[lodge]

I bought a new frame last year, bought as a 20.5 top tube, now that the frame is built up the bike seems big for a 20.5 so i got the tape measure out and to my surprise the top tube measures 21.25 C to C.
I still have the manufactures box which states model size and colour and sure enough it states 20.5.
Am I missing something here or is it cut and dried that the wrong frame was in the box, to add to the confusion the seat tube has a really relaxed angle 69 i think so i wondered if this makes a difference when measuring.
Any thoughts advise, opinions, pee takes etc appreciated.

[bof]

Any pictures and what frame is it. 

[lodge]

Mutiny Eden 2006  do want pics of just frame or the tape measure against the frame.

[Trev]

if anything, i'd expect the top tube to be slightly shorter than stated as they are measured from slightly different places sometimes (i.e. centre of headtube to centre of seat tube), but i wouldn't expect it to be longer.

[lodge]

if anything, i'd expect the top tube to be slightly shorter than stated as they are measured from slightly different places sometimes (i.e. centre of headtube to centre of seat tube), but i wouldn't expect it to be longer.

I thought center to center across top tube was a standard way to measure Top Tube Length?

[Trev]

if anything, i'd expect the top tube to be slightly shorter than stated as they are measured from slightly different places sometimes (i.e. centre of headtube to centre of seat tube), but i wouldn't expect it to be longer.

I thought center to center across top tube was a standard way to measure Top Tube Length?

I would have thought so.

[lodge]

[MartyC]

It looks if you measure the centre of the top tube all the way along the length of the tube you will get 20.5", but try it and see what you get.  You are measuring a diagonal based on the pic you've posted.  It's subjective as it has a sloping top tube so in reality it is the equivalent of a traditional 21.5" frame that does not have a sloping top tube.  Hope this makes sense 

[lodge]

It looks if you measure the centre of the top tube all the way along the length of the tube you will get 20.5", but try it and see what you get.  You are measuring a diagonal based on the pic you've posted.  It's subjective as it has a sloping top tube so in reality it is the equivalent of a traditional 21.5" frame that does not have a sloping top tube.  Hope this makes sense 

Thanks Marty, I still get 21.25 if I measure along the center of the top tube, In your opinion is it a medium or an XL frame.