Reynolds 753?

I started a new thread to hopefully get more opinions.

Got a track bike yesterday (53cm) and have been trying to identify it. Now I'm looking at the type of steel it's made out of. It's got a 0.7mm seat tube so as far as I understand this limits it to 653 or 753? The weight is surprisingly light.

Forks with crown race = 665g
Frame with bottle bolts, seat bolt, bottom bracket and headset cup = 1570g

If the Ofmega BB, headset cups and bolts weigh 300g that would mean the frame is only 1270g

With a frame that light is it possible for it not to be 753?

Could it be 731 OS ?

PeterPerfect":2yr9wbw1 said:

Could it be 731 OS ?

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I wouldn't of thought so with how skinny the tubing is.

Re:

It could be 531 pro. Bit unlikely for a track frame but I believe the guages were very similar to 753.
Don't rule out the possibility of another brand of tube such as Columbus or Tange or, if it is a true custom frame, it could have a mixture of tubes in there.
Incidentally, if you do the maths a wall thickness of .7mm equates to a seat pin size of 27.4mm. this is very unusual and most frames built with this material are 27.2mm because the brazing process distorts the seat lug area and it has to be reamed back to accept a round post. Because the tube is so thin it's often unwise to ream to 27.4 because if it is out of round part of the tube will be left too thin to take the clamp bolt force.

Seatpost is 27.2mm

Does anyone know what other tubing there is with a 0.7mm seat tube? Whatever it is it's very light and stiff to me although I'm only 68kg.

What colour is the braizing? I think I read somewhere 753 is silver brazed but I cold be wrong.

fossala":26vzzd2e said:

Seatpost is 27.2mm

Does anyone know what other tubing there is with a 0.7mm seat tube? Whatever it is it's very light and stiff to me although I'm only 68kg.

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Which part of the tube are you measuring as 0.7mm? A 753 seat tube is single butted with 0.7 at the BB end.

originalshinkicker":2nysgihn said:

fossala":2nysgihn said:

Seatpost is 27.2mm

Does anyone know what other tubing there is with a 0.7mm seat tube? Whatever it is it's very light and stiff to me although I'm only 68kg.

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Which part of the tube are you measuring as 0.7mm? A 753 seat tube is single butted with 0.7 at the BB end.

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I measured it at the seatpost end.

753R for example is 0.7/0.5 single butted - the 0.5 is at the seat pin end with 0.7 at the BB end. That is on Imperial 753R. 531Pro will be the same. 531c is 0.8/0.5 (the same 0.5 at the seat pin end). So 0.7 at the seat pin end is either very thick or incorrect?

originalshinkicker":2x33fhhk said:

753R for example is 0.7/0.5 single butted - the 0.5 is at the seat pin end with 0.7 at the BB end. That is on Imperial 753R. 531Pro will be the same. 531c is 0.8/0.5 (the same 0.5 at the seat pin end). So 0.7 at the seat pin end is either very thick or incorrect?

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I'm off to bed in a second (covering the baker at work so up at 3am :shock I'll take pictures when I get home. The paint will account for something but it doesn't look thick. I'll grab my wifes DLSR with a macro lens.