Reynolds 531sl or 531???

[Mr Weirdo]

Hello I have been told that possibly my bicycle frame, which I believe has been repainted may not be what I thought it was regarding to the Reynolds steel used.

On the forks and frame it has 531sl decals. So I have weighed (using mechanical bathroom scales) the frame without the forks then found out the approx weight of my BB and deducted it from the original figure. I have a final figure of approximately 1741g.

I was informed by a fellow cyclist that a Reynolds 531sl depending on size of frame of course should weigh between 1650g and 1800g. The seat tube from c-t is approximately 21".

So what does everyone think?

Thank you...

 

[hamster]

Have you any clue about its age from the frame number?
The difference between 531C and SL is only 150g or so, which to me puts it inside the usual variability caused by size, lug choice plus geometry differences.

I don't think you will ever know.

 

[Mr Weirdo]

Well this may be also be an issue. The frame is french and a Lejeune so has no frame number. I was informed by the other cyclist that the cable guides on the RGF bbs which are on the top and not on the bottom would then most likely make it pre 1975. It has a Velo Orange BB. I thought Reynolds 531sl was manufactured post 1975?

Have you any clue about its age from the frame number?
The difference between 531C and SL is only 150g or so, which to me puts it inside the usual variability caused by size, lug choice plus geometry differences.

 

[hamster]

531SL was from 1976 as far as I understand, replaced by 531Pro from 1982.

Also I assume it's in metric tube sizes being French, which might alter the weight by a few grams.

 

[Mr Weirdo]

Well this may be also be an issue. The frame is french and a Lejeune so has no frame number. I was informed by the other cyclist that the cable guides on the RGF bbs which are on the top and not on the bottom would then most likely make it pre 1975. It has a Velo Orange BB. I thought Reynolds 531sl was manufactured post 1

Puzzling...to me anyway . Oh well it is light but ignore the decals I guess.

 

[callFromTheGrave]

I've a 56cm 531SL frameset and frame is right around that 1750grams... Not sure if I should even ride it at 85kgs.

 

[Mr Weirdo]

Thanks Grave.
Not sure on the weight ratio thing? But I'm sure on Retrobike someone will have an opinion lol. It's just that if my frame is pre 1975 it can't be SL but it does fall within the weights specified at the beginning (1650g to 1800g). All the best.

 

[pigman]

Have you any clue about its age from the frame number?
The difference between 531C and SL is only 150g or so, which to me puts it inside the usual variability caused by size, lug choice plus geometry differences.

I don't think you will ever know.

531sl and 531c were of different eras ( I think)
531db existed alongside 531sl
531c existed alongside 531 pro

 

[hamster]

Yes, agreed. I didn't express it at all well, what I was trying to get over was that there was such a variety of tubesets with small differences that between db, SL, Pro and C, combined with different sizes and geometries there is huge overlap. A pair of scales cannot give a definitive answer!

 

[Mr Weirdo]

Thank you both for your info. It's always appreciated. I realise after carrying out more searches on this subject and there are lots of similar posts it's all a bit of a minefield. But all very interesting imo..