What are these markings? Please

[GT60]

Hi whilst my son is sanding the frame of my Carlton Corsa he has found some markings and is asking what they are.#
One is on the down tube where the gear lever goes and is a raised Triangle
some are either numbers or Letters either side of the bottom bracket ( they are not the frame number )
see please see photo.
The other he has found is like an S at the rear inside of the wheel hanger but on the tubing again please see Photo.

Thanks

View attachment 123218 View attachment 123218 View attachment 123218 View attachment 123218

 

[ayceejay]

My guess is that they are markings to tell the frame build er which tube goes where.

 

[midlife]

The triangle on the downtube is to stop the band slipping down.....

Shaun

 

[GT60]

Thanks for the replies
Does anyone know what the raised "S" shape is for?
Thanks

 

[midlife]

is it where the chain has got stuck and it just looks like an S?

Shaun

 

[GT60]

Could be but is looks too uniformed and too high on the frame

 

[Dogtrousers]

Secret code. It could be that this bike belonged to the Knights Templar.

 

[mikeymustard]

Secret code. It could be that this bike belonged to the Knights Templar.

The Corsa Nostra more like