Frame Stamps

[marching_out]

Probably been discussed before but too lazy to look it up. Found these on my 1967 DeLuxe. Curious the meaning if anything. Frame number maybe? M77 on outside right drop out and 1224 on inside left dropout..

 

[GTs58]

Those are part numbers. With all the different bikes Schwinn produced, one preformed drop out does not fit all the bikes, stay angles are different so the drop outs have to be made different to where they meet up with the stays. This started years ago and the stampings were on the inside and very light stamps so hardly noticeable.