Old 10-03-20, 01:55 PM
  #12  
Terzot
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Originally Posted by T-Mar View Post
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So, it is ttalian built but the Reynolds decals are suspect. 531DB, as indicated by the decal, would typical uses a 27.0-27.2mm post on an Italian frame, as they used imperial standard tubing with a 28.6mm outer diameter. However, metric 531DB would use 26.4mm so you should verify the outside diameter of the seat tube, just to be sure, even though it would be highly unusual on an Italian frame. Metric seat tubes have a 28.0mm outer diameter.

Assuming imperial tubing, a 26.4mm post is quite small for the era. That's borderline for a lightweight hi-tensile steel. I wouldn't expect the builder to be putting effort into features like reinforcing tangs at that level. So, I should also ask if the post is the correct size (i.e when the binder bolt is tightened, is the cinch in the back of the seat tube slot parallel or close to parallel? Or is it notably pinched at the top?)

Here's what you are looking for the in the steering column. Just take off the front wheel and look up, into the steering column. However, based on the seat post size, I doubt you'll find the ridges.
So:
1) about 5 ridges - as you can see on the photo belowed there are 5 ridges:

2) about seat post, i've measured as in the photo belowed:

also there is a number on my seatpost: 26.4

and about how it looks like when i strightend the bolt:

hope it's going to help you!
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