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Yesterday I saved a Raleigh granada frameset from 1986. It's in ok condition but without any of the original parts.

The plan is to build it up with leftover parts. So no original restauration on this one.

I tried to figure out the seatpost diameter by measuring the hole in the frame with a calliper but I couldn't be sure it was a 27.0 seatpost. Do you know? Or are there any other more reliable way to measure?

Sorry for the bad image but that's all I got. It's just drying up after being carefully cleaned.

Sorry for the really bad image quality but it's all I got

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  • Since the opening is rarely a perfect circle, it's difficult to get a reliable measure just measuring the opening with a caliper -- better to find a post that fits well and measure the post. (That style of clamp tends to maintain it's circularity well, however, so a caliper inside the clamp should come close.)
    – Daniel R Hicks
    Commented May 17, 2018 at 11:40
  • Yes. I looked on my bikes but didn't have any close to 27? I'll see what I can find from friends as well.
    – Ola
    Commented May 17, 2018 at 11:45
  • Or could I measure the circumference outside the seatpost a bit further down, subtract the wall thickness and dividi with pi?
    – Ola
    Commented May 17, 2018 at 11:47
  • Another option is to take the frame to a bikeshop and try to find a fitting post. On a steel frame of that period a 27.2mm post is the most likely thing. Measure the opening front to back, left to right and at several angles and take the average. Also check whether the slot at the rear of the seat-tube isn't deformed by the clamping screw.
    – Carel
    Commented May 18, 2018 at 10:22

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I ordered a 27.0mm seatpost and it fitted perfectly!

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  • Good luck with the build. That is beautiful frame!
    – sam
    Commented Jun 12, 2018 at 18:29
  • Based on the age I would have guessed 25.4mm / 1" seat post, and that's the size in my Raleigh Arena from 1981. Good work getting it right first time!
    – Criggie ♦
    Commented Jun 12, 2018 at 19:27

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