Internal. Then reference standard seat post sizes for given tubesets.
A caliper would be the best choice for measuring if you don't have a suitable seatpost or seat post measuring seat (stepped-width seat post).
@rodabod started
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Internal. Then reference standard seat post sizes for given tubesets.
A caliper would be the best choice for measuring if you don't have a suitable seatpost or seat post measuring seat (stepped-width seat post).