Originally Posted by
T-Mar
During manufacturer, it is fairly common to experience distortion of the seat tubes. This can cause manufacturers to use smaller posts. Some manufacturers routinely ream/hone to correct this and in some cases will go one size larger, to ensure the tube is round. It's also easy to become too aggressive with this operation. Consequently, it is fairly common to see posts that vary +/- 0.2mm from the nominal size.
There are also cases where manufacturers will request a custom tube. Centurion did this with the Turbo and Ironman models. Despite the Tange #1 decal, the tubesets are a custom blend and typically are fitted with 27.0-27.2mm posts.
The bottom line is that it fairly common to see posts that +/- 0.2mm from nominal, after allowing for clearance.
I hear what your saying TMar.
What was confusing to me was those SR frames (Araya) that both are advertised as using TANGE #2 which should have been 26.6 posts, and even considering that my SR Maxima went to 26.8mm which falls into your +/- 0.2mm, that advertised Pro AM was actually + 0.4mm using the 27mm post. I'm just more of the belief that they, Araya in this case, didn't hold to a true TANGE #2 tubeset on these bikes. Or at the very least Araya was doing some serious reaming (almost making double butted into a triple butted seat tube (0.9 X 0.6 X 0.7).
