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29er / Re: Simple question for you geometry gurus…
« on: September 27, 2024, 08:30:44 PM »
If ETT is the same on both bikes they shouldn't feel any different when seated and stationary. Effective top tube calculation accounts for differences in seat tube angle. Effective top tube is the virtual distance from a horizontal line that runs between the top of the head tube and the imaginary line extending from the seat tube that it would intersect. Think of it as the "seated reach" of the bike.
And reach is the distance between a vertical line that runs through the bottom bracket and the top of the center of the head tube? So this is the "standing reach" of the bike.
Look at the Light Carbon 917 and 918. The 917 has a shorter reach (421.2) but slightly longer top tube (600) because it's seat tube angle is 73. The 918 has a 14mm longer reach (435mm) but shorter top tube (598.8MM) because it's seat tube angle is steeper (74.75). With same seat, stem, spacers, bar; these 2 bikes should feel very much the same when you sit on them.
In your case things will be a little different because the FS will sag a little so I think puts your weight back a little more than the HT. But how far you have to stretch to hold the grips should still be the same.
And reach is the distance between a vertical line that runs through the bottom bracket and the top of the center of the head tube? So this is the "standing reach" of the bike.
Look at the Light Carbon 917 and 918. The 917 has a shorter reach (421.2) but slightly longer top tube (600) because it's seat tube angle is 73. The 918 has a 14mm longer reach (435mm) but shorter top tube (598.8MM) because it's seat tube angle is steeper (74.75). With same seat, stem, spacers, bar; these 2 bikes should feel very much the same when you sit on them.
In your case things will be a little different because the FS will sag a little so I think puts your weight back a little more than the HT. But how far you have to stretch to hold the grips should still be the same.