Confused about the stack/reach ratio
10-31-18, 10:20 AM
#28
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Saddle setback is listed, subtract from saddle to bar and that’s the reach value. We’re fudging to illustrate but it’s ok as stem length is a constant. Reach changes as the seat tube angle changes but top tube stays constant. There is the uncounted reach from bb to seattube clamp which needs to be accounted for for fit but is not seen in the regular reach value.
Since this is how different bikes of the same “size” are often designed it makes determining proper fit dependent on more than just one or two measurements, or their ratio. I’m on my phone if this still doesn’t make sense I’ll see what I can explain of find to help once I get in front of a computer.
Since this is how different bikes of the same “size” are often designed it makes determining proper fit dependent on more than just one or two measurements, or their ratio. I’m on my phone if this still doesn’t make sense I’ll see what I can explain of find to help once I get in front of a computer.
Last edited by Spoonrobot; 10-31-18 at 10:25 AM.
10-31-18, 10:31 AM
#29
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Saddle setback is listed, subtract from saddle to bar and that’s the reach value. We’re fudging to illustrate but it’s ok as stem length is a constant. Reach changes as the seat tube angle changes but top tube stays constant. There is the uncounted reach from bb to seattube clamp which needs to be accounted for for fit but is not seen in the regular reach value.
Since this is how different bikes of the same “size” are often designed it makes determining proper fit dependent on more than just one or two measurements, or their ratio. I’m on my phone if this still doesn’t make sense I’ll see what I can explain of find to help once I get in front of a computer.
Since this is how different bikes of the same “size” are often designed it makes determining proper fit dependent on more than just one or two measurements, or their ratio. I’m on my phone if this still doesn’t make sense I’ll see what I can explain of find to help once I get in front of a computer.
10-31-18, 12:31 PM
#32
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11-01-18, 10:19 AM
#34
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production frames have often had weird choices as far as reach goes. Most times, larger frames have reach/top tube length that is too short for the average tall person. Some companies have had the same top tube length on all of their frames. It's definitely worth looking at reach, I'm sure you'll find some anomalies. I'm not sure that a size range of a given model with the same ratio makes sense either, but I have never been in the position of guessing what the best measurements are for a random population walking into a bike shop looking for a bike that fits them.
11-17-18, 12:46 PM
#35
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Visualize it like this: if you take a frame with a certain S/R ratio and draw a line between the top of the head tube and the BB, any frame whose headset falls along that line will have the same S/R ratio. That can include a frame that fits you, but also a frame that is three sizes too small (or big).
So, when you're comparing S/R ratios, you also need to only look at frames that have a stack in the range you want.
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