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· Registered
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Discussion Starter · #1 ·
Geo info on my current bike lists TopTubeLength (horizontal) & TopTube Actual lengths; the frames I'm considering list Effective TTL so is Eff. the horizontal length or the Actual length?

TTL (horizontal)= 615mm, TTL Actual= 590mm

Where to where is the measurement for Actual & Effective (if they're not the same)?

Thanks for the help!
 

· local trails rider
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I think I can be more accurate...

Actual: tube length measured along the center of top tube, from center of head tube to center of seat tube.

Virtual/Effective: horizontal distance. Usually measured from the center of head tube, where the top tube meets it, to the center of the seat post.

Of course, how that translates to cockpit length also depends on seat tube angle...
 

· Shaman
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630 Posts
perttime said:
I think I can be more accurate...

Actual: tube length measured along the center of top tube, from center of head tube to center of seat tube.

Virtual/Effective: horizontal distance. Usually measured from the center of head tube, where the top tube meets it, to the center of the seat post.

Of course, how that translates to cockpit length also depends on seat tube angle...
perttime is right, if you have a laid back seat tube you will have a longer top tube but the bike will still feel same, especially when standing. There is a rarely used in the US measurement called front center which measure from the bb horizontal forward to where a plumb line from the top of the headtube would meet up. I think this is the best way to compare the front end size of mountain bikes.
 

· local trails rider
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Some call that horizontal distance from BB to head tube "Reach". At least Transition bikes has been giving that in their geometry tables.
 

· Advanced Slacker
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perttime said:
Some call that horizontal distance from BB to head tube "Reach". At least Transition bikes has been giving that in their geometry tables.
Yes, I think "reach" would be a huge improvement over "effective tt" for comparing different frames. Seat tube angle is largely correctable with saddle adjustment (to a point)
 
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