Take two frames with the same reach - but different seattube angles and toptube lengths, and you could easily find that you can make one fit you and not the other.
Fit is all done relative to the BB, yes. But if the ST angle dictates whether you can or can't be in the correct position relative to the BB then it becomes important.
Take two frames with the same reach - but different seattube angles and toptube lengths, and you could easily find that you can make one fit you and not the other.
Fit is all done relative to the BB, yes. But if the ST angle dictates whether you can or can't be in the correct position relative to the BB then it becomes important.