I've seen some with 73 degree ST angles, some with 73.5, and some with 74 and even 74.5 degree ST angles (primarily smaller sizes).
Makes me wonder - why? Why so steep? Well I guess 73 is normal, but I'd love to learn more about why the use of other steeper angles like 74 and 74.5 on smaller sizes.
Oh and I'm right in my assumption that a steeper seat tube angle actually makes for a longer effective top tube given the same head tube angle through size ranges correct? It sorta seems counterintuitive, but this is what I remember from other posts/threads. Slacker seat tube angles actually cause a shrinking of ETT as the seatpost and saddle raise to higher and higher lengths above the TT, thus actually "cramping" the cockpit more as the saddle raises - right?
So for example - how much real difference in ETT would there be for two frames with the following geometry numbers.
74.5 ST angle, 71 degree HT angle and a 22.5 inch Actual Top Tube length and a 16" Center to top seat tube length
vs
73.5 ST angle, 71 degree HT angle and a 22.24 inch Actual Top Tube length and a 18" Center to top seat tube length
Would the difference in ETT be minimal between these two bikes? If so, the 16" will provide more standover and possibly more exposed seat tube (possibly actually helping with ride quality in terms of lessening some hartdail backend harshness).
Are there any production frames utilizing a slacker angle than 73? If so, who are they?
Who's got a theory? Time for GT and jn and bcd and others to chime in here. Thanks.
Makes me wonder - why? Why so steep? Well I guess 73 is normal, but I'd love to learn more about why the use of other steeper angles like 74 and 74.5 on smaller sizes.
Oh and I'm right in my assumption that a steeper seat tube angle actually makes for a longer effective top tube given the same head tube angle through size ranges correct? It sorta seems counterintuitive, but this is what I remember from other posts/threads. Slacker seat tube angles actually cause a shrinking of ETT as the seatpost and saddle raise to higher and higher lengths above the TT, thus actually "cramping" the cockpit more as the saddle raises - right?
So for example - how much real difference in ETT would there be for two frames with the following geometry numbers.
74.5 ST angle, 71 degree HT angle and a 22.5 inch Actual Top Tube length and a 16" Center to top seat tube length
vs
73.5 ST angle, 71 degree HT angle and a 22.24 inch Actual Top Tube length and a 18" Center to top seat tube length
Would the difference in ETT be minimal between these two bikes? If so, the 16" will provide more standover and possibly more exposed seat tube (possibly actually helping with ride quality in terms of lessening some hartdail backend harshness).
Are there any production frames utilizing a slacker angle than 73? If so, who are they?
Who's got a theory? Time for GT and jn and bcd and others to chime in here. Thanks.