Actual head tube angle / changing fork atc
Hi, not sure if this would be the correct forum for this...
I am trying to figure out what my actual head tube angle is on my bike.
You can see this frame has a 74 degree HTA with a 366 fork length. I am currently running a 420 fork. I have searched around, and read the rule of thumb is every 10mm of fork atc will alter the head tube angle by .5 degrees. So based off that, I determined a 71.3 HTA.
But not sure about that. I actually threw on a 375 atc fork with 38mm of rake this weekend expecting a dramatic difference, and it really wasn't much.
Tried some trig on it to attempt to get the angle, but didn't have much luck. The only part I know for sure would be the atc + head tube length. Which isn't enough.
Thanks for any help.