When I first got into tris, I looked at new & used bikes. I noticed that most of the older ('90s through '01-02ish) tri bikes were just about all 78* frames. Since then, most are 76*. My understanding is that a 78* bike will allow you to be lower (ie more aero) while keeping a decent hip angle. The only downside to this I can see is that it may make for a bit more of a stiff neck.
I ended up finding a '95 Klein Aeolus and that’s what I’ve ridden for the past couple of years.
Now, I’ve made an impulse buy and bought a new Javelin Varese which has a 76* SA and I’m a little worried. I’m a MOP and I probably shouldn’t be concerned with this. I think I may just be agonizing over the fact that I’m going to have to get ride of the Klein.
Yes, from what I understand is that 78 gets you more aero (and more neck strain) while 76 would get you a tad less aero (but less neck strain)…in general that is what I understand.
Whatever makes you the most aero AND the most comfortable. I had a 78 now I’m on a 76…though I haven’t ridden the 76 enough yet to know/feel the true difference.
don’t worry about it. saddles have rails for a reason, you can just move it forward on the rails if you feel you aren’t far enough forward–and some saddles are shaped so that you sit more towards the front (and some have longer rails).
With all that said, forward is not necessarily faster, nor is it inherently ‘more aero’.
Get a 30 cm long saddle like a Fizik Arione Tri 2 or a Profile Tri Stryke and slam it forward- that will get you up to 79 degrees on a 76… Just cross your fingers about the steering…