Based on Friel's terminology, my biggest limiter is aerobic endurance. To improve endurance, I'm going to make my early A priority race a 75 mile race. Would I be better off continuing with a Base 4 then a Build phase? Right now I only have time for the 3 base phases and 1 build. Would I be better off just staying in base and continuing the volume increase and then after the race start the build phases for the 20-40 mile road races in July and August? Is there such a thing as too much base, especially for a newbie? Thanks.

this makes no sense to me. It's like someone saying their strength is climbing and making their a race a flat crit. race to your strengths.

I think you need to look up the definition of aerobic.

But the problem is that newcomers often don't actually know their strengths.

To the OP, I think you can never have too much aerobic endurance - fwiw before I got inured my plan to peak for a 90-mile RR was to do 3 base blocks, two build blocks.

Mikey's back!

And in flying form, I might add!

fwiw, I just ride a lot and take a short break/slow ride when I'm tired. I don't do much VO2 max or any anaerobic training at this point in the year, but I don't obsess over blocks and crap like that.

hey I haven't really made an ass out of myself too much recently, so I figured I should pick up the pace.

You are over thinking all of this. Yes, fitness is important in bike racing, but knowing how to ride a race is even more important. I'd suggest starting with the "sticky" started by botto at the top of the forum.