Audax rides

I generally ride at a pace that means I could happily carry on and on even after the ride has finished. Irrespective of the distance of the ride.

In other words, I'll tend to ride the first 100km of an Audax at the same speed regardless of the overall ride length (whether it's just 100km or some stupid 1000km+ ride).

Obviously there are some rides where I have to push it because it's very hilly, the weather is crap (constant headwind), I'm on fixed or, more likely, all of those things. At the end of those rides I'm unlikely to want to even see my bike again and slumping on a floor is all that I'm good for.

Many others approach it differently and judge the ride well so that they're a lot more spent at the end of it. Sure, they're generally faster/fitter anyway, but I've seen people at the end of a 300 who could barely consider doing another 20km whilst I got back on my bike and did another 100km to get home.

The more rides you do, the more you get to understand how your body reacts to all this stuff. You also stop less frequently (between controls) and take less time at controls, which all makes for a faster ride without riding faster. Eating on the bike between controls so that stops are just a rest, refill and a restock rather than waiting for slow service in a cafe. You've noticed this, to an effect, with your 300. Most people do their fastest 200 on a 300 as the controls are less frequent and the focus is on the bigger distance.

The more cycling you do the faster you'll get too, even if the improvements are slower than targeted training. Audaxes are rarely just all plodding along at the same pace. Hills, headwind, etc make for varied intensities required == not just hours of Zone 2 training.