Mashka, I thought that your favourite type of cycling is riding for a long time. Why are you going so hard?
Max heart rate achieved really depends on the individual. Imagine two individual with identical physiological characteristics except for heart volume and just for the sake of argument that both can put out the same amount of maximum power. Now obviously, the guy with the bigger heart is simply going to pump his heart less at maximum power.
The thing is for any individual, the larger and stronger the heart becomes with training, it’s only going to beat less for a certain power output. If you have achieved a new high HR compared to before, you need to know also whether you have achieved a new high in power as well because HR can continue to rise without getting any gain in power.