35km/h may be a push but 30km/h is fairly easy to maintain for me. Perhaps you have a different style of bike? Mine is a city bike with very narrow wheels.
Your bike might have issues, your posture might not be very aero, you might not be using your gears to maintain an efficient cadence, or your fitness isn't as good as you think. Play around with the following calculator: https://www.gribble.org/cycling/power_v_speed.html
Just using the default numbers of a 75 kg rider on a 7.7 kg bike with a frontal area of 0.5 m^2, C_d = 0.63, and drivetrain loss of 2%, maintaining 30 km/hr requires approximately 150 W of output. 35 km/hr, that goes up to 225 W. A functional threshold power (power one can sustain for an hour) of 200 W isn't exceptional.
Anecdotally, I have a lot of weight to lose and I can maintain an average moving speed of 30 km/hr on a mostly flat, 100 km course.
yes, on a mostly flat course i'd be able to keep it up too. maybe i misinterpreted it a bit, but i pictured original commenter cruising at 30+km/h _in london_ (city proper) on a city- or trekking bike.
during the summer my ftp was around 270 (~3.8w/kg) and i had a hard time staying close to 30km/h avg on a local bike path where one does have to stop and slow down occasionally for safety reasons (i.e. real world conditions - even though my computer pauses when i come to a full stop). in the city i can go 30-40km/h on my single speed if i ride on the road in car traffic, but on bike paths that's usually way too dangerous because of the speed difference to other cyclists and pedestrians.
sure, on tempus fugit i can go close to 40km/h for 100km with a TT bike.
Maybe there's some misunderstanding about what I mean by cruising speed.
I mean it in the sense of the speed I pick when the road is clear ahead of me. Analogous to the cruising speed in an aeroplane, which is usually quite close to its max speed, but not quite.
I can sprint fast for short bursts, but 30km/h is for me comfortable to maintain indefinitely. My heart rate will be around 160 vs my resting of 45, max of 200 and 120 when walking.
ok sorry, in that case i misinterpreted you. i thought you meant you were able to keep up 30km/h averages "cruising" point-to-point through london, which, imo, would be a challenging feat for alleycat racers.