Gear position plays a big part when riding a motorcycle, everyone knows that.
If you use low gears and high RPM when you are NOT riding fast, it’s not very smooth. Every little adjustment on the throttle makes the bike either accelerate or decelerate quickly. A nightmare for a passenger on a long road trip.
I have noticed that the faster a rider is on a race circuit, the lower (not higher) the gears they’ll use for the slower turns/ hairpins turns. For example, a slow or medium level trackday rider will usually use second gear for these slow turns and hairpins, where a faster rider will use first gear (referring to +/- standard road gearing) and this works well for both parties.
The later a rider brakes for a turn the more helpful engine braking is to help slow the bike down on entry, take some load off the front and help the bike turn tighter. Those same fast riders will also want the engine producing power immediately when it’s time to accelerate from the turn.
When leaned over in a corner, the more the rider opens the throttle the more the bike gains speed and runs wide. Obvious right? Well the same is true for the opposite. The more the rider closes the throttle at full lean the more the bike reduces speed and turns on a tighter arc. When a rider is riding fast but the gear position is high (RPM low), when the throttle is opened the bike will run wider as usual but with less response, and when the throttle is reduced it will still reduce speed and turn tighter but with only half the effect it would if the gear position was one gear lower. Basically, once a rider is going fast enough they will need this extra response. Until then they won’t .
When slower riders go into a slow turn in second or even third gear, they’ll have no trouble slowing the bike down because they weren’t approaching the turn crazy-fast in the first place. Then when they release the brake the bike does not have the same inertia pushing straight ahead at this lower speed so the extra engine brake is not needed then either. In the centre of the slow corners though, the higher gear position will usually make the rider carry just a little too much speed because the higher gear does not reduce the speed enough , which often means a little wider arc through the turn and possibly running out to the edge of the track sooner. That’s not a big problem when riding at a slower lap time. The positive of the higher gear is that it feels nice and smooth and easy to manage. Usually when the slower riders try 1st gear (because they asked what gear I use) they hate it. It’s not smooth, its difficult to manage and the extra two gear changes (one on the way in, one on the way out) plus instability, wheelies with the higher horsepower, a jumpy and over sensitive throttle response, overall making it hard work. But, once the rider is more experienced and lap their lap times are reduced to the point of “fast trackday rider / slow racer”, this extra work is essential if the rider wants to advance further.
The faster/ more experienced rider will select the lower gear during braking in the corner entry, blipping the throttle while using a minimum of clutch to make the transition smooth but not freewheeling longer than necessary. Hard on the front brake during the last part of corner entry while reducing the brakes the extra engine brake now takes a little load off the front tyre and actually helps pull the bike around on a tighter arc than was previously possible or believable … allowing thoughts of an even higher entry speed next time. With practice, care and some finesse, the lower gear also makes it quick and easy to reduce the speed in the centre of the turn, so the bike stays next to the paint on the inside of the turn a little longer/later, and this helps set up the exit making it possible to stand the bike up earlier and use the power now available from the low gear position/high RPM to launch the bike off the tight turn. Often it’s easier to sort-shift (change early) to 2nd gear before the bike produces a little too much power than is possible to control, but… the time is already won.