Advice: Make the gear change

Make the gear change

Each engine configuration has a different type and level of vibration. When the revs and load change, the vibration produced by the engine changes also. Obviously the higher the rpm, the higher the 'pitch' of the vibration and the same is also true for the reverse (the lower the rpm, the lower the 'pitch' of the vibration). What does this have to do with riding a corner? Perhaps we should quote the master (Keith Code) once again ...

"The second problem with going down too many gears and red-lining the engine in a turn is that engine vibration can hide the vibration of the tyres biting into the road. You need this vibration to tell you your traction situation. There is a vibration when the tyres are gripping well and not sliding because they are taking the maximum load. When the tyres begin to slide the vibration is different and much finer.

A HIGH REVVING ENGINE CAN, IN A TURN, CAUSE THE RIDER TO BELIEVE HIS TYRES ARE SLIDING.

"Your sense of traction allows you to know what conditions your cornering speeds and lean angles are creating for the tyres - how well they are biting into the asphalt. The vibration from this carries up through the frame and you sense it at the handlebars, seat and footpegs.

THE CHANGES IN THAT VIBRATION GIVE YOU A PICTURE OF THE TRACTION AT EVERY MOMENT.

If the engine vibration is "drowning out" or smothering that information, it becomes difficult to sense exactly what the tyres are doing." (Source: A Twist of the Wrist by Keith Code). (more here.)

This means that not only does what gear you are in effect how well the bike will accelerate from the turn, it will also influence things like traction and indeed what line you are able to hold. Racers will know that running a bike through a turn (particularly a GP bike which has little or no useable power below the 'powerband') with the engine in too high a gear, will cause it to go wide. The physics behind this are fairly simple, but often confused If the acceleration from the turn is not great enough to overcome the inertial forces created by the steering change, the bike will attempt to continue in it's original path, meaning it will run wide.

Trying to hold a bike to a particular arc without enough acceleration to keep it on line will cause this. If your bike feels like you still have to 'steer' it late in the turn, or you're physically having to 'hold' the bike on line, then you probably don't have enough acceleration for the bike to continue on the new course that you have steered it into. So if we have it in too low a gear and the engine's spinning too high in the rev range, we may limit our ability to sense the available traction. This would make it feel like you're going really quickly and are on the absolute limit of traction, yet right at that precise moment when you have that thought, someone passes you like you're standing still. You are left awestruck and wondering what wonderful piece of equipment or anatomy allows them to do that, when it could be simply what rpm the bike is running at, or, what gear you're in.

On the other hand if you have the engine spinning too low, the bike may run wide on the exit, making you wrongly think that you are going too fast for that corner, as the bike just won't hold the line and always runs wide. So the question must be asked once again; what gear should I use for that corner? The answer is; the tallest one possible that gets the engine spinning in the correct rev range. Have I made this important enough for you yet?

Good luck with your riding...

Steve Brouggy is the owner of the

Contact:
2 / 76 Rushdale St
Knoxfield, VIC 3180
Australia

Phone: 1300 793 423
+613 9763 3338