IV - THE MAIN PROBLEMS Handling difficulties
Load distribution has a significant impact on occurrence of vehicle handling difficulty.
The presence of added or modified accessories: Topbox, bags, streamlining, windshield, handles, seat, non-original handlebar ends, etc...
The general condition of the motorcycle:
Uniformity of spoked wheels, damaged wheels. Bearing wear. Fork: Alignment, seals, oil, etc... Steering column. Swingarm. Shock absorber. Damaged frame, engine mounting
But the tyres are not always the cause...
When the tyres are partly responsible for handling problems
Weaving KICKBACK Shimmy Vibration
LEVEL OF WEAR Big effect Some effect Some effect Weak effect INFLATION PRESSURE Big effect Some effect Some effect No effect STRUCTURE: BIAS/RADIAL Big effect Some effect Some effect No effect CENTERING OF TYRE ON RIM Big effect Some effect Some effect Big effect BALANCE OF WHEEL AND TYRE ASSEMBLY Weak effect No effect No effect Big effect
It is not always easy to determine the causes and origins of various handling problems. Handling problems may come from tyres (type of tyre, incorrect pressure) and/or a change to the vehicle (accessory, load, etc.). Tyres are not always the cause.
Handling difficulties defined
weaving kickback shimmy vibration
It is a wavering movement, of variable extent occurring on straight lines or bends, usually starting at an average speed of around 140 kph (90 mph).
It is a sharp sideways movement at the front (fork moves back and forth), it is intermittent and very fast, occurring particularly whilst accelerating. It is triggered by an external source such as a bump or join in the tar.
It is a sideways, continuous oscillation of the fork at low speed (<100 kph / 60 mph) usually whilst slowing down.
It appears at the level of the fork / wheel assembly usually at speeds of around 90 to 130 kph (55 to 80 mph).
MICHELIN 2wheel - 176
Technical data