Counterintuitive Fix

Joined
Jan 28, 2002
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#1
'99 KDX 220 - bought it almost new with stock tires. Tire pressure 16psi here in the rockies to prevent rim cuts. [many enduro riders run 18 - 20 here]. PROBLEM -- severe front end washout / understeer @ 30mph and above on flat corners. Changing front tire made no difference and "climbing" way forwards in corners did nothing. Installed RT Gold Valves [stock HS compression was excessive] and stiffened up rebound. Still very little improvement.
Finally, because the front end was bottoming on steep downhills, I installed .38 front springs [.35 stock] - and the set rear sag @ an excessive 4"............................................
The washout vanished & It now corners like my KX!!! Raising the front / lowering the rear should have exaggerated the [understeer] problem shouldn't it ?
 
Joined
Nov 8, 2003
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#3
Robcolo
When it comes to handling performance everyone instantly blames the suspension as this is usually the only tunable medium. By changing the ride height front and rear you have altered the geometry which has increased ground trail at the front wheel. As you turn the wheel a horizontal torque is being applied to the tyre to make it steer. Increase the trail and you increase the torque. This creates greater leverage on the contact patch of the tyre, producing better grip and more effective steering. you may notice the bars feel a little heavier in your hands now compared to before. Marcus correctly pointed out the other side of the coin. Excessively steep angles reduce the trail and minmize grip.