Turning

This column will deal with a question that is most frequently asked:  why doesn't my bike turn well? 

The answer is not simple because you may be experiencing one of two different problems, with multiple potential cures for each.

First let’s say your turning problem is that the bike doesn't turn tight enough – i.e.- it runs wide in a turn (I refer to this as understeering).   Here are some possible problems and solutions:

• The front forks may be too long, causing the rake – i.e. the angle of the forks – to be too far from vertical.  This can be caused by the fork being too far down in the triple clamps, or by fork springs that are too stiff.

• Fork compression dampening may be too stiff or rebound fork dampening may be  too fast or soft, which can cause too much fork rake.

• Too much rear shock race sag or too soft of a rear shock spring can cause too much fork rake.

• Rear shock compression dampening could be too soft or rebound dampening too slow or hard, which can cause too much fork rake.

• Tire selection could also contribute to the problem – a too soft compound tire on a hard ground track.  Different tires, makes, and/or styles may affect the handling.

• Riding style can cause the bike to run wide – i.e. a rider sitting too far back on the bike, not powering through a turn, pulling in the clutch,  or having a foot touching the ground.  During a ride, you can’t correct a bike’s setup problem or a tire problem, but you can make adjustments in your riding style.  Possible changes include moving further forward on the bike and/or getting on the gas to get the back wheel to step out farther than the front wheel (making the front of  the bike turn tighter).

The second problem may be that the front end turns too tight – i.e. tucks in (I refer to this as oversteering).  Here are some possible problems and solutions:

• The front forks may be too short, causing the fork rake to be too steep from vertical.  This can be caused by the fork being too far above the top triple clamp, or by fork springs that are too soft.

• The fork compression dampening may be too soft or the fork rebound dampening too slow or hard, which can cause the fork rake to be too steep.

• There may not be enough rear shock race sag.  If your rear spring is too stiff, if your shock compression dampening is too stiff, or if your rebound dampening is too fast or soft, the back end will be too high, causing the fork rake to be too steep.

• Incorrect tire selection or tire pressure that is too low can cause the front end to knife or tuck in a turn.

• Rider position (too far forward) or too much throttle can also cause the front end to tuck in.

As you can see, there are many variables and I have not given you any absolute answers.  You have to come up with the best compromise or balance for your situation.  I have had my bike exhibit all three traits in a single day:  it turned perfectly, over-steered, and under-steered.  Therefore, I had the perfect balance for the course.

To summarize, you can’t change your setup or tires during the race, only your riding style.  Since the terrain is constantly changing you will have to look ahead, size up the terrain, and make adjustments to your riding style to maximize your results. If your bike turns wide the majority of the time, or tucks the majority of the time, go back to the section covering your problem and change the setup to achieve that perfect or near perfect balance. 

Until next time, here’s to smooth riding.