SUSPENSION ADJUSTMENT You Might find something usefull in here

The following information is a basic starting point for exploring the ins and outs (for some of us the ups and downs) of suspension adjustment and tuning. This information can be used by both the sportbike owner and touring/cruiser pilots as all the basic premises apply to both types of bike. The ability to directly translate most of the information will be easier for the sportbiker as this style of bike generally has much more adjustable suspension equipment, although the newest generation of cruisers isn’t far behind. This is intended as a guide only and I can’t be responsible for how this information is used (or misused). Now that the disclaimer of ANY liability is done, let’s get started.

Tires
Setting sag
Weight bias
Dampening adjustment
Glossary


1. TIRES

The first element in your suspension is the tires the bike rolls on. In 9 out of 10 ten cases, if you ask the rider of a particular bike what his tire pressures are, you get a blank look.

When you ask the last time they were checked, a mumbled “I don’t know� is the predominant answer even among those who know what their tire pressures should be.

I have consulted with the area racing school owners and this is the first and most overlooked area for their students.

Each manufacturer has a specific recommendation for tire pressures and the maximum to be used in that tire is marked on the sidewall. The minimum to use is listed in your owner’s manual. Most riders find a happy area between those numbers. The more aggressive your riding style and/or the more horsepower and weight is involved, the more critical the pressures. The pressures need to be checked at least once a week, more often in the spring or the fall when temperature swings can affect tire pressures by as much as 5 psi. They also need to be checked COLD. Checking pressures hot will give you an idea what they should be at temperature only if they start from a consistent cold setting. So check you tires before beginning your day’s theatrics. Be certain to buy a GOOD tire gauge. Some of the better ones are VDO and Camel. Motorcycle Consumer News runs test of gauges from time to time, so they are a good reference source. On our racebikes we use the Accugauge with the whip and stop valve. It is a bit big to carry on the street, but the accuracy and repeatability with the last tire pressure held in the gauge until released makes it less likely I will forget what I’m in the middle of when setting up the tires for the day at the racetrack.

One thing people ask about when they see the bikes is “what are all the numbers for?� I write the pressures on the front forks and swingarm for each bike to make reference easier, as we will sometimes be running up to four different wheel/tire/bike/rider combinations and it can get very confusing. On track days, be certain to talk to the tire rep there to determine the initial pressures to use. Too low a pressure and you can chunk a tire, even on a 600. Too high a pressure and the tire will be slow to come up to temperature and you spend more time in the way. A Sharpie marker is great for this and other things you will cover further on. As one final note, do not use Nitrogen in your tires, as the expansion characteristics are dramatically reduced and the initial pressures will be meaningless.

When is a tire worn? When is it worn out?

In the suspension tuning area, one of the common threads carried through with ALL my riders was if the adjustments weren’t achieving the desired results and you are starting out from a reasonable baseline, put on new tires. New tires are the virtually universal suspension tuning trick. Doesn’t your bike handle better right after you put on new tires? As tires wear, they are subjected to heat cycles, which are caused by the heating up of the tires and their