DAUNTED BY YOUR BIKES MYRIAD SUSPENSION ADJUSTERS? FILLED WITH FEAR AT THE PROSPECT OF TWEAKING AND TWIDDLING THOSE CURIOUS LITTLE SCREWS? THINK THAT PRELOAD MEANS PACKING YOUR PANNIERS THE NIGHT BEFORE A TOURING TRIP? RECKON A SETUP IS THE SOLE PRESERVE OF CORRUPT COPPERS? LOSE YOUR TECHNOPHOBIA, DESIGNED TO HELP YOU GET THE VERY BEST FROM YOUR BIKES SUSPENSION.
PRELOAD The amount of tension on the suspension springs. SAG The amount the suspension moves when the bikes weight is lifted off it. LOADED SAG The amount the suspension moves down when the rider sits on the bike. COMPRESSION This controls the downward movement of the suspension REBOUND This controls the upwards movement of the suspension. TRAVEL This is the distance the suspension travels while the bike is being ridden. FORK HEIGHT The amount the fork legs protrude through the top fork yoke. RIDE HEIGHT The distance between the rear axle and the tail piece. STEERING HEAD ANGLE This is the angle of the forks from vertical.
996 SUSPENSION PB RECOMMENDED SETTINGS
REAR SHOWA Static Sag 10mm (measured vertical from wheel spindle)
Loaded Sag 30mm
Compression Three turns
Rebound 1.5 turns
Ride Height Standard
Tyre Pressure 29psi Track 39psi Road
Static Sag 22mm
Compression 10 clicks
Rebound 8 clicks
Fork Height 19mm
Tyre Pressure 31psi Track 35psi Road
Preload Six rings showing
Steering Head Angle Steep position (one degree less than standard)
Bike set up can seem daunting at first because of the number of variables rider weight, riding style, the list goes on. Its impossible to give perfect settings that will work for every rider on every bike every time. Whats possible to acquire is an understanding of general suspension principles, which combined with the specifics of your own bike will help you master your suspension.
So this month we take Ducatis 996 round the roller coaster ride that is Oulton Park, followed by a rigorous road workout, to find the best all-round setup.
The starting point for any setup on a bike is to set the preload on the front and rear springs, because this controls the ride height and steering geometry.
Sag is the amount that the suspension travels down from its fully extended position when the bike and riders weight combined settle on it. Static sag is with the bikes weight only and loaded sag is with the rider on the bike.
Push down on the forks to settle them. Mark the stanchion with a felt pen where the dust seal is sitting. Next, get two people to lift on the bars so the front wheel is just off the ground and measure the amount the forks have travelled down. This is the sag, changed by adjusting the spring preload (more preload, less sag).
REAR STATIC SAG
On the Ducati there is no really easy place to measure this. So mark a point on the can directly above the rear axle, using that felt pen again. Then measure the distance from the centre of the rear axle to your pen mark. Next lift the rear of the bike and check the distance again. The difference between the two figures is your static sag. Bike should be on the ground. Not on a paddock stand.
REAR LOADED SAG
Noting the static sag measurement, sit the rider on the bike with his feet on the footpegs and measure the amount the rear moves down, then add this to the static sag and you have your loaded sag. This is changed by adjusting the spring preload. Again more preload, less sag.
These adjust how fast the suspension compresses (goes down). The 996s adjusters are found up through the bottom of the front forks and on the shock reservoir at the rear. All adjustments are made by turning the adjusters all the way in and then counting the number of clicks or full turns out. Screwing adjusters all the way in gives maximum damping. Its important to note the position of the adjusters before making any changes. Count turns/clicks.
These control how fast the suspension rebounds (comes up). These adjusters are found on the tops of the forks and on the bottom of the rear shock. They are adjusted the same way as the compression adjusters.
This is easy to check and provides important information for ironing out problems. Put a cable tie around one front fork stanchion and the rear shock shaft, then slide them up against the moving part of the units. Ride the motorcycle and check the amount of travel used (no wheelies or stoppies as they give a false reading). As a general rule five to 10mm from full compression is about right. If there is more than 10mm reduce compression damping followed by spring preload. Less than 5mm and the reverse applies. If you cant seem to get this right, consult someone like Maxton as the spring weight or damping may be wrong for your situation.
These are often over-looked when a handling problem arises, they can affect handling more than you would imagine. Pressures should be checked regularly and altered for track work. Tyre temperatures run much hotter during track use, so to compensate for this lower pressures are used.
We tested the 996 with a 190 and a 180 rear tyre and found the 180 allowed higher mid corner speed and increased stability when driving hard out of turns. We put this down to the rounder profile of the 180 which gave a bigger contact patch while turning and less tyre flex.
On most road bikes changing this is not an option, but Ducati give you choice of 23.5o or 24.5o . This should only be altered after all the other changes have been made and you are comfortable on the bike. If the Duke displays any instability problems they need to be sorted out first, as this steering head angle change will magnify these characteristics.
To make this adjustment remove the locating dowel and loosen the two clamp bolts, then with a C-spanner turn the castellated nut under the top yoke clamp 180o. Refit the dowel and tighten the clamp bolts. The steering damper then needs repositioning to the forward position. The change to 23.5o will making the bike steer into corners faster and hold a tighter line through turns, the downsides are less straightline stability and a steering lock that doesnt work, because the position of the top yoke has changed.
This is the position of the forks in the yokes, its measured with a ruler or by the grooves in fork top to the top yoke. Increasing the measurement by moving the forks through the clamps has the same effect as reducing the steering head angle. Always measure from the same position on both forks. When making these changes check for clearance between front tyre and radiator at full compression.
On the 996 this is adjusted by changing the length of the tie-rod to raise or lower the ride height. The standard setting is with the rod at its shortest i.e., lowest ride height. Measure as in static sag then adjust rod and re-measure, changes should be made in five to 10mm increments. Raising the ride height has the same effect as reducing the head angle.
SETTINGS THE STANDARD
On standard settings there was very little feedback from front or rear ends and the bike was very twitchy over bumps. As we went softer on compression and rebound the feedback got better and the bike became more stable. When we went too soft the rear wheel chattered under hard braking so we increased the front compression and rear rebound.
Once we were happy with the setup it was time to make it turn, so we reduced the steering head angle. This transforms the bike into making it possible to brake late into turns and still hold a tight line. The downside to this was the extra load on the front end caused the forks to bottom and the front wheel to chatter under hard braking. More front spring preload and compression damping had the problem sorted. The final problem we had was the rear end squirming exiting turns especially coming onto the start/finish straight. After no improvement was gained from stiffer rear suspension settings the 180 rear tyre was fitted. The increased grip and reduced the tyre flex making accelerating out of turns hard much less scary.
Because of the 996s power characteristics its essential to carry loads of corner speed to achieve quick lap times, but unfortunately the standard Ducati suspension settings dont encourage this kind of behaviour.
The stiff setup makes the Duke twitchy and unwilling to hold a tight line. Our setup makes the bike more supple so it soaks up the bumps and this in turn allows you to run less steering head angle so the bike will turn.
The narrow rear tyre also helps to increase corner and stability. The original fitment springs on the 996 are slightly too hard, this means they will work better with a heavier rider (Maxton recommended softer springs front and rear). But with our final setup they coped well on track and road, solo and two up.
For serious track use a steeper steering angle (i.e., more rear ride height combined with the steepened front) could be used but, for a good all-round track and road combination the set-up described here should get most Ducati riders out there doing Foggy imitations.