HOW do you want your bike to feel? Racy and quick into turns or steady and stable? It’s all down to suspension.
Top racers spend more time working on suspension settings than anything else. The ad slogan is spot-on – power is nothing without control.
In part one of this two-part special, MCN enlisted the help of former grand prix racer Ron Haslam to explain the basics of suspension and to show you where to find the adjusters on your bike and how to work them.
Now, we’ve enlisted the help of one of the most experienced men in the suspension business to explain the terminology and effects that adjusting front and rear pre-load, rebound and compression damping can have on your bike.
Richard Brandish is the UK race manager for top suspension firm Ohlins and he’s worked at GP level with stars like former 500cc world champion Wayne Gardner and Britain’s Niall Mackenzie.
He says: " The ultimate aim is to keep both tyres in contact with the ground as much as possible. When you accelerate the front wheel comes up and that’s happening to a lesser extent in corners, too. Our job is to keep those wheels on the ground. "
Achieving this is all down to getting the weight distribution right. Too much bias over the front or rear will result in the bike being unstable under acceleration, braking and cornering.
But get one thing clear from the start. Suspension is always a compromise and there’s no such thing as a perfect set-up. Whatever you do to the front of the bike will affect the rear and vice-versa.
Brandish says: " It’s hard to say if anyone has ever come up with the perfect set-up even for just one race. There’s always something more to be learned. But it’s almost certain that you can improve on the way your bike is at the moment. "
Last week we showed you how to put your bike on a neutral setting and get it back from a handling horror. If you missed it, the basic idea is to set everything on halfway setting between fully-in and fully-out to get a good base to work from.
Once you’ve done that you’re ready to go out and try and feel what your bike’s doing and use this guide to get an idea of how to set up your bike for your style of riding. For example, do you want your handling on a knife-edge or do you want the bike to be as stable as the QEII? Just change one thing at a time and always keep notes of what you’ve done so you can go back and start again if it all goes wrong. Follow Brandish’s tips in the boxes below and right.
•Sag is the amount of suspension travel your bike takes up just supporting its own weight. It should be around 10-15mm at the rear for the road and 5-10mm for racing. Increase the pre-load and the bike will sag less.
•More pre-load will raise the rear ride height, which will make your bike steer quicker and change direction faster. But too much will make it unstable.
•Too much pre-load will also make the rear end more prone to " topping out " , making the tyre skip over depressions in the road.
•Slacken off the pre-load too far and your bike will squat down under acceleration, especially if you have a pillion.
•Too little pre-load can make the bike difficult to turn.
REAR REBOUND DAMPING
•Turn it up a little and the bike will be better-suited to track days, but too much will cause it to run wide.
•Too much rear rebound will overload and chew up the rear tyre when riding hard.
•It will also make the bike unstable, with the back end kicking up over bumps.
•Backing off the rear rebound damping too far will cause the back of the bike to bounce around.
•It will also mean the rear tyre isn’t being worked hard enough, so it will take longer to reach the optimum temperature for maximum grip.
•Lower the rebound damping too much and the bike will push the front end wide under power.
REAR COMPRESSION DAMPING
•This controls the rate at which the shock is squeezed – wind it up too much and you’ll be bouncing out of the seat over bumps.
•Too much rear compression will put the tyre under too much stress as you put the power down.
•Get it spot-on and the bike will track straighter and hold a tighter line.
•Back the rear compression off too much and the rear of the bike will squat down, causing understeer.
•It will also cause the front tyre to go light. The result is that you will run wide in corners.
•Wind it off too much and the bike will bottom-out over bumpy roads and wallow around under power.
•More pre-load stops the forks diving under braking but be careful as too much makes the front more likely to lock up under heavy braking.
•It also pushes more weight on to the rear of the bike, which gives better traction and allows you to get on the throttle harder in a corner.
•Overdo it and the bike will not turn as well or as quickly as there’s less weight on the front tyre.
•This gives more sag at the front end and puts more weight over the front tyre.
•You will achieve more feel from the front when turning in to corners, especially under braking.
•Go too far and the forks will dive too much under braking. You might even find yourself doing an accidental stoppie.
FRONT REBOUND DAMPING
•Turning up the damping will firm the bike up for a track day, but you need a steady rise from the forks otherwise the front end could wash-out.
•Too much front rebound will cause the front tyre to hug the road and not let forks react to bumps.
•Overdoing it will also cause the bike to be slow-turning as it can’t recover from bumps quickly enough.
•Back it off too much and the forks will spring back too fast, unloading the front tyre too quickly under braking.
•Too little rebound damping will cause the bike to jump around at the front and may lead to tankslappers.
•It can cause the bike to run wide in corners and make it harder to hold a constant line through bends.
FRONT COMPRESSION DAMPING
•Wind it up a bit and your bike will dive less under braking and work much better on smooth roads and track days with much more feel from the front tyre.
•Too much compression will firm up the ride and turn a bike from a smooth ride in to a bone-shaker.
•Overdo it completely and the forks won’t compress quickly enough, causing instability especially over bumpy roads.
•Back the compression damping off and your bike will cope with bumps better and use more of its travel to make things smoother.
•Turn it off too much and the front tyre will load up under braking and the forks will move too freely.
•The forks may also skip over bumps rather than soaking them up.