Now I'm no expert, what I know is from reading and listening to other people with knowledge and experience. A couple of good sources of info, are the Ohlins web site and the Sportrider magazine web site.

Its almost impossible to cover all suspension setups on all types of bikes. The following is generalized and based primarily on sports bikes. If you don't have all of the adjustments mentioned below the main thing you can do is get the suspension balanced between the front and the rear.

Some Terminology

Preload

Preload is an adjustment of length of the springs in the fork and/or over the rear shock(s). As the name suggests it pre-loads the spring, in other words partially compresses the spring.

Many people confuse the role of the springs and the role of the damping system. The springs compress and rebound in proportion to the force applied to them by a bump/hole in the road and acceleration/braking forces. Without any damping the spring would continue to alternately compress and rebound (bike wallowing up and down) at a rate related to the spring rating and the size of the force applied to it and make you sea sick.

Preloading the spring means that the spring will not start to compress or rebound until a certain minimum force is applied to it. The use of the preload adjusters on a bike is to set the sag (see below).

Sag

Sag is the amount the spring(s) compress under weight. Free sag is the amount the springs sag under the weight of the bike alone. Rider sag is the amount the suspension sags with the rider in place on the bike. Both are important and should be set before any damping adjustments are made.

Damping

Damping damps the compression and rebound of the spring(s). That is to say that, the damping controls the rate at which the spring compresses and rebounds. The idea being to ensure the spring only compresses once and rebounds once for each force applied to it. Damping is what stops the springs from endlessly compressing and rebound after a single bump. Damping typically consists of fluid (usually oil) being forced through holes and/or forcing back shims.

Compression damping slows the compression of the spring, rebound slows the rate at which the spring rebounds back from a compression.

Ride Height

Changing front or rear ride height will affect both the weight bias of the bike (proportion of weight over the front and rear wheels) and the angle of the front suspension. In general, dropping the front (or raising the rear) of the bike will make the bike steer "quicker" but will reduce high speed stability. However, its more complicated than that, with effects on traction etc.

Setting Up Your Suspension

You will require two other people, a tape measure, some adhesive tape, paper and pen, whatever tools are used to turn your adjusters (typically a spanner and a flat head screwdriver) and a stretch of road with a mix of tight and open corners, straights and some bumps.

Before you start

Ensure your tyres are at the pressures you would normal have set set to for street riding. If your tyres are badly worn, particularly if they are squared off, then you may be wasting your time adjusting your suspension. You can probably set the sag and not have to worry about it again, but its pointless chasing damping issues if your tyres are a bigger issue.

The First and Most Vital Step - Setting Sag

Don't even think about fiddling with the damping adjusters until you have set up the sag using the preload adjusters. This step sets the suspension for you weight. You should only have to do it once for street, unless your weight changes significantly.

Write down what your current preload settings are. Front preload is usually measured as so many lines visible at the top of the fork legs above the upper triple clamp. Rear (shock) preload is usually measured as mm of thread showing at the top of the shock or if with hydraulic adjustment, so many clicks from fully in.

Some people suggest that before setting your sag you should adjust all rebound and compression damping to fully out/soft however others either do not mention it or suggest it isn't necessary for us mere mortals.

While Friend No. 1 steady's the bike from the rear, get Friend No. 2 to lift the front of the bike so that the front tyre is off the ground and the forks are hanging under the weight of the front wheel. Measure the length of exposed fork slider (shiny part). Call this F1 and write it down. Return the bike to the ground and with Friend No. 1 still steadying the bike, bounce the front suspension lightly a couple of times (Don't hold the brakes on while doing this). Now measure the length of exposed fork slider and write this down as F2. Now repeat the procedure for L2 but with you (the rider) on the bike in normal riding position. Get Friend No.2 to measure and record the length of exposed fork slider as F3.

F1-F2 = Front static sag and should be in the range 15-30mm F1-F3 = Front rider sag and should be in the range 35-50mm Alternately front sag can also be defined as F1-(F3+F2)/2 with an acceptable range of 30-35mm ....or I've also heard that rider sag should be 25-30% of the full uncompressed length of the springs. Which typically means around 30-35mm for a sports bike.

If you mainly ride on smooth roads and/or prefer a firm ride then you would be targeting the lower end of the range, but if ride more bumpy roads and/or prefer a softer ride then aim for the longer end of the range.

If your sag is outside the above above ranges then you need to adjust the preload adjusters. They are usually the spanner adjustable knobs at the top of the fork leg, above the upper triple clamp (with the screwdriver adjustable rebound adjusters inside of them). Adjust the preload and re-measure F1, F2 and F3 as many times as necessary until you reach the required static sag and rider sag measurements. If you run out of adjustment before you reach the required sag measurements than the forks springs do not suit you and need to be replaced with a spring of the correct rating. Talk to a suspension specialist to ensure you get the right springs.

Now repeat the same procedures on the rear of the bike with Friend No. 1 steadying the bike from the front. R1-R2 = Rear static sag and should be in the range 10-20mm R1-R3 = Rear rider sag and should be in the range 25-40mm Alternately front sag can also be defined as R1-(R3+R2)/2 with an acceptable range of 25-30mm ...or I've also heard that rider sag should be 25-30% of the full uncompressed length of the spring. Which typically means around 25-30mm for a sports bike.

The rear preload is usually adjusted by moving the two threaded rings on top of the spring. The upper ring is a lock nut while the lower ring adjusts the preload. Spin the upper ring up and clear of the lower ring then adjust the lower ring. When you have a final suitable preload adjustment spin the upper ring down onto the lower ring. Some shock absorbers have a hydraulic preload adjustment which allows preload to be adjusted by turing a knob - much quicker and simpler.

Again if you can not achieve suitable sag measurements with the available adjustment then the spring (but not necessarily the shock absorber) is not suited and should be replaced. Talk to a suspension specialist.

While you have some friends handy and trained up, you could also determine some settings for carrying a pillion and for the track. If your usual pillion is available repeat the above sag measurements and adjustments with them on the bike when the rider is on. If they aren't available or you don't have a single regular pillion then any person will do to get a better pillion setting than with rider alone or by just guessing. Record these settings for use when you are carrying a pillion in future. For track use preload is typically stiffer (less sag), particularly for the forks and so the acceptable ride sag for the forks can be reduced to match the rear. Again re-measure and readjust to get track preload settings and record these for use at the track.

Return the bike to your new street preload settings

Setting the Damping

While there are guidelines for getting good rebound and compression damping settings, ultimately the best settings are those that you prefer the feel of (unless you are racing and chasing lap times rather than rideability). So getting your favourite damping settings requires plenty of test riding. Find a road that has a variety of bend styles, straights, and road surface conditions that you would encounter on a typical ride. Pack the necessary spanner(s), screwdriver(s), paper and a pen where they can be easily accessed. Then follow the one of the procedures below.

Rebound has more effect and is therefore more important to get right first .... and you thought compression was all that mattered didn't you!

Some of the adjusters can be hard to find, so if in doubt, check the owners manual. It should also have the stock settings listed.

Method 1 (Long, involved and potentially confusing).

• Record standard/existing settings so you have something to go back to if it all goes wrong!!!
• Wind all damping adjusters out to fully soft. Test ride the bike and write down your experience.
• Adjust the front rebound (typically at a screwdriver adjustment at the top centre of the fork legs) in to fully hard, test ride and write down experience.
• Adjust the front rebound to halfway, test ride and write down experience.
• Decide if you prefer the softer or harder side of of half way.
• Adjust to half way between the halfway point and the full side you prefer (ie go to either 1/4 fully in or 3/4 fully in).
• Write down settings, test ride and write down experience.
• Continue to "halve the difference" until you have a setting for front rebound.
• Repeat process for front compression (typically a screwdriver adjustment at the bottom rear of the fork legs), rear rebound (typically a screwdriver adjustment at the bottom of the shock) and rear compression (typically a screwdriver adjustment at the top of the shock on a remote reservoir). Then without adjusting the other adjusters go back to the front rebound, then each of the other damping settings as each will have some effect on the other. This may take 2 or 3 complete cycles to get to a final setting. Then bounce the bike by pushing down on the rear of the tank (without applying any brakes and ensure both ends of the bike act together. If the front and rear suspension action isn't balanced you don't have a bad set up.

Method 2 (shorter, less involved, but still potentially confusing)

• Record standard/existing settings so you have something to go back to if it all goes wrong!!!
• Adjust all adjusters to halfway between fully hard and fully soft.
• Starting with front rebound turn a few clicks toward soft, record settings, test ride and write down experience.
• Adjust rebound to a few clicks on the hard side of halfway, record settings, test ride and write down experience.
• Which of the last two settings was best and which was second best?
• If soft was best and halfway second then go to a few clicks softer than the soft setting.
• If halfway was best and soft was second, adjust to the partway between these two settings.
• If halfway was best and hard was second, adjust to the partway between these two settings.
• If hard was best and halfway was second, adjust to a few clicks harder than the hard setting.
• Record the setting now, test ride and write down experience.
• Which three settings were best now?
• Keep chasing a preferred setting in this way.
• Then repeat for rear rebound, front compression and rear compression.
• Then without changing anything else go back to the front rebound, then rear rebound, front compression and rear compression once more. Method 3 (simpler and more scientific?) - thanks to Sport Rider magazine
• Set all damping adjusters to their halfway point.
• Bounce the front suspension (without applying the brake), adjust front rebound to full hard position and bounce again, set to fully soft and bounce again.
• Notice that the suspension will now rise (rebound) above the normal resting point before settling back to the normal resting point.
• Adjust the front and rear rebound until each end just rises and stops at the resting point from a forceful shove (no brakes applied) without overshooting, but does not take more than one second to get there. Err on the side of too hard if its hard to pick exactly.
• Write your new settings down.
• Go for a test ride. Write down how it felt.
• Starting with the front rebound. We know its on the too hard side of ideal so turn a couple of clicks softer. Write down the settings, test ride and write down how it felt - better or worse? Fine tune until you've got it right. Next, do the same with the rear rebound.

Now adjust the front compression, then rear compression using something similar to Method 2 above. But only on the compression adjustment, we've already got the rebound sorted.

Whichever method you have used, when you push down on the rear of the tank on your bike it should compress and rebound evenly front and back. If so then you now have found YOUR perfect street set-up. Now all that's left to do is find that patient pillion for pillion damping setting testing (actually this should not be far from your rider only setup, then a day at the track to get a track setup (you would expect things to be slightly harder than your street settings).

Too Lazy For All That (Like Me)?

If all of the above is just too much to contemplate then the Sportrider Web site has a list of recommended settings for an amazing number of bikes. Unfortunately, the list doesn't indicate the weight of the rider the settings were determined for so be careful of taking them as gospel, particularly if you are outside what would be considered average weight ... for American riders.

Sean Hawley