Road race ace Ron Haslam’s years of experience of tracks and public-road circuits have taught him something that’s a mystery to most of us – how to set up a bike.
Suspension changes are the only worthwhile modifications most riders can make to their bikes without bolting on new parts.
But most of us haven’t got a clue about where to start – unlike Haslam.
Modern sports bikes usually come with a baffling range of possibilities for adjusting rebound and compression damping and spring pre-load at both ends of the bike.
Setting them up right is so daunting the adjusters are often left alone for fear of making the bike worse, not better.
Haslam is capable of setting up bikes which have proved too much for other riders. And his expertise can help you get your suspension to suit your riding style.
To set up your bike you need to be methodical and take notes. Every time you make a change, test your bike over the same stretch of road in the same conditions.
And to be sure you are comparing like with like, wear the same riding kit too, as this can affect how the bike feels. And don’t concentrate so much on the bike you forget about the other traffic!
It’s rare for manufacturers to get it wrong these days, and the stock settings usually work well for most people, though they’re generally set up on the soft side, says Haslam.
If you’re fast
Faster riders can benefit from firming up the bike, but note that the best results often come with increased compression damping and reduced rebound damping.
Compression damping controls how fast your suspension dives under braking or when it hits a bump. Rebound controls how fast it bounces back.
You can start your adjustments before riding the bike. First, increase the rear pre-load by 2mm – usually two turns if it’s a screw adjuster.
Then bounce the bike. You can learn about the rebound damping and sag from this, but not compression damping.
Note how the bike returns from a bounce with the rebound on full. It should be noticeably slow. Then back it off about four clicks and try again.
Keep doing this to the point where you can detect the damping working.
This is a good starting point. Go too far and the bike will spring back up with no obvious resistance from the damper. If this happens, increase the damping again.
Sag is the amount a bike settles on its springs when it is standing still with no rider aboard. On road bikes it’s easy to set – 25mm at the front suits most bikes.
At the rear, 125cc machines need no sag at all, so the shock and forks will still be at the top of their travel when the bike’s standing.
Most 250s need very little, while a 750 should have about 10mm of sag. To check it, lift the bike at each end and get someone to measure how far it moves up.
Heavier bikes need more sag, but 15mm is usually enough. Change it by altering the pre-load.
Compression and rebound: trial and error
Compression damping should be set to its firmest position as a starting point – usually with the adjusters fully in, but on some bikes they’ll be fully out!
You’ll need to ride the bike to set this properly, and it helps if you can pop wheelies! As the front wheel lands again the forks should feel very solid.
Back off the damping slightly, then try again, and keep doing this until the solid feel goes away. This will be about right.
Alternatively, ride over a set of cat’s eyes at a narrow angle. With the compression damping on full you’ll feel the tyre moving or skipping across the road.
Back off the damping until you can still feel the thumping but without the front end moving.
Rebound at the front can be checked on the move by braking hard then releasing them suddenly.
If the front doesn’t feel like it’s springing back, the rebound damping is too firm. If the front flies up, it’s too soft.
You’re unlikely to need to change the springs at the front unless you’re very small or large, and on road bikes you shouldn’t need to worry about altering the level of the oil in the forks, which is a way of adjusting the change of spring rate.
If you want to know exactly how much your forks are moving, put a zip-tie round one leg above the dust seal. This will record how far your forks have moved.
At the rear it’s more difficult, but you can learn something by sprinkling talcum powder on the shock’s bump-stop rubber.
If there is a big imprint on it after a ride, it’s being flattened too hard and the pre-load needs increasing. A very small imprint is how it should be.
But you should not alter things if you’ve hit a big pot-hole or done anything else unusual. Just tune the suspension for normal riding on unexceptional roads.
To increase the rate of turn, increase the ride height by 10-15mm.