Myths and Misconceptions

Are Aftermarket Shocks the solution to poor suspension action?

You have to establish what level of performance you want to gain by modifying the suspension. For the rear shock, a new spring and a revalve will take a lot of the harsh feel out of the shock, and will improve plushness and help control squat. These mods will give you a superior shock when compared to the standard unit. The aftermarket shock will have an advantage, mostly in the way the adjusters work, the piston design and the slippery surface finishes.


My suspension appears to handle better two-up than solo?

People often say a bike that is underdamped and undersprung works better with more load. It actually doesn't but will move around less. The suspension action will still be harsh and to get the best you would need to re-spring and at least revalve or consider PMA options. The harshness will be masked by the extra load and give the impression of a better ride. Basicly you need to decide what application/ riding style is most important to you (e.g. ride-day, sports, touring) and from there you can narrow down the equipment necessary to do the job.


Steering is too light and shakes - I need a steering damper?

Most headshake problems, especially with an application of sports/touring come from the rear shock. It unloads the front as the back squats too far, and this causes headshake in most situations.

A steering damper's job on a roadbike is to control side-to-side oscillations of the front wheel (headshake). As an extreme example - consider a Race Bike where the front wheel will very likely come off the track. If it hits a bump when it comes down it can cause headshake; the job of a steering damper is to stop these oscillations. They may be of a particular amplitude to not self-cancel. The steering damper does this for you. When the suspension is correctly set-up with springs and damping to suit the rider and the application, for most road and not-too-serious track conditions, the steering damper is not needed.


Nitride treatment to forks makes a substantial difference?

No, while the surface is a lot more slippery, it doesn't produce massive real-world differences. It also means you can't repair stone damage - it just will not polish up like chrome, it's too hard. The surface treatment demands closer tolerances, better alignment or the advantages will be mostly lost in a sloppy front end. So if you want the best in low friction and you put a high end coating on, then the rest of the fork must be brought up to a similar high end level of engineering.


Does the rear actually RISE under acceleration?

"Does the rear actually RISE under acceleration? If the swingarm were not connected to the bike via a rear shock, the force of the drivechain would obviously pull the swingarm away from the tail unit and it would spin around the swingarm pivot towards the front wheel. If the bike is moving, will the momentum of the rider force the rear to squat? or will the force of the drivechain still make the rear end rise?" (Jack Anstice)

Graham Byrnes -
Yes, but it depends. It's not just the chain, but the fact that the tyre is pushing back against the road and so the road is pushing the bottom of the tyre forward, equal and opposite reaction, Newton's 3rd law. Which is after all what causes the bike to accelerate.

Now if you look at the swingarm, it slopes down to the rear axle. So when the tyre is pushing the axle forward, it tries to move forward underneath the swingarm pivot, which lifts the back of the bike. This is easy to check; squeeze the front brake and start feeding out the clutch as though to do a burn-out and the back will rise. This is called "anti-squat" geometry. If you use the rear brake, it will pull down because the force is being applied to the brake caliper rather than the ground.

However, there are 2 complicating factors:

• As you accelerate, the bike tries to tip backward, requiring more "holding up" force from the back suspension. So this tends to compress the back (squat), in opposition to the lifting effect (anti-squat) from the swingarm angle. Depending on how high the centre of gravity is and how steep the swingarm is angled, one of these will win out and the bike will either rise or fall. That's one reason racers sometimes adjust the swingarm pivot up or down, to get just a small rise. Drag racers go the other way... if the bike squats, the CoG is lower and the bike is less likely to wheelie (but more likely to wheelspin).
• If you're in the middle of a corner or riding up a hill, the rear suspension will be more compressed to start with, so there will be less swingarm angle. Hence if you open the throttle mid-corner, the rear is less likely to rise and more likely to squat than when accelerating in a straight line. That's a reason race bikes are often given much stiffer rear springs, to reduce the change in attitude between straights and corners.