Articles

The Need For Upgraded Suspension

Overview

Motorcycle manufacturers have to produce a motorcycle at an affordable price for the "average" rider. To achieve this each component must be produced to a strict budget. The fine tolerances required by hydraulic components such as suspension units do not lend themselves to cheap mass production.

We have yet to meet the mystical "average" rider that all bikes are set up for. Every rider has different requirements from their suspension.

When working with race teams we often see that two riders can ride identical bikes with their own preferred suspension settings around a racetrack at lap record pace within a hundredth of a second of each other. If the riders then swap bikes neither can understand how the other gets round the track so fast with those settings.

There is no magical setting that suits all riders.

Improving the suspension allows you to brake later, carry more corner speed and accelerate earlier, so reaching your top speed quicker.

Springs

Aftermarket Shock Springs

The springs support the mass of the rider and the motorcycle, not how fat the mass moves. Without the correct spring rate for your weight the suspension will not perform to it's full potential. If necessary we change the springs to suit your individual requirements.

Damping

Damping force measured on a dyno.

Damping controls how fast the mass moves. Well-damped suspension has a balanced relationship between low-speed and high-speed damping on both the compression and rebound strokes. Low and high-speed damping refers to shaft velocity, or how fast your wheels are moving up and down, not the speed of the motorcycle.

It is imperative that the relationship between low and high speed is set up correctly internally, this is rarely the case with production bikes. The damping solutions we use have been dyno tested as well as tested on the road and track.

Cartridge Forks.

Cartridge Fork Pistons

Some manufacturers control the damping of the forks using pistons with very small orifices and others use large orifices.

Small orifices work fine at low velocities, however hitting a sharp bump causes the forks to compress at high velocity. The rise in damping force is very severe with small ports as the orifices cannot displace enough fluid. This results in a harsh fork action.

Large orifices work fine at high velocities, but the orifices displace too much fluid at low velocities. This gives a lack of feedback and a mushy feeling from the forks.

Our solution is to replace poorly designed pistons, or re-valve the stock items to more accurately meter the fluid flowing through them.

Damper Rod Forks.

Damper Rod Forks

The Damper Rod Fork has been with us since the 70's, it should really have disappeared by now, but is still fitted to some current models as it's a very cheap design to produce. They use a rod with fixed orifices to control the damping. The bottom set of orifices control the compression damping, and the top set of orifices control the rebound damping.

The biggest problem with these forks is that they generate a progressive damping curve. The orifices are either too large to provide adequate low-speed damping, or not large enough to eliminate hydraulic lock, neither of which is desirable.

To overcome the inherent design faults of these forks we install Race Tech Emulators which allow the damper rod forks to operate with a variable orifice, giving a much wider range of operation.

Shock Absorbers

Manufacturers invest very little in the design and quality of the shocks. Although standard shocks have external adjustment capabilities, these adjusters have their limits and typically affect only a small portion of the entire damping range. They will not compensate for the large tolerances required for mass production, or poor internal valving design. The majority of standard shocks have a whole catalogue of faults, only some of which are correctable. The cost to achieve this would be close enough to the cost of a precision aftermarket shock, making replacement the only sensible option.

Custom engineered suspension allows the full potential of bike and rider to be achieved.


Suspension Courses.

For those interested in learning more, we run a series of Suspension Courses where you can learn in-depth techniques on servicing and suspension theory.

http://www.reactivesuspension.com/courses.php


Course Booklets