Suspension Options
The Fraser Basic Kit is based around the De dion rear suspension and the wide track outboard front suspension.
Front Suspension
Widetrack Outboard Front suspension with Cycle Guards
Widetrack, Inboard Front suspension with Cycle Guards
Race Setup Extra Widetrack Inboard Front suspension with cycle guards
All of our cars have benefited by increasing the front track to a measurement similar to the rear track.
The first two options use Ford Cortina Uprights. The standard front brakes are from the Ford Cortina or you can choose to upgrade to our Wilwood 4 piston brake and rotor kit.
Inboard Front Suspension
A major failing of the conventional placement of the spring/shock absorber is called falling rate suspension. As the wheel progresses through its bump travel the spring becomes increasingly horizontal and thereby becoming softer in the vertical direction (the one that matters). At absolutely horizontal of course the effective spring rate is 0.
By introducing a pushrod and rocker assembly, carefully engineered, the angle of the pushrod to rocker and rocker to shock can be maintained as a near right angle at ride height therefore introducing rising rate suspension. This is of course more desirable giving a more linear wheel deflection and better control. It has resulted in much lighter springs being required to do the same job.
There is an aerodynamic advantage in putting the coil/shock unit out of the air stream.
There is significantly less unsprung weight in replacing the coil/shock with a pushrod. Ride height is easily adjusted with pushrod length.
Option three, Race set up, uses:
New Triumph uprights for light weight with lower spherical joint conversion
Extra Widetrack / Inboard
Alloy Hubs for reduced unsprung weight
Wilwood 4 piston caliper and vented rotor for amazing stopping power
A very light weight effective design for the ultimate handling and riding Fraser Clubman
Inboard Front suspension is Inclusive
Rear Suspension
Fraser De dion design - using Nissan, Ford or Mazda differentials and brakes. (Up to 350H.P)
De Dion Rear Axle
This is a composite system taking advantages from both live and independent systems. Technically it is still a live axle because the rear wheels are rigidly connected by a "beam". One wheel cannot deflect without affecting the attitude of the other. The mass of the diff head and the half mass of the axles is transferred from being unsprung to sprung. It has three big advantages over the escort axle.
In such a light car (550 kg) ride quality, road holding and directional stability are very much a function of unsprung weight. (Tyres, wheels, axle, 50% springs etc.) at about 150kg, total. This represents 27% of the total mass.
This means that when one wheel hits a bump the inertia of the unsprung weight is more easily transferred to the body when it is such a large percentage of the mass. This problem exists on all lightweight vehicles and is why race car builders spend huge amounts of money developing light wheels, carbon fibre brakes, chrome moly suspension, lightweight tyres etc.
The Fraser De dion arrangement reduces the rear end unsprung mass by 22kg, corresponding with a decrease in the rear of approx 20% unsprung weight.
The live axle is located by 4 trailing arms and a panhard rod. An inherent deficiency of such a link is that over large suspension travel there is a small amount of sideways displacement due to the arc. This is not substantial and is tolerated in many production cars the world over. The lateral link in the De dion is the A frame which has a true vertical motion with no sideways component through its travel.
The roll centre is also on one side of the car giving unequal suspension characteristics right to left.
When a De dion axle is used the diff head is no longer dynamic. i.e. it remains stationary and a bolted in component of the chassis. Therefore much less provision has to be made for suspension travel in the transmission tunnel, resulting in the De dion cars now incorporating a glove compartment in the top half of the transmission tunnel.
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