Parabolic Leaf Spring Kits with Fitting Position Front Axle, Rear Axle for FOTON TUNLAND P201 4WD

A parabolic leaf spring kit for the P201 4WD TUNLAND supplies the springs and every fastener that has to go on with them, which is what gets the ride improvement you paid for.

Fitting parabolic springs onto worn bushes and stretched U-bolts gives back most of the advantage before the vehicle leaves the workshop.

What Comes in Your P201 4WD TUNLAND Parabolic Leaf Spring Kit

Each kit is assembled for one axle on one vehicle, and the contents follow the application.

The parabolic springs are the core, supplied as a pair and rated to a constant load band with a nominated lift height.

U-bolts are included in the correct length for the pack. A parabolic pack sits differently in the stack to the conventional one it replaces, so the original U-bolts are rarely the right length.

Bushes come with the kit, covering the spring eye and generally the shackle as well.

Shackles and pins are supplied where the application needs them, with greasable versions on kits where that suits the vehicle.

Check the listed contents against your P201 4WD TUNLAND, because what one platform requires another does not.

Why Your P201 4WD TUNLAND Kit Rather Than Parabolic Springs Alone

Free movement is the whole point of a parabolic design, and worn hardware takes it away.

These springs work by removing friction between the leaves so the suspension responds to small inputs. A perished spring eye bush or a worn shackle bush reintroduces exactly the restriction the design exists to eliminate, at the mounting point instead of between the leaves.

U-bolts are the second reason to buy the kit. They are torqued into their yield range and stretch permanently, so a reused set clamps well below what it did when new.

Fixed pins are the third, having sat clamped under load and corroding for the life of the old pack.

Buying the lot together also stops the job halting halfway while something is ordered.

How Parabolic Kits Change the Ride in Your P201 4WD TUNLAND

The change is immediate and it comes from the leaves no longer rubbing.

A conventional pack has every leaf in contact along its full length, and that friction has to be overcome before the spring flexes at all. Small bumps get transmitted into the vehicle rather than absorbed.

Parabolic leaves touch only at the ends and the centre, so there is almost nothing resisting the initial movement. The spring starts working with the road rather than against it.

Noise disappears for exactly the same reason. The squeak from an ageing leaf pack is dry metal sliding on dry metal, and a design with a gap between the leaves does not develop it.

Corrosion between the leaves largely stops being a problem too, since water passes through rather than sitting on a contact face where nobody inspects.

P201 4WD TUNLAND Parabolic Kits Against Conventional Leaf Spring Kits

Both arrive as a complete package for one axle, so the comparison comes down to the springs inside.

A conventional kit supplies a multi-leaf pack with every leaf in contact along its length. It is proven, it carries weight well, it costs less, and it rides firmly over small inputs because friction has to be overcome before the spring flexes.

A parabolic kit supplies tapered leaves that touch only at the ends and the centre. It rides considerably better unladen, articulates further, runs quieter and weighs less, at a higher price and with more responsibility placed on the dampers.

Load capacity is comparable band for band, so this is not a choice between comfort and capability. Both are specified around the same constant load ratings.

The deciding factor is how often the vehicle runs empty. A pack that is always loaded sits in the firmer part of its range regardless of design, so the comfort advantage has less to work with.

Multi-Stage Behaviour in a Parabolic Kit

A parabolic pack responds progressively, which is what lets one spring suit an empty tray and a loaded one.

Unladen, the main leaves alone are carrying the vehicle, and the spring is soft enough to absorb inputs a conventional pack would pass straight through.

As weight goes on, the leaves deflect toward each other and the second leaf begins contributing, which lifts the effective rate.

Load it further and a free floating overload leaf engages, sitting below the pack and making no contact at all until the suspension compresses under real weight.

Three stages of response from one assembly is why a parabolic sprung vehicle can ride well empty without sagging when it is working.

Load Ratings on Your P201 4WD TUNLAND Parabolic Kit

Constant load is the number that decides whether the kit performs.

It refers to the weight permanently on the vehicle rather than the vehicle's own weight. A canopy, drawers, water, a fridge and recovery gear add up through the bands faster than owners expect.

Rate it below what you carry and the pack sits low loaded. Rate it well above and the ride advantage disappears when the tray is empty, which defeats the point of buying parabolic in the first place.

Front and rear are specified separately where a vehicle has leaf springs at both ends, since one carries accessory weight and the other carries payload.

Weigh the vehicle fitted out if you can, because estimates run low.

Budget for Shocks With Your P201 4WD TUNLAND Parabolic Kit

This is the one thing worth planning for before ordering.

Inter-leaf friction in a conventional pack provides a degree of self damping. A parabolic pack does not have it, so the shock absorbers carry the full job of controlling the spring.

Factory dampers were valved for a spring that damped part of its own movement. Put parabolic springs under tired ones and the vehicle can feel loose over undulations, which reads as the springs being wrong when it is the dampers being out of their depth.

The same kit with appropriate shocks rides considerably better than the pack it replaced.

Have the shocks assessed when the kit is specified, not after it is fitted.

Where a Parabolic Kit Is Not the Right Choice for Your P201 4WD TUNLAND

Worth saying plainly, because parabolic is not the answer for every vehicle.

A ute permanently loaded to its limit and never run empty gains less from the comfort advantage, since it sits on the loaded part of the range all the time. A correctly rated conventional heavy duty pack can suit that use better and costs less.

Extreme off road work is the other case. Some parabolic designs have clearance limitations around the overload leaf at full articulation, which is worth discussing before ordering on a vehicle used hard.

Cost is a legitimate consideration alongside those two. On a work vehicle where ride comfort is not the priority, that money may do more elsewhere in the build.

Where a parabolic kit genuinely earns its place is the vehicle that alternates between empty and loaded, covers long distances and spends time on corrugated roads.

P201 4WD TUNLAND Parabolic Kit Weight Saving and Payload

A parabolic pack matched to a conventional one for capacity weighs around a third less.

Almost all of that saving is unsprung mass sitting below the springs, which is the weight the suspension has to accelerate over every bump. Less of it means the wheel follows the surface more closely and the dampers have less work to do.

There is a second benefit on a vehicle near its limits. Weight taken off the springs is weight freed up for payload, which matters on anything fitted out for touring.

Torquing Your P201 4WD TUNLAND Parabolic Leaf Spring Kit

Fit the supplied U-bolts and torque them evenly in a cross pattern rather than one leg at a time, so the pack clamps square.

Confirm the fixed pin head seats fully into the locating hole in the axle seat before the U-bolts are tightened, since that head holds the pack in position.

Fit the new bushes rather than carrying old ones over, because free movement at the eyes and shackles is part of what the kit is delivering.

Handle the springs carefully through the whole job. A parabolic leaf is thinner through most of its length than a conventional one, and a gouge in the surface creates the stress point a fatigue crack starts from.

Retorque the U-bolts after the first few hundred kilometres once the pack has bedded in, then have a wheel alignment done.

P201 4WD TUNLAND Parabolic Leaf Spring Kit Warranty

Formula 4x4 leaf springs carry a three year or 100,000 kilometre warranty, whichever comes first, subject to the applicable terms.

Find a Parabolic Leaf Spring Kit for Your P201 4WD TUNLAND

Select your P201 4WD TUNLAND to see the parabolic leaf spring kits available for it, with the U-bolts, bushes and shackle hardware the application requires. Choose the load band around what the vehicle permanently carries, and have the shocks looked at while the kit is being specified.