The kit includes new C-hubs, stub axles and mounting systems.

I myself have been involved in the development of these parts since July 2024, and they have been successfully used by the team drivers for several months now. I always joke that I'm 10 years younger now since I am using these parts, but my results speak for themselves.

In fact, my 6th place in the 2024 European Championship and my performance in the World Championship are closely linked to the use of this new front C-hubs/carriers.

But what does it actually do? Is it really useful?

There are 4 major changes in this new option:

• addition of Kingpin Angle or KPI
• fixed caster value
• different Ackermann geometry for the spindle carrier
• new mounting system to limit play
• additional setting options

We won't go into too much theoretical details here, as we will always go in favor of the results on track. On the “classic” MP9 or MP10 front geometry, the pivot axis (i.e. the line drawn by the 2 Kingpin mounting points) and the wheel axis are parallel.

On the new steering system, the pivot axis is no longer parallel to the wheel axis, which we call KPI (King Pin Inclination). This value is measured in degrees, and is what we find on cars with pivot-ball steering cars such as Mugen, Sworkz and AE. Don't ask me the value of this angle, it won't really change our understanding here :-)

The effect of this angle will vary as you travel the steering wheel from left to right.

When the wheels are in line, your camber is set, usually to a negative degree value.

With a “classic” front axle without KPI, the inside wheel will tend to take on positive camber when turning. This is not the case with the addition of the Kingpin angle, which counters this phenomenon and keeps less positive camber to maintain more tire-ground contact area.

The scrub radius effect : The scrub radius is the distance between the intersection of the extension of the pivot axis and the axis of the wheel at its center. With the MP10's original front axle, the scrub radius value is positive: the offset is on the inside of the wheel in relation to its center. With today's new option, scrub radius is negative.

In dynamics, the effect of the scrub radius will change your car's behavior under acceleration and braking, through toe-in and/or toe-out gain and the force beeing applied more outside the wheel during cornering.

KPI: What are the benefits?

The main advantage of the KPI is the tilting of this “scrub radius” from the inside of the wheel to the outside.

On track, this makes the car less nervous, especially around the neutral point, at corner entry. The car is easier to drive, less twitchy, also making the rear more stable.

I find this change essential in all track conditions, and I see no disadvantage in using this system on all tracks, even slippery ones, although the gain will be enormous on high-grip tracks and less significant on slippery ones.

In the past, we had to increase the caster angle to limit the car's aggressiveness on high bite tracks, which considerably reduced corner speed on tight corners. It is not needed anymore with this option. Of course, we will still increase caster on high grip tracks, but without killing corner speed as much.

In fact, the 2nd advantage of the added angle on the Kingpin axle is the increased steering capability of the car mid to exit into the corner when the throttle is applied. A double advantage: you'll feel more at ease, but you'll also be faster in all conditions.

Fixed caster angle

The limited-edition IFW643 kit comes with a fixed 18° caster angle. The 20° and 22° C-hubs will be available as additional options later on. The plastic insert has been removed for greater reliability and less play.

The spindle carrier has a different Ackermann geometry.

The spindle carrier is now fitted with an aluminum plate secured by 2 M3 screws (we strongly advise you to degrease and glue them to the threadlock when first mounting).

These interchangeable plates will subsequently allow several Ackermann settings to be made to modify the angle of the outside wheel in the corner, and therefore the car's steering characteristics. This is already the case with this “World Edition” version, compared to the original.

New mounting system to reduce play

The mounting system has been redesigned. Farewell to M5 screws, the spindle carriers are now held in place by two flattened pins locked by M4 set screws. We strongly advise you to degrease and threadlock these screws.

An M3 set screw also locks the axle in the C-hub. The pin therefore spins only in the arm, and the caster block will not take up any play. With all these little details added together, the caster block/spindle carrier pair has no play when new and takes no play when in use, a real plus over the original MP10 version.

Additional settings

This new front-end geometry is also accompanied by new possibilities. It is now possible to adjust the height of the spindle carrier in the caster block: by raising the spindle carrier (i.e. bringing the wheel axle up), you can further reduce the car's twitchyness.

Conversely, lowering it increases front-wheel driveability and steering efficiancy.

From now on, the caster blocks can also be moved 3mm on its axis to increase or decrease the wheelbase, and above all the angle formed by the car's axis and the wheel's universal joint. This allows you to influence the car's nose-up attitude, as well as the front-end dive under braking.

Be careful, however, if you use the set-back position (the 3mm washers at the front of the C-hub), you'll need to machine the rear of the wishbone with a grinding wheel to ensure that the spindle comes to rest against the hub at maximum steering lock and doesn't touch the wishbone.

Advised starting setups

• tie rod at center hole
• spindle as low as possible
• caliper set back 2mm in the arm (2mm in front, 1mm behind)

Limited Edition?

The IFW643 complete kit is available as a limited edition. In fact, this reference will only be available as a kit when it is released.

After that, you'll have to buy all the parts separately, and the price will therefore be higher.

What about a new MP10e TKI3 or MP10 nitro TKI4 kit?