Toe control canceller bush / Mazda Miata

This bush is used mainly for the knuckle part of the FR cars’ rear wheel.
In the case of Miata/MX-5 it is used in the following way:

Maruha toe control canceller

Let’s take a look at Maruha’s toe control canceller.

1. The used material is urethane
At Maruha we don’t use hard materials like Duracon.
Compared to the genuine rubber bush or the heavy-duty rubber bushes Urethane is hard. For this reason, it can preserve its shape for a long period of time.
In other words, it is a very good material for street tuning.

2. The adjustment of the size
After the first trials we found out that its size was not appropriate. For this reason we changed its outline and size.

3. The bolt collar’s anti corrosion treatment

A steel bolt collar is being inserted into the urethane bush’s center.
The suspension has to function for a long time under severe conditions like rain, mud etc.
For this reason anti corrosion treatment has to be carried out thoroughly.
On Maruha’s collar black coating is being carried out.
Its anti rust effect is very good.

4. About the installation
Please keep in mind the following facts when carrying out the installation:

If after removing the genuine bush from the knuckle you find rust, it is necessary to remove it.
Please use grease when installing the toe control canceller. (apply it to the urethane bush’s surroundings and the bolt collar’s inner side)
The most suitable grease is the clutch grease we’ve introduced before.

The toe control canceller’s function

The Miata/MX-5 has got racing suspension with double wishbone at the front and rear.
However, it doesn’t mean that the Miata’s double wishbone is the best.
One of the ideal suspensions is the multi-link one.
Let’s take a look at Nissan:

The structural drawing shows Nissan’s Laurel generation. It’s almost the same as the first Miata/MX-5.

The arm’s structure:
Up: front upper arm, rear upper arm 2pcs
Center: lateral rod 1pc
Down: A-type lower arm 1pc

It is a construction of 4 supporting arms.
In the case of multi-link anti-diving (front diving) happens under braking and anti-squatting (rear squatting) under acceleration.

In reality the suspension has many functions.

Nissan multi-link rear compliance toe in

Set up the A arm’s body bush’s rigidity toward the rocker shaft flexibly and harder toward the axis and the right angle. This way the lateral link doesn’t move towards the horizontal shaft.

In this way during revolution side force is being applied to the outer wheel or during braking braking force is being applied and because of the bush’s deflection it moves to the toe in direction. (compliance toe in)
By this compliance toe in the tire’s cornering force becomes better.

If you read the Miata/MX-5 handbook you’ll get to know that the Miatas too are set up with the toe-in function. The only problem is that there is not enough explanation in the manual. We checked many magazines, Miata NA/NB handbooks but we couldn’t find sufficient information.
What is the toe control canceler’s function?

It has the function to make driving safe for anyone. However, it is not too good for winding drive or circuits.

Lately, there are many heavy-duty bushes on the market.
At Maruha, we use these bushes during our work.
At the rear’s lower arm’s member side we use heavy-duty bushes by Mazda Speed at 2 places.

Rear upper arm member side Rubber hardness 65°
Knuckle bush (toe controller bush) Rubber hardness 65°
Rear lower arm (member side) Rubber hardness 55°
Rear lower arm (tire side) Rubber hardness 65°

Maruha’s advice

1. If you are aiming for sports and circuits we recommend the heavy-duty bush.
Otherwise, the genuine bush is enough.

2. The urethane toe control canceller’s effect becomes better if used together with the heavy-duty bush.

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Maruha Motors Co., Ltd.
Ushizuma 2095-6, Aoi-Ward
421- 2106 Shizuoka city, Shizuoka prefecture
Japan
TEL: 0081-54-294-0076
FAX: 0081-54-294-1312
E-mail: info@maruhamotors.co.jp