You might hear mechanics talking about ring and pinions or crown wheel & pinions.

But, what is behind these technical terms?

Why are these parts essential in the driveline of your 4x4?

When & why would you replace a ring & pinion set?

According to Wikipedia :

"this bevel gear set-up transmits a rotational movement between two concurrent non-parallel shafts (often at a right angle). These devices are called "angle transmission" when the transmission is in a ratio of 1 to 1. Sometimes used in the secondary transmission of motor vehicles, it is more often to reduce speed."

Unless you have studied mechanical engineering you probably still need our help to see clearer!

Read on!

Ring & Pinions

The final drive is a gear set that comprises 2 parts that interlock with each other located in the front and rear axle. It consists of a pinion called the drive pinion and a serrated crown known as the large crown or ring. The teeth of these two parts are hypoid type, so that they work together silently. The drive pinion is integral with the transmission shaft, and the ring gear is fixed to the differential.

We say ring & pinion because these two parts are inseparable. They are "paired", that is to say, run in together. This is why you cannot take a drive pinion from a vehicle with a large crown wheel and fit it to a different crown wheel.

Function 1: Right angle transfer

On almost all vehicles, including 4x4s, the drivetrain operates longitudinally, that is to say in the axis of the vehicle. The engine creates a rotary movement which is then transmitted to the gearbox and then to the transmission shafts.

However, when this movement arrives at the axle, there is a problem. It must change its axis and travel transversely in order to make the two wheels of the same axle turn together. In short, it must be transferred at an angle of 90°. This is where the ring & pinion (or crown wheel & pinion) come into action.

Their role is therefore to transmit and transform this longitudinal movement into a transverse movement i.e through a right angle

Function 2: Gear reduction

The ring & pinion not only transfers the power through 90° it also gears down the speed of the propeller shaft to a suitable road wheel speed.

Explanation: a ring & pinion with a ratio of 1 would mean that, for one revolution of the driveshaft, the wheels would make one revolution. This is not very interesting because, in this case, the engine would have to work overtime to simply move the vehicle. Thanks to the ring & pinion, the gearing can be increased at the final drive.

It's a bit like when you use a snatch block when winching. Try pulling a 4x4 with a "2 ton" model. You will get there, but the winch will force and may well overheat. On the other hand, if you increase the gearing by using a snatch block the effort required from the winch will be reduced and that small winch will perform much more efficiently.


When a 4x4, leaves the factory, depending on the weight of the vehicle and especially the size of the tires, the ring & pinion ratio can vary from 3:1 to 5:1, which means that for 3 or 5 revolutions of the propeller shaft the wheel will only make one revolution.

This ratio is particularly important because the engine performance will be tailored accordingly. However, when you change the size of the tires, you put everything in question. If you considerably increase the tyre size, the final drive ratio may no longer be suitable. The drivetrain gearing will be inadequate. the final drive gearing will be too long & the drivetrain will be underpowered by 10 to 15% resulting in less torque at low speed. In other words, it will be harder to pull away. Then, when you get up to speed the engine will only have to rotate at say 1800rpm rather than 2200rpm for the same speed. This will make the vehicle feel gutless and less pleasant to drive because the Suddenly, the vehicle is less pleasant to drive, and you will have to accelerate more to get the necessary torque.

The solution is to reduce the final drive gearing by replacing the ring & pinion with a set offering a greater reduction. With this change, the engine will be back to operating in the correct power range. Suddenly, the 4x4 is more pleasant, accelerates again as before and fuel consumption returns to normal.


Depending on how you use your 4x4, it may be tempting to opt for ultra-short gearing. Especially if you do a lot of off-roading.

At first glance, there are distinct advantages. The reduction is so short that the torque is so powerful you will hardly need to accelerate. The only concern is that if the ratio is too high, as soon as you use your 4x4 on the road, it will quickly peak in speed and the engine will head quickly into high revs. Also, short gearing means more strain is exerted on the ring & pinion which can result in gear teeth breakage in particularly demanding conditions. Similarly, the extra strain on drive shafts can lead to failure. So in a nutshell, ultra-short ring & pinions can self destruct or eat through drive shaftsInformation Good to know!

Now when you replace your standard tyres with considerably bigger models, you know what you have to do. So do not forget to include the final drove upgrade in your budget!

Short gear options

Here are a few examples of "short"  (i.e high ratio) ring & pinion sets that can be fitted depending on the make of 4x4:

  • Jeep : 4.56 : 4.88 : 5.39 : 1
  • Land : 4.11 : 1
  • Suzuki : 4.57 : 1
  • Nissan : 4.88 : 5.12 : 5.43 : 1
  • Toyota : 3.72 : 4.10 : 4.56 : 4.88 : 5.29 : 5.71 : 1

Alternatives: modified transfer box

When you change the final drive, you reduce the entire drivetrain by the same ratio, whether you are in high or low range gear. Depending on how you use your 4x4 , this may not be ideal for you.

There is another solution: change the gears in the transfer box. With this method you can work on the reduction ratio of each range separately. For example reducing the low range  by 20% and the long by only 10% and vice versa. Almost anything is possible.



We offer a range of ring & pinions for  over 20 makes of 4x4/

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For example: Toyota Land Cruiser KZJ73

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Please note: Euro4x4parts publishes this information to help its customers, but cannot be held responsible for the advice given here and their consequences when used.