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Video Transmission
Video Gearbox-gripes
Video History 1
Video History 2
Video Var. Speed Gearbox 1
Video Var. Speed Gearbox 2
Video Var. Speed Gearbox 3
Video Var. Speed Gearbox 4
Video Var. Speed Gearbox 5
Video Light commercial veh.
Video Shift Possibilities
Video Gearshift Lever
Video Transmission (truck)
Video Ecosplit Gearbox
Video Gearshift (truck) 1
Video Gearshift (truck) 2
Video Truck Multi-axle Gearbox
Video Group/Splitter Gearb.
Video Gearbox Lubrication
Video Axilliary Drive
Video Retarder 1
Video Retarder 2
Video Retarder 3
Video Overdrive
Video Synchronising 1
Video Synchronising 2
Video Two-Shafts Gearbox
Video Gearbox (de)mounting 1
Video Gearbox (de)mounting 2
Video Front - Cross-engine
Video 3 Shafts (not coaxial)
Video Gear Shaft
Video Transmission Design
Video Tractive Power
Video Direct Shift Gearbox 1
Video Direct Shift Gearbox 2
Video Direct Shift Gearbox 3
Video Form. 1 Transmission
Video Motorcycle Gearbox

Video Transmission Ratio
Video Three-shafts Gearbox
Video Two-shafts Gearbox
Video Gear Spreading

Video Manual Gearbox 1
Video Manual Gearbox 2

          A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Synchroniser (3 friction cones)

The individual components are fitted into each other from left to right.


One of the few components in the vehicle that can be badly damaged by incorrect handling is the synchronisation of the gear box. Tugging the gear lever too fiercely, particularly when downshifting, forces a fast constant velocity of the friction areas, leading to undue wear and tear. The car manufacturers, in their attempts to achieve a certain amount of long service life for as many components as possible, have introduced improvements for the 1st to 3rd gears.

How it works

The synchronisation should bring, as the name says, the synchronizer with sliding clutch (far right) and the gear wheel (far left) to the same RPMs and only then allow them to mesh with each other. All components shown above have bevelled surfaces. As long as no synchronisation is reached, the overlapping of the sliding clutch onto the pre-gearing is blocked by another geared rim in the second synchronising ring. Starting point of the double synchronisation is a gear wheel with pre-gearing. The diameter is considerably larger than that of the friction cone. This way, space is created for the first synchronising ring with two friction surfaces and a washer with also two friction surfaces. The following, second synchronising ring is almost unchanged. It fits, with its three (red) gaps, in such a way, into the synchronizer that it can only misconnect by a half a cog in either direction.

The non-slip (blue) connection between the gear wheel and the washer is important for the effect of the three friction surfaces. At the same time through (green) claws, both synchronising rings are also connected with each other. Thus the Synchronisation facility works like a multiple-disc oil bath clutch. From a logical point of view, more than two synchronising rings are possible. 09/08               Top of page               Index
2001-2015 Copyright programs, texts, animations, pictures: H. Huppertz - E-Mail
Translator: Don Leslie - Email:

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