Part No: MED-3100-DGM+MED-3100-SF-ROD
Regular price £1,900.00 £1,583.33 EXC VAT
Regular price Sale price £1,900.00 £1,583.33 EXC VAT
Availability: In Stock


The MED gear kit is machined in the UK to exacting tolerances, with a five-dog engagement for slick, confident gear changes and excellent longevity for full-competition usage.

We've designed the kit to run with very little backlash, to eliminate gear tooth wear commonly associated with other dog-engagements gear kits.

The MED design has been continually developed and enhanced over 15 years of strenuous motorsport use, to create the very best kit on the market.


    • Kits available for rod or remote change gear housing.

    • Gears machined from VAR S156 steel then Cryogenic treated.

    • Five-dog engagement for slick gear changes.

    • Selector forks CNC machined from 7075 aluminium, with the same tensile strength as steel.

    • Needle roller bearing suport for both ends of the laygear.

    • CNC-machined EN24T steel first and third motion locknuts.

    • Tolerances CMM checked in cutting-edge inspection facility. 

    • Optional superfinished version.

Gear ratios:

    • First - 2.239:1

    • Second - 1.568:1

    • Third - 1.244:1

    • Fourth - 1:1

Kit contents:

    • Complete main shaft assembly – fully assembled

    • 1st motion gear – 4th gear

    • Laygear

    • 1st to 2nd modular selector fork

    • 3rd to 4th modular selector fork

    • Reverse gear

    • Laygear needle roller bearings

    • 1st motion to 4th gear needle roller bearing

    • 1st and 3rd motion lock nuts 

We also offer a superfinished version. This surface-processing technique means the gears will experience reduced friction, lower operating temperature, less wear, better scuffing resistance, and better contact fatigue resistance. If the budget allows, this is a great upgrade.

For further recommendations please see the additional information tab.

Also see the MED Pinion Support Housing, which is ideally suited to this gear set installation.


Additional Information

Gearset choice
We offer four different gearsets for the Mini/Metro gearbox, all straight-cut close-ratio types for high performance applications. The Clubman gearset allows you to re-use first and reverse gear from the standard setup, but is only suitable for later rod-change gearboxes.

The Three-synchro gearset is intended for early Minis with three-synchro gearboxes.

Next, the MED Race gearset utilises the same ratios as the original Special Tuning conversions and comes with new a first/reverse gear. It is available for both rod and remote-change gearboxes.

We then have the MED dog-engagement gearset, which does away with the baulkrings for ultimate strength in competition applications. This can be supplied for rod or remote change gearbox housings, with an optional superfinish for even greater durability and reduced friction.

Straight-cut vs helical-cut gears
The design of helical-cut gears, as found in standard gearboxes, leads to increased side (or axial) loadings on the transmission. As power outputs increase, this places greater strain on the transmission casing and bearings, in-turn leading to reduced reliability.

Using straight-cut gears allows us to design a stronger transmission within the standard casing. It also reduces power losses to make the most of the engine's power. We estimate between 5-7bhp can be gained at the wheels by using a straight-cut gearset.

Road suitability
Dog-engagement gearsets are not intended for road usage, however we have supplied these to owners of high-performance trackday and rally cars used occasionally on the road. You will find the gearset a bit hardcore for regular road usage and there is no provision for a mechanical speedo cable, so the car will need a digital setup.

The MED race gearset still uses the standard synchro hubs and is probably better suited to fast road use than a dog box.

Close ratios
Closer ratios give a reduced engine RPM drop when changing up a gear. This keeps the engine within its optimum power band more effectively, resulting in better acceleration through the gears. Fourth gear is still the same 1:1 ratio, but first gear tends to be taller than with a standard gearset, to bring the ratios closer together.

The final drive ratio and wheel size need to be carefully considered to give the best results - contact us if you're unsure.