Strathpeffer Junction: Home of the Original & Best ringfield motor upgrade kits. 

We only use high-quality, branded motors and the very best materials. Every one of our products is vigorously tested before being offered to the public and every motor is checked by hand before shipping. We provide the most detailed assembly instructions and support videos on the market and offer a no-quibble refund in the unlikely event you're not happy. All of our adaptors are made using precision European plastics that can withstand the rigours of railway modelling for the long haul.


This listing is for a brand new OO Gauge 12mm Lima ringfield motor conversion kit for UK outline Bo-Bo diesels and DMUs (see compatibility list below).

Each LA2 (12MM/Bo-Bo) kit includes: 

This adaptor kit provides excellent top speeds, but normally requires a diode voltage dropper and/or CV5 adjustment to protect the motor. We sell those too! We've got quick and easy pre-assembled droppers and surface mount (SMD) or through-hole self-assembly kits. Check out our other listings for options.

If you'd like to avoid voltage droppers, you may prefer our 12V motor adaptor kit (LA6) which can be dropped in without worrying about over-voltage. You can find it under 'see other items'. If you've got any questions about which kit may be best for your needs, please just drop us a message and we'll be happy to help.

A note about postage: We are happy to combine postage for multiple orders and most listings should do this automatically. If postage doesn't automatically combine, please drop us a message before you pay and we'll sort out a revised invoice. If you've already paid, drop us a line and we can refund the extra.



With these adaptors, installation is easy. They enable you to quickly replace aged ringfield motors in OO gauge models with CD-type motors, without the need for any messing around with glue or fiddly shaft alignment. 

You simply remove the old motor and gear, pop the new motor into the adaptor, trim down the new gear and fit it onto the shaft, and then install the new assembly into the motor bogie. Everything is lined up and ready to go!

This kit requires no permanent adaptation to be made to the motor bogie and therefore the original ringfield (pancake) motor can be reinstalled at any time; the motor, adaptor and/or gear can be replaced with ease, if ever the need arises.

To read more about our ringfield adaptor kits and download detailed, step-by-step instructions. please the Strathpeffer Junction website. You can also watch our installation tutorial video on YouTube: https://www.youtube.com/watch?v=A8Pgx9IUDRM



We have tested the adaptor in UK outline models marked with an asterisk below. Based on visual assessment, this adaptor should also work with all ringfield models listed. Very occasionally, light sanding may be required around the lugs to ensure clearance.

★ We also have separate listings for 10mm/Co-Co Lima adaptors and special Small Loco Lima adaptors (suitable for Class 08/09 shunters and GWR Prairie). Click on 'see other items' above for more information.


Important considerations

1. Our replacement motors are low-noise DC motors designed for CD/DVD drives. The output from a DCC decoder or a DC controller can exceed their voltage rating depending on how hard hard the loco is being worked. Whilst our own tests (and those of many others before us) show that these motors are capable of handling voltages higher than their rating, in order to avoid motor burn-out, prolong motor life and achieve prototypical speeds, we recommend:

2. With all CD-style motor conversions, it is good practice to:

i) maintain very high speeds for relatively short periods only,

ii) keep running on steep inclines to a minimum,

iii) avoid coupled up with excessively long rakes of coaches/wagons, and

iv) where less robust 10mm motors are fitted, resist the temptation to fit additional weight to the loco.

3. It is recommended that locomotives fitted with our 3D printed adaptor kits are not run for more than an hour continuously; this is to prevent the motor temperature from exceeding the glass transition temperature of the plastic.

4. We recommend that locomotives fitted with can-style CD motors are:


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We can accept no liability or responsibility for any damage or injury occurring from the installation and use of our motor replacement kits. Installation requires modifications and the use of tools, some of which have the potential to damage you and/or you models, as well as other components and equipment. Users must not commence work unless they are confident that they have the skills and experience necessary to complete it successfully, and install these kits and undertake work to their models at their own risk.