The majority of maintenance on a Brompton is no different to that of a conventional bike. However the fold is what sets our bike apart from the conventional, and this does mean a slight addition to the usual routine.
All moving parts on a bicycle - or indeed any machine - require lubrication. Folding bikes have a few extra moving parts in the mix, so it is important to pay close attention to these and ensure that your Brompton continues to fold without fuss.
The hinges on the main frame and handlebar support pivot around a steel pin that is pressed into the hinge casting, and clamped closed using the hand lever and aluminium clamp plate. We recommend that you lubricate the pin with a light chain lubricant as part of your most frequent maintenance routine, when you lubricate the chain and check that the wheel rims are clean. Apply a couple of drops of lubricant to the area where the two hinge casting meet, around the pin. Open and close the hinge a few times to work the lubricant in, and then wipe away the excess to avoid attracting any dirt.
If you find that either of these hinges become stiff, a little penetrative lubricant from an aerosol can help to alleviate this. On the other end of the scale, eventually it is possible that these hinges develop some movement. If this occurs, take your bike to your local Brompton dealer for an assessment. Torsional play can be remedied with a replacement hinge pin, but this is pretty invasive surgery and best avoided by following a good lubrication routine.
Keep an eye on the condition of the aluminium plates that pinch close these hinges. Eventually these will wear, and the gap between the plate and the hinge castings will reduce. Once this is less than 1mm, the plates will need replacing to ensure that the hinge closes securely.
The rear hinge pivot is lubricated by copper bushings coated in nylon. Eventually the nylon will wear, and the bushings will need to be replaced at your local Brompton dealer. For more information on rear hinge servicing, please see this article here.