A simple steel spaceframe chassis is used on all Noble M12 versions. Noble riveted aluminium panels to the chassis to enclose the cockpit and strengthen the structure further. It's very effective but does lead to one of the M12's key weaknesses: chassis corrosion.
Water gets between the aluminium panels and steel chassis, setting up electrolytic corrosion that can be very difficult to spot. Water can also lurk around the edges of the flat floor, so lift the carpets and feel for dampness all round the cabin. If corrosion has set in, the aluminium panels need to be removed and the rust treated before the panels are reattached. This isn't as major a job as it sounds and can be completed by a competent home mechanic, but care is needed to align the panels properly.
Double wishbones are used at each corner of the Noble and use coil springs, shock absorbers and anti-roll bars. Be certain the wishbones have no rust on them, but don't be surprised if the track rod ends and hubs are corroded. Early GTO's ball joints wear quickly, but uprated ones are available.
Brakes need careful inspection as the flexible pipes used on early GTO models deteriorate due to heat from the brakes. Solid brake pipes were used on later cars, though this was subject to a recall from Noble so every car should have been sorted by now. Only use DOT5.1 brake fluid to preserve pedal feel. The brakes themselves are 330mm drilled and vented discs front and rear but with no anti-lock ever fitted. Tyres are 225/50 ZR18 on the front and 265/35 ZR18 at the back, while the M400 switched from Bridgestone S-03s to Pirelli P-Zero Corsas.
Other changes for the M400 included slowing the steering rack's ratio from 2.0 turns lock-to-lock to 2.5 turns to make it easier for the driver to catch tail slides on track. Noble also added dynamic dampers to the M400 for better body control at high speed. The 3R also had its own 10-spoke wheel design. Rear hub nuts can shear and a common upgrade is to use Porsche Boxster nuts.
Noble M12 Buying Guide Index: