The rear suspension is the area where the MGF and MG TF diverge most sharply. The MGF uses double wishbones with Hydragas displacer units, an interconnected fluid-and-gas system with each rear displacer linked to the corresponding front displacer via a hydrolastic fluid pipe. The MG TF replaced this system entirely with a multi-link rear axle using conventional coil springs over telescopic dampers, a clean-sheet design with no component carryover from the MGF. No rear suspension parts are interchangeable between the two models, and the rear subframes are different castings to accommodate the fundamentally different geometry.
MGF Rear Hydragas
On the MGF, rear suspension loads are carried by the Hydragas displacer at each corner, with a separate telescopic damper controlling damping rate. Front-to-rear interconnection gives the MGF its distinctive pitch control character, fluid transferred between front and rear displacers under braking or acceleration resists nose-dive and squat. The rear displacer uses the same specification as the front displacer (one part number for standard MGF, one for Trophy), so owners refreshing the Hydragas system typically order matched sets for all four corners. Rear Hydragas pipes are the most complex part of the system.
The rear LH pipe on standard (non-Trophy) MGFs changed at VIN YD517619, so standard cars use an early pipe up to YD517618 and a later pipe from YD517619 onwards. MGF Trophy cars use entirely different rear pipe assemblies along with additional intermediate pipes unique to the Trophy's higher-rate Hydragas calibration. All Hydragas pipe unions use rubber O-rings that should be renewed whenever a pipe is disturbed.
MG TF Multi-Link Rear
The MG TF rear suspension was engineered from a clean sheet using Adams suspension modelling software, with the design brief of providing progressive and predictable breakaway characteristics at the limit, addressing a known issue with the MGF's tendency toward abrupt rear-end slip under provocation. Multiple locating arms control the rear wheel independently in each plane (camber, toe, fore-aft), with coil springs and gas-filled telescopic dampers providing the springing and damping function. The rear subframe is solidly mounted to the bodyshell (an approach first used on the MGF Trophy and carried over to all MG TFs), containing the damper reaction forces within the subframe rather than feeding them into the body. MG TF rear dampers and springs changed at VIN 5D639631 alongside the front, earlier cars use the firmer original calibration, later cars use the softer-valved 2005 MY specification.
The same VIN breakpoint applies to bump stops and bump-stop cups.
Coil Spring Conversion for MGF Owners
For MGF owners whose Hydragas displacers have failed, several conversion paths exist, ranging from canister-type coil-spring conversion kits (Suplex, Mike Satur FCCKit) that replace the Hydragas displacer within the existing mounting points, through to the complete MG TF subframe swap that replaces the entire rear suspension with MG TF coil-and-multi-link hardware. These options are covered in more detail on the Upgrades & Alternatives child page, which also covers the MG TF 85th Anniversary's Bilstein/Eibach specification as an upgrade path for MG TF owners.
Five Child Pages
Rear Springs & Shock Absorbers covers the MGF rear Hydragas displacers, MG TF rear coil springs (with VIN 5D639631 variants), MG TF rear dampers (early, later, and lowered specifications), the Bilstein mono-tube dampers as fitted to the 85th Anniversary, and adjustable aftermarket options from Spax, Gaz, and Koni. Rear Arms, Hubs & Roll Bar, MGF covers the MGF Hydragas-era rear lower arm, tie bar, track control rod, upper arm, pivot shaft, rear anti-roll bar and links, rear hubs with ABS and non-ABS variants, and the MGF-specific polyurethane rear bush upgrade kit. Same page as reachable via the Hubs section. Rear Arms, Hubs & Roll Bar, MG TF covers the MG TF multi-link rear lower arm (two production variants), compliance bush and bracket assembly, adjustable and non-adjustable trailing links, rear anti-roll bar, rear upper arm, MG TF-specific rear hubs and upper ball joint, and targeted polyurethane bush upgrades including the 85th Anniversary anti-roll bar link.
Hydrolastic Suspension Fluid covers the specialist fluid required for topping up the MGF Hydragas system during service, the same child page as on the Front Suspension parent, shared between both Hydragas pages since the fluid is a single system consumable.