We are very grateful to AST / MOTON for providing us with a set of prototype lowering springs for our G90 M5. Being a prototype set, AST hasn't yet finalized the rates for the G90 progressive lowering springs, but the overall lowering specs should be fairly close to those provided by the final production set. As such, we'll reserve judgement on the ride and handling improvements we've already seen to wait on the official product.
The AST G90 M5 Lowering Springs provide the following lowering:
1.25" front drop
1.125" rear drop
With BMW's "double wishbone" front suspension on the M5, you're able to keep the factory alignment specs even when lowering the ride-height, so our recommendation for wheel spacer sizes is going to remain the same at 12mm Front and 12mm Rear whether on stock ride-height or when lowered.
On smaller BMW models with MacPherson style front struts, lowering the ride-height generally results in a bit more front camber, so you typically want to move to a slightly larger spacer to keep the same fender-fitment. Not needed here.
Recommended Fitment / AST Lowering Springs: 12mm F / 12mm R
With all the interest from the enthusiast community in running the rear wheels all around as a square setup (21x11 et28 with 295/35R21), we took the liberty of also installing this squared 21x11 setup with and without spacers. A 12mm spacer in the rear is still ideal and while you can get away without a spacer up front, adding a 5mm spacer will retain the flush fitment achieved with our spacer recommendations on the OE 20x10.5" wheels.
Recommended Fitment / AST Lowering Springs / Square 21x11 et28: 5mm F / 12mm R
No Spacers / AST Lowering Springs / Square 21x11 et28
We must say that running the OEM 21x11" square setup on AST Lowering Springs significantly enhances the G90 M5's stance and presence. The M5 should have come this way from the factory!
