When the Aston Martin DB9 was launched in 2004 its exceptional chassis stiffness and resistance to twisting was widely recognised. The VH chassis was made largely of bonded and riveted aluminium, similar to the system pioneered by Lotus. However the DB9 Volante chassis strength was not quite so rigid, losing the roof meant a loss in structural torsion. this caused the handling to be less precise (not helped by the lack of rear anti roll bar on the Volante) and caused the occasional bit of scuttle shake.
As the DB9 was developed Aston Martin increased the stiffness of the DB9 and DBS Volante through Shear panels, aluminium panels under the floor that tied the sides of the car together with multiple fixings on the rear subframe making it far more rigid.
Rear Shear Panel
In the photo above, on the right is the plastic cover that is bolted to the underneath of the rear subframe, this is mainly for aerodynamics. On the left is a heavy gauge aluminium shear panel that fixes to the subframe and both side sills of the car, tying them all together and making the car more rigid. This was fitted to the DBS and post 2013 DB9s
There is a similar stronger replacement panel at the front of the car, fitted to the DBS, Sports pack DB9s and post 2009 Volantes, this appears to be simply a bolt on replacement.
The rear panel will need some adapting and tailoring, new brackets making and welding in place, spacers as below to fit properly to fit my 2006 DB9 Volante, but will substantially increase the DB9 Volante chassis strength.
The Mounting of the rear subframe is different on the DB9 to the DBS and so i made these stainless spacers to mount the shear plate securely to the subframe mounting brackets.
At can be seen above, the underbody stiffening for the DB9 Volante changed significantly. Originally there was no stiffening at all for the rear of the chassis until the DB9.2 was launched in 2013, however the DBS had rear stiffening from its launch in 2008.
This is the new rear shear plate with fixing points outlined in colours. Aston Martin part No. FD33-L17C857-AB
- Red – Uses the original fixing points on the subframe
- Blue – Uses the fixing points on the subframe mounts but spacers needed
- Green – New brackets needed , welded onto subframe
- Yellow – New fixing points needed in the outer sills, Rivnuts
The areas marked in Blue are the front mounts for the DB9 rear subframe, these are alloy castings supporting the front of the subframe, they are bolted to the chassis, by removing the outer bolt, installing a spacer and using longer (35mm) M10 High tensile bolts the shear plate is rigidly mounted to the subframe mounts.
The sides of the rear shear plate need attaching to the subframe in 3 places each side, I made these brackets out of 3mm steel bar, with an M10 nut welded inat the bottom, these are then welded to the subframe and then bolted to the shear plate. These were marked in green
Front Shear Panel
In 2009 the DB9 Volante and the DB9 Coupe with Sports pack gained the stiffer front shear plate from the DBS and this continued onto the DB9.2. The DB9 coupe has a torsional stiffness of 27,000KN, the DB9 Volante 15,500KN and the DBS Volante over 20,000KN, a 30% improvement over the DB9. Aston Martin part No. 9G43-11262-BA
The updated front shear panel is almost a direct replacement for the original shear panel, it bolts on using the same fixing points except new bolting points have to be created on the outer sills as the original shear plate doesn’t extend as far as the outer sills. the new shear plate also has a turned edge creating a stiffer more rigid shear plate.
Front Shear Plate 9G43-11262-BA
Rear Shear Plate FD33-L17C857-AB