Roof wing with side flaps

Mansory Roof Wing with Side Flaps for Mercedes-Benz G-Class W465 Gronos

The Roof Wing with Side Flaps is the aero-functional middle option in the W465 Gronos roof line. It keeps the geometry of the standard Mansory roof wing but adds vertical end-plate-style flaps on each tip. Those small surfaces do an outsized job: they cut span-wise air leakage off the ends of the wing, and that single change translates into a measurable downforce gain on the rear axle. For owners who want the visual presence of a tuned aero pack and a real, tested function without committing to the most aggressive cant angle of the performance wing, this is the part to specify.

This page covers what the side flaps actually do aerodynamically, the material spec, mounting, how it sits versus the plain Roof wing, the Roof wing performance, and the top-tier Roof wing performance with side flaps, and how to order it as part of a complete Mansory Body Kit for Mercedes Benz G-class W465 Gronos build or as a single retrofit.

Why side flaps - span-wise leakage explained

A wing develops downforce because the upper and lower surfaces run at different pressures. Air on the high-pressure underside wants to find its way to the low-pressure topside, and the easiest path is around the open tip. That migration is called span-wise flow, and every centimetre of it is downforce that never reaches the structure. On a roof-mounted wing sitting in the wake of a tall G-Class roofline, the effect is amplified because the wing is already operating in disturbed, low-energy air.

The side flaps act as miniature endplates - the same device that has lived on Formula 1 front wings, Le Mans prototypes and DTM rear wings for decades. By blocking the tip path with a vertical surface, the flap forces pressure to equalise through the wing chord rather than around the ends. The wing now operates closer to its theoretical 2D performance, and the rear axle feels it as steadier load at motorway speed and through long sweepers.

Measurable downforce gain over the baseline wing

Mansory's bench numbers and our own customer feedback put the gain in the range of roughly 10 to 18 percent additional downforce versus the plain roof wing at typical autobahn cruise speeds (130-200 km/h), with the wider end of that band showing up at higher speeds where tip vortex losses scale fastest. The flaps also reduce induced drag at the wing tips, so the net cost in straight-line top speed is essentially nothing - you are recovering force that was already being thrown away.

For a G-Class with a tall centre of gravity and a flat rear, that extra rear-axle load shows up as calmer behaviour over crests, less rear-end lightness when lifting at high speed, and a more planted feel during lane changes on heavy 23-inch wheels. It is not a track-day part on a G-wagen, but the gain is real and physically measurable, not cosmetic. Drivers who do regular long-distance autobahn runs notice it most: the rear stays settled when the truck is loaded with luggage and the suspension is working hard, and the steering feels more honest at the limit of the front tyres because the rear is no longer the variable in the equation.

The same physics also helps in crosswinds. A wing that is leaking air around its tips behaves unpredictably when yaw angle changes - the side that gets the disturbed air loses downforce first, and the truck twitches at the rear. With the flaps in place, both tips stay sealed regardless of yaw, so crosswind behaviour is more symmetric and the driver works less to hold a straight line. It is a small thing, but combined with the stiffer Mansory lowering springs and the wider track, it adds up to a G-Class that feels much less like a tall brick at speed.

Carbon construction and layup

The wing body and the side flaps are produced as a matched set. The shell is a pre-preg carbon fibre laminate cured under vacuum in heated tooling, with a structural foam or honeycomb core through the chord to keep torsional stiffness high without putting unsprung-style mass on the roof. The flaps share the same layup philosophy and bond into the wing tips with structural epoxy plus mechanical fixings, so the two pieces behave as a single rigid unit at speed.

Finish is up to the customer. Standard delivery is the OEM Mansory raw 2x2 twill weave clear-coated, gloss or matte. We also offer body-matched paint, contrast paint with carbon accent strips, and bespoke colour-matched flap inlays. Every shell is UV-stable clear-coated regardless of finish so the carbon does not yellow under sun.

Mounting and fitment

Mounting points are identical to the plain roof wing - the side flaps do not require any extra holes in the roof skin or any change to the roof rails. The wing pad bonds to the rear roof section using OEM-spec urethane plus stainless threaded inserts, with the load distributed across the factory roof reinforcement so there is no point loading on the sheet metal. Fitting takes a competent body shop roughly half a working day.

If you are already running the standard Roof wing and want to step up, we supply the side flaps as a retrofit kit that bonds to the existing wing tips - you do not have to replace the wing body. Ask for the retrofit option when you order.

How it compares to the other roof wings

The W465 Gronos roof wing line is a four-step ladder. Below the part on this page sits the plain Roof wing - same chord and cant angle as this one, but no flaps, so it loses a portion of its theoretical downforce to tip leakage. Above sits the Roof wing performance, which keeps the open tips but moves to a steeper cant angle and a larger chord for more aggressive downforce at the cost of higher induced drag. The top step is the Roof wing performance with side flaps, which combines the steeper performance geometry with the same endplate trick - that one is the maximum-downforce option and the most visually aggressive of the four.

This part - the standard wing with side flaps - is the balanced choice. You get a real, measurable aero gain and the more sculpted look that the flaps give the rear three-quarters, without the extra drag and the more extreme stance of the performance wing. For a road-driven G-Class this is usually the right answer. Pair it with the Roof Panel "Gronos" with 2 lights for a finished roof that ties the front lighting cluster to the rear wing visually.

How to order

The roof wing with side flaps is offered as a single SKU - body plus matched flaps, no separate part number to track. Specify finish (raw weave gloss, raw weave matte, or paint code), and let us know whether it is going onto a fresh build alongside the rest of the Mansory Body Kit for Mercedes Benz G-class W465 Gronos or onto an existing car. Cars already wearing the plain wing can be quoted for the retrofit flap kit only.

Lead time is 10 to 14 weeks from deposit, made-to-order in carbon. Pricing is in EUR, ex-works our European hub, with worldwide shipping handled by our logistics team. Browse the rest of the catalogue in the Mansory collection while your build slot is being scheduled.

Talk to a build advisor on WhatsApp or write to [email protected] with your VIN, current spec, and finish preference - we come back with a confirmed quote, lead-time slot, and a render of the rear three-quarters with the flaps on your colour.

FAQ

Q: How much downforce do the flaps actually add?
A: Roughly 10-18 percent more rear-axle downforce than the plain roof wing at 130-200 km/h, by closing off span-wise leakage at the wing tips. The exact number depends on speed and yaw angle.

Q: Do the side flaps add drag?
A: Marginally - and that is offset by reduced induced drag at the tips. Net effect on top speed is essentially zero. You are recovering downforce that was already being thrown away.

Q: Can I add the flaps later if I already have the plain wing?
A: Yes. We supply a retrofit flap kit that bonds to the tips of the existing standard wing - no need to replace the wing body. Specify retrofit when ordering.

Q: How heavy are the flaps versus the plain wing?
A: Around 0.4 to 0.6 kg extra over the baseline roof wing for the matched pair. Negligible at the vehicle level, well below what one passenger weighs.

Q: Should I jump straight to the performance variant with flaps?
A: Only if you want the steeper cant angle and the more aggressive look. The performance wing trades road-friendly drag for more downforce. This part is the balanced road choice; the performance with side flaps is the maximum-aero option.