You switch an Atlas seat from GT to Formula by swapping the upper section on the shared lower base. You keep the base and the side brackets in your cockpit, fit the Atlas Formula upper section with its matching Formula cushion set, and then reset the seat angle, the pedal height and the wheel position. You do not need a second complete seat.
This guide explains how the patented Atlas design works, what you need before you start and how the switch changes the feel of your rig. So you know exactly what to expect when you go from GT3 to open wheel racing.
What makes the Atlas seat switchable?
The answer sits in the base of the seat, which also gave the Atlas its name.
One base, two upper sections
Most sim racing seats are one solid shell. The SIMGASM Atlas is different. It has a shared lower base, an upper section and a cushion system that work together as one seat. The GT upper section supports your torso and shoulders in an upright position. The Formula upper section puts you lower and further back, like in a single seater.
Because the base stays the same, the mounting points on your cockpit stay the same too. That is the big idea behind the patented design. You change the character of the seat, not the way it sits on your rig.
SIMGASM | Atlas Sim Racing Seat Formula - Black
Why the cushions change with the shell
Each upper section has its own shape. So each one also has its own washable memory foam cushion set. When you add the Atlas Formula upper section, the matching Formula cushion set comes with it. This keeps the padding tight against the shell, so you do not slide around under braking.
SIMGASM founder Johan Akkerman knows this problem well. He started sim racing in 2008, welded his first frame from used gas pipes and bolted a scrapyard seat to it. Later, at Trak Racer, he was responsible for the design of the TRX seat. That experience is why the Atlas shell, cushion and base are designed as one system.
What do you need before you switch?
Check these parts first, so the switch goes smoothly in one session.
The parts list
You need your current Atlas GT seat with its lower base, the Atlas Formula upper section with the Formula cushion set and the seat brackets that already hold the seat in your cockpit. The Atlas uses side mounting. The SIMGASM seat bracket set connects the seat to the cockpit and lets you set the mounting height and angle. You keep those brackets during the switch.
SIMGASM | Seat Cushion Set for Atlas Formula
A clear space and the right tools
Take the seat out of the cockpit if you want easy access to the base. Lay a soft blanket on the floor, so the shell finish stays clean. Use the tools that fit the bolts on your brackets, and keep every bolt in a small tray. It sounds simple, but one lost bolt easily turns a quick job into a long one.
How do you switch from GT to Formula step by step?
Follow these four steps and check your position after each one.
Step 1: remove the GT cushions and upper section
First remove the GT cushions. They come off for cleaning anyway, so this takes little effort. Then release the GT upper section from the shared lower base and put it aside on the blanket.
Step 2: fit the Formula upper section
Place the Formula upper section on the base and fasten it the same way the GT section was fastened. Then press the Formula cushion set into place. Make sure every cushion sits flat and lines up with the edges of the shell.
Step 3: set the seat angle on the brackets
Mount the seat back in the cockpit. Now use the brackets to set the angle. A Formula seat sits lower and more reclined than a GT seat. Read our guide on the best recline angle for a sim racing seat if you want a good starting point.
SIMGASM | Sim Racing Seat Atlas Gran Turismo - Black
Step 4: move the pedals and the wheel
This is the step most people forget. In a Formula position your feet sit higher, so the pedal deck needs to go up. The wheel moves lower and often a little closer. Our article on GT or Formula seating position explains the geometry in more detail.
How does the Formula position change your rig?
The seat swap is only half of the story, because your whole cockpit has to follow.
Your cockpit needs room to adjust
An aluminium profile cockpit makes this easy. You slide the pedal deck and the wheel mount along the profiles and lock them again. On a Pro chassis with a 40 x 160 mm main profile, you have plenty of reserve for a direct drive wheelbase and load cell pedals in both positions. See how to set up a GT or Formula position on a Pro cockpit.
What it feels like on track
In GT mode you sit upright and look over the wheel. In Formula mode your legs point forward and your eyes sit close to the top of the rim. Braking feels different, because you push the pedal more forward than down. Give yourself a few sessions to adapt before you judge your lap times.
Is switching better than buying a second seat?
For most drivers who race both disciplines, the answer is yes.
A second complete seat takes space, costs more and needs its own mounting. With Atlas, you store one extra upper section and one cushion set. That is a smart choice in a small sim room. SIMGASM designs these parts from its base in Wijk bij Duurstede in the Netherlands, where product development started in January 2026. The goal was always simple: give drivers two real racing positions on one platform.
Questions about switching an Atlas seat
Here are short answers to the questions we hear most often.
Do I need new brackets for the Formula configuration?
No. The shared lower base keeps the same side mounting points, so your current seat brackets stay in place. You only reset the height and angle.
Is the Formula cushion set included with the upper section?
Yes. When you add the Atlas Formula upper section, its matching Formula cushion set is included.
Can I switch back to GT later?
Yes. Keep the GT upper section and its cushions. You swap them back the same way and reset your pedals and wheel for the upright position.
Which cockpit suits a Formula position best?
Any SIMGASM aluminium profile cockpit lets you raise the pedals and lower the wheel. For heavy direct drive and load cell setups, the Sport or Pro chassis gives the most reserve.
Want to learn more? The SIMGASM experts are happy to help.
