This one started with a customer’s classic 911. He runs OMP HTE-R Carbons in it, and he has come to dread the part where he actually has to get in. The head supports on an HTE wrap a long way round your helmet, and in a cabin as tight as an early 911 they meet the door aperture coming the other way. His question to us was simple. How deep are those head supports, and which seats do the same job with less sitting in front of your face?
That question took more digging than anything else we have been asked this year, because the depth of a head support is the one dimension seat makers almost never print. Width, yes. Height, in generous detail. How far the wings come forward, silence.
What is on this page
We went through the official dimension drawings for every head restraint bucket seat we stock: OMP, Sparco, Cobra, Corbeau, Mirco, Recaro, Sabelt and Bimarco. Two makers print a front-to-back figure at head support level. Sparco puts it on their seat sizing chart, and Cobra draws it across the top of their side views. Everyone else publishes widths and heights only. Sabelt do print a top-of-seat depth, but they measure it all the way to the front of the seat cushion, so it cannot be compared with the others and we have left it out.
So the straight answer to the first half of the question: OMP does not publish the depth of the HTE’s head support system. No dealer does either, because there is no factory figure to copy.
What OMP does publish turns out to be nearly as useful. Their drawings give two widths at head level: 490mm across the outside of the supports, and 330mm between them. Subtract one from the other and halve it, and there is roughly 80mm of shell and padding sitting beside each ear. Run the same sum on a Sparco Circuit QRT and you get 50mm a side. That is the bulk our customer feels as depth when he is threading his head past the door shut line.
Fit puzzles like this one end up on my bench, so the rest of this page runs the way I would actually work the numbers. I am Cameron, by the way.
Three measurements matter for a small cabin, and no seat on this page publishes all three. Depth at head support level is the maker’s own front-to-back figure across the top of the shell. The two widths are measured across the outside of the head supports and between them. Where a cell says not published, that is the maker’s choice, and we would sooner show you a gap than invent a number.
One honest caveat. Each maker draws their own seats, and nobody audits how another brand positions an arrow. Treat a 20mm difference between brands as noise. The gap between 230mm and 340mm is real.
| Seat | Depth at head support level | Across the outside | Between the supports |
|---|---|---|---|
| OMP HTE-R Carbon | Not published | 490mm | 330mm |
| OMP HTE-R 400 | Not published | 400mm | 315mm |
| Sparco Circuit QRT | Not published* | 510mm | 410mm |
| Sparco Circuit II QRT | Not published* | 540mm | 440mm |
| Sparco Pro ADV Carbon | 230mm | Not published | Not published |
| Cobra Sebring T Pro-Fit | 340mm | 530mm | Not published |
| Cobra Sebring Pro Ultralite Carbon | 300mm | 550mm | Not published |
*Sparco prints 260mm and 280mm for the fibreglass Circuit shells. The chart leaves the QRT column blank, so we have too.
Before looking at other brands, it is worth knowing OMP already builds a version of this exact seat for tight cockpits. The HTE-R 400 is the HTE-R shell with the head supports pulled in to 400mm across the outside, a full 90mm slimmer than the Carbon our customer runs, with 315mm still clear between them for your helmet. Same seat underneath, same harness slot layout, same FIA approval.
The shell is fibreglass, so you give up the carbon weave and a few kilos of saving. What you keep is the shape and the hold. If the problem is the doorway and the answer needs to stay OMP, this is the shortest route.
The Circuit pair are the seats I point at first when someone with a small classic asks about head protection. The supports are thin walls, about 50mm of structure and padding a side against roughly 80mm on the HTE, and the pocket between them is wide at 410mm on the Circuit and 440mm on the II. In practice that means more daylight in your side vision and less to negotiate at the door, even though the shell measures a touch wider outside.
QRT is Sparco’s resin transfer construction, which keeps the shell light without carbon money. The Circuit starts at £528, which makes it the cheapest way onto this page by a distance. The II is the same idea sized for a bigger driver, wider at the shoulders and taller in the shell. Both are FIA approved and take a harness through proper slots.
If the question is purely which seat puts the least in front of your face, this is where the published numbers point. Sparco’s chart gives the Pro ADV Carbon 230mm front to back at head support level, the smallest published figure on this page. Their own plain-backed shells only run 30mm less.
It is also the natural like-for-like swap for an HTE-R Carbon owner. Carbon shell, serious motorsport seat, and it hangs on side mounts the same way. The price sits in the same territory as the seat it would replace, so the doorway problem gets solved without giving anything up.
Cobra are the other maker honest enough to draw the number, and the Sebring T carries 340mm at head level on their factory drawing. That is the deepest published figure on this page, and it still reads as a GT seat with room to move: the supports sit wide at 530mm across, so the wings frame your helmet without hugging it.
Where the Sebring earns its place is value and fit. It is a British-built fibreglass GT seat with a proper head restraint at a fraction of carbon money, and Cobra trim it in-house so colour options are genuinely open. The standard shell suits everyday-sized drivers and there is a wider GT version if you need it. For a classic that gets driven to the circuit as much as around it, this is the sensible middle.
The Ultralite is the Sebring shape rebuilt in carbon, and the factory drawing gives it 300mm at head level with a 550mm width across the top. The shell figure on Cobra’s drawing is 6.1kg, so the name is earned. Like the Pro ADV Carbon, it belongs in the same conversation as the seat it would replace.
Between the two carbons, the Sparco publishes the smaller depth figure and the Cobra gives you the wider, airier feel around the helmet. That choice comes down to your head and your taste, which is exactly the sort of thing a showroom visit settles in five minutes.
The seat is only half the sum in an early 911. The other half is what it sits on. A fixed bucket on side mounts and runners changes your height and reach, and in a cabin this size 20mm of seat height is the difference between your helmet in the headlining and not. Every seat on this page is a side-mount design, and we build the mount and runner package to the car, so tell us what you are putting it in and we will spec the hardware with it.
Worth reading alongside this page: our reclining seat guide for the classic 911 if the car is more road than track, and our universal sliding runners guide for how handle widths and runner heights work.
OMP does not publish that figure, and no dealer has a factory number to quote. What OMP does publish is the width picture: 490mm across the outside of the supports and 330mm between them, which works out at roughly 80mm of shell and padding beside each ear. If you need the literal front-to-back millimetre, ask us and we will get the measurement for you.
It is a superb seat, and the wrap-around head protection is the whole point of the design. The question in a small classic is purely one of space: the deeper the supports, the more of the door aperture they use up. That is a fit consideration, the same as shoulder width or base length.
Of the makers that publish the figure, the Sparco Pro ADV Carbon is the smallest at 230mm front to back at head level, with the Cobra Sebring Pro Ultralite at 300mm and the Sebring T at 340mm. Sparco’s plain-backed shells run 160mm to 205mm at the same point, for scale.
The seats on this page are FIA approved and take a full harness through proper slots, which is what a frontal head restraint needs. The support depth changes how much seat sits beside your face; the device itself mounts to you and your harness, so it works the same either way.
The HTE’s removable cushions are in the leg area, and the head support padding is part of how the seat does its job, so that is not the route. Choosing a shell with slimmer supports keeps the protection engineered as the maker intended and gains you real room.
The XL shell adds height and width lower down, and OMP’s drawings show the same 490mm and 330mm at the head supports on both sizes, so the picture at the door stays the same.
For the customer whose 911 started this page: sit in a Sparco Circuit QRT first. The thin supports and the wide pocket answer the exact complaint, for a tenth of the cost of replacing carbon with carbon. If it has to stay carbon and stay serious, the Pro ADV Carbon holds the smallest published depth figure of anything we sell. And if the answer is to keep the seat he already knows, the HTE-R 400 is OMP quietly agreeing that some cars need slimmer supports.
We would sooner show you a gap in a table than a number nobody can stand behind, and this subject is mostly gaps. The three figures that do exist tell a consistent story though: head protection does not have to come forward very far to work, and the seats that keep it trim are nicer to live with in a small car every single day you own it. Message us with the car and the driver and we will find the seat that fits both. Ask for Cameron.
The five reclining sport seats we rate for the VW Corrado, with the Cobra, Sparco, Planted Technology and Corbeau frame routes that bolt directly to the factory mounting points across all years from 1988 to 1995.
A classic 911 owner asked how deep the head supports on his OMP HTE-R Carbons really are. Nobody prints that number, so we went through every maker’s drawings. Here is everything that is published, and the seats that give your head more room.
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A Sylva Fury owner sent us six cockpit measurements and asked which of our narrow bucket seats would fit. Cobra Roadster 7, Mirco SX5, SX6 and LS sized against a real Fury, with every dimension drawing.
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