Office Chair Base Compatibility: Which Seats Convert, And Which Never Should
From the car to the desk, hole centre to hole centre
A customer rang us this week wanting to put a car seat on an office base, which is one of the most satisfying jobs on the site when the seat suits it and one of the most disappointing when it does not. So here is the whole answer in one place, including the part we say no to.
An office base kit is not universal, and the reason is a single piece of steel. The adaption plate between the seat and the column is cut for a bolt pattern, and our plates reach a maximum of 345mm across. Everything on this page comes back to that number.
- An office base kit is three parts: the five arm star on castors, the gas lift column and the adaption plate that joins them to the seat
- The plate is the only part that cares which seat you own, and ours reach a maximum of 345mm across the bolt pattern
- Sparco and OMP base mount seats sit at 345mm x 271mm, the widest pattern that converts. Cobra and Corbeau sit at the narrower 291mm
- Recaro at 405mm is past the ceiling, so a Recaro bucket does not convert on our plates. Recaro build finished office chairs instead
- We do not recommend converting an OEM car seat: the weight is wrong for a gas lift base and the mounting points do not line up
What an office base kit actually is
Every office base kit we sell is the same four parts. A five arm star on castors, a gas lift column that gives the height and the swivel, the seat mechanism that sits on top of that column and carries the height lever, and an adaption plate that bolts onto the mechanism and picks up the seat. The seat is never included, and the seat supplies its own recline if it has one. The base supplies height, swivel and castors, and nothing else.
Five parts, and only one of them cares which seat you own. Get the plate right and the rest is bolt together work with hand tools.
The plate is the whole questionFour of those five parts are the same whichever seat you own. The plate is cut for a bolt pattern, so the plate is the part that either lines up or does not. When we ask you which seat you have before taking an order, that is the only thing we are working out.
The patterns our plates reach
Two patterns the adaption plate is cut for, and one it is not. The 345mm figure is the ceiling: it is the widest the plate reaches, which is why a Recaro shell and the wide Cobra recliners stay in the car.
Our plates are cut for two of the base mount families. The wide one is 345mm x 271mm, which Sparco and OMP share, and it is the widest pattern that converts. The narrow one is the 291mm Cobra and Corbeau spacing. A Corbeau shell is the easy case here because Corbeau drill their seats for both worlds, so a Corbeau will find holes on either plate.
The pattern that does not convert is Recaro at 405mm x 290mm, and the wide Cobra recliners alongside it. Those sit 60mm past what the plate can span, and there is no version of our plate that reaches them. If a Recaro at the desk is the goal, Recaro build finished office chairs from the factory and that is the route. Full pattern detail for every brand is in our seat bolt patterns guide.
Which kit for which seat
| Your seat | The kit | Pattern the plate is cut for |
|---|---|---|
| Cobra base mount buckets and recliners | Cobra Office Seat Base, part ACCES10 | 291mm Cobra spacing |
| Corbeau base mount buckets and Sportline recliners | Corbeau Office Seat Base, part CORH24QZ241 | 291mm, fixings are M8 |
| OMP base mount seats | OMP Office Seat Base, part OMP-Office-Base | 345mm x 271mm |
| Sparco base mount seats | The OMP kit | 345mm x 271mm, the pattern Sparco and OMP share |
| Auto Style base mount seats | Auto Style Office Seat Base, part AUTCGZNY269 | 345mm wide, but not the Type Classic SS50Z |
| Recaro, and the wide Cobra recliners | None of them | 405mm, past the 345mm ceiling |
| Anything else | Endurance base with adaption bars | Bars that can be positioned, not a fixed cut |
The kits are brand specific on purpose, because each plate is cut for one spacing. A base bought for another marque will not line up, so order the kit that matches the seat. The Auto Style exception is the one to read twice: the kit covers most of that range but the Type Classic shell uses a different rail arrangement.
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Those four are examples from the range and each comes in black or chrome. The rest of the base kits and plates sit in office racing chair accessories, and if you would rather skip the conversion entirely, the finished office and gaming chairs arrive built.
Why we will not convert an OEM car seat
This is the one we get asked most and the one we turn down. Somebody has a seat out of a road car, often something with a badge worth sitting in, and wants it behind a desk. We do not recommend it, for two plain reasons.
The first is weight. A production car seat is built to be bolted to a floor pan, so it carries a heavy steel frame, deep foam and usually its own runners, and some of them carry motors as well. A gas lift column and a five arm star are built to carry a sports seat and a person. Hanging a car seat off one puts load somewhere it was never meant to go.
The second is the mounting points. An OEM seat is not drilled to a motorsport pattern at all. Its fixings sit where the car needed them, often four points at four different spacings, sometimes on rails that are part of the seat and cannot come off. Our plate is cut for 345mm or 291mm, and an OEM seat will rarely put a hole near either figure.
What we will do insteadTell us the look you are after and we will point you at a sports seat that gives you it and bolts up properly. Most of the retro and classic shells were designed for exactly this job, and a seat built for a base mount plate will sit square, swivel properly and stay that way. That is a better desk chair than a converted car seat on the wrong hardware.
When the seat is not one of the four brands
Plenty of seats fall outside Cobra, Corbeau, OMP and Auto Style, and there are two ways through. Our own Endurance Motorsport kit swaps the single cut plate for adaption bars that run under the seat and pick up on its own base mount holes. Because the bars can be positioned, they cover a wider spread of seats than a plate cut for one maker. If you already own a height adjustable base and only need the joining piece, the adaptor plate is sold on its own: laser cut steel with round holes and slots on all four edges, so it picks up seat rails at more than one width.
The third listing below is the one people forget. A bar stool base sits taller and does not run on castors, which puts a converted seat at counter or workbench height. For a garage, a showroom or a bar it is the right base. For a desk it is not.
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Again these are examples from the range. Base mount seats vary in rail width, in spacing and in whether the underside is flat enough to take a bar at all, so send us the make and model before you order and we will tell you whether the bars pick up on it. It is a two minute answer at our end and it saves a plate arriving that is a few millimetres out.
Side mount seats cannot do this
One hard limit worth stating early, because it catches people who own the nicest seats. A side mount seat bolts through the sides of the shell and has no bottom rails, so there is nothing for the plate to pick up on. No amount of adapting fixes that: the seat has no floor to bolt down to. If your shell has fixing points on its flanks and a bare underside, it is a side mount seat and it stays in the car. Our base mount or side mount guide walks through telling the two apart.
Measuring yours before you order
Turn the seat over and measure hole centre to hole centre, never edge to edge. Width across the seat first, fore and aft second. Land within a millimetre or two of 345mm and you are in the Sparco and OMP world, land near 291mm and you are in the Cobra and Corbeau one, and anything at 405mm is past what our plates reach. Send Cameron those two numbers with the seat make and model and a photo of the underside, and the answer usually takes one reply.
Common questions
Can I put my car seat on an office base?
If it is a base mount sports seat from one of the brands we cut plates for, yes, and the kit is on this page. If it is the seat out of a road car, we advise against it. The weight is wrong for a gas lift base and the OEM mounting points will not line up with a 345mm or 291mm plate.
Is there a Sparco office base kit?
There is no kit badged Sparco, but there does not need to be. Sparco and OMP base mount seats share the same 345mm x 271mm pattern, so the OMP kit is the one to order for a Sparco seat.
Will a Recaro convert?
Not on our plates. Recaro run their own 405mm x 290mm pattern, which is 60mm wider than the plate reaches. Recaro do build finished office chairs from the factory, and that is the route to a Recaro at a desk.
I have the base already and just need the plate.
The adaptor plate is sold on its own. It is the laser cut steel piece with round holes and slots on all four edges, so it picks up base mount rails at more than one width. It is also the part to order if an older kit has lost or bent its plate.
Can I use a base bought for a different brand of seat?
No, and this is the most common ordering mistake we correct. Auto Style rail spacing is not Cobra or Corbeau spacing. If there are mixed brands in the house, order the base that matches the seat.
What if my seat is not a brand you list?
Then the Endurance kit with adaption bars is the one to look at, because the bars can be positioned instead of being fixed by a single cut pattern. Tell us the seat first and we will confirm the bars pick up on it.
Does the base give me a recline?
No. The base gives height, swivel and castors. Any recline comes from the seat, so a reclining sports seat converts into a reclining office chair and a fixed back bucket converts into a fixed one.
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The next stepTell us the seat and we will name the base
Two measurements off the underside and the make and model of the seat is all we need. Ring 0115 9893488 and Cameron will tell you which kit fits, or whether the adaption bars are the better answer. Garreth has been doing these conversions since long before they were a trend, so if you are still choosing the seat, ask first and the plate will never be your problem.
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