Bought A Seat We Do Not Sell? Here Is How To Work Out What It Bolts To
Fitting advice
A call this week, and we get a version of it most weeks. Bloke has bought a pair of reclining seats second hand, they are a brand we do not sell and have never had on the floor, and he wants to know what they bolt to. Fair question. Awkward one to answer if you are the shop that did not sell them.
“We do not sell them,” Cameron said, putting the phone down. “That is not the same as we cannot help him.”
Garreth was already reaching for a tape measure. “He needs to turn one over and give me two numbers. Then I can tell him.”
So here is what we actually do when the seat is not ours. This week’s call is the worked example: a pair of NRG Prisma seats going into a Toyota GT86.
- Two measurements settle almost every one of these: across, and front to back
- Plenty of makers publish no bolt pattern at all, so there is nothing to look up
- Where Planted make a bracket for the car, that is the one we would use
- If the seat maker does a bracket for your car, we will say so even though we do not sell it
The two measurements
Turn the seat upside down on a bench. Measure centre to centre between the mounting holes in the base, across the seat, then again front to back. That is it. Those two numbers decide which frame, which runner and which bracket, and nobody can tell you either of them down the phone.
Two numbers. They are what every frame, runner and bracket decision hangs on, and nobody can tell you either of them over the phone.
If a slider is already bolted under the seat, measure that too, because you now have two interfaces to satisfy: the seat to the slider, and the slider to whatever is going under it.
Send the numbers over with a photo of the base and the tape across it. That is genuinely all we need, it costs you nothing, and we do not ask where the seat came from.
What to compare your number against
There are four patterns worth knowing. Between them they account for most base mount seats sold in this country.
| Pattern | Who uses it | What it means for you |
|---|---|---|
| 345mm x 271mm | Sparco, OMP, Corbeau | The most common by a distance. Frames and runners everywhere. |
| 291mm x 330mm | Cobra | Cobra frames and Cobra runners. Their own ecosystem, and a tidy one. |
| 405mm x 290mm | Recaro | Wider than everything else. Needs a Recaro pitch runner. |
| 290mm centres | Generic FIA sliders | What a lot of universal runners are drilled to. |
Taken from our own product data. There is a fuller brand by brand breakdown with drawings coming shortly, and in the meantime base mount or side mount covers the rest of the stack.
“Most of them land on one of those four,” Cameron reckons, “and when it does you have got the run of the catalogue.” Garreth is less romantic about it: a good proportion of what comes through the door is somewhere between two of them, and that is fine too, it just means an adapter goes in the middle.
What we found on this week’s seat
NRG Prisma, part RSC-710, sliders already bolted on. We have never had one in the building.
So Cameron spent twenty minutes doing exactly what the customer had already spent an evening doing, and hit the same wall. “There is no number,” he said. “Not on the seat page, not on the slider page, not on their own chart. It just says universal.”
Which is worth saying out loud, because it stops you hunting for something that is not there. Plenty of makers publish a bolt pattern. This one does not, and that is not a fault in your searching.
Garreth found the other thing. The sellers do not agree on what is even in the box: some say the seat arrives with a universal bottom mount bracket and needs no drilling, and at least one says flatly that it cannot be bolted to your car without the right bracket, sold separately. “So he does not know what he has got,” Garreth said, “and neither do we until he measures it.”
So this is where we put him
Planted Technology, every time, wherever they make one for the car, and Garreth does not really entertain the alternatives any more, nor has he for years.
The bracket bolts to the factory seat mounting points, so nothing is cut and nothing is drilled. It is sided, so the order is unambiguous. And it gives you a platform with a drop tab at each corner instead of committing you to one mounting style before you have even measured the seat, which is precisely what you want when the seat is an unknown quantity.
On the GT86 in this week’s call that is part SB161 at £222.60 a side, and Planted price one bracket as one side of the car, so a pair of seats is two of them and two sets of whatever goes on top.
The adaption bars earn their place here as well. They sit between the floor and the seat hardware and bridge a spacing mismatch that would otherwise have you fabricating something on a Sunday, which is exactly the corner an unlisted seat backs you into. The quarter inch spacers deal with the other common one, a seat fouling a sill or a buckle stalk by a couple of millimetres.
Between the bracket, the bars and the spacers there are very few of these we cannot get bolted in properly, so send us the two numbers and we will tell you which of them you need.
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Three things we would want you to know about this seatNRG’s own product page carries the line that their products are designed for off road use only. We found no FIA homologation claimed anywhere for the RSC-710. And one retailer warns it is not intended for use with a five point harness without a proper roll cage and harness bar. None of that is us running the brand down, it is what the maker and their sellers say, and you would want it before you fit them, not after.
Common questions
Will you help if I did not buy the seat from you?
Yes, send the two measurements and a photo and we will tell you what fits.
What if my measurement matches nothing on the list?
Then it wants an adapter in between, and that is what the adaption bars are for. They cover most of these. Send us the numbers and we will tell you straight whether yours is one of them.
Do I measure the seat or the runner?
Both, if a runner is already fitted. The seat to runner joint and the runner to frame joint are two separate problems and they can want two different answers.
Can I keep the factory seat belt buckle?
Usually, though the buckle often ends up somewhere new once a bucket seat is in. It is worth checking it still reaches and is not fouled before you drive the car.
Why Planted and not one of the others?
Because it bolts to the factory points, it is sided so there is no guessing at the order, and the four corner tabs leave your options open on top. That last part matters most when nobody knows what the seat wants yet.
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Whatever you boughtSend us two numbers and a photo
Across, front to back, and a picture of the seat base with a tape on it. That is enough for us to tell you what fits, whether the seat came from us or from a forum classified six years ago. Call 0115 9893488 or send it over.
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