Question 1

What do you need from me to check fitment?

Accepted Answer

The registration, the size or the look you are after, and anything on the car that is not standard. Specifically: whether it is on standard or aftermarket suspension, whether the brakes have been changed, and whether the arches have been modified. If you already know the wheel you want, send the full specification — diameter, width, offset, PCD and centre bore — rather than just the model name, because most wheels are made in several fitments and the name alone does not identify one. If you are replacing an existing set, the back of the current wheel is usually stamped with its size and offset, and a photo of it answers half the questions in one go.

Not covered here? Tell us the vehicle and what you’re after and we’ll come back with a straight answer.

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info@s1automotivegroup.co.uk

Question 2

What do PCD, ET and centre bore actually mean — and why do you keep asking for them?

Accepted Answer

PCD is the pitch circle diameter: the number of studs and the diameter of the circle they sit on, written as 5×112 — five bolts on a 112 mm circle. It has to match the hub exactly. ET is the offset in millimetres, from the German Einpresstiefe, and describes how far the wheel’s mounting face sits from its centreline; a higher ET pulls the wheel inwards, a lower one pushes it outwards. Centre bore is the hole in the middle that locates the wheel on the hub — it must be equal to or larger than the hub spigot, and where it is larger, spigot rings centre it properly. Get any of the three wrong and the wheel either will not go on or will not run true.

Question 3

Is a registration enough on its own?

Accepted Answer

For a standard car, usually. The registration gives us the model, the factory fitments and the hub data, which is enough to quote from. It stops being enough the moment the car has been changed — coilovers or lowering springs alter clearance, a big brake kit changes the minimum diameter and the spoke profile the wheel needs, and wide-arch bodywork changes the offset entirely. It also tells us nothing about what you want the car to look like. That is why there are usually a couple of questions after the reg rather than a price straight off it.

Question 4

What is a staggered setup, and do I need one?

Accepted Answer

Staggered means the rear wheels are wider than the fronts, often larger in diameter too, with tyre sizes to match. Plenty of rear-wheel-drive cars leave the factory staggered. On others it is a choice about stance and grip balance rather than a requirement. It is not automatically better — a staggered set cannot be rotated front to rear, so the rears wear out on their own, and on four-wheel-drive cars mismatched rolling diameters can put load through the drivetrain. Where a car is better square, we will say so. Per-corner setups — a different specification at each of the four corners — are possible on forged, and are usually about getting an even, correct fit on a car that is not symmetrical to begin with.

Question 5

What is the difference between forged, flow-formed and cast?

Accepted Answer

Cast wheels are poured into a mould. They are the cheapest to produce and the heaviest for a given strength, and they account for most factory and budget aftermarket wheels. Flow-formed wheels — also sold as rotary-forged — are cast at the centre, then the barrel is spun and stretched under heat and pressure, which aligns the grain through the barrel and allows it to be made thinner, so the wheel comes out lighter and stronger than a cast equivalent without the cost of full forging. Forged wheels are pressed from a solid billet of aluminium under very high force, then machined to their final shape; the grain runs continuously through the wheel, which makes it the strongest and lightest of the three. Forged is also the only one where the specification is genuinely open, because the wheel is machined rather than cast to an existing mould.

Question 6

How long does a set of custom forged wheels take?

Accepted Answer

They are made to order, so there is no single answer — and we would rather explain what drives it than quote a number we cannot hold to. Four things move it. Construction: monoblock is one process, while 2 and 3-piece add barrel manufacture and assembly. Finish: a standard gloss or satin is quicker than a multi-stage brushed finish or a custom colour. Whether the specification is settled, because a change part-way through restarts part of the process. And the queue at the point the order is placed. Stock wheels and tyres are a different matter and come down to availability at the time of enquiry. Either way, you get a realistic time with the quote, and you hear from us if it moves.

Question 7

Do you supply tyres with the wheels?

Accepted Answer

Yes, and it is usually the better way to do it, because the tyre size is part of the fitment rather than a separate decision afterwards. Going up a wheel diameter without dropping the tyre profile changes the rolling diameter, and that affects the speedometer reading, the effective gearing and, on some cars, the ABS and traction systems. We size the tyre to hold the rolling diameter close to standard unless you have asked for something different. We supply Michelin, Pirelli, Continental, Bridgestone, Goodyear, Dunlop, Yokohama, Toyo, Falken, Hankook, Nankang and Davanti, so the choice is normally about budget and how the car is used rather than what we can get.

Question 8

Can you source a specific wheel or brand?

Accepted Answer

Ask. We source and supply from BBS, OZ Racing, Work Wheels, RAYS, BC Forged, Vossen, Rotiform, Titan 7, Forgeline, Vorsteiner, Method, American Racing, KMC, TSW, Team Dynamics, Calibre, Cades and Dare, among others. To be clear about what that list is: it is what we source and supply, not a claim to be an authorised distributor for each name on it. If a wheel has been discontinued, or the fitment you want was never made in the first place, the honest answer is often that a forged set built to the specification will get you there sooner than waiting for something to reappear.

Question 9

Do you work with trade, and how does that work?

Accepted Answer

The Retail Partnership Program is how we work with the trade — retailers, garages, fitting centres and resellers. Partners get access to our wheel and tyre supply across everyday, performance and motorsport fitments, quoted with the fitment data behind it rather than left to work it out themselves, and can run our kiosk software so their own customers can look up what fits in the showroom or workshop. We supply partners rather than compete with them for retail work. The starting point is a conversation about what you sell and how you sell it.

Common Questions.

What do you need from me to check fitment?+

What do PCD, ET and centre bore actually mean — and why do you keep asking for them?+

Is a registration enough on its own?+

What is a staggered setup, and do I need one?+

What is the difference between forged, flow-formed and cast?+

How long does a set of custom forged wheels take?+

Do you supply tyres with the wheels?+

Can you source a specific wheel or brand?+

Do you work with trade, and how does that work?+