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Measuring Your Own Bolt Pattern

A four-bolt ATV pattern is one measurement: centre to centre between two studs diagonally opposite each other. What to record, what the figure settles, and what it does not.

Gary Bauch/

The measurement

A four-bolt hub carries its studs at ninety-degree intervals. Two studs opposite one another therefore sit on the full diameter of the bolt circle, and the distance between their centres is the figure the pattern is named for. That is the entire measurement: centre to centre, across the diagonal, in millimetres.

Take it with the wheel off and the tape on the studs themselves. A wheel’s own holes are frequently larger than the studs that pass through them, and on some wheels they are slotted so that one wheel covers more than one pattern. A figure read off the wheel is a figure read off clearance, not off the hub.

Take both diagonals. The second reading is a check rather than a second figure: on a four-stud hub the two diagonals describe the same circle and should read the same. Two readings that disagree mean the tape came off a stud centre, or the hub has more than four studs and two of them were stepped over.

Record the result the way fitment listings record it — bolt count, slash, circle diameter in millimetres. Four studs on a 110 mm circle is written 4/110.

A four-stud and a five-stud wheel hub, with the measurement each one givesThree schematic drawings. On the left, a hub face seen from the front with four studs spaced at ninety-degree intervals around a bolt circle. Both diagonals are drawn between opposite studs; each passes through the centre of the hub and both are marked as equal, so each diagonal is the diameter of the bolt circle itself. On the right, the same hub with five studs at seventy-two-degree intervals. No two studs are opposite one another, so the longest stud-to-stud line steps over the top stud and passes above the centre rather than through it: it is drawn against a dashed diameter of the same bolt circle, drawn parallel to it, and it is the shorter of the two lines. Below both, two studs of one hub seen enlarged, with three parallel measurements marked: across the outside edges of the pair, across their inside edges, and between their centres, which is the midpoint of the other two. The drawings are schematic and carry no dimensions; nothing is to scale.FOUR-STUD HUBboth diagonals cross the centreso each reads the bolt-circle diameterFIVE-STUD HUBthe bolt-circle diameterwhat the tape readsno two studs are oppositethe longest reading is a chord, not a diameterWITHOUT EYEING A CENTREacross the outside edgescentre to centreacross the inside edgesthe midpoint of the twoedge readings is thatcentre distance
Fig. 1. Left: a four-stud hub, drawn from the front. The studs sit at ninety-degree intervals, so each diagonal passes through the centre and reads the bolt circle’s own diameter; the tick marks are why the second diagonal is a check rather than a second figure. Right: five studs at even intervals, drawn because two diagonals that disagree can mean a stud was stepped over. No two of the five are opposite, so the longest line the tape can take between studs is the chord across the top of the circle, and the bolt-circle diameter is the dashed line below it, through the centre. Below: two studs of one hub enlarged, with the outside-edge and inside-edge readings whose midpoint is the centre distance. Schematic — nothing is to scale and no dimension is drawn. — Original drawing for The Quad Track Log, 2026-09-27

The patterns the manufacturers publish

Kimpex publishes the Commander WS4 in two bolt-pattern variants. Between them they name the patterns an ATV hub is most likely to be:

4/110, 4/115, 4/137
4/156Kimpex, Commander WS4 Track Kit, read 2026-09-26

Camso publishes no pattern list for its current ATV systems. The T4S and the X4S describe the hub in the same words:

Cast steel multi-bolt (4) pattern hubCamso, ATV T4S and X4S product pages, read 2026-09-26

Four bolts, more than one pattern, and no statement of which patterns. So on a Camso system the measurement is not what resolves the order — the vehicle-specific mount kit is keyed to the machine, and the pattern is something to hand over rather than something to look up.

Two of the published patterns are five millimetres apart

4/110 and 4/115differ by five millimetres on the diameter, two and a half on the radius. A steel tape hooked over a cast stud, read at arm’s length on a machine sitting on its own wheels, does not reliably resolve that. Neither does a tape read across a hub face with a season of mud dried onto it.

So record the measurement, not the conclusion. “It measured 112 mmon both diagonals” is a checkable statement that a fitment desk can work with. “It’s a 4/110” is a conclusion that has already thrown the evidence away, and if it is wrong there is nothing downstream that can catch it.

Two habits remove most of the error. Measure across the outside edges of the two studs, then across the inside edges, and take the midpoint of the two readings: with equal studs that is the centre distance without having to eye a centre at all. Then write both raw readings down next to the result, so the figure can be audited later instead of taken on trust.

What the pattern settles

On the Kimpex side it settles which of the two published variants a machine takes. That is what the two variants are for, and it is the one place where the measurement is the answer rather than an input to it.

On the Camso side the pattern is not the field the published data exposes. The vehicle-specific part of a Camso kit is the mount kit, whose weight both product pages list separately from the four track units, read 2026-09-26. What the mount kit covers per machine is not published as a bolt pattern.

Nor is the pattern something you can look up in the published applications. Across 13 makes, 1,022 distinct machine titles and model years 1986–2026, the catalogue holds 1,389published ATV applications, and carries no wheel-bolt-pattern field in any of them. What it does record per row is the machine title, the model years, the rear suspension type and the sprocket pair — 656 rows publish a rear suspension value and 733 publish none. So the rear suspension type is the other thing to establish about your own machine before you ask anybody anything: the listings are keyed on it, and they are not keyed on the wheel pattern.

Counted from the published applications, read 2026-09-26. Both manufacturers revise their lists, so re-check a figure before you order against it.

The pattern is not readable off a catalogue number

Kimpex presents the two bolt-pattern variants as options on one product page and attaches no distinct catalogue number to either, read 2026-09-26, and publishes no mapping from a part-number family to a bolt pattern. A number on a box or in an old invoice therefore does not tell you which variant is in it.

That matters most buying used. A catalogue number off a box or an old invoice will not tell you which of the two patterns a kit was built for, so ask the seller which machine it came off — the model it was fitted to is better evidence than the part number — and measure your own hub before you agree a price. Guessing gets you the wrong hub hardware, paid for, shipped, and discovered on a bench with the wheels already off.

What to send with the measurement

The pattern narrows the hardware. It does not resolve a kit on its own, because the vehicle-specific parts are keyed to the machine rather than to the hub. Kimpex publishes the ordering sequence in its own words:

Select the proper track adapter (BOM1) depending on your VTT model
Select the proper Front anti-rotation (BOM2) and rear (BOM3)Kimpex, Commander WS4 Track Kit, read 2026-09-26

Three vehicle-specific selections sit behind the track kit, each keyed to the model. So the message that actually resolves something is: the model year; the model and trim as the machine is badged rather than as it is usually called; the rear suspension type where it is known; the measured pattern together with the raw readings it came from; and whether the machine already carries track hardware of any kind.

Where the desk comes back with a published condition against the application — a suspension lift required, an interference — that is Camso’s flag. Camso publishes the flag and defines it in a legend; it does not publish what the condition interferes with on a given machine. 117 of 1,389 published applications carry at least one. What those flags mean on a bench is the subject of Field Notes. Ask the desk what comes off the machine before you agree to the order, because the flag itself does not say.

Kimpex publishes no per-application condition data at all: every Commander WS4 record in this catalogue has an empty remarks field. The absence of a WS4 entry below means nobody has published a condition for it — not that none exists. Camso is the only manufacturer here that publishes these flags, so this page is necessarily a Camso view of the catalogue.

Two adjacent pages carry the rest of the identification work: reading the model designation the catalogue files a machine under is on the Identify index, and working out what is already bolted to a used machine is on An Unmarked System in a Barn.

Manufacturer figures on this page were read on 2026-09-26 and catalogue figures on the date in the margin. Both change. Re-check either before quoting it anywhere that carries commercial weight, and if a figure here disagrees with a manufacturer's own current page, theirs is the one to use.