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Offset, backspacing and poke

Wheel offset calculator

Swapping a 2027 Nissan Frontier's stock 17x7.5 +30 mm wheels for 17x8.5 0 mm moves the wheel face 1.7 in out and, with 285/70R17s, the tire’s edge 1.6 in; inside it gains 0.7 in of room. Backspacing goes from 5.43 to 4.75 in.

Now

Stock
mm
%
in
31.6 in · 803 mm tall
Maker
in
Maker
mm

17x7.5 +30 mm · backspacing 5.43 in

New

mm
%
in
32.7 in · 831 mm tall
in
mm

17x8.5 0 mm · backspacing 4.75 in

For my vehicle

Fills in the stock wheel, offset and tire from the maker's documents. Only vehicles whose maker publishes the offset are listed.

2027 Nissan Frontier PRO-4X Crew Cab 4x4 SWB

Stock wheel
17 x 7.5J (aluminium)
Maker
Offset
+30 mm
Maker
Stock tire
265/70R17
Maker

Sources: 2027 Frontier Owner's Manual and Maintenance Information (opens in a new tab) · 2027 Nissan Frontier Press Kit (specifications and pricing) (opens in a new tab)

17x7.5 +30 → 17x8.5 0

Math on nominal sizes

On a 2027 Nissan Frontier PRO-4X Crew Cab 4x4 SWB

Tire edge moves

+1.6in

+40 mm out

Wheel face moves

+1.7in

+43 mm out (poke)

Room inside

+0.7in

at the wheel's inner lip; tire +0.8 in

Backspacing

4.75in

from 5.43 in

HUB FACE← INBOARDOUTBOARD →FENDER REF.285/70R17+1.6″+0.7″
Cut through the axle, looking from the front, to scale. Dashed: now. Solid: new. The fender reference is your current tire’s outer edge, the one you know fits; your fender, brakes and suspension aren’t drawn.
From the hub face, in inches
EdgeNowNewChange
Tire, outside+4.04+5.61+1.57
Wheel lip, outside+3.07+4.75+1.68
Wheel centreline−1.180.00+1.18
Wheel lip, inside−5.43−4.75+0.68
Tire, inside−6.40−5.61+0.79

Plus is outward, toward the fender; minus is inboard, toward the suspension. Backspacing is the inside lip’s distance as a positive number.

What it means

Guidance, not advice

  • Outside

    Sticks out

    The tire's outer edge moves out 1.6 in (+40 mm), the wheel face 1.7 in. Check fender and flare coverage at full lock and with the suspension compressed: past the fender a tire throws mud and stones, and some places have rules about it.

  • Inside

    More room

    +0.8 in more room at the tire's inner edge and +0.7 in at the wheel's inner lip.

  • Less offset

    Steering feel

    The wheel's centreline moves 1.2 in outward. That lengthens the scrub radius: heavier steering, more kickback over bumps, and more load on the wheel bearings. Track width grows 2.4 in across the axle.

Fitment also depends on your brakes, fender, suspension and steering. This is math on nominal sizes, not a test fit: a tire’s real width changes with the wheel it’s on, and lift, alignment and load move what it can touch.

Compare the tire sizes →Nissan Frontier spec plate →

Formulas

How we calculate

Everything is measured from the hub face, where the wheel bolts on. Offset says where the wheel's centreline sits from that face; width says how far the wheel spreads either side of it.

Lip-to-lip width

nominal width + 1 in (the flanges add about ½ in a side)

e.g. 7.5 + 1 = 8.5 in

Backspacing

(width + 1) ÷ 2 + offset ÷ 25.4

e.g. (7.5 + 1) ÷ 2 + 30 ÷ 25.4 = 5.43 in

Front spacing

(width + 1) ÷ 2 − offset ÷ 25.4

e.g. (7.5 + 1) ÷ 2 − 30 ÷ 25.4 = 3.07 in

Wheel face moves out

(new width − old width) ÷ 2 + (old offset − new offset) ÷ 25.4

e.g. (8.5 − 7.5) ÷ 2 + (30 − 0) ÷ 25.4 = +1.68 in

Room inside

old backspacing − new backspacing

e.g. 5.43 − 4.75 = +0.68 in

Tire edge moves out

(new tire width − old tire width) ÷ 2 + (old offset − new offset) ÷ 25.4

e.g. (11.22 − 10.43) ÷ 2 + (30 − 0) ÷ 25.4 = +1.57 in

Offset from backspacing

(backspacing − (width + 1) ÷ 2) × 25.4

e.g. (4.5 − (8 + 1) ÷ 2) × 25.4 = 0 mm

Tire widths are nominal: the section width printed on the sidewall, measured on its maker’s reference wheel. On a wider wheel the same tire stands a little wider.

Stock wheel sizes and offsets come from the makers’ documents, each linked when you pick a vehicle. We list only the vehicles whose maker publishes the offset.

FAQ

Questions people ask

What is wheel offset?

The distance from the wheel’s centreline to the face that bolts to the hub, in millimetres. Positive offset puts that face outboard of the centreline and tucks the wheel in; negative pushes the wheel out. At 0 mm the wheel is centred on the hub face.

How much will a 0 mm offset wheel poke?

Against a +30 mm wheel of the same width, 30 ÷ 25.4 = 1.18 in further out at the face and at the tire. Going one inch wider at the same time adds another half inch on each side, so a 17x8.5 0 mm sits 1.68 in further out than a 17x7.5 +30 mm.

What backspacing is a +30 mm offset?

It depends on the width: 5.43 in on a 7.5 in wheel, 5.68 in on 8 in, 5.93 in on 8.5 in. Backspacing = (width + 1) ÷ 2 + offset ÷ 25.4.

Will a wider wheel hit the suspension?

At the same offset, every extra inch of width adds half an inch on each side, so the inner lip moves half an inch closer to the control arm, coil and tie rod. To keep the inside where it was, lower the offset by half the extra width: one inch wider, 12.7 mm less offset.

Does offset change steering and bearings?

Less offset moves the tire’s centre further from the steering axis. That lengthens the scrub radius: heavier steering, more kickback over bumps and more load on the wheel bearings. Wheel spacers do the same thing.

Is the math enough to know it fits?

No. It tells you how far everything moves from where it is now. Whether that clears depends on your brakes, fender, suspension, lift, steering lock and the tire’s real shape: test-fit at full lock and with the suspension compressed before you buy a set.

Data

Stock wheels and offsets

The makers who publish their wheel offset, and every stock wheel we have for them.

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