Fitment guideCalculatorWheel fitment, explained.
Flush, poke, sunk, stretch, meaty, camber. Here is what all of it means, with diagrams you can play with. Every figure on this page uses the same maths as our wheel fitment calculator, so what you see here is what you'll get when you plug in your own sizes.
Offset (ET)
Offset is the distance in mm between the middle of the rim and the face that bolts to your hub. It's stamped on the wheel as ET, short for the German Einpresstiefe.
For the same wheel width, a higher offset pulls the wheel into the car and a lower or negative offset pushes it out. The width sets how wide the wheel is; the offset sets where that width sits.
Flush, poke & sunk
Drop an imaginary plumb line straight down from the edge of your fender. Where the outer lip of the wheel sits against that line is your fitment.
All three figures use the same 18" tire and the same car. Only the wheel width and offset change.
Distance from the hub mounting face out to the fender lip. Measure it with a straight edge dropped from the fender.
- Measure your current wheel and fender before buying. Our calculator tells you how much further in or out the new wheel will sit.
- The tire's sidewall usually bulges a few mm past the rim lip. Allow for it when you're aiming for flush.
- Going wider or lower in offset also moves the inner rim. Check the clearance to the strut and spring, not just the fender.
- Don't run poke if your local laws require the tread to be covered. Fender flares or rolled arches can bring it back in.
Camber
Camber is how far the wheel leans in or out when you look at the car from the front. Negative camber tilts the top of the wheel in towards the car.
Because the wheel pivots around where the tire meets the road, a few degrees of negative camber pull the top of the rim in under the fender. That's how a lot of stanced cars get away with a poking wheel.
- A little negative camber (about −0.5° to −1.5°) helps grip in corners and is common on stock and lowered cars.
- Lowering a car usually adds negative camber by itself. Get an alignment after fitting coilovers or springs.
- Big static camber wears the inside edge of the tire fast and reduces braking grip in a straight line.
- Adjustable top mounts, camber bolts or arms let you dial it in. Your car's alignment spec is the safe baseline.
Stretched vs meaty tires
Every rim width has a range of tire widths it's designed for. Fit a tire narrower than that range and the sidewalls angle inwards: that's stretch. Go wider and they bulge out past the rim: meaty.
Stretch helps a wide wheel tuck inside the fender. Meaty protects the rim lip from curbs and gives a chunkier, more off-road look.
- Stay within the tire maker's approved rim widths for that size. It's printed in their spec sheets.
- Mild stretch is common for fitment, but keep pressures up. Low pressure makes a stretched bead easier to unseat.
- Don't run extreme stretch on a daily driver. A bead that pops off the rim mid-corner is an instant flat.
- Changing tire width or profile changes overall diameter, and with it your speedometer reading.
Reading a tire size
The size on the sidewall tells you its width, sidewall height and the wheel it fits. Type your size in to decode it. From that we can work out its overall diameter, which is what your speedometer cares about.
The numbers after the size, like 91W, are the load index (how much weight each tire carries) and speed rating (W = 168 mph). Match or beat your car's original ratings.
Glossary
The words you'll see on forums, wheel listings and in our calculator.
- Offset (ET)
- Distance in mm from the rim's centreline to the hub mounting face. From the German Einpresstiefe. Positive values put the face towards the outside of the wheel.
- Backspacing
- Distance from the mounting face to the inner rim lip. The US way of describing the same thing as offset. We call it inset in the calculator.
- Poke
- How far the outer rim lip sits from the mounting face, or past the fender.
- Flush
- Rim lip in line with the fender lip.
- Sunk / tucked
- Wheel sits inside the fender. Tucked usually means the tire sits up inside the arch on lowered cars.
- Fitment
- How a wheel and tire combination sits in the arch: its width, offset, diameter and tire choice together.
- Camber
- Tilt of the wheel seen from the front. Negative camber tilts the top inwards.
- Stretch
- Tire narrower than the rim's recommended range, so the sidewalls angle inwards.
- Meaty
- Tire at or above the widest recommended size, so the sidewalls bulge outwards.
- Aspect ratio / profile
- Sidewall height as a percentage of the tire's width. 225/40 has a 90 mm sidewall.
- PCD / bolt pattern
- Number of studs and the diameter of the circle they sit on, e.g. 5x114.3.
- Center bore
- The hole in the middle of the wheel that centres it on the hub. Use hub rings if the wheel's bore is larger.
- Spacer
- A plate between hub and wheel that reduces the effective offset by its thickness.
FAQ
Quick answers to the questions we get asked most.
What does flush fitment mean?
Flush fitment means the outer edge of the wheel (the rim lip) sits in line with the edge of the fender when you drop a vertical line down from it. The wheel neither sticks out past the bodywork (poke) nor sits deep inside it (sunk).
How do I calculate wheel poke?
Poke from the hub mounting face is half the rim width minus the offset. Convert the rim width to mm first (1 inch = 25.4 mm). An 18x9 ET25 wheel is 228.6 mm wide, so it reaches 114.3 − 25 = 89.3 mm out from the hub. Compare that with your current wheel to see how much further out the new one sits.
Does a lower offset make the wheel poke more?
Yes. Lowering the offset moves the mounting face towards the inside of the wheel, which pushes the whole wheel outwards. Going from ET45 to ET35 on the same width wheel moves the face 10 mm further out and the inner rim 10 mm further from the suspension.
Is wheel poke legal?
It depends on where you live. Many US states and most European countries require the tire tread to be covered by the bodywork, often judged within a set angle in front of and behind the axle. Check your local regulations before running poke, or use fender flares or arch rolling to bring the fitment back in line.
What is a stretched tire?
A stretched tire is narrower than the recommended range for the rim it sits on, so the sidewalls angle inwards from the rim to the tread. A little stretch helps a wide wheel clear the fender. Too much puts extra load on the bead, which can unseat it under hard cornering or low pressure.
What is a meaty tire?
A meaty tire is at or above the widest recommended size for the rim, so the sidewall bulges out past the rim lip. It protects the rim from curb rash and gives a chunky look, but it can blur steering response and needs more room in the arch.
Does negative camber wear tires?
Some negative camber improves grip in corners, but a lot of static negative camber concentrates wear on the inner edge of the tire in a straight line. Mild settings of about −0.5° to −1.5° are common on street cars; stanced cars running −5° or more trade tire life for looks.
How much does tire size affect my speedometer?
Your speedometer is calibrated for the original tire's overall diameter. A tire that is 3% larger in diameter makes the car travel 3% further per wheel turn, so the speedo reads 3% low. Keeping the overall diameter within about ±2–3% of stock is a common rule of thumb.