GuidesATV Wheel Offset Explained
Wheel TechATV Wheel Offset Explained
Two numbers with a plus sign between them decide how wide your quad sits, how it steers, and how hard your wheel bearings work. Here is how to read them.
Offset is where most people quietly give up and buy whatever the last guy in the pits was running. It does not deserve that reputation. The notation looks cryptic, but it is describing something completely physical: where the hub sits inside the wheel, and therefore where your tyre ends up relative to the machine.
Get it right and the quad sits the way the chassis was designed to sit. Get it wrong and you have changed your track width, your steering feel and the load path into your wheel bearings, all without meaning to.
Two different things are both called “offset”
This is the source of most of the confusion, so deal with it first. You will see offset written two ways in the ATV world and they are not the same measurement.
- The A+B notation — 4+1, 3+2, 3+5, 4+5. This is what appears in an ATV wheel’s name. It describes where the hub mounting face sits inside that specific wheel.
- A millimetre figure — +10mm, +12mm, +15mm. This is the automotive-style convention, and it is how a machine’s recommended offset is usually quoted. It is what the fitment guide reports for your year, make and model.
Reading 4+1, 3+2 and 3+5
The A+B numbers are inches, measured from the hub mounting face — the flat surface that bolts against your hub — outward to each bead seat.
- The first number is the inboard side: hub face to the inner bead seat, the half of the wheel that sits toward the machine. This is what people mean by backspacing.
- The second number is the outboard side: hub face to the outer bead seat, the half you can see.
- Add them together and you get the rim width.
That last point is the sanity check that makes the whole thing click. A 10x5 (4+1) is a 10 inch diameter wheel, 5 inches wide, with 4 of those inches inboard of the hub face and 1 inch outboard. Four plus one is five, and five is the width in the name. A 9x9 (4+5) is 9 inches wide: four in, five out.
Once you can read it, comparing two wheels becomes trivial. A 10x5 (3+2) and a 10x5 (4+1) are the same diameter and the same width. The only difference is that the 3+2 has moved the whole wheel one inch further outboard. Fit those to both sides of an axle and your track is two inches wider.
The offsets RWI actually builds
| Wheel | Width | Inboard | Outboard | What it does |
|---|---|---|---|---|
| 10x5 (4+1) | 5" | 4" | 1" | Tucks the front wheel in tight — the narrowest of the two 10x5 fronts |
| 10x5 (3+2) | 5" | 3" | 2" | Sits one inch further out per side than the 4+1, for two inches more front track |
| 8x8 (3+5) | 8" | 3" | 5" | Most of the wheel outboard of the hub — the classic rear proportion |
| 9x8 (3+5) | 8" | 3" | 5" | Same proportion, larger diameter |
| 10x8 (3+5) | 8" | 3" | 5" | Same proportion again at 10 inch diameter |
| 9x9 (4+5) | 9" | 4" | 5" | The widest rear in the line, and the double beadlock |
Every one of these is a live beadlock wheel or rolled lip wheel part. The 10x5 (4+1) is also the R6 rolled lip front on the MX1 and GP1 race kits.
What offset actually changes on the machine
Offset is not a cosmetic spec. Moving the wheel outboard or inboard changes four things at once.
- Track width and stability. A wider track resists rolling over in a corner and gives you more of a platform to lean on. It also makes the machine harder to flick from rut to rut and wider on a tight woods trail.
- Steering feel. Moving the front wheels outboard increases the leverage the tyre has against the steering, so bumps talk to you louder through the bars. Fast, rough ground is where you notice it.
- Bearing and hub loading. The further the tyre sits from the hub, the longer the lever arm working on your wheel bearings and spindles on every impact and every hard corner. This is the failure mode nobody plans for.
- Clearance. Inboard offset can bring the tyre closer to your A-arms, shock bodies, chain and brake hardware. Outboard offset can put it into the fender or outside your class rules.
RWI’s own guidance on this is short and worth repeating: for racing, stay within the factory offset range for your machine. Most sport ATVs run a +10mm offset, and running too far positive or negative affects handling, steering geometry and bearing life. Our race kits ship pre-configured with the offset chosen for that application, which is the honest shortcut if you would rather ride than measure.
Wheel spacers are not the same as offset
A spacer widens your track by pushing the existing wheel outboard. The result looks similar to running a wheel with more outboard offset, but the load path is different: you have added a joint between the hub and the wheel, and you have moved the tyre out without changing where the wheel’s own structure sits.
If widening the track is what you want, choosing the wheel that already has the offset you need is the cleaner answer. That is exactly why the 10x5 exists in both 4+1 and 3+2 — the two-inch track difference is built into the wheel rather than bolted on in front of it.
Choosing without guessing
- 01Confirm your bolt pattern first — nothing else matters if the wheel does not mount. ATV bolt patterns explained covers it.
- 02Look up your machine in the fitment guide and note the offset range it publishes for you, along with the front and rear widths.
- 03Pick the RWI wheel or race kit that sits inside that range rather than at the edge of it.
- 04If you deliberately want more front track for stability, step from a 4+1 to a 3+2 rather than adding a spacer, and accept that the steering will feel busier.
- 05Check clearance with the tyre you actually run, not the one that was on it when you bought it. The wheel size guide covers the diameter and width side of that.
Common questions
It means the wheel is 5 inches wide, with 4 inches of that width sitting inboard of the hub mounting face and 1 inch sitting outboard. The two numbers are inches measured from the hub face to each bead seat, and they always add up to the rim width in the wheel’s name.
Not wider — further out. Both are 5 inch wide wheels. The 3+2 sits one inch further outboard than the 4+1, so fitting a pair gives you two inches more track across that axle. The wheel itself is the same width.
Stay within the factory offset range for your machine. Most sport ATVs run a +10mm offset, and running too far positive or negative affects handling, steering geometry and bearing life. RWI race kits are pre-configured with the offset chosen for that application.
Not reliably in your head, because the two conventions are measured from different references. Use the A+B number to understand the wheel in front of you, and use the millimetre figure the fitment guide publishes for your machine as the range you should stay inside.
Moving the tyre further from the hub lengthens the lever arm acting on the bearings and spindle every time you hit something or load a corner, which is why running far outside the factory offset range shortens bearing life. Staying inside the published range for your machine is the simplest protection.