Why Is the Steering Wheel Not Straight After a Wheel Alignment?

A steering wheel that sits off-centre after a wheel alignment usually means one of two things: the total toe was set correctly but divided unevenly between the two front wheels, or rear toe and thrust angle were not corrected before the front was adjusted.

Total toe can measure perfectly in specification while the steering wheel is visibly crooked. The fault is almost always in the sequence and the setup of the alignment, not in the final numbers on the printout.

The numbers can be right and the wheel still wrong

Total toe is the combined toe angle of both wheels on an axle. Individual toe, also called partial toe, is the toe angle of a single wheel measured on its own. Supertracker’s guide to wheel alignment angles defines both, along with the other angles referenced throughout this article.

The steering wheel is centred by how that total is divided between the left and right wheels. It is not centred by the total itself. Wind one tie rod out and the other in by the same amount and the total toe reading does not change, but the steering wheel has moved. This is precisely why a printout can show every angle sitting in the green and the customer can still return the next morning with a crooked wheel.

Supertracker’s angles guide states the mechanism directly: if the front toe angles are not set equally to the centre line, this shows up as the steering wheel not being straight. The one exception given is deliberate thrust angle compensation, which is covered below.

Off-centre and pulling are two different faults

These get reported by customers in almost the same words, but they have different causes and different fixes. Separating them at the road test saves a great deal of time.

A vehicle can present both at once. Writing in CarParts.com, reviewed by ASE Certified Master Automobile Technician Anthony Harlin, an improper thrust angle is described as producing pulling, leading, wandering, an off-centred steering wheel and dog-tracking. Where the thrust angle is out, expect to see more than one symptom.

Five reasons the wheel ends up off-centre

1. The steering wheel was not centred and locked before adjustment

If the wheel is not held in the straight-ahead position while toe is being set, the machine records the toe split relative to wherever the wheel happens to be sitting. Every adjustment made after that point is referenced to the wrong starting position. This is the simplest cause and the easiest to prevent.

2. Front toe was split unevenly across the two tie rods

The most common cause of a comeback. A technician sees total toe out of specification, corrects the whole error at one tie rod because it is the more accessible one, and brings the total back into range. The total is now correct and the steering wheel has moved by the full amount of the correction. Adjustment needs to be shared so that the individual toe figures stay balanced either side of the thrust line.

3. Rear toe and thrust angle were not corrected first

Rear toe sets the thrust line, and front toe must be set relative to that line rather than to the vehicle’s geometric centre line. Supertracker’s angles guide notes that rear wheels set unequally introduce a thrust angle, and that the effect of this is uneven tyre wear and a steering wheel that will not be straight. Where the rear is adjustable and out of specification, correct it before touching the front. Where the rear is not adjustable, thrust angle compensation is the correct approach: front toe is set to the thrust line so that the wheel sits straight and the vehicle tracks true.

4. The vehicle was measured on an unlevel surface or without correct support

Readings taken on ground that is not level, or on a two-post lift without proper alignment tables, can be distorted before any adjustment is made. Supertracker’s STR 130RW can be used on a full wheel alignment lift, a standard four-post lift, a platform scissor lift, a pit, a level surface, or a two-post lift when used with Supertracker wheel alignment tables. Confirm the setup before you trust the first set of figures.

5. The steering wheel is clocked wrong, or a component is worn

If the steering wheel has been removed and refitted a spline out, no amount of toe adjustment will centre it without throwing the geometry out to compensate. Worn track rod ends, a worn idler arm or play in the steering rack or box will also allow the wheel to sit differently from the road wheels. Inspect the steering and suspension before adjusting anything, because wear will defeat whatever settings you dial in.

The steering angle sensor step that is easy to miss

On vehicles fitted with electronic stability control or driver assistance systems, the steering angle sensor frequently has to be reset once the alignment is complete. Many vehicles require the sensor to be reset or recalibrated after an alignment, or after steering components have been replaced, and describes three categories of procedure: systems that self-calibrate, systems that need a specific button or wire sequence, and systems that require a scan tool.

Skip this and the vehicle may drive perfectly straight with a centred wheel yet still show a warning light, or a driver assistance feature may behave inconsistently. Supertracker CCD machines are compatible with most ADAS calibration systems through an ADAS upgrade kit. More detail on the alignment and ADAS relationship is covered in the Supertracker article on wheel alignment and ADAS.

A diagnostic sequence for a comeback

Work through this in order. Each step removes a variable before the next one is assessed.

1. Road test on a level, straight road and establish which fault you actually have: off-centre, pulling, or both.
2. Check the tyres first. Pressures, matched sizes and types across each axle, condition, and any sign of conicity.
3. Re-measure with the vehicle on a level surface and correctly supported.
4. Read rear toe and thrust angle before you look at front toe.
5. Compare individual toe left and right, not only the total.
6. Inspect the steering and suspension components for wear before making any adjustment.
7. Centre and lock the steering wheel, correct the rear where it is adjustable, then set front toe to the thrust line.
8. Reset the steering angle sensor where the vehicle requires it.
9. Road test again, and retain the before and after printout as evidence the vehicle left in specification.

Preventing it in the first place

Where the complaint arrives alongside uneven tyre wear, the wear pattern itself will often point to the angle at fault. The Supertracker guide on how to read tyre wear patterns covers that diagnosis in full.

Why Choose Supertracker Wheel Alignment Equipment?

Supertracker has manufactured wheel alignment equipment in Britain since 1987, with over 17,000 systems built and a nationwide service team behind them as part of the Straightset group. The full range runs from green laser systems through to computerised CCD machines, all manufactured and assembled in the United Kingdom.

For the work described in this article, sensor count matters. Both the six-sensor and eight-sensor computerised systems provide full four-wheel data covering toe, thrust, camber, caster and SAI. The eight-sensor STR 420RW adds two further sensors across the rear, providing a measurement for rear set back and taking track width into account when measuring rear toe, which is exactly the data you want in front of you when a thrust angle is driving an off-centre steering wheel.

Prices start from £1,999 + VAT depending on model and configuration. To see the systems working on a vehicle, book a demonstration at the Supertracker Wheel Alignment Studio in Worksop, or call the team on 01909 480055.