How does AGV drive wheel preload improve traction?

AGV drive wheel preload improves traction by using a spring or suspension mechanism to keep enough normal force on the driven wheel. The page calculator uses the friction relationship Fmax = mu x N, then flags when floor contamination, incline, or acceleration makes the estimate unsafe without wheel/floor testing.

What happens if the preload is too high on a heavy-duty AGV wheel?

Excessive preload raises polyurethane deformation, heat buildup, bearing load, and caster unloading risk. Treat the calculator result as a screening value: confirm allowable wheel load, duty cycle, speed, and spring travel against the wheel supplier datasheet before pilot release.

Does this traction calculator work for omni or mecanum wheels?

No. Omni and mecanum wheels have different traction dynamics due to their free-spinning rollers. This calculator is designed for standard heavy-duty AGV wheels used in single-steer, differential, or four-wheel drive layouts.

How do I adjust the preload on an existing heavy-duty AGV?

Most industrial heavy-duty AGV wheel assemblies use adjustable spring tensioners or a suspension stop. Do not adjust by spring compression percentage alone. Measure loaded ride height, confirm remaining spring travel, verify caster contact, and run a slip test on the actual floor.

Heavy Duty AGV Wheel & Preload Calculator

Calculate AGV Drive Wheel Preload to Improve Traction

Estimate whether AGV drive wheel preload can improve traction, then see the conditions that can invalidate the result before release.

Traction & Preload Input

Enter your AGV parameters to calculate the required traction force and spring preload.

Total Mass (AGV + Payload) (kg)

Screening range: 100-20,000 kg.

Drive Layout

Floor Condition

Matches the lower end of published Vulkollan-on-smooth-concrete guidance.

Max Incline (%)

0-15% sustained grade.

Accel (m/s²)

0-2 m/s² profile.

Screening assumptions

Assumes the pair of drive wheels carries about 40% of static vehicle load before preload adjustment. Rolling resistance is fixed at 0.02 for this first-pass estimate.

1. Enter route load

Mass, grade, acceleration, layout, and floor state.

2. Compare force reserve

Required traction versus available static grip.

3. Decide next action

Adjust preload, test floor grip, or review layout.

Calculation Results

Required forces to prevent drive wheel slippage.

System Within Limits

Static drive-wheel load already covers the selected traction demand. The preload target shown is a contact reserve, not an extra traction demand.

Required Traction Force

1,981 N

Required Normal Force

3,302 N

Static Weight on Drives

7,848 N

Recommended Spring Preload

1,962 N

Friction coefficient

0.60

Dry smooth concrete

Static drive ratio

40%

Differential two-drive layout

Available static traction

4,709 N

Static drive load multiplied by floor coefficient.

Extra traction preload

0 N

Added normal force only when static grip is below drive demand.

Contact reserve preload

1,962 N

Screening allowance to keep the wheel engaged over floor unevenness.

Reported target

Higher of those two values

Final spring setting still depends on geometry, travel, and supplier load charts.

Next step

Use this as an RFQ screening value, then confirm wheel load, spring travel, and slip margin with a floor test.

Discuss Heavy-Duty Wheel Solutions

Why Use Preload to Improve Traction?

A common issue in heavy-duty AGV operations is drive wheel slippage. When an AGV accelerates, decelerates, or encounters an incline, the traction force required to move the vehicle increases. According to Coulomb's law of friction, the maximum traction force is directly proportional to the normal force (the downward weight on the wheel).

AGV drive wheel preload improves traction by using suspension mechanisms (typically heavy-duty springs) to artificially increase the normal force on the drive wheel without needing to increase the overall weight of the vehicle.

Key Engineering Conclusions

Preload is a traction reserve tool

Use preload when the driven wheel needs more normal force to transfer torque without slip on ramps, joints, or uneven floors.

More preload is not always safer

Excessive preload can overheat the tread, increase bearing load, and unload casters enough to hurt stability.

Floor data decides confidence

Dry concrete estimates are useful for screening. Wet, oily, dusty, or coated floors still need on-site slip testing.

Calculation Method and Assumptions

The calculator estimates required drive force from rolling resistance, ramp grade, and acceleration. It then divides that force by the selected floor coefficient to estimate the minimum normal force required at the drive wheels. Recommended preload is the extra normal force needed beyond estimated static drive-wheel load, with a minimum contact reserve for floor unevenness.

Step	Screening Equation	Important Boundary
Required drive force	`mass x 9.81 x 0.02 + ramp force + acceleration force`	Rolling resistance is fixed at 0.02 for screening only.
Required normal force	`required drive force / floor coefficient`	The floor coefficient must be verified on the actual route.
Preload target	`required normal force - static drive load`	Spring travel, caster load share, and wheel rating can override the target.

Evidence Layer Reviewed July 7, 2026

The page uses source-backed ranges where public manufacturer guidance exists and labels the remaining values as screening assumptions. These are engineering starting points, not universal constants.

Evidence Need	Public Source	How It Is Used Here
Friction and normal force logic	Vulkoprin driving-force guidance	Supports the force relationship and the use of a lower, safer coefficient for dry concrete screening.
Load capacity derating	IndustrialWheels Vulkollan load-capacity guide	Supports duty-cycle, speed, and driven-wheel derating factors used in the preload risk table.
Drive wheel material tradeoffs	IndustrialWheels drive wheel material guide	Supports the distinction between polyurethane efficiency, rubber grip, heat buildup, and floor condition limits.
High-load Vulkollan use case	Covestro Vulkollan application case	Supports Vulkollan as a high-load industrial wheel material while keeping final sizing supplier-specific.

Vulkollan Polyurethane Limits & Derating Factors

Heavy-duty AGV drive wheels almost exclusively use high-performance polyurethane (PU) such as Vulkollan. However, excessive preload increases internal heat buildup, leading to rapid material degradation, flat-spotting, or tread delamination. Use supplier load charts as the final authority and apply derating before raising spring preload:

Operating Condition	Public Derating Factor	Impact on Preload & Wear
Driving Wheel (Motorized)	0.70x	Drive wheels endure shear forces and torque. Their static load rating must be derated before extra preload is added.
Continuous 24/7 Duty	0.75x	Constant deformation generates heat. High preload in 24/7 operation can shorten PU life without cooling intervals.
Speed: 6–10 km/h	0.80x	Higher speeds increase friction and thermal load, reducing safe allowable load.
Speed: 10–16 km/h	0.70x	High-speed AGVs face severe thermal limits. Preload must be strictly controlled.

Material Selection & Floor Friction

To avoid accelerated wear, match the wheel's durometer to the floor condition:

Dry smooth concrete or epoxy: polyurethane can be efficient and wear-resistant, but use a conservative friction value until the actual coating is tested.
Uneven concrete: preload may help keep the drive wheel in contact, but suspension geometry and caster load share become more important than the raw number.
Wet, oily, dusty, or outdoor floors: do not solve traction by preload alone. Review tread profile, rubber alternatives, cleaning control, and route speed reduction.

Risk Controls Before Increasing Preload

Risk	Why It Matters	Minimum Control
False grip confidence	A clean-floor coefficient can fail on dust, oil, film, or condensation.	Run slip tests on the worst route segment before pilot approval.
Caster unloading	Too much drive preload can reduce support-wheel load and destabilize steering.	Measure caster reaction force after preload adjustment.
Thermal overload	Tread deformation, torque, and continuous operation build heat inside polyurethane.	Apply derating factors and add cooling intervals or larger wheels where needed.

Validation Checklist

Confirm the calculator mass includes chassis, battery, payload, tooling, and maximum carried load.
Verify spring preload at loaded ride height, not only at bench-set spring compression.
Check wheel supplier load rating after driven-wheel, continuous-duty, and speed derating are multiplied together.
Run a route test with acceleration, emergency stop, ramp hold, and the least favorable floor condition.

Decision boundary: this calculator is suitable for early AGV drive wheel preload screening. It is not a substitute for supplier load charts, detailed suspension geometry, measured floor friction, or a pilot slip test.

Frequently Asked Questions