Tire & Wheel Advisor

An AI skill dedicated to tires and wheels — sizing and fitment math, seasonal strategy, load and speed ratings, TPMS, wear diagnosis, and storage.

Description

Tires are the only part of the vehicle touching the road, and the most commonly mis-purchased. The Tire & Wheel Advisor goes deeper than the general skills: full sizing math (diameter, speedometer error, load index), seasonal changeover strategy, reading wear patterns as a diagnostic tool, TPMS behavior after swaps, and matching tire choice to actual driving rather than marketing categories. It covers cars, SUVs, vans, and EVs, with motorcycle-specific guidance delegated to the Motorcycle Mechanic skill.

Audience: Anyone buying tires or wheels, seasonal-swap households, and drivers diagnosing wear or vibration issues.

Capabilities

• Sizing math — decode size markings (e.g., 215/55R17 94V), calculate overall diameter changes and speedometer/odometer error for alternative sizes, plus-sizing and minus-sizing (winter downsizing) rules, load index and speed rating requirements vs. the vehicle placard
• Wheel fitment — bolt pattern (PCD), center bore and hub-centric rings, offset effects on scrub radius and bearing load, clearance to struts/calipers/fenders, wheel load ratings, lug torque and re-torque practice
• Selection — summer vs. all-season vs. winter compounds and when each actually matters, highway vs. all-terrain vs. mud-terrain for SUVs/trucks, EV-specific considerations (load, noise, low rolling resistance, faster wear), run-flat tradeoffs, wet-grip and noise label systems
• Seasonal strategy — when to switch (the 7°C rule of thumb), whether a second wheel set pays off, storage (position, temperature, sunlight, age limits)
• Wear diagnosis — reading wear patterns (center, shoulders, one-sided, cupping, feathering) as evidence of pressure, alignment, or suspension problems; measuring tread depth and interpreting date codes; repairable vs. non-repairable damage
• TPMS — direct vs. indirect systems, behavior after rotations and seasonal swaps, sensor batteries and service kits, relearn procedure types
• Practice — rotation patterns (directional, staggered, full-size spare), pressure strategy for load/towing, breaking in new tires, mixing rules (best pair to the rear)

Example Prompts

My car came with 215/55R17 94V. Can I run 225/50R17? Show the diameter
and speedometer math, and check the load and speed rating requirements.

Front tires are worn smooth on the outer shoulders only, rears are even.
What does this pattern tell me and what should I have checked?

I drive an EV in a region with snowy winters. Recommend a two-set wheel
strategy: sizes, tire categories, and whether to downsize for winter.

After my seasonal wheel swap the TPMS light stayed on. Second set has no
sensors. What are my options, from cheapest to cleanest?

Two of my tires are 7 years old with plenty of tread, made in week 30 of
2019. The other two are 2 years old. Replace, rotate, or run them?

Recommended Workflow

1. Start from the placard, not the tire. Share the vehicle’s door-jamb placard sizes, load index, speed rating, and pressures — the current tires may already be wrong.
2. Describe the actual driving. Climate, annual distance, highway vs. city split, towing/loading, and what you care about most (longevity, quiet, grip, price).
3. For size changes: ask for the full calculation — diameter delta, speedometer error, load capacity check, and clearance risks — before purchasing.
4. For wear problems: measure tread depth at inner/center/outer on each tire and report the numbers; patterns across positions are the diagnosis.
5. Confirm the install details. Torque spec and re-torque after ~50–100 km, TPMS relearn, and pressure set to placard (not sidewall maximum).
6. Log date codes and rotation history so future sessions can advise on age and rotation timing.

Limitations

• The vehicle placard and manufacturer approvals are authoritative. Alternative sizes the math permits may still be unapproved for your vehicle or illegal in your jurisdiction (e.g., load index shortfalls, fender coverage rules).
• Tire models change constantly — the skill advises on categories and selection criteria confidently, but specific current models and prices should be verified against recent tests and local availability.
• Cannot see the tire. Sidewall damage, puncture position, and cord exposure need physical inspection; when in doubt about repairability, a tire shop’s judgment rules.
• Vibration diagnosis overlaps with suspension — wheel balance is one cause among several; persistent vibration belongs in Vehicle Troubleshooting.
• Winter traction devices (chains, studs) and their legality vary by region — verify local rules.

Related Skills

• Vehicle Customization Advisor — aesthetic and performance wheel upgrades in a build context
• Vehicle Troubleshooting — vibrations and noises beyond the tires themselves
• EV Assistant — why EVs eat tires and what to do about it