2018 Cadillac ATS Wheel Interchange

2018 Cadillac ATS Wheel Fitment Guide | wheelinterchange.com

Known OEM Fitment For 2018 Cadillac ATS

The specs below are taken from available OEM data for the 2018 ATS. Cadillac offered multiple wheel and tire packages, and some values can vary by trim or option package. Use your tire placard, owner’s manual, or a dealer VIN lookup to confirm your exact factory sizes before comparing in the calculator.

Note: The table shows an 18 inch wheel and a separate 17 inch tire entry. This indicates Cadillac used more than one OEM package on the ATS. Do not assume your car has both. Confirm your stock size on the driver door placard and then use the calculator on this page to compare any changes.

How To Use The Wheel Interchange Calculator

Start by setting Installed on to 2018 Cadillac ATS so your vehicle stays fixed on the right side. Next, choose Wheels from to match the donor vehicle or the aftermarket wheel specs you are considering. If you are testing custom specs, open Custom wheel size and enter rim diameter, rim width, and offset. If you change rim diameter, the tool updates the tire diameter in the comparison, but you should still set Custom tire size to a realistic section width and aspect ratio so the overall diameter remains close to your OEM reference.

Watch the comparison metrics for inner clearance to the strut and brake components, and for outer poke relative to the fender. A small outward change can affect rubbing on compression or steering lock, while a small inward change can contact the knuckle, spring perch, or liner. Use the tire diameter comparison to keep the overall rolling diameter close to stock for speedometer accuracy and ABS stability. When in doubt, measure your current clearances at full lock and near full bump, then mirror those measurements in the calculator to verify margin.

Fitment Checklist Before You Buy

Match the bolt pattern exactly at 5x115. Do not rely on force-fitting 5x114.3. The center bore on the hub is 70.3 mm. Your wheel’s center bore must be 70.3 mm or larger. If it is larger, use quality hub-centric rings to fill the gap. The thread size is M12 x 1.5. Confirm the lug seat style required by the wheel, and make sure you have adequate thread engagement with your chosen lug nuts or bolts.

Compare offset and backspacing in the calculator against your verified OEM baseline. Small changes can have big effects, especially on inner clearance to the strut and brake caliper. Check brake caliper barrel clearance for smaller diameter wheels and spoke clearance for aftermarket designs. Verify load rating on both wheels and tires that meets or exceeds OEM. Keep overall tire diameter close to stock to protect driveline, gearing feel, and driver aids. If your ATS is AWD, keep front and rear rolling diameters closely matched according to OEM guidance. Plan for TPMS: either transfer your sensors or buy compatible units and perform a relearn after installation.

Plus Sizing And Common Upgrades

Plus sizing means increasing wheel diameter while reducing tire sidewall to maintain a similar overall diameter. For example, owners sometimes move from a 17 inch OEM package to an 18 inch option with a lower profile tire. Use this as a modeling exercise only, not a recommendation. In the calculator, set your verified OEM tire size from your door placard, then test an 18 inch rim width and offset that match your chosen wheel, and choose a tire aspect ratio that keeps overall diameter close to stock. Confirm inner and outer clearances and brake clearance. For track or appearance setups, also evaluate staggered widths carefully and remember that wider tires often require offset adjustments to avoid rubbing. Always confirm with physical measurements and, when available, a manufacturer brake template for your specific calipers.

Installation Tips

Test fit one corner first without the tire or with the tire unseated to check spoke and barrel clearance over the caliper. Clean the hub face and wheel mounting pad so they are flat and free of rust. If your wheels are hub-centric with rings, seat rings fully and squarely in the wheel bore. Hand start all fasteners and snug in a star pattern. Lower the vehicle partially so the tire just kisses the ground, then torque to the factory specification from your owner’s manual using a calibrated torque wrench. Re-torque after 50 to 100 miles. After installation, perform a TPMS relearn if sensors were replaced or moved, and verify there is no rubbing at full steering lock and over bumps.

Tools And Helpful Supplies

These items make wheel swaps safer and easier. Verify compatibility and sizes for your specific wheels and lugs.

• 1/2 inch drive torque wrench: Shop options
• M12 x 1.5 lug nuts or bolts, correct seat style: Shop options
• Hub-centric rings for 70.3 mm hub to your wheel bore: Shop options
• GM TPMS relearn tool: Shop options

FAQs

What is the 2018 Cadillac ATS bolt pattern?
5x115.

What center bore does the ATS use?
70.3 mm. If your wheel bore is larger than 70.3 mm, use hub-centric rings. If it is smaller, the wheel will not seat on the hub.

What is the thread size for the wheel fasteners?
M12 x 1.5. Confirm the lug seat style required by your wheels before purchasing lug nuts.

Can I use 5x114.3 wheels on a 5x115 ATS?
It is not recommended. Even small differences can cause vibration, fastener stress, and safety issues. Use the correct 5x115 pattern or professionally engineered adapters where appropriate.

Why do I see both 18 inch wheel data and a 17 inch tire size listed?
Cadillac offered multiple OEM packages. Your car may have 17 or 18 inch factory equipment. Verify your exact OEM size on the door placard, then use the calculator to compare to any potential change.

What offset works on the ATS?
One known OEM example is ET 42 mm on an 18 x 8.0 wheel. Other trims may differ. Use the calculator to compare your verified OEM setup to any new wheel, and check inner and outer clearance carefully.

Do I need new TPMS sensors?
You can typically reuse OEM sensors if compatible with the new wheels. If you install new sensors, you will need a relearn procedure and possibly a relearn tool. Follow the owner’s manual for your ATS.

How close should overall tire diameter be to stock?
Keep it as close as practical to preserve speedometer accuracy and stability system calibration. Use your verified OEM size as the baseline and compare in the calculator, adjusting tire aspect ratio as you change wheel diameter.

How can I confirm my exact OEM wheel and tire size?
Check the driver door jamb tire placard, owner’s manual, and the original build sheet or RPO codes. A Cadillac dealer can confirm by VIN. Then enter that verified size into the calculator as your baseline for accurate comparisons.