2008 Cadillac CTS Wheel Interchange

2008 Cadillac CTS Wheel Fitment Guide

Known OEM Fitment For 2008 Cadillac CTS

The values below are verified for at least one factory wheel and tire package on the 2008 Cadillac CTS. This model year had multiple OEM wheel and tire options, so your specific trim may differ. Always confirm against your door jamb sticker, owner manual, or a GM dealer using your VIN, and validate changes with the on-page calculator.

Notes:

• The 18 x 8.0 ET 48 wheel and the 235/55R17 tire indicate that multiple factory packages existed. Do not assume they were paired together. Verify what your CTS left the factory with before planning changes.
• The 235/55R17 tire has an overall diameter of about 27.2 in. Some trims may use a different size. Use the calculator to compare overall diameter against your current tire and aim to keep changes small for accurate speedometer and ABS behavior.

How To Use The Wheel Interchange Calculator

The calculator on this page lets you compare a donor wheel and tire to your 2008 Cadillac CTS, and also try custom sizes. Follow these steps:

• Set Installed on to 2008 Cadillac CTS.
• Option A - Comparing a known wheel: Select Wheels from for the donor vehicle or enter its rim width, diameter, and offset. Enter the donor tire size if known.
• Option B - Trying a custom setup: Use Custom wheel size to set rim diameter, width, and offset. Use Custom tire size to set section width and aspect ratio. When you change rim diameter, the calculator updates overall tire diameter so you can see the effect.
• Review the comparison and pay attention to inner clearance to the strut and brakes, and outer poke relative to the fender. Keep overall tire diameter changes small to protect drivability and electronics.
• If anything is unknown or varies by trim, measure your current wheel and tire and confirm clearances with a careful test fit before driving.

Fitment Checklist Before You Buy

• Bolt pattern must be 5x120. Do not attempt to use 5x120.65 or 5x4.75 in patterns.
• Center bore is 67.0 mm on the hub. If an aftermarket wheel has a larger bore, use hub centric rings that reduce to 67.0 mm.
• Offset target is the documented ET 48 for a known OEM 18 x 8.0 wheel. Stay close to this and use the calculator to check both inner clearance and fender poke when changing width or diameter.
• Backspacing for the known 18 x 8.0 ET 48 wheel is 5.89 in. If you only know backspacing on a candidate wheel, convert to offset to compare properly.
• Brake and suspension clearance must be verified. Larger diameter wheels may clear brakes more easily, but wider wheels or lower offsets can reduce inner clearance. Test fit and rotate the wheel lock to lock.
• Tire overall diameter should stay close to your stock setup. A small variance is generally recommended. Use the calculator to compare.
• TPMS: Plan to transfer your sensors or install compatible replacements and perform the relearn per the owner manual or GM service procedures.
• Load rating: Wheels and tires must meet or exceed the vehicle load rating. Check manufacturer specs.
• Lug hardware: Use the correct M14 x 1.5 lug nuts with the seat style that matches your wheel. Ensure full thread engagement as specified by GM.

Plus Sizing And Common Upgrades

Plus sizing changes wheel diameter and tire profile while keeping overall tire diameter similar to stock for proper speedometer and ABS behavior. The 2008 CTS was available with different OEM packages, including 17 and 18 inch configurations. Use the calculator to:

• Keep overall tire diameter close to your current setup. Enter your existing size, then try a potential upgrade and compare overall diameter.
• Check offset impact when increasing wheel width. A wider wheel with the same offset will move the inner barrel closer to suspension. Adjust offset carefully and verify with the calculator.
• Decide between a square setup for tire rotation or a staggered setup for appearance and traction. If you stagger, confirm that both front and rear clear properly.
• For winter packages, downsizing in diameter can be useful if brake clearance allows. Confirm brake clearance and overall diameter, then choose an appropriate winter tire width and aspect ratio.

Installation Tips

• Clean the hub face and wheel mounting pad to remove rust and debris. This prevents runout and vibration.
• If using hub centric rings, seat them fully on the hub and ensure they match the wheel bore and 67.0 mm hub size.
• Hand start all M14 x 1.5 lug nuts, then snug in a star pattern. Final tighten with a calibrated torque wrench to the torque specified in your owner manual or GM service information.
• Re-torque after 50 to 100 miles of driving.
• Verify TPMS operation and perform the relearn after installation.
• After test fitting, turn the steering wheel lock to lock and check for rubbing at full compression. Inspect inner clearance to struts, control arms, and brake hoses.

Tools And Helpful Supplies

• 1/2 inch drive torque wrench
• M14 x 1.5 lug nuts that match your wheel seat style
• Hub centric rings 67.0 mm inside diameter for aftermarket wheels with larger bores
• Tire pressure gauge to set pressures after install

FAQs

• Will wheels from another 5x120 GM or non-GM vehicle fit my 2008 CTS

  Not automatically. You must match bolt pattern, center bore 67.0 mm or use rings, offset, brake clearance, and load rating. Use the calculator to compare width, offset, and tire size, then perform a physical test fit.

• Can I use 5x120.65 or 5x4.75 in wheels on the CTS

  No. The 2008 CTS is 5x120. Mixing patterns can damage studs and hubs and is unsafe.

• What offset should I choose for aftermarket wheels

  The documented OEM 18 x 8.0 wheel uses ET 48. Stay close to that and verify inner and outer clearances with the calculator when changing width or diameter. Always test fit before driving.

• Do I need hub centric rings

  Use rings if the aftermarket wheel center bore is larger than 67.0 mm. Rings help the wheel center on the hub to reduce vibration. They do not replace proper lug tightening.

• Can I reuse my TPMS sensors

  Yes, you can transfer your existing sensors to new wheels if they are compatible with the wheel design. Otherwise use compatible replacements and complete the TPMS relearn per the owner manual or GM procedures.

• How close should my new tire diameter be to stock

  Keep overall diameter changes small to maintain speedometer, ABS, and traction control behavior. Use the calculator to compare your current size to the new size. The listed 235/55R17 is about 27.2 in diameter, but other OEM sizes may exist for this model year.

• Will 17 inch wheels clear my brakes

  Some 2008 CTS trims came with 17 inch tires, but brake sizes can vary. Verify with the calculator and a test fit to ensure caliper clearance on your specific trim.

• What is backspacing and why does it matter

  Backspacing is the distance from the wheel mounting pad to the inner rim edge. It affects inner clearance to suspension and brakes. The known OEM 18 x 8.0 ET 48 wheel has 5.89 in backspacing. Compare any candidate wheel against this using the calculator.