1999 Chevrolet Blazer Wheel Interchange

1999 Chevrolet Blazer Wheel Fitment Guide

Known OEM Fitment For 1999 Chevrolet Blazer

Notes: Fitment can vary by trim or option package. If your vehicle’s sticker or owner manual lists a different wheel or tire size, use that as the baseline and verify all measurements with the calculator and OEM documentation. Never assume a wheel will fit based only on diameter.

How To Use The Wheel Interchange Calculator

The calculator lets you compare a donor wheel and tire to your 1999 Chevrolet Blazer. It shows inner clearance, poke, and diameter changes so you can judge safety before buying.

• Start with the OEM baseline shown above. If your Blazer has different factory specs, enter those as the Installed on values.
• In Wheels from, enter the donor vehicle or the aftermarket wheel specs you are considering.
• Use Custom wheel size to set rim diameter, width, and offset if the exact donor specs are not listed.
• Use Custom tire size to set section width and aspect ratio. The tool updates tire diameter when you change rim diameter so you can keep overall diameter close to stock.
• Review the results:
  • Inner clearance change. Negative numbers mean the wheel sits closer to the strut, spring, or control arm.
  • Outer poke change. Positive numbers mean the wheel sticks out farther toward the fender.
  • Ride height and speedometer change from tire diameter difference. Aim to keep overall diameter within about ±3 percent of stock.
• If anything looks tight in the calculator, physically test fit and inspect brake caliper and fender clearance before driving.

Fitment Checklist Before You Buy

• Bolt pattern. Your Blazer uses 5x120.70 mm. A 5x4.75 in listing is the same pattern. Do not use 5x120 mm.
• Center bore. Hub bore is 70.3 mm. If the new wheel’s center bore is larger, use hub-centric rings sized 70.3 mm to your wheel’s bore. If the new wheel’s bore is smaller, it will not fit.
• Offset and backspacing. Compare to OEM +50 mm and 5.47 in backspacing. Large increases in backspacing reduce inner clearance to suspension and brakes. Large decreases can push the wheel outside the fender.
• Brake and suspension clearance. Confirm caliper barrel clearance and spoke clearance. The calculator flags inner clearance changes but always test fit.
• Load rating. Wheel and tire load indexes must meet or exceed the Blazer’s GAWR and GVWR. Check the door jamb label and tire sidewalls.
• Tire diameter. Keep overall diameter close to stock to maintain speedometer and ABS behavior. The calculator displays the percentage change.
• Lug nuts. Thread is M12 x 1.5. Match seat type to the wheel design and follow OEM torque. Do not mix conical, mag, or ball seats.
• Brake hardware. If using spacers for clearance, use only hub-centric spacers that maintain 70.3 mm hub engagement and install with extended studs as required. Re-check torque frequently. Spacers are a last resort.
• TPMS. Most 1999 vehicles did not use in-wheel TPMS. If your wheel uses sensors, verify compatibility and sealing.
• Test fit. Mount one front and one rear, spin by hand, turn lock to lock, compress suspension if possible, and check liner and bumper clearance.

Plus Sizing And Common Upgrades

You can explore larger diameters while keeping overall tire diameter near stock for speedometer accuracy. These are example sizes to try in the calculator. They are not guaranteed to fit every trim or brake package. Always verify clearance and load rating.

• 15 in alternatives to gain width. Try 225/70R15 or 235/70R15 with appropriate wheel width and offset. Check inner clearance and fender poke.
• 16 in upgrade examples. Try 225/70R16 or 245/60R16. Keep diameter change within about ±3 percent.
• 17 in upgrade examples. Try 235/60R17 or 245/55R17. Wider tires may require lower offsets to clear the inner side, which can increase poke.
• Backspacing tuning. If you increase wheel width, you often need a different offset to keep the inner lip off the control arm while avoiding fender rub. Use the calculator to balance inner clearance and poke.
• Off-road oriented sizing. Mild upsizes in section width and aspect ratio may improve ride and light-trail traction. Verify clearance at full lock and full compression.

Installation Tips

• Safety first. Park on level ground, chock wheels, lift at approved points, and support with jack stands before removing wheels.
• Prepare hubs. Clean hub faces and wheel mounting pads until bare metal. Remove rust ridges that can cause runout.
• Hub-centric rings. If needed, install rings sized 70.3 mm to your wheel’s center bore. Seat them fully before mounting the wheel.
• Lug nuts. Confirm M12 x 1.5 thread and correct seat type for your wheel. Hand start all lugs. Snug in a star pattern, then torque in stages to the OEM spec from the owner manual or service information.
• Clearance check. After mounting one wheel, rotate by hand, turn steering lock to lock, and inspect caliper, spoke, and liner gaps.
• Final steps. Inflate to the tire placard pressure, road test gently, and re-torque lugs after 50 to 100 miles.

Tools And Helpful Supplies

• 1/2 inch drive torque wrench
• M12 x 1.5 lug nuts (verify seat type for your wheels)
• Hub-centric rings 70.3 mm (outer size must match your wheel bore)
• Floor jack and jack stands set

FAQs

• Is 5x120.70 the same as 5x4.75?
  Yes. 5x120.70 mm is the metric expression of 5x4.75 in. Do not confuse it with 5x120 mm.

• What center bore do I need?
  The Blazer hub is 70.3 mm. A wheel with a larger bore can be centered with a 70.3 mm hub-centric ring. A wheel with a smaller bore will not fit over the hub.

• What lug nuts fit the 1999 Blazer?
  The thread is M12 x 1.5. Match the lug seat style to the wheel manufacturer’s requirement and torque to the OEM specification in your owner manual or service manual.

• How much can I change offset or width?
  There is no single limit because clearance depends on brake package, suspension, and tires. Use the calculator to compare inner clearance and poke to OEM +50 mm offset and 7.0 in width, then test fit before driving.

• What tire diameter keeps my speedometer accurate?
  Use the calculator to match overall diameter to the OEM 205/75R15 baseline. Many aim to stay within about ±3 percent. Larger changes can affect speedometer reading and gearing feel.

• Do I need spacers?
  Only if required to clear brakes or suspension after confirming with the calculator and a test fit. If used, choose hub-centric spacers that maintain a 70.3 mm hub interface and install longer studs if needed. Re-torque frequently.

• Can I run 16 or 17 inch wheels?
  Often possible, but not guaranteed. Enter the new wheel and tire sizes in the calculator to keep overall diameter close to stock and verify brake and fender clearance. Always test fit.

• Where can I confirm OEM specs for my exact trim?
  Check the driver door jamb tire and loading label, the owner manual, and OEM service information. Use those values as your Installed on baseline in the calculator.