1989 GMC Suburban — 1500 4wd
The 1989 GMC Suburban 1500 4wd came from the factory equipped with 235/75R15 tires. If your vehicle has since been fitted with aftermarket or upsized wheels, your actual tire size may no longer match this factory spec — always confirm against your door placard before buying.
235/75R15
| Section width | 235 mm |
|---|---|
| Aspect ratio (sidewall height) | 75% (176.3 mm) |
| Rim diameter | 15" |
| Overall tire diameter | ~28.9" |
| Revolutions per mile | ~698 |
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What this size means for your GMC Suburban
On the 1989 GMC Suburban 1500 4wd, the factory 235/75R15 measures about 28.9″ in overall diameter with a 176.3 mm (6.9″) sidewall, and completes roughly 698 revolutions per mile. Its 75-series aspect ratio gives a tall sidewall of the kind used on trucks, SUVs, and older passenger cars, built for cushioning and load. In tire terms it is a passenger (P-metric / Euro-metric) size.
Because the 1989 GMC Suburban predates many current tire lines, confirm this size is still stocked before ordering — some vintage fitments are now served mainly by specialty and classic-car tire suppliers.
Other 1989 GMC Suburban trims
GMC Suburban tire sizes by year
- 1999 GMC Suburban 235/75R15
- 1998 GMC Suburban 235/75R15
- 1997 GMC Suburban 235/75R15
- 1996 GMC Suburban 235/75R15
- 1995 GMC Suburban 235/75R15
- 1994 GMC Suburban 235/75R15
- 1993 GMC Suburban 235/75R15
- 1992 GMC Suburban 235/75R15
- 1991 GMC Suburban 235/75R15
- 1990 GMC Suburban 235/75R15
How to read a tire size
A tire size like 225/45R17 breaks down into three parts:
the first number is the section width in millimeters
(the tire's width from sidewall to sidewall), the second is the
aspect ratio — the sidewall's height as a percentage of
that width — and the number after the "R" is the rim
diameter in inches. A letter prefix (P or LT) indicates
Passenger or Light Truck construction; its absence usually means
Euro-metric sizing.
Some trucks and off-road tires instead use "flotation" sizing, like
37X12.50R17 — here the numbers are the tire's overall
diameter and width in inches directly, with the rim diameter last.
Always verify against the tire information placard on your driver's-side door jamb or your owner's manual before purchasing — tire size can vary by factory option package even within the same trim.