1985 Chevrolet Astro — Base Model
The 1985 Chevrolet Astro Base Model shipped with 3 different factory tire sizes, depending on the wheel package it left the factory with (this can also reflect a staggered front/rear setup). Check your tire sidewall or door placard to confirm which one applies to your vehicle.
This trim shipped with more than one tire size (staggered fitment, front/rear, or optional wheel package). Confirm which one matches your vehicle by checking your tire sidewall or door placard.
205/70R15
| Section width | 205 mm |
|---|---|
| Aspect ratio (sidewall height) | 70% (143.5 mm) |
| Rim diameter | 15" |
| Overall tire diameter | ~26.3" |
| Revolutions per mile | ~767 |
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205/75R15
| Section width | 205 mm |
|---|---|
| Aspect ratio (sidewall height) | 75% (153.8 mm) |
| Rim diameter | 15" |
| Overall tire diameter | ~27.1" |
| Revolutions per mile | ~744 |
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245/60R15
| Section width | 245 mm |
|---|---|
| Aspect ratio (sidewall height) | 60% (147 mm) |
| Rim diameter | 15" |
| Overall tire diameter | ~26.6" |
| Revolutions per mile | ~759 |
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What this size means for your Chevrolet Astro
On the 1985 Chevrolet Astro Base Model, the factory 205/70R15 measures about 26.3″ in overall diameter with a 143.5 mm (5.6″) sidewall, and completes roughly 767 revolutions per mile. Its 70-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.
The 205/70R15 and 205/75R15 differ by about 0.8″ (3%) in overall diameter; a gap this size is enough to affect speedometer and odometer readings, so confirm which one your vehicle actually left the factory with.
Because the 1985 Chevrolet Astro 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.
Chevrolet Astro tire sizes by year
- 2005 Chevrolet Astro 215/70R16
- 2004 Chevrolet Astro 215/70R16
- 2003 Chevrolet Astro 215/70R16
- 2002 Chevrolet Astro 215/75R15
- 2001 Chevrolet Astro 215/75R15
- 2000 Chevrolet Astro 215/75R15 / 225/70R15
- 1999 Chevrolet Astro 215/75R15 / 225/70R15
- 1998 Chevrolet Astro 215/75R15 / 225/70R15
- 1997 Chevrolet Astro 215/75R15 / 225/70R15
- 1996 Chevrolet Astro 205/75R15 / 245/60R15
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.