1973 GMC Rally Tires

The 1973 GMC Rally uses six primary tire sizes: F78-14, G78-14, G78-15, H78-15, 800-16.5, and 875-16.5. Those sizes are tied to specific G1500, G2500, and G3500 wagon configurations, so there is not one universal tire size across the full Rally lineup.

Getting the right tire starts with the exact sub-model, GVWR, and wheel diameter already on the van. A G1500 may use a 14-inch fitment, a G2500 moves into 15-inch sizes, and a G3500 uses 16.5-inch truck tires, so checking the existing wheel and sidewall marking before selection prevents an avoidable mismatch.

A 1973 GMC Rally may use 14-inch, 15-inch, or 16.5-inch rims depending on the sub-model and tire size. F78-14 and G78-14 use 14-inch rims, G78-15 and H78-15 use 15-inch rims, and 800-16.5 and 875-16.5 use 16.5-inch rims.

Wheel diameter is the first thing to confirm because it immediately narrows the correct tire choices. It is also worth checking wheel width and the actual installed setup, especially on older vans that may have seen wheel changes over time, since the Rally spans passenger-style and heavy-duty applications within the same model family.

The 1973 GMC Rally covers a broad range of wagon configurations, from G1500 models to heavier G2500 and G3500 versions, and that spread creates multiple tire sizes. The fitment differences track with the van's duty level, GVWR, and wheel diameter rather than one single shared setup.

That means the correct tire cannot be chosen by year and model name alone. The buyer should confirm the exact sub-model description, look at the existing wheel diameter, and compare the current sidewall size so the next tire matches the Rally's real configuration rather than a different weight-rating version.

F78-14 is a bias-ply primary tire size for the 1973 GMC Rally. It appears on certain G1500 wagon applications and uses the vintage alphanumeric sizing system associated with period-style bias-ply construction rather than a modern radial format.

That matters because a buyer deciding between staying with bias-ply or considering a radial alternative is making a construction change, not just a brand change. The van's wheel size, wheel width, and available clearance should be reviewed before any conversion, especially if the Rally has been altered from its original wheel or suspension setup.

Radial equivalents for G78-15 include 205R15 as an 80-series metric radial, P215/75R15 as a 75-series P-metric radial, P225/70R15 as a 70-series P-metric radial, and 710R15 as a bias-look radial. These alternatives preserve the 15-inch rim diameter while offering different sizing conventions and profile families.

The useful distinction is that the metric and P-metric sizes present more modern radial labeling, while 710R15 keeps a more traditional bias-look appearance. G78-15 equivalents are associated with a 6-8 inch recommended rim-width range, and the final choice should still be checked against the Rally's wheel width, overall package dimensions, and steering or body clearance.

A 1973 GMC Rally conversion from bias-ply to radial starts with matching the correct primary size to the correct radial equivalent for that specific application. On lighter 14-inch and 15-inch fitments, that means confirming the original size first, then comparing the equivalent radial against the van's wheel diameter and rim-width needs.

The next step is checking how the actual vehicle is set up today. Wheel width, suspension condition, steering clearance, ride height changes, and any aftermarket wheels can all affect whether a radial alternative remains a sound fitment choice, even when the equivalent size is in the proper comparison range for the original tire.

Start with the exact tire size, wheel diameter, and sub-model because the 1973 GMC Rally covers everything from 14-inch G1500 fitments to 16.5-inch G3500 truck applications. Once the fitment is confirmed, the main selection factors become bias-ply construction style, sidewall appearance, and whether the van needs a passenger-style or heavy-duty truck-oriented tire series.

A lighter-duty Rally may call for whitewall presentation, while a heavier van may be better matched to blackwall truck series. It also helps to compare rim-width guidance, load figures where stated, and the way the van will actually be used, since a show-oriented wagon and a load-carrying G3500 place different priorities on tire selection.

1973 GMC Rally tires are available in several sidewall styles, including wide whitewall, narrow whitewall, dual-white-stripe, and blackwall. The available style depends on the tire size, with lighter 14-inch and some 15-inch applications offering more decorative passenger-style choices, while the 16.5-inch heavy-duty sizes stay in blackwall truck form.

That variety makes sidewall style an important appearance decision once the correct size is settled. A whitewall or stripe can support a more dressed passenger-van look, while blackwall tires suit utility-focused builds and heavier-duty G3500 configurations, so the sidewall should match both the van's stance and the character the owner wants to preserve.

Available 1973 GMC Rally tires come from Coker Classic, BFGoodrich, and STA. Brand availability depends on the size, with Coker Classic and BFGoodrich appearing in passenger-style whitewall applications and STA covering several blackwall truck-oriented choices in G78-15, H78-15, 800-16.5, and 875-16.5.

Brand choice works best as a second step after confirming the proper size and wheel diameter. Once the fitment is correct, the buyer can compare each brand's available tire series, sidewall treatment, and any stated load or rim-width details to narrow the selection toward either a restoration-minded look or a more commercial-style presentation.

A period-style 1973 GMC Rally tire starts with the correct original-format bias-ply size for the exact sub-model, then moves to the visual character that suits the van. Lighter-duty G1500 and some G2500 applications have whitewall and stripe choices, while the heavier G3500 sizes are represented by blackwall truck-style bias-ply tires.

That means appearance should be chosen after fitment, not before it. Owners aiming for a more historically faithful presentation should compare the van's current configuration with photos, build documentation, or marque-specific references, because a tire can be strongly period-looking without automatically being the exact tire style that particular Rally carried when new.

Tire construction changes the look of a restored 1973 GMC Rally because all primary fitments here are bias-ply, and bias-ply tires carry the sizing format and sidewall presentation associated with the era. On lighter applications, that can include wide whitewall, narrow whitewall, or dual-white-stripe styling, while heavier applications remain more utilitarian in blackwall form.

A radial alternative may be useful for some 14-inch and 15-inch applications, but it changes the construction even if the overall look stays traditional. Buyers concerned with restoration appearance should decide whether the priority is maintaining original-type construction, preserving a vintage visual impression, or balancing that appearance with modern radial-format alternatives.

Yes, modifications can affect tire fitment on a 1973 GMC Rally even when the chosen size is correct for the original application. Aftermarket wheels, changed wheel widths, suspension alterations, brake conversions, and body modifications can all influence how a tire sits and clears on a vintage van.

That is especially important on a model line that spans 14-inch, 15-inch, and 16.5-inch wheels. A Rally that no longer carries its original-style wheel setup should be checked at the wheel itself, not just by model name, and steering travel and body clearance should be verified before committing to a replacement tire or a radial-equivalent alternative.

Before driving a 1973 GMC Rally on new tires, inspect the wheels for condition and correct diameter, confirm proper inflation, and make sure the mounted tire matches the intended size for the van's sub-model. It is also smart to check lug hardware, valve stems, and visible clearance at the fender, suspension, and steering components.

A vintage van benefits from a short, careful road check before regular use. Watch for rubbing during turns, recheck inflation after the first miles, and pay attention to any pull or vibration, since problems may come from wheel condition, alignment, or an old suspension issue rather than the tire size alone.

Tires on a collector 1973 GMC Rally should be kept properly inflated, inspected regularly for cracking, cuts, bulges, irregular wear, and air loss, and protected during storage from prolonged sunlight, heat, moisture, and ozone sources. That applies whether the van wears whitewall passenger tires or heavier blackwall truck-style bias-ply tires.

Low annual mileage does not eliminate the need for inspection. Collector vehicles often age their tires through time and storage rather than tread wear, so a Rally that sits for long periods should still have its tires, wheel condition, and general roadworthiness checked before highway use or before carrying passengers and cargo on a longer trip.