1931 Graham Special Tires

A 1931 Graham Special uses either 550-18 or 6.00-17, and both are bias-ply sizes. The 6 Cyl. version uses 550-18, while the 8 Cyl. version uses 6.00-17. Those sizes also correspond to different wheel diameters, so the correct choice depends on the exact version of the car.

That means the first step is not choosing a brand or sidewall style, but confirming whether the car is a 6 Cyl. or 8 Cyl. model and checking the wheel diameter already on it. On a prewar car, wheel swaps or long-ago repairs are always possible, so matching the tire to the actual wheel and vehicle configuration matters.

The 1931 Graham Special uses either an 18-inch rim or a 17-inch rim, depending on the sub-model. The 6 Cyl. version is paired with the 550-18 tire on an 18-inch rim, while the 8 Cyl. version uses the 6.00-17 tire on a 17-inch rim.

Rim diameter should be verified before anything else because these two tire sizes are not meant for the same wheel. Measuring the wheel or confirming the marking on the existing tire helps prevent ordering a tire that matches the car by name but not the actual wheel currently installed.

No. The 1931 Graham Special 6 Cyl. and 8 Cyl. do not use the same tire size. The 6 Cyl. uses 550-18, and the 8 Cyl. uses 6.00-17, so the model name alone is not enough to select a tire correctly.

This is one of those early-car fitment situations where the sub-model makes a real difference. Once the exact version is confirmed, the buyer can focus on the available bias-ply choices and sidewall presentation rather than trying to compare two sizes that belong to different wheel diameters and different vehicle setups.

Start by confirming that the car is the 1931 Graham Special 6 Cyl., since 550-18 belongs to that sub-model. From there, the main choices are among bias-ply tire series and sidewall styles, including blackwall, wide whitewall, and double-whitewall presentations from brands such as Excelsior, Firestone, BFGoodrich, and Michelin.

Selection usually comes down to how the car will be presented and driven. A blackwall can give a more restrained prewar look, while whitewall treatments can shift the appearance toward a stronger restoration-oriented style. Rim-width specifications are also worth comparing, especially if the car has non-original wheels or has been off the road for many years.

For the 550-18 fitment used on the 1931 Graham Special 6 Cyl., available sidewall styles include blackwall, wide whitewall, and double-whitewall. Those choices can change the visual character of the car significantly even when the tire size remains the same.

Sidewall style should be chosen with the vehicle's overall presentation in mind rather than as a purely cosmetic afterthought. A buyer aiming for a traditional roadgoing look may prefer one style, while a more formal restoration theme may point toward another. When originality matters closely, it is smart to compare the tire appearance against period photos or marque-specific references.

For the 550-18 size used on the 1931 Graham Special 6 Cyl., available brands include Excelsior, Firestone, BFGoodrich, and Michelin. Those options appear across several vintage tire series, so the choice is broader than simply selecting a single period-style brand name.

Brand is only one part of the decision on a prewar fitment like this. Sidewall presentation, rim-width compatibility, and the tire series itself may affect which option makes the most sense for the car. It also helps to confirm whether the vehicle still carries the proper wheel diameter before comparing brands too closely.

A period-style 1931 Graham Special should stay with its correct primary bias-ply size for the exact sub-model: 550-18 for the 6 Cyl. or 6.00-17 for the 8 Cyl. Keeping the proper size and construction is the foundation for maintaining the vehicle's early-1930s stance and visual character.

After size is settled, the appearance decision usually comes down to tire series and sidewall style. Blackwall, wide whitewall, and double-whitewall treatments can all create very different impressions on the same car. For a tightly researched restoration, it helps to compare the finished look against period photographs, club guidance, or other model-specific historical references.

Yes, correct tire fitment matters greatly on a 1931 Graham Special restoration because the tire size affects both appearance and wheel compatibility. Using the proper sub-model size preserves the vehicle's proportions, and staying with a bias-ply construction maintains the traditional profile expected on a prewar automobile.

A restoration can look noticeably off if the wheel diameter or tire section is wrong, even before the car moves. Tire choice also affects practical details such as clearance and how naturally the car sits on its suspension. Sorting out the exact sub-model first keeps the restoration process aligned with the vehicle rather than with a generic Graham fitment.

Yes, modifications can affect tire fitment on a 1931 Graham Special, especially if the car has replacement wheels, altered suspension components, brake updates, or bodywork changes from an earlier restoration. Even when the correct original tire size is known, those changes can alter the wheel width, diameter, or available clearance around the tire.

That is why the wheel on the car should be checked, not assumed, before ordering vintage tires. Steering clearance, fender clearance, and the vehicle's ride height all matter on an older chassis. Any Graham that has been modified over the years deserves a careful inspection so the selected tire matches the current setup as well as the model fitment.

Before driving a 1931 Graham Special on new tires, inspect the wheels, valve stems, mounting surfaces, and overall condition of the suspension and steering components. The tires themselves should be checked for proper installation and inflation, while the car should also be examined for any obvious rubbing points, uneven stance, or signs that wheel fitment is not correct.

A short, careful test drive is the best next step once those basics are covered. Pay attention to tracking, steering response, and any evidence of tire contact during turns or over bumps. On collector cars that spend long periods parked, it also makes sense to recheck pressure and wheel fasteners after the first few miles.

550-18 tires on a collector 1931 Graham Special should be maintained with regular pressure checks, visual inspections, and clean, dry storage conditions. Early cars often see limited use, so sidewall cracking, flat spotting, air loss, and age-related deterioration can become more important than tread wear alone.

Good maintenance also includes keeping the car away from prolonged sunlight, excess heat, moisture, and ozone sources during storage. The tires should be inspected before each outing, especially after long stationary periods. A vintage bias-ply tire can look fine at a glance, so it is worth checking closely for cuts, bulges, or changes in how the car sits.