1926 Pontiac Tire Fitment Guide

1926 Pontiac vehicles use two tire sizes: 29X4.75 and 4.75-20. Both sizes apply to the 1926 Pontiac 6 Cyl., and both are bias-ply constructions mounted on 20-inch rims. There is no separate model split within the 1926 Pontiac range, because the year's lineup is centered on the 6 Cyl. model.

The practical difference is that the two sizes use different naming systems rather than representing a simple modern-style plus-or-minus fitment change. Start by reading the size stamped on the tire or checking the wheel setup already on the car, then compare that with the type of restoration you are pursuing. That approach is usually more useful than choosing by appearance alone.

On a 1926 Pontiac, 29X4.75 is an antique diameter-by-section size. The first number, 29, refers to the tire's overall diameter in inches, while 4.75 refers to the nominal section width. That sizing language belongs to the earlier tire conventions common on mid-1920s vehicles, and the construction is bias-ply.

That matters because a buyer used to later numeric or modern metric sizing may assume the first number is the wheel diameter, which it is not in this case. If your Pontiac is being restored to an earlier visual standard, this size format often aligns better with the period presentation. Confirm the wheel and existing fitment before deciding, especially if the car has been apart or modified over the years.

On a 1926 Pontiac, 4.75-20 is a numeric bias-ply size. The 4.75 refers to the nominal section width in inches, and the 20 refers to the wheel diameter in inches. That makes it easier for many buyers to read than the earlier antique format, but it is still a period-style bias-ply tire rather than a modern radial metric size.

The useful takeaway is that this marking points directly to a 20-inch rim, so wheel diameter confirmation is straightforward. If your car currently wears numeric bias-ply tires or has records pointing to that format, 4.75-20 is the size family to investigate first. It is still wise to compare the actual wheel and the intended restoration standard before making a final selection.

For a 1926 Pontiac, both 29X4.75 and 4.75-20 are bias-ply choices, so the decision is not about bias-ply versus radial behavior. It comes down to matching the correct period size system to your car's wheel setup and restoration direction. Both sizes mount on 20-inch rims, but the way the tire is designated reflects different era conventions.

If your goal is a restoration that follows an early-1920s appearance closely, the 29X4.75 format may be the more natural fit visually. If your Pontiac is already set up around a numeric 4.75-20 specification, staying with that designation keeps the fitment path simpler. The smartest first step is to verify the size already associated with your wheels rather than choosing only by the printed code.

1926 Pontiac tire options in this year-make summary center on the two correct bias-ply sizes, 29X4.75 and 4.75-20. Brand choice depends on which of those sizes you need, since antique and early numeric applications are often grouped by size family rather than by vehicle badge alone. The important point is to begin with the correct size before narrowing to a particular brand or tread presentation.

That size-first approach is especially important on an early car like a 1926 Pontiac, where authenticity and wheel compatibility often matter more than broad brand shopping. Once the size is settled, compare the available products in that size for sidewall presentation and overall period character. Buyers restoring for judged events should also compare what is currently on the car with accepted Pontiac-era restoration practice.

Sidewall style is one of the most visible choices on a 1926 Pontiac because it strongly affects how authentic the car looks at a glance. Both listed sizes are firmly in the pre-war bias-ply world, where sidewall treatment can change the visual tone of the car even when the dimensions are correct. The right choice depends on the exact product offered in the size you need.

For a careful restoration, sidewall appearance should be chosen with the same care as the size itself. Early Pontiacs generally look most convincing with sidewall styling that matches period expectations rather than a later decorative treatment. If the car is being prepared for formal judging, compare the tire's sidewall look with marque references and period photography instead of treating all blackwall-era tires as interchangeable.

1926 Pontiac tires in the listed 29X4.75 and 4.75-20 sizes both fit 20-inch wheels, which establishes the critical wheel diameter. Rim width still matters, because an early bias-ply tire needs to be matched to an appropriate wheel contour and width to maintain the intended section shape. The exact wheel on the car should always be checked before final selection.

That is especially true for cars that have changed hands many times, because replacement wheels and mixed-era parts are common in long-term restorations. Measure the actual wheel and compare it with the tire's accepted fitment range before mounting anything. If the car has wooden artillery wheels or restored steel rims, inspect their condition at the same time instead of treating the tire change as a stand-alone job.

A 1926 Pontiac sits squarely in the era when tube-type fitments were a normal part of tire service, especially with 20-inch bias-ply tires and early wheel designs. Whether a specific product is tube-type should be confirmed from the tire's own sidewall marking and the wheel construction being used. Tube decisions on vintage cars are tied to both the tire and the wheel, not only the size code.

In practice, that means you should inspect the wheel's sealing surface, valve-stem arrangement, and overall condition before assuming an old rim can be run any other way. If the car has not been on the road recently, replacing old tubes and flaps is often worth considering during the tire change. Doing that work up front helps avoid chasing slow leaks later.

Original 1926 Pontiac wheels can often be compatible with both listed tire sizes because 29X4.75 and 4.75-20 are both 20-inch fitments. That means the rim diameter requirement aligns, which is the first hurdle. The remaining issue is whether the wheel itself matches the specific tire's intended application and condition.

A restorer should still confirm the actual wheel width, bead condition, and overall straightness before treating the two sizes as freely interchangeable. Early wheels can be sound enough for display use yet still need attention before regular driving. If the wheels are original to the car, this is also the right time to confirm that the tire marking you choose matches the restoration standard you want to present.

A 1926 Pontiac should be stored in a cool, dry, dark space away from direct sunlight, electric motors, battery chargers, welders, and other ozone sources that accelerate rubber aging. Bias-ply tires also tend to flat-spot more readily during long static periods than later radial designs. Keeping the car clean and the tires properly inflated helps reduce stress while it sits.

If the Pontiac will be parked for an extended season, roll it periodically or use stands in a way that supports the car safely without distorting the tires. Avoid letting one section of the tread carry the load for months at a time. Owners who value sidewall appearance should also keep dressings and harsh cleaners off the rubber, since cosmetic shine products can do more harm than good over time.

Tires on a 1926 Pontiac should be judged more by age and condition than by mileage, because collector cars often accumulate very few miles each year. A good rule is to evaluate them closely once they reach about five to seven years of age and to treat around ten years as a serious replacement checkpoint regardless of remaining tread. The DOT date code on the tire helps establish age.

That timeline matters even more on a lightly used pre-war car, where the rubber may look serviceable from a distance but still have hardened internally. Cracking, persistent pressure loss, vibration, or visible casing distress should move the inspection from routine to immediate. For a car that sees parade, show, and occasional touring use, calendar age is usually the better guide than tread depth.

Tires on a 1926 Pontiac should be inspected before every drive and again before any longer outing or event. Check for sidewall cracking, tread separation, cuts, embedded debris, uneven wear, and any sign that the tire is not holding air evenly. On an early tube-type setup, valve stems and any related tube hardware deserve the same attention as the outer casing.

Frequent inspection is part of normal stewardship with a 1920s car, not a sign that something is wrong. Early cars often spend long periods parked, then return to road use suddenly, which is when age-related problems reveal themselves. A quick walk-around before departure can catch issues that are easy to correct in the garage and much harder to deal with at the roadside.

A 1926 Pontiac 6 Cyl. would have been fitted in the bias-ply era, and the listed 29X4.75 and 4.75-20 sizes both align with that period of tire construction. The correct original-spec direction for a car of this age is the proper period size and a bias-ply casing rather than a modern radial interpretation. The exact choice between the two size notations should follow the wheel setup and the car's established restoration standard.

Owners aiming for high authenticity should treat brand, sidewall appearance, and size marking as separate decisions rather than assuming any 20-inch vintage tire looks equally correct. Old photos, surviving paperwork, and Pontiac or GM-era marque resources can help narrow what is most appropriate for a particular car. That extra research is worthwhile because first-year Pontiacs attract buyers and judges who notice the details.

Correct tire fitment matters a great deal when showing a 1926 Pontiac, because judges and knowledgeable enthusiasts tend to look at size, construction, and sidewall presentation as part of the car's overall authenticity. A bias-ply tire in the proper period style supports the visual stance and historical character expected of a mid-1920s Pontiac. An obviously later construction or mismatched sidewall style can stand out quickly.

For local display events, a close visual match may be enough, but more formal judging often rewards accuracy in the details. That makes it wise to settle the correct size notation first, then compare sidewall appearance against period references and club guidance. If the car is being judged to a specific standard, event rules and marque expertise should guide the final decision more than personal preference.

The tire size format matters on a 1926 Pontiac restoration because 29X4.75 and 4.75-20 do not read the same way, even though both are period bias-ply fitments for the 6 Cyl. model. The earlier antique diameter-by-section style and the later numeric style each carry a different visual and historical tone. On a car from 1926, small details like that can affect how authentic the finished restoration feels.

Using the right format helps the tire look like it belongs to the car instead of simply fitting the wheel. Restorers who are pursuing a careful presentation should compare existing wheels, surviving photos, and any previous restoration records before making the call. It is one of those choices that may seem minor in the garage but becomes obvious once the car is fully assembled.

1926 Pontiac tires can be suitable for road use when they are in sound condition, correctly matched to the wheels, and used within the limits of their construction type. Both listed sizes are bias-ply, which means the driving feel will be more traditional than modern, especially in tracking, steering response, and flat-spot tendency after storage. On a car of this age, the broader mechanical condition often matters as much as the tire itself.

Highway use should be approached with the realities of a 1920s automobile in mind, including brakes, steering, suspension, and the overall condition of the chassis. A well-sorted Pontiac on fresh, properly fitted tires is a very different proposition from one that has sat for years. Before any sustained road trip, evaluate the whole car as a system rather than assuming new tires alone make it ready.

Inflation pressure for 1926 Pontiac tires should follow the factory recommendation for the car when available, while also respecting the tire manufacturer's own pressure guidance for the specific reproduction tire selected. The listed sizes, 29X4.75 and 4.75-20, should not be treated as interchangeable for pressure by assumption simply because both fit 20-inch wheels. Pressure always needs to match the exact tire and application.

That means the safest habit is to start with the vehicle literature or marque reference you trust, then confirm that the chosen tire's construction and rating support that range. Avoid using a generic vintage-car pressure rule across all early Pontiacs. Consistent pressure checks are especially important on collector cars because long storage periods can hide gradual losses that affect handling and tire life.

Before taking a 1926 Pontiac on a longer drive, inspect every tire for cracks, bulges, cuts, exposed cord, irregular wear, and stable air pressure. Include the spare, because on a pre-war car it is often the only practical backup if a roadside issue develops. If the setup uses tubes, pay attention to valve stems and any signs of leakage around them as well.

That tire check should be part of a broader pre-drive review that includes brakes, steering play, wheel bearings, fluids, and basic fastener security. A longer outing places more heat and sustained load into the tire than short neighborhood operation. Catching a small problem before departure is far easier than dealing with it miles from home in a car built nearly a century ago.