1968 Rolls Royce Tire Fitment Guide

1968 Rolls Royce vehicles use two tire sizes: 205R15 and 815-15, and both apply to the Silver Shadow. Each size mounts on a 15-inch rim. For wheel width, 205R15 products call for a 5.50- to 6.00-inch rim, while 815-15 products fit a wider 5.00- to 6.50-inch range.

That means the basic fitment question is not model-to-model variation within 1968 Rolls Royce, but which construction style you want on the car. The radial 205R15 follows a later metric format and the 815-15 remains a traditional bias-ply size, so checking the actual wheel width and the look you want is the right first step before narrowing down products.

On a 1968 Rolls Royce, 205R15 is a Euro-metric radial size. The 205 refers to the tire’s section width in millimeters, the R identifies radial construction, and the 15 is the wheel diameter in inches. In this older metric format, the aspect ratio is not written out and is conventionally treated as an 80-series profile.

For a Silver Shadow owner, that code signals a more modern tire format than the older numeric bias-ply alternative. It still preserves the correct 15-inch wheel diameter, but it changes the way the tire is categorized and usually aligns with buyers who want a radial option rather than a strictly period-style bias-ply presentation.

On a 1968 Rolls Royce, 815-15 is a numeric bias-ply size. The 8.15 designation refers to nominal section width, and the 15 identifies the wheel diameter in inches. Unlike a radial metric code, it does not use millimeters or an R construction marker because it belongs to an earlier American-style sizing system.

That matters if your Silver Shadow is being restored with a strong emphasis on period appearance and era-correct tire character. Numeric bias-ply sizing looks right on many 1960s luxury and collector cars, but owners should still verify wheel width and sidewall preference before choosing between a narrow whitewall treatment and a more stylized whitewall-redline version.

For 1968 Rolls Royce, the model covered here is the Silver Shadow, and it uses both available sizes: 205R15 and 815-15. There is no split where one size belongs to one Rolls-Royce model and another size belongs to a different one. The fitment conversation is centered on one model with two valid size and construction paths.

That gives buyers a clearer decision tree. Once you know you have a 1968 Rolls Royce Silver Shadow, the next step is not identifying between model families but deciding whether you want radial construction, bias-ply construction, and which sidewall treatment best suits the car’s intended finish and use.

A 1968 Rolls Royce Silver Shadow can use either 205R15 radial or 815-15 bias-ply tires, and both fit 15-inch wheels. The 205R15 is the modern radial-format choice, while the 815-15 preserves a traditional numeric bias-ply format more closely associated with period presentation. Each path is valid, but they serve different ownership goals.

Choose 815-15 if originality in look and classic driving character matter most, especially for a restoration-minded car. Choose 205R15 if you prefer the tire language and road-use character associated with radial construction. Because wheel width ranges are not identical between the two sizes, confirm the actual wheel before making the final decision.

1968 Rolls Royce tire choices include several distinct sidewall styles. In 205R15, Phoenix offers a 2.50-inch wide whitewall and Avon offers a blackwall. In 815-15, BFGoodrich offers both a narrow whitewall and a whitewall-redline combination.

For most Silver Shadow owners pursuing a formal luxury-car appearance, whitewall treatments tend to align more naturally with the period character of the car than a redline treatment. Blackwall can suit a more understated look, while the final choice should reflect how original, personalized, or road-focused you want the finished car to appear.

Three brands cover 1968 Rolls Royce fitments across the two sizes: Phoenix, Avon, and BFGoodrich. Phoenix and Avon serve the 205R15 radial size, while BFGoodrich covers the 815-15 bias-ply size. That gives Silver Shadow owners access to both European-style radial naming and traditional American collector bias-ply construction.

Brand choice should follow size and construction choice first, not the other way around. If you know you want a radial, your options sit in 205R15; if you want a bias-ply presentation, BFGoodrich carries the 815-15 choices. After that, compare sidewall styling and any speed-rating details that matter for how the car will actually be driven.

Rim width requirements differ slightly between the two 1968 Rolls Royce sizes. The 205R15 radial fits 5.50- to 6.00-inch rims, while the 815-15 bias-ply fits 5.00- to 6.50-inch rims. Both use a 15-inch wheel diameter, but the acceptable width range is not identical.

That difference is important when moving between radial and bias-ply choices on a Silver Shadow. A wheel that works with 815-15 may fall outside the preferred range for some 205R15 applications, so measuring the actual wheel width before purchase is a smart way to avoid fitment mismatch and preserve the intended tire shape on the car.

Inner-tube status is not marked in the size descriptions for the 205R15 and 815-15 products here, so the practical approach is to confirm the construction details on the specific tire you intend to use and the condition of the wheel itself. That is especially important on a 1968 Rolls Royce, where wheel age, rim condition, and restoration history can affect the final setup choice.

A specialist familiar with Silver Shadow wheels can help determine whether a given tire-and-wheel combination should run tube-type or tubeless. Even when the tire itself is suitable, the wheel must also be appropriate for the setup. Checking that before mounting is far better than treating all 15-inch collector wheels as interchangeable in service requirements.

Both tire sizes used on a 1968 Rolls Royce Silver Shadow share the same 15-inch rim diameter, so original 15-inch wheels can generally serve as the starting point for either 205R15 or 815-15 fitment. The key difference is wheel width compatibility, because the radial and bias-ply sizes do not share exactly the same approved width range.

That means the wheel diameter itself is not the obstacle; the actual measured width and condition of the wheel are what matter. Before switching from one size type to the other, verify the wheel width, inspect the rim carefully, and confirm that the tire you want is appropriate for the wheel rather than assuming every original Silver Shadow wheel will suit both equally well.

A 1968 Rolls Royce should be stored in a cool, dry, dark environment away from direct sunlight, electric motors, welders, furnaces, and other ozone sources that accelerate rubber aging. Keep the tires clean, maintain proper inflation, and move the car periodically if possible. Bias-ply tires are generally more prone to temporary flat-spotting during long static storage than radials.

If the Silver Shadow will sit for an extended period, many owners either roll it occasionally or support it in a way that reduces prolonged loading on one contact patch. Storage habits matter as much as miles on a collector car. Good storage preserves sidewalls, helps the tires hold shape, and reduces the chance of finding age-related cracking before the next outing.

Tires on a 1968 Rolls Royce should be judged more by age and condition than by mileage, because collector cars often accumulate relatively few miles. A practical rule is to begin careful age-based evaluation in the 5- to 7-year range and to treat around 10 years as the point where replacement deserves serious consideration, even if tread depth still looks good.

Check the date code on the tire and inspect for sidewall cracking, hardening, irregular wear, and any loss of confidence in the carcass. A Silver Shadow may look lightly used and still be riding on old rubber. Reproduction and collector tires can age out before they wear out, so calendar age should always be part of the maintenance decision.

Tires on a 1968 Rolls Royce should be inspected before every drive and again before any longer trip or event. Look for sidewall cracking, cuts, bulges, uneven tread wear, pressure loss, and any sign that the tire has changed shape during storage. Because these cars are often driven intermittently, issues can develop between outings rather than during daily use.

A brief walkaround catches many problems early, especially on a heavy luxury car where tire condition has a strong effect on ride quality and stability. Include the spare in the inspection routine, and if your chosen setup uses tubes, check valve stem condition closely as part of the same process. Consistent inspection is one of the simplest ways to avoid preventable roadside trouble.

A 1968 Rolls Royce Silver Shadow belongs to a period when bias-ply construction was still historically familiar but radial adoption was becoming increasingly relevant in premium motoring. The two sizes associated with 1968 Rolls Royce here are 815-15 bias-ply and 205R15 radial, both on 15-inch wheels. That places the car right at the intersection of traditional and more modern tire thinking.

For a factory-authentic restoration, the exact original fitment can vary by market, delivery specification, and restoration history, so marque clubs and original handbooks remain the best sources for final confirmation. Most buyers approach the choice by deciding whether they want the car judged and presented in a strongly period-correct way or driven with a more modern radial-style tire format.

Correct tire fitment matters on a 1968 Rolls Royce because judges and knowledgeable enthusiasts often notice size format, construction type, and sidewall treatment immediately. A Silver Shadow shown for originality can be marked down if the tire’s profile or sidewall presentation looks out of period, even when the wheel diameter is correct. Whitewall style can be as visually important as the size itself.

That does not mean every show car must wear the same tire, but it does mean the choice should match the standard you are building toward. If the car is aimed at concours-style authenticity, verify the expected construction and sidewall appearance with marque experts. If it is a touring or preservation car, a sensible compromise may still be appropriate depending on the event.

Both 815-15 BFGoodrich options for the 1968 Rolls Royce share the same basic construction, series, load figure, pressure figure, rim diameter, rim width range, and weight. Each is a bias-ply tire from the Silvertown Classic Bias Ply family with a 15-inch rim diameter, a 5.00- to 6.50-inch rim width range, a 1610-pound load rating, and a 32 psi reference figure.

The real difference is visual treatment. One uses a 1.00-inch narrow whitewall, while the other combines that whitewall with a 3/8-inch redline for a more customized appearance. On a formal luxury car like a Silver Shadow, the narrower whitewall will usually read as more restrained, while the redline version adds a noticeably more personalized look.

1968 Rolls Royce tires can be suitable for highway driving when they are in good condition, correctly inflated, and matched to the way the car is used. The 205R15 size includes an Avon option with a V speed rating, which corresponds to a 149 mph ceiling. The 815-15 bias-ply products do not show a speed letter in the size description, so they should be approached in keeping with traditional collector-tire use and the overall capabilities of the vehicle.

On a Silver Shadow, tire safety is only one part of the highway question. Brake condition, suspension health, alignment, steering components, and the age of the tires often matter more in real driving than headline speed potential. A thorough pre-drive inspection and realistic cruising expectations are the right approach for any 1960s Rolls-Royce.

Inflation pressure for a 1968 Rolls Royce depends on the exact tire selected. The 205R15 Phoenix tire carries a 1609-pound load figure at 34 psi, while the 815-15 BFGoodrich tires carry a 1610-pound load figure at 32 psi. Those figures describe the tire’s rated load relationship and should not be treated automatically as the vehicle’s factory running pressure.

Use the original Rolls-Royce handbook or factory service literature for the car’s baseline pressure recommendation, then confirm that your chosen tire’s operating range is appropriate. Do not transfer a pressure value from one size to the other just because both fit a 15-inch wheel. The final setting should respect both the vehicle and the specific tire on the car.

Before a longer drive in a 1968 Rolls Royce, inspect each tire for visible cracking, cuts, bulges, uneven wear, and proper inflation. Check that the spare is usable and that valve stems are in sound condition. On a collector car that may sit for stretches, also make sure no tire has developed a flat-spotted feel or a noticeable loss of pressure since the last outing.

That tire check should happen alongside a broader mechanical review of fluids, brakes, steering, suspension, and lighting. A Silver Shadow is a substantial, sophisticated car for its era, and road confidence depends on the whole vehicle being ready, not just the tread looking acceptable. A careful inspection routine helps turn a longer drive into an enjoyable one rather than a recovery exercise.