The 2008 Mercedes-Benz Trucks R320 comes from an era when Mercedes blended wagon-like utility, three-row comfort, and road-focused refinement into a full-size luxury people mover. That makes tire choice especially important, because the R320 depends on the right combination of load-carrying capability, ride quality, and wheel compatibility to feel as intended. This model uses radial tires in either 255/50R19 or 255/55R18, so the first step is confirming which wheel diameter is actually on the vehicle. With both sizes sharing the same overall diameter, the decision centers on matching the correct rim, then choosing a tire that suits original-style road use, replacement needs, and any wheel changes made over time.
Which Tire Size Is Right for The 2008 Mercedes-Benz Trucks R320
The 2008 Mercedes-Benz Trucks R320 uses two primary tire sizes, and both are radial fitments with different rim diameters. The key difference is wheel size: one fits an 18-inch rim and the other fits a 19-inch rim. Before selecting a tire, confirm the exact wheel diameter on the vehicle, since that determines which of the two sizes applies.
255/50R19 is a modern metric radial size in which 255 refers to the nominal section width in millimeters, 50 is the aspect ratio, R indicates radial construction, and 19 is the rim diameter in inches. On the 2008 Mercedes-Benz Trucks R320, this size is used with a 19-inch wheel and keeps the vehicle in a contemporary road-oriented tire format. Its practical role is straightforward: if the R320 is equipped with 19-inch wheels, this is the size to match. Checking the actual wheel setup matters, especially on vehicles that may have seen wheel swaps or trim-related changes over time.
255/55R18 is also a modern metric radial size, with 255 denoting nominal section width in millimeters, 55 identifying the aspect ratio, R for radial construction, and 18 for the wheel diameter in inches. For the 2008 Mercedes-Benz Trucks R320, this size belongs on an 18-inch rim and provides the alternate factory-style fitment path for this model line. Because it shares the same overall diameter as the 19-inch option, the real distinction is wheel compatibility rather than a dramatic change in tire height. This is the size to evaluate when the R320 is running 18-inch wheels and a standard replacement fitment is the goal.
The covered R320 sub-model fitment is simple in one sense and important in another: the R320 CDI can use either of the two primary tire sizes. What matters most is confirming whether the vehicle has 18-inch or 19-inch wheels before choosing a replacement tire.
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2008 Mercedes-Benz Trucks R320 CDI
The 2008 Mercedes-Benz Trucks R320 CDI uses radial tires and can be fitted with either of the two primary sizes depending on wheel diameter. Tire selection starts with verifying whether the vehicle is on 18-inch or 19-inch rims, then matching the replacement tire to that setup rather than choosing by appearance alone.
The tire sizes listed on this page assume factory-standard vehicle configuration. The following modifications may affect tire fitment and are not reflected in this guide:
Suspension changes (lowering, lift kits, spring replacements)
Body alterations (fender modifications, custom bodywork)
If your vehicle has been modified from factory specifications, verify tire clearance before purchase.
Frequently Asked Questions
For a 2008 Mercedes-Benz Trucks R320, the main tire questions usually come down to size selection, 18-inch versus 19-inch rim fitment, replacement strategy, and the checks worth making before putting the vehicle back into regular road use.
Tire Size & Fitment
What tire size fits a 2008 Mercedes-Benz Trucks R320?
A 2008 Mercedes-Benz Trucks R320 uses either 255/50R19 or 255/55R18 tires, both in radial construction. Those are the two primary fitments for this model, and the correct one depends on the wheel diameter installed on the vehicle.
The two sizes share the same overall diameter, but they do not fit the same wheel. That means the first check is not tread style or brand, but whether the R320 is running 18-inch or 19-inch rims. Looking at the sidewall of the current tire and confirming the actual wheel size will prevent ordering a tire that matches the vehicle generally but not the wheels currently on it.
What size rim does a 2008 Mercedes-Benz Trucks R320 use?
The 2008 Mercedes-Benz Trucks R320 uses either an 18-inch rim with 255/55R18 tires or a 19-inch rim with 255/50R19 tires. Both tire sizes are radial, but each one is tied to its own wheel diameter.
That rim difference is the most important fitment detail on this vehicle. A 255/55R18 cannot be mounted on a 19-inch wheel, and a 255/50R19 cannot be mounted on an 18-inch wheel, even though the two sizes are similar in overall height. Checking the wheel itself is especially important on used R-Class vehicles that may have changed wheels during their service life.
Why does the 2008 Mercedes-Benz Trucks R320 have more than one tire size?
The 2008 Mercedes-Benz Trucks R320 has more than one tire size because it can be equipped with two different wheel diameters: 18 inches or 19 inches. That creates two correct tire-size paths, 255/55R18 and 255/50R19, rather than one universal fitment.
In practical terms, that means tire choice starts with the wheels already on the vehicle. Since both sizes carry the same overall diameter, the difference is mainly in how the tire is proportioned around the wheel. The safest way to choose is to confirm the exact wheel diameter on the R320 CDI and then stay with the corresponding tire size unless a qualified professional is evaluating a broader wheel-and-tire change.
Choosing the Right Tire
What should I consider when choosing a tire for a 2008 Mercedes-Benz Trucks R320?
Start with the correct size for the wheel on the vehicle: 255/55R18 for 18-inch rims or 255/50R19 for 19-inch rims. Since both are radial fitments and both share the same overall diameter, the main selection issue is matching the tire to the actual wheel rather than deciding between two unrelated sizes.
After size confirmation, look at how the R320 is used. A road-driven family or touring vehicle may call for a different replacement emphasis than a lightly used example that spends more time parked. Tire age, wear pattern, load needs, and the condition of the alignment and suspension are all worth reviewing so the new tires work well with the vehicle instead of masking an existing chassis problem.
How do I choose between the available 255/50R19 and 255/55R18 tires for a 2008 Mercedes-Benz Trucks R320?
Choosing between 255/50R19 and 255/55R18 is not a matter of preference if the wheels are already on the vehicle. The right tire is determined by rim diameter: 255/50R19 belongs on a 19-inch wheel, while 255/55R18 belongs on an 18-inch wheel.
If the R320 still has its current wheel set, match the existing diameter and stay within the correct tire size. If the vehicle has aftermarket wheels or a previous owner changed the setup, verify the wheel markings and measure carefully before replacing tires. Similar overall diameter does not make the two sizes interchangeable at the wheel, so visual comparison alone is not enough.
What matters most when replacing tires on a 2008 Mercedes-Benz Trucks R320 CDI?
On a 2008 Mercedes-Benz Trucks R320 CDI, the most important point is confirming whether the vehicle is fitted with 18-inch or 19-inch wheels. That determines whether it uses 255/55R18 or 255/50R19, and both sizes are proper radial fitments for this sub-model.
Once wheel diameter is confirmed, inspect the existing tires for uneven wear, old age, or sidewall damage that may point to alignment or suspension issues. An R320 that has spent long periods parked can look fine at a glance while still having age-related deterioration. Replacing tires without checking those underlying conditions can lead to disappointing ride quality and shortened tire life.
Restoration & Appearance
Does correct tire fitment matter for a 2008 Mercedes-Benz Trucks R320 restoration?
Yes. Even on a newer collector or preservation-minded vehicle like a 2008 Mercedes-Benz Trucks R320, correct tire fitment still matters because the vehicle was designed around specific wheel diameters and radial tire proportions. Using 255/50R19 on 19-inch wheels or 255/55R18 on 18-inch wheels keeps the fitment aligned with the intended wheel-and-tire relationship.
For an appearance-focused project, the goal is usually to preserve the proper stance and overall look without creating avoidable clearance or compatibility issues. Since both sizes have the same overall diameter, the visual character comes largely from the wheel size already on the vehicle. Checking the actual setup first helps keep a restoration-minded replacement consistent with how the R320 presents on the road.
Which tire should I choose for a period-style 2008 Mercedes-Benz Trucks R320?
A period-style choice for a 2008 Mercedes-Benz Trucks R320 starts with staying in the correct original-size family for the wheels on the vehicle. That means 255/55R18 if it has 18-inch rims or 255/50R19 if it has 19-inch rims, both in radial construction.
For this kind of modern luxury vehicle, period-style appearance usually comes from preserving the correct sizing relationship rather than switching to an older construction type. The R320’s design reads best when the tire matches the intended wheel diameter and overall profile. If wheel changes were made in the past, returning to the proper size for the installed rim is often the cleanest way to regain an authentic presentation.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2008 Mercedes-Benz Trucks R320?
Yes. Modifications can affect tire fitment on a 2008 Mercedes-Benz Trucks R320, especially if the vehicle has aftermarket wheels, altered suspension height, or body changes that influence clearance. Even though the primary tire sizes are 255/50R19 and 255/55R18, wheel width and offset changes can alter how those tires sit in the wheel openings.
A used R320 should never be judged only by its model name when fitment is being checked. Looking at actual wheel diameter, wheel width, suspension condition, and steering clearance will tell a clearer story. Any rubbing marks, unusual tire wear, or mismatched wheel hardware are signs to slow down and verify the setup before mounting replacement tires.
What should I inspect before driving a 2008 Mercedes-Benz Trucks R320 on new tires?
Before driving a 2008 Mercedes-Benz Trucks R320 on new tires, inspect the wheels for damage, confirm the wheel diameter matches the tire size, and check the old tires for wear patterns that could point to alignment or suspension problems. It also helps to look over the valve stems and make sure the tires are inflated properly.
A fresh set of tires can only perform as well as the vehicle underneath them. Brake condition, steering response, and suspension wear all influence how the R320 feels once new tires are installed. A short, careful road test after installation is worthwhile so any vibration, pull, or clearance issue can be caught early instead of wearing the new tires unevenly.
How often should tires on a 2008 Mercedes-Benz Trucks R320 be inspected?
Tires on a 2008 Mercedes-Benz Trucks R320 should be inspected regularly, not just when tread looks low. A quick visual check every month and a closer inspection before longer drives is a sensible routine, especially for a vehicle that may alternate between regular road use and long periods of storage.
Pay attention to sidewall cracking, bulges, cuts, uneven tread wear, and gradual air loss. Since this R320 can use either 18-inch or 19-inch wheel setups, it is also worth confirming that all four tires still match the intended size for the vehicle’s wheels. Catching age or fitment issues early can prevent ride problems and help preserve the new tires once installed.
