The GMT800 generation Sierra 2500HD established GMC’s commitment to heavy-duty performance with robust construction and reliable capability. This first-generation platform introduced advanced engineering that set the foundation for future Sierra models, delivering exceptional towing capacity and payload performance for commercial and recreational users. The table below shows factory tire sizes for the 1999-2006 GMC Sierra 2500HD along with flotation size conversions to make tire shopping easy.
| Diameter | Standard Sizing | Flotation Sizing |
|---|---|---|
| 16 Inch | LT245/75R16 | 30.47 x 9.65 x 16 |
Note: The Light Truck designation is denoted with LT.
The GMT900 platform brought significant refinements to the Sierra 2500HD lineup, featuring improved powertrain options and enhanced structural integrity. This generation offered expanded tire size options to accommodate diverse user needs, from work-focused applications to performance-oriented configurations. Advanced engineering delivered superior towing and payload capabilities while maintaining the durability demanded by commercial operators. The table below shows factory tire sizes for the 2007-2017 GMC Sierra 2500HD along with flotation size conversions to make tire shopping easy.
| Diameter | Standard Sizing | Flotation Sizing |
|---|---|---|
| 17 Inch | LT245/75R17 | 31.47 x 9.65 x 17 |
| 17 Inch | LT265/70R17 | 31.61 x 10.43 x 17 |
| 18 Inch | LT265/70R18 | 32.61 x 10.43 x 18 |
| 20 Inch | LT265/60R20 | 32.52 x 10.43 x 20 |
| 20 Inch | 275/55R20 | 31.91 x 10.83 x 20 |
| 20 Inch | 285/50R20 | 31.23 x 11.22 x 20 |
| 22 Inch | 285/45R22 | 32.1 x 11.22 x 22 |
*Note: The Light Truck designation is denoted with LT.
The K2XX generation Sierra 2500HD brought refined engineering and enhanced capability to the heavy-duty truck segment, establishing new benchmarks for payload capacity and towing prowess. This third-generation platform introduced advanced aluminum construction techniques that reduced overall weight while maintaining structural integrity demanded by commercial and recreational users alike. The table below shows factory tire sizes for the 2015-2019 GMC Sierra 2500HD along with flotation size conversions to make tire shopping easy.
| Diameter | Standard Sizing | Flotation Sizing |
|---|---|---|
| 17 Inch | LT245/75R17 | 31.47 x 9.65 x 17 |
| 17 Inch | LT265/70R17 | 31.61 x 10.43 x 17 |
| 18 Inch | LT265/70R18 | 32.61 x 10.43 x 18 |
| 20 Inch | LT265/60R20 | 32.52 x 10.43 x 20 |
| 20 Inch | 275/55R20 | 31.91 x 10.83 x 20 |
| 20 Inch | 285/50R20 | 31.23 x 11.22 x 20 |
| 22 Inch | 285/45R22 | 32.1 x 11.22 x 22 |
*Note: The Light Truck designation is denoted with LT.
The T1XX represents the latest evolution in Sierra 2500HD engineering, incorporating cutting-edge technology and advanced materials for superior performance. This generation features updated powertrains, improved aerodynamics, and enhanced connectivity features while maintaining the rugged capability that defines the Sierra brand. Modern design elements complement functional improvements for today’s demanding work and recreational applications. The table below shows factory tire sizes for the 2020-2026 GMC Sierra 2500HD along with flotation size conversions to make tire shopping easy.
| Diameter | Standard Sizing | Flotation Sizing |
|---|---|---|
| 17 Inch | LT245/75R17 | 31.47 x 9.65 x 17 |
| 17 Inch | LT265/70R17 | 31.61 x 10.43 x 17 |
| 18 Inch | LT275/70R18 | 32.83 x 10.83 x 18 |
| 20 Inch | LT275/65R20 | 34.1 x 10.83 x 20 |
*Note: The Light Truck designation is denoted with LT.
The two things that affect tires are time and mileage. Naturally, the compounds on tires have a limited lifespan as they begin to breakdown over time. The mileage on a tire is only a general indication of it’s wear and usage. Neither time nor mileage are accurate indicators of a tire’s usability. The reason for that is because factors such as tire storage and care can improve or diminish lifespan. Typically most tires are manufactured to last at least five years under normal circumstances. If your tires are older than 5 years, it may be a good idea to consider replacements.
Reading the sidewall and understand tire sizing options can seem difficult at first. Once you learn the basics of what these numbers and markings mean, it becomes much simpler. Oftentimes original equipment tires use standard sizing designations, such as 255/70R17. However, when upgrading tires, especially for the Sierra 2500HD, you may come across flotation sizing designations. These will typically read as 35×12.50×17.
At Rolling Big Power, we use flotation sizing (like 31.47 x 9.65 x 17) because it's easier to understand. The first number is overall diameter, second is width, and third is wheel size - all in inches. Standard sizing (like LT245/75R17) uses metric measurements that can be confusing.
Many sizes are compatible! For example, LT245/75R17 and LT265/70R17 work on 2007-2017, 2015-2019, and 2020-2026 models. However, we always recommend checking your specific vehicle's load requirements and clearance before upgrading.
The LT275/65R20 (34.1 x 10.83 x 20) available on 2020+ models provides the largest overall diameter at 34.1 inches. For earlier generations, the LT265/70R18 at 32.61 inches offers good clearance while maintaining proper load capacity.
Yes! We stock some factory sizes for all Sierra 2500HD generations, plus popular upgrade options. Our team can help you choose the right size for your specific needs and ensure proper load rating compliance.
Absolutely! Moving from 17" to 20" or 22" wheels is popular. We'll calculate the right tire size to maintain your overall diameter and speedometer accuracy. For example, going from LT265/70R17 to 285/45R22 keeps similar overall dimensions while giving you that aggressive look.
