Ram 2500 Bolt Pattern, Wheel & Tire Sizes
TL;DR
8x165.1 mm bolt pattern and 121.3 mm center bore have stayed the same on SRW Ram 2500 trucks since 1994; stud thread moved from 9/16-18 UNF to M14x1.5 around 2010-2011, and wheel diameters grew from 16 inches to 18-20 inches on newer trims.
Ram 2500 wheel bolt pattern by generation
The Ram 2500 (single rear wheel, SRW) has used the same 8x165.1 mm (8x6.5 inch) lug pattern and 121.3 mm center bore across every generation reviewed here, from the second-generation (1994-2002) trucks through the current lineup. What is not constant is the wheel stud thread and the factory wheel/tire sizing, which changed as the truck grew larger wheels over time. Note: dual-rear-wheel (DRW / 3500-style) Ram 2500-badged trucks and any special HD packages can differ - always confirm on the specific vehicle.
What changed: stud thread
Aftermarket wheel-fitment data indicates the stud thread was 9/16 inch-18 UNF on 1994-2010 trucks, switching to the metric M14x1.5 thread from roughly 2011 onward. Because this transition year is sourced from aftermarket references rather than a factory service manual, confirm your truck's exact thread by checking a lug nut removed from your own wheel or asking a tire shop to measure it.
Where to get the number that matters for YOUR truck
- The tire size and load rating molded into your tire sidewall
- The certification label on the driver's door jamb (lists tire size, wheel size and cold inflation pressures)
- Your owner's manual, in the wheels and tires section
- A wheel shop can measure bolt pattern, center bore and stud thread directly off the hub
Generation-by-generation specs
| Generation / years | Bolt pattern | Centre bore | Stud thread | Stock wheel sizes | Common tire sizes |
|---|---|---|---|---|---|
| 2nd gen, 1994-2002 | 8x165.1 mm (8x6.5 in) | 121.3 mm | 9/16 in-18 UNF | 6.5Jx16, 7.5Jx16, 8Jx16 | 225/75R16, 245/75R16, 265/75R16 |
| 3rd gen, 2003-2009 | 8x165.1 mm (8x6.5 in) | 121.3 mm | 9/16 in-18 UNF | 7.5Jx17, 8Jx17 | 245/70R17, 265/70R17 |
| 4th gen (early), 2010 | 8x165.1 mm (8x6.5 in) | 121.3 mm | 9/16 in-18 UNF | 7.5Jx17, 8Jx17, 8Jx18 | 245/70R17, 265/70R17, 275/70R18 |
| 4th gen, 2011-2018 | 8x165.1 mm (8x6.5 in) | 121.3 mm | M14x1.5 | 7.5Jx17 up to 8Jx20 (trim-dependent) | LT245/70R17 up to LT285/60R20 |
| 4th/5th gen, 2019-present | 8x165.1 mm (8x6.5 in) | 121.3 mm | M14x1.5 | 7.5Jx17 or 8Jx18 | LT245/70R17 or LT275/70R18 |
Lug torque figures vary by source and were not independently verified for every generation here, so this page does not state a single torque number - use the torque printed in your owner's manual or on the underside of the spare tire cover.
Summary
| Bolt pattern (all gens, SRW) | 8x165.1 mm (8x6.5 in) |
|---|---|
| Centre bore (all gens, SRW) | 121.3 mm |
| Stud thread, 1994-2010 | 9/16 in-18 UNF |
| Stud thread, 2011-present | M14x1.5 |
| Wheel sizes, 1994-2002 | 16 inch |
| Wheel sizes, 2011-2018 | 17 to 20 inch (trim-dependent) |
| Wheel sizes, 2019-present | 17 or 18 inch |
Full diagnostics
For the complete step-by-step diagnostic and repair guide, see Ram 2500: Common Problems, Fault Codes & Repairs.
Frequently asked questions
Has the Ram 2500 bolt pattern ever changed?
Not for single-rear-wheel (SRW) trucks. Every generation reviewed here, from 1994 through the current model, uses 8x165.1 mm (8x6.5 inch). Dual-rear-wheel (DRW) versions use a different rear setup, so confirm which configuration you have.
What is the Ram 2500 center bore?
121.3 mm across the generations checked (1994 to present). If you are fitting aftermarket wheels with a larger bore, you will need hub-centric rings to keep the wheel centered on the hub.
What thread size are the wheel studs?
Aftermarket fitment data points to 9/16 inch-18 UNF on trucks built through about 2010, and metric M14x1.5 from roughly 2011 onward. Because the exact changeover year is not confirmed against a factory manual, check a stud on your own truck or ask a tire shop to verify before ordering lug nuts.
Where can I find the exact tire size for my Ram 2500?
Check the certification label on the driver's door jamb, the sidewall of your current tires, or the tires and wheels section of your owner's manual - these reflect the exact trim, wheel package and load range your truck left the factory with.