OEM Stock Gearing - MX Big Bikes
OEM Stock Dirt Bike Gearing Chart
Use this motocross gearing reference chart to compare common OEM front and rear sprocket sizes for popular Honda, Yamaha, Kawasaki, Suzuki, and KTM 250F / 450F motocross bikes.
What the Numbers Mean
The front number is the countershaft sprocket tooth count. The rear number is the rear wheel sprocket tooth count.
Higher Ratio
A higher final-drive ratio generally gives quicker acceleration and a shorter feel in each gear.
Lower Ratio
A lower final-drive ratio generally gives more top-end speed and a taller feel in each gear.
Honda OEM Stock Gearing
| Make | Model | Year Range | Front | Rear | Final Ratio |
|---|---|---|---|---|---|
| Honda | CRF250R | 2011-2017 | 13 | 49 | 3.77 |
| Honda | CRF250R | 2018-2021 | 13 | 48 | 3.69 |
| Honda | CRF250R | 2022-2026Updated | 13 | 50 | 3.85 |
| Honda | CRF450R | 2009-2016 | 13 | 48 | 3.69 |
| Honda | CRF450R | 2017-2026Updated | 13 | 49 | 3.77 |
Yamaha OEM Stock Gearing
| Make | Model | Year Range | Front | Rear | Final Ratio |
|---|---|---|---|---|---|
| Yamaha | YZ250F | 2009-2011 | 13 | 49 | 3.77 |
| Yamaha | YZ250F | 2012-2026Updated | 13 | 50 | 3.85 |
| Yamaha | YZ450F | 2010-2018 | 13 | 48 | 3.69 |
| Yamaha | YZ450F | 2019-2025Updated | 13 | 49 | 3.77 |
| Yamaha | YZ450F | 2026New for 2026 | 13 | 51 | 3.92 |
Kawasaki OEM Stock Gearing
| Make | Model | Year Range | Front | Rear | Final Ratio |
|---|---|---|---|---|---|
| Kawasaki | KX250F / KX250 | 2011-2026Updated | 13 | 50 | 3.85 |
| Kawasaki | KX450F / KX450 | 2010-2026Updated | 13 | 50 | 3.85 |
Suzuki OEM Stock Gearing
| Make | Model | Year Range | Front | Rear | Final Ratio |
|---|---|---|---|---|---|
| Suzuki | RM-Z250 | 2010-2018 | 13 | 49 | 3.77 |
| Suzuki | RM-Z250 | 2019-2026Updated | 13 | 50 | 3.85 |
| Suzuki | RM-Z450 | 2010-2026Updated | 13 | 50 | 3.85 |
KTM OEM Stock Gearing
| Make | Model | Year Range | Front | Rear | Final Ratio |
|---|---|---|---|---|---|
| KTM | 250 SX-F | 2013-2016Corrected | 13 | 50 | 3.85 |
| KTM | 250 SX-F | 2017-2026Updated | 14 | 51 | 3.64 |
| KTM | 450 SX-F | 2014-2015 | 14 | 52 | 3.71 |
| KTM | 450 SX-F | 2016-2019 | 13 | 48 | 3.69 |
| KTM | 450 SX-F | 2020-2022 | 13 | 49 | 3.77 |
| KTM | 450 SX-F | 2023Updated | 13 | 51 | 3.92 |
| KTM | 450 SX-F | 2024Updated | 14 | 51 | 3.64 |
| KTM | 450 SX-F | 2025-2026Updated | 13 | 51 | 3.92 |
Dirt Bike Gearing FAQ
Is stock gearing always the best choice?
No. Stock gearing is a good starting point, but many riders change gearing based on track layout, soil conditions, riding style, engine character, and skill level.
What happens if I add teeth to the rear sprocket?
Adding teeth to the rear sprocket usually makes the bike feel shorter geared. This can improve acceleration and help the bike pull harder out of corners, but it may reduce top speed in each gear.
What happens if I remove teeth from the rear sprocket?
Removing teeth from the rear sprocket usually makes the bike feel taller geared. This can help stretch each gear longer and reduce shifting, but it may soften low-speed acceleration.
Should I replace the chain when replacing sprockets?
For best performance and wear life, it is usually recommended to replace the chain and both sprockets together, especially if the existing parts show wear.
Are all of these bikes 520 chain?
Most modern full-size motocross bikes use 520 chain, but chain length and sprocket fitment can vary by model year. Always confirm before ordering.
Need Chain & Sprocket Help?
MX Parts Direct can help you choose the right gearing setup for motocross, off-road riding, and race-day maintenance.
Fitment and OEM gearing information is provided as a reference only. Always consult your owner’s manual, OEM parts fiche, or current sprocket markings before purchasing. Regional models, factory editions, and previous-owner modifications may vary.