Rear Chain Sprocket (37T) | Honda CB500K / CB550K / CB550F
The entire drivetrain on a Honda CB550 is made up of continuous wear items, and the rear sprocket is no exception — high mileage and missed chain maintenance leave the teeth thin and pointy. This is a 37-tooth exact replacement for the factory rear sprocket on CB500K, CB550K, and CB550F motorcycles, made from high quality steel in the factory 530 chain pitch.
Why You Need This
How well the previous owners kept up with chain adjustment and lubrication decides how much life is left in your rear sprocket. When the teeth go thin and pointy, it is done — and the rear cannot be flipped for a second life the way a Honda front sprocket sometimes can. The rear is the driven sprocket, made of softer steel than the front, and it wears in one direction only.
Changing the rear tooth count changes your final-drive ratio: more teeth gives greater acceleration with less top end, while fewer teeth gives better top end with reduced acceleration. The 37 tooth here is the factory size for the CB550K and CB550F, so it keeps your gearing stock — and either way, the chain length has to match your front and rear combination.
Specifications
| Spec | Detail |
|---|
| Replaces OEM Part Numbers | 41201-374-000 |
| Fits Models | CB500K0–K2 (1971–1973), CB550K0–K4 (1974–1978), CB550F (1975–1977) |
| Chain Pitch | 530 |
| Tooth Count | 37T (factory stock for CB550K / CB550F) |
| Chain Type Required | Standard (non-sealed) 530 roller chain |
| Sold As | Sold Individually |
Note: A new drive chain cut to the proper link count must be installed when changing to a different sprocket size — the chain length changes with the tooth count.
Note: Run a standard or heavy-duty non-sealed 530 chain on these models. O-ring and X-ring chains are too wide at the front sprocket and will dig into the crankcase.
Model-Specific Notes
- CB500K0–K2: Fits, but the CB500's factory rear sprocket was a 34 tooth — running this 37 tooth shifts your gearing toward acceleration, and the chain length changes with it.
- CB750: Does NOT fit. The CB750 used a different, larger rear sprocket — this one is for the CB500K / CB550 family only.
- CB350 / CB360 / CB450 families: Different rear sprockets — see the CB350 / CB360 rear sprocket or the CB450 / CL450 / CB500T rear sprocket.
Installation
Difficulty: Intermediate
Replace the rear sprocket, front sprocket, and drive chain together — a fresh part running against worn ones wears out early. The factory CB550K / CB550F setup is a 17-tooth front, this 37-tooth rear, and a 100-link chain; if you change tooth counts anywhere, count the chain against the new combination.
Once the wheel is back in, set the drive chain slack to 1–2 cm (3/8–3/4 in.) measured at the midpoint between the sprockets, and keep the chain lubed — chain care is what preserves sprocket life.
Our Sprockets 101 video covers how sprockets wear, how front and rear tooth counts change the final-drive ratio, and how to figure the chain length you need after a swap — including the 550's sprocket layout.
Frequently Asked Questions
Is 37 tooth the stock size for my bike?
For the CB550K and CB550F, yes — the factory setup is a 17-tooth front, 37-tooth rear, and 100-link chain. On the CB500K the factory rear was a 34 tooth, so this 37 tooth will lower your gearing slightly toward acceleration.
Can I run an O-ring or X-ring chain?
No. On these models a sealed chain is too wide at the front sprocket and will dig into the crankcase. Run a standard or heavy-duty non-sealed 530 roller chain.
Can I convert to a 520 chain?
These bikes were built around the 530 chain pitch — the 520 pitch was used only on the CB175 / CB200 and smaller models, so there is no off-the-shelf 520 conversion. Stick with the 530 pitch.
Do I need a new chain and front sprocket too?
Replace all three together — a new chain on worn sprockets, or the reverse, wears the fresh part out early. The matching front sprocket comes in 17, 18, and 19 tooth, and our 530 roller drive chain is cut to your specified link count before shipping.
Does this fit the CB750?
No. The CB750 used a different, larger rear sprocket. This 37 tooth fits the CB500K, CB550K, and CB550F only.
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Last updated: June 2026
