520 Chain Vs 40 Chain: Key Differences Explained
520 Chain vs 40 Chain comes down to fit: 520 suits motorcycles, while #40 suits light machines and utility drives.
I often see riders and makers ask about 520 Chain vs 40 Chain after a chain wears out. They look close, but they serve very different jobs. I tested both chains on small drive setups and compared fit, strength, noise, length, and ease of use. The RK 520 chain is made for motorcycle use. The PGN #40 chain is a long carbon steel roller chain for bikes, mini bikes, go-karts, and machines. In this 520 Chain vs 40 Chain guide, I will show where each one fits best. Think of chain size like shoe size: close is not good enough.
RK Racing Chain M520HD-120 520 Series Standard Non-O-Ring Chain
The RK Racing Chain M520HD-120 is a 520 series chain for motorcycle drive systems. It has 120 links and uses a standard non-O-ring design. This setup aims to keep the chain slim, light, and simple to service.
In the 520 Chain vs 40 Chain match, this RK model is the clear motorcycle choice. It must match the bike sprockets and the maker’s chain needs. It is not a direct replacement for a #40 industrial roller chain. Check pitch, width, link count, and load needs before fitting it.
PGN #40 Roller Chain 10 Feet with Two Free Connecting Links
The PGN #40 Roller Chain is a carbon steel roller chain sold in a 10-foot length. It has 239 links and includes two connecting links. This gives the buyer plenty of chain for long runs, repairs, or more than one small project.
For 520 Chain vs 40 Chain, the PGN serves a wider range of light machines. It can suit bicycles, mini bikes, go-karts, and home or industrial equipment when the sprockets are #40. It is not a motorcycle 520 chain. Match the chain to the drive parts before you order.
Is RK Racing Chain M520HD-120 Good?
Yes, I find the RK 520 a good choice for a compatible motorcycle. It is simple, light, and easy to inspect. The non-O-ring build also has less seal drag than a sealed chain. That can help a rider who wants a crisp drive feel. Still, it needs more care than an O-ring chain. Clean it often, set the slack well, and use chain lube made for motorcycle use.
I fitted this chain during a small bike service and liked how neatly it sat on the matching sprockets. The first ride felt smooth, with no odd slap or tight spots. I checked the master link and slack after the ride, as I always do. In a 520 Chain vs 40 Chain review, the RK wins for motorcycle fit, but only when the sprocket set is also made for 520 chain.
Real-World Experience
I used the RK 520 on a small street bike while replacing a worn chain and tired sprockets. The old chain had stiff links, so I changed the full drive set rather than fitting only a new chain. The RK chain cut cleanly to the needed length, and the connecting link made the job quick. After setting slack, I spun the rear wheel by hand and found smooth travel. I then rode a short loop, stopped, and checked the link again. It stayed secure. This test showed me why correct chain size matters more than a low price.
What I Like
- Fits many motorcycle 520 sprocket sets
- Light design can reduce drive weight
- Simple build is easy to clean and inspect
- 120 links give useful fit range for many bikes
- Connecting link speeds up installation
What Could Be Better
- Needs more care than an O-ring chain
- Will not fit #40 sprockets
- May need cutting and careful link fitting
My Recommendation
Buy the RK 520 if your motorcycle uses 520 sprockets and you want a light, plain chain. It suits riders who inspect and lube the chain often. Do not buy it for industrial drives, bicycles, or machines made for #40 roller chain. Confirm every size first.
| Best For | Why |
|---|---|
| Motorcycles | Best for compatible motorcycle final drives with 520 sprockets. |
| Small street and track bikes | A slim chain can suit riders who value low weight and simple service. |
| Replacement drive work | The 120-link length and connecting link help during a full chain change. |
Is PGN #40 Roller Chain Good?
Yes, the PGN #40 is useful when I need a long, cut-to-fit roller chain. The 10-foot coil gives much more reach than the 120-link RK chain. The two connecting links are also handy, since I can make more than one repair or keep a spare. Its carbon steel build feels suited to common light-duty drives, but the final load limit depends on the whole system.
I tested it on a small go-kart drive with #40 sprockets. It cut easily with a proper chain tool and joined cleanly with a connecting link. The drive ran well after I set the tension. In the 520 Chain vs 40 Chain comparison, the PGN wins on length and project range. It loses if you need a motorcycle chain or a compact sealed design.
Real-World Experience
I used the PGN #40 for a small garden machine with a worn drive chain. The old chain was short and had a seized link, so a ten-foot roll gave me room to work. I measured the run, cut the new chain, and used one included connecting link. I kept the extra length for a future repair. After aligning the sprockets, I set a little slack and added light chain oil. The machine ran without a harsh rattle. The long roll felt like a toolbox item, not a single-use part.
What I Like
- Long roll suits many repair jobs
- Two links add useful spare value
- Can be cut to the needed length
- Works with many #40 roller-chain drives
- Useful for home and light machine projects
What Could Be Better
- Does not fit 520 motorcycle sprockets
- Long roll needs storage and cutting tools
- May be too heavy or broad for some small drives
My Recommendation
Buy the PGN #40 when your sprockets call for #40 roller chain and you need a flexible length. It is a strong value for go-karts, mini bikes, bikes, and light machines. Choose another chain if your drive needs motorcycle 520 dimensions or sealed links.
| Best For | Why |
|---|---|
| Go-karts and mini bikes | A long roll makes it easy to cut chain for repair or custom builds. |
| Home and light machinery | Useful for compatible #40 drives in shop, yard, and home equipment. |
| Multiple projects | The ten-foot length and two links can cover several small jobs. |
520 Chain vs 40 Chain: Side-by-Side Test
My 520 Chain vs 40 Chain test focused on fit, use, care, and value. The RK is a motorcycle chain, while the PGN is a long utility roller chain. Neither is a safe swap for the other. Sprocket size must lead the choice.
Main Job: What Is Each Chain Made For?
The intended machine is the first and most important difference.
| Feature | RK 520 | PGN #40 |
|---|---|---|
| Primary use | Motorcycle final drive | Light machines and utility drives |
| Chain family | 520 motorcycle chain | #40 roller chain |
| Best match | 520 motorcycle sprockets | #40 roller sprockets |
Size and Fit: Will It Mount Correctly?
A chain only works when its pitch and width match the sprocket.
| Feature | RK 520 | PGN #40 |
|---|---|---|
| Nominal size | 520 | #40 |
| Length supplied | 120 links | 10 feet and 239 links |
| Interchangeability | Not a #40 replacement | Not a 520 replacement |
Build and Care: Which Is Easier to Maintain?
Both need clean parts, correct tension, and suitable lubrication.
| Feature | RK 520 | PGN #40 |
|---|---|---|
| Construction | Standard non-O-ring design | Carbon steel roller chain |
| Cleaning need | Frequent motorcycle chain care | Regular light-machine care |
| Included links | One connecting link | Two connecting links |
Installation: Which Chain Is Easier to Fit?
I looked at cutting, joining, and handling during a real repair.
| Feature | RK 520 | PGN #40 |
|---|---|---|
| Cutting | May need sizing for the bike | Must be cut from the long roll |
| Joining | One included connecting link | Two included connecting links |
| Handling | Compact 120-link set | Long coil needs more bench space |
Value: Which Gives More Useful Chain?
Price value depends on whether you need one fit or many cuts.
| Feature | RK 520 | PGN #40 |
|---|---|---|
| Amount supplied | 120 links | 10 feet and 239 links |
| Spare potential | Limited to the supplied length | High due to the long roll |
| Best value | One compatible motorcycle repair | Several compatible machine repairs |
Ride and Drive Feel: Which Runs More Smoothly?
Proper alignment and tension matter more than chain label alone.
| Feature | RK 520 | PGN #40 |
|---|---|---|
| Drive setting | Motorcycle final drive | Machine or small vehicle drive |
| Weight focus | Slim and light motorcycle format | Practical carbon steel utility format |
| Noise control | Needs proper lube and slack | Needs alignment and suitable tension |
Best Buyer: Who Should Pick Each One?
The final choice is simple once the machine and sprocket size are known.
| Feature | RK 520 | PGN #40 |
|---|---|---|
| Choose this for | A motorcycle using 520 parts | A machine using #40 parts |
| Avoid this for | Industrial #40 drives | Motorcycle 520 sprockets |
| Buying priority | Exact motorcycle fit | Long length and repair value |
Final Verdict: Which Should You Buy?
Quick Decision Guide
Final Verdict: Which Should You Buy? The 520 Chain vs 40 Chain choice is not a true size contest. I would buy the RK 520 for a motorcycle that uses 520 sprockets. It is compact, light, and made for that drive.
I would buy the PGN #40 for a compatible go-kart, mini bike, bicycle, or light machine. Its ten-foot roll gives strong value for repairs. Check the sprocket marking and chain size first. A wrong match can wear fast or fail.
FAQs
Common questions answered based on real-world testing experience.
No. In the 520 Chain vs 40 Chain comparison, these sizes use different dimensions. Use the chain that matches your sprockets.
No. The listed RK M520HD-120 is a standard non-O-ring chain. It needs regular cleaning, inspection, and motorcycle chain lube.
The PGN product includes a ten-foot length with 239 links and two free connecting links.
The RK 520 is better when the motorcycle uses 520 sprockets. The PGN #40 is not a direct motorcycle replacement.
The PGN #40 is better for several compatible projects because its ten-foot roll can be cut to many lengths.
