X-Ring Upgrade Chain & Sprocket Kit [Full 520 Conversion – Hyosung RT125 RX125
Stop fighting your drivetrain. The factory 428 “skinny” chain is the weak link on the RT/RX/XRX series. This exclusive 520 X-Ring kit replaces fragile components with 650cc-strength hardware. The result? 50mph in 3rd gear and 3X the lifespan of OEM.
- ✅ Go Faster: Extended top speed and relaxed cruising—no more engine screaming.
- 🛠️ Off-Road Ready: X-Ring sealing resists dirt, mud, and grit far better than O-rings.
- ⚙️ Zero-Stretch Tech: Heavy-duty 520 links mean significantly fewer adjustments.
- 📦 Exclusive Bundle: Premium 520 Sprockets, X-Ring Chain, & Stainless Bolt Pack.
Description
The Hyosung 125cc single-piston engines (RT, RX, and XRX) are legendary “thumpers,” but they are held back by an undersized 428-pitch drivetrain. Whether you’re green-laning on an XRX125, commuting on an RX125 SM, or touring on an RT125D “Karion,” the stock chain is prone to rapid stretch and sprocket wear. Our #HyoRiders Exclusive 520 X-Ring Conversion is a professional-grade overhaul that brings 650cc-strength durability to the 125cc platform.
💎 Touring Performance with the Daily Reliability!
By switching to a 520 pitch, the chain surface area is increased, distributing the engine’s torque pulses more evenly. This doesn’t just add strength; it changes the bike’s gearing dynamics entirely. With this kit installed, riders can expect to see 50mph in 3rd gear (out of 5), leaving the engine much more relaxed at cruising speeds. No more “chain rattle” or constant weekly adjustments—just smooth, reliable power to the rear wheel.
| 3X Longer Life 520 X-Ring tech outlasts 428 setups. |
Top Speed Boost Relaxed RPMs at 60-70mph cruising. |
| Off-Road Durable Sealed against mud, sand, and grit. |
Luggage Friendly Handles extra weight with less strain. |
📜 Confirmed Fitment Guide (Single Piston Models)
This kit is a 100% direct “Swap & Go” for the models listed below. Forgo the “skinny” 428 chains and upgrade to a setup you can actually trust on a long-distance trip or a mountain trail.
✅ RX125 / RX125D / RX125 SM (All Years – Supermoto & Trail)
✅ XRX125 / XRX125 SM (1999-2006 Enduro & Street)
Reference OEM #s: 64511H93B00, 64511HM5400, 64511H93B01, 27600HM5400, 27600HG5801
Worn bearings cause uneven sprocket wear. This is the perfect time to inspect your rear wheel bearings. If you hear grinding or feel a “wobble,” get yourself a Wheel Bearing Kit for a total back-end refresh. We do sell the brake shoes though, click here to see the brake shoes
🔧 Expert Installation & Gearing Notes
- Chromoly Steel: Our front sprockets are SCM420 Chromoly—built to survive the toughest conditions.
- Hardware Included: Includes a genuine Hyosung front sprocket washer and 4x Stainless Carrier Bolts to replace your rusty originals.
- Maintenance: X-Ring chains retain lubrication internally. Simply keep the outside clean of grit to enjoy thousands of miles of drama-free riding.
📧 FITMENT QUESTIONS? Email us with your bike photos. For technical advice or performance discussions, visit the HyoRiders Forums.
Additional information
| Weight | 3 kg |
|---|---|
| Dimensions | 30 × 30 × 5 cm |
| Bike Model | RT125, RX125/XRX125 SM |
1 review for X-Ring Upgrade Chain & Sprocket Kit [Full 520 Conversion – Hyosung RT125 RX125
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madbikeruk –
Got a set for my project bike a 12 front 48 rear on my xrx125 and it has made a lot of difference to the way the bike rides, it’s not a gear setup I got for top speed I wanted more acceleration so went with a 12/48 set up now the bike not only holds it’s top speed but I am able to go up hills or against head winds without changing down a gear, I can even accelerate up hills and change up gears that a normal 125 would struggle with.
Apart from the way it helps the bike run, the look of the new setup is so much better than the stock setup.
I can’t say how long it will last as only done a couple hundred miles, so far it looks good.
It’s a simple upgrade that’s worth the money