X-Ring Upgrade Chain & Sprocket Kit [Full 520 Conversion – Hyosung RT125 RX125
Stop fighting your drivetrain and relax your screaming motor. This is the only store to offer a complete heavy-duty chain conversion built to swap out fragile original links with 650cc-strength hardware, making a fresh Hyosung RT125 520 chain kit conversion the absolute ultimate way to hit 50mph in third gear with ease.
- Cruising // Drops engine stress at high speed for a relaxed cruise while stretching out your overall top gear capabilities.
- X-Ring Tech // Sealed links hold lubrication inside permanently to block dirt, mud, and trail grime far better than stock links.
- Lifespan // Delivers up to three times the running durability of old skinny factory setups with minimal stretch adjustments.
- In Stock // Package comes fully packed with matching uprated 520 front & rear sprockets, a premium x-ring chain, front sprocket lock washer and stainless bolts for the rear hub.
Description
The single-piston engines used across the RT, RX, and XRX lines are legendary, hard-working thumpers, but their power delivery is completely held back by an undersized factory drivetrain setup. Whether you are attacking green lanes, navigating traffic on a daily commute, or loading down for a long-distance touring project, the thin original chain setup suffers from rapid stretch and accelerated tooth wear. This is the only store to offer this exclusive uprated 520 conversion pack—a professional-grade restoration overhaul that brings heavy-duty durability straight to the 125cc platform. It completely stops excessive chain slap and rules out the need for weekly tool adjustments.
By switching your entire final drive system over to a wider 520 pitch layout, you vastly increase the active contact surface area. This distributes the single-cylinder power pulses much more evenly across the teeth. It does not just provide incredible structural strength; it alters the bike’s gearing dynamics for the better. With this custom kit installed, you can comfortably hit 50mph in third gear before clicking up, leaving your engine relaxed, smooth, and running at lower stress levels when cruising at high speed.
💎 FINAL DRIVE HARDWARE HYOSUNG RT125 520 CHAIN KIT SPECIFICATIONS
| Triple Endurance LifespanPremium X-Ring sealing tech that comfortably outlasts original configurations. | Relaxed Cruising SpeedsAlters the tooth ratio to lower engine stress significantly at high steady speeds. |
| Trail Dirt DefenseSealed rubber ring walls that lock out sand, mud, and water during off-road excursions. | Luggage Load StrengthHandles the extra strain of heavy panniers and travel packs without flexing out of line. |
📜 Confirmed Fitment Guide (Single Piston Models)
Single-Cylinder Thumper Group: Sprocket mount specifications are verified as a direct direct swap-and-go upgrade for the models noted below. See the diagram picture for rear hub mounting details.
- Hyosung RT125 / RT125D Karion: Fits all production years for sand, street, and adventure setups.
- Hyosung RX125 / RX125D / RX125 SM: Fits trail and supermoto variants across all model years.
- Hyosung XRX125 / XRX125 SM: Fits traditional enduro and naked street variants built from 1999 to 2006.
Original Factory Equivalents: Engineered to replace parts matching original code lines: 64511H93B00, 64511HM5400, 64511H93B01, 27600HM5400, and 27600HG5801.
🔧 Expert Installation & Gearing Notes
- Chromoly Steel Build: Our front engine sprockets are machined from specialized high-tensile steel designed to easily withstand rough trail conditions and intense single-cylinder vibrations.
- Full Hardware Pack Included: This package arrives with a genuine factory-spec lock washer and four unrustable stainless carrier bolts to completely replace your original weathered mounting screws.
- Simple Cleaning Maintenance: Because the specialized seals lock your internal link grease away permanently, you never need to soak the components. Simply spray the grit off the outside mesh and wipe down with a clean rag to enjoy thousands of miles of completely drama-free riding.
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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Independent Shop supplying ride enhancements and quality spares with fast dispatch. Need assistance? Access our workshop guides, manuals, tutorials or drop by the forums for troubleshooting help.
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