{"author":{"email":"alex@hayorov.me","name":"Alex Khaerov","url":"https://hayorov.me/"},"content_markdown":"> 🚲 Bike: Decathlon Riverside hybrid  \n> 🔧 Upgrade: Shimano CUES FC-U4000 crankset + Hollowtech II BB  \n> 📍 Part 2 of the [Riverside upgrade series](https://hayorov.me/posts/riverside-commuter-rigid-fork-swap/)\n\nIn [Part 1](https://hayorov.me/posts/riverside-commuter-rigid-fork-swap/) I swapped the heavy Zoom suspension fork for a TOSEEK carbon rigid. That shaved over a kilogram off the front end and transformed the steering. Naturally, once you fix one thing, the next weak link becomes impossible to ignore — and on the Riverside that was the drivetrain.\n\n![The stock drivetrain — B'Twin square-taper crankset with plastic chain guard, 11-36T cassette, and the original bottom bracket. Functional, but nothing more.](https://hayorov.me/riverside-upgrade/stock-drivetrain.jpg)\n\n---\n\n## 🔍 Why the Crankset Had to Go\n\nThe stock B'Twin crankset is a square-taper unit with a riveted plastic chain guard and a stamped steel chainring. It works, but the interface is loose after a few thousand kilometers, the chainring wears unevenly, and the whole assembly feels like it belongs on a department-store bike. The square-taper bottom bracket cartridge was also overdue — the bearings had developed a gritty feel that no amount of grease would fix.\n\n**Symptoms that forced the swap:**\n\n- Creaking under load, especially climbing\n- Visible play in the crank arms\n- Chainring teeth worn into shark fins\n- Bottom bracket bearings grinding on rotation\n\n---\n\n## 🆕 The Upgrade: Shimano CUES\n\nShimano's CUES line is their answer to the \"good enough for commuters, actually engineered properly\" segment. I went with the FC-U4000 crankset and a matching Hollowtech II bottom bracket:\n\n![Shimano CUES crankset and Hollowtech II bottom bracket — still in factory wrapping. The 32T chainring with Dynamic Chain Engagement+ and external bearing cups with orange seals.](https://hayorov.me/riverside-upgrade/shimano-cues-parts.jpg)\n\n| Spec | Stock B'Twin | Shimano CUES |\n|---|---|---|\n| Interface | Square taper | Hollowtech II |\n| Chainring | Stamped steel, riveted | 32T, Dynamic Chain Engagement+ |\n| Bottom bracket | Cartridge, sealed | External bearing cups |\n| Chain guard | Plastic bolt-on | None needed (narrow-wide ring) |\n| Feel | Vague, creaky | Solid, silent |\n\nThe narrow-wide chainring profile means no chain guard and no dropped chains. One less thing hanging off the bike.\n\n---\n\n## 🔩 Teardown\n\nFirst step — strip the old drivetrain down to the bare bottom bracket shell.\n\n![The old B'Twin crankset and square-taper cartridge bottom bracket laid out after removal. The crank bolts, chainring, and plastic guard all come off as one unit.](https://hayorov.me/riverside-upgrade/old-crankset-removed.jpg)\n\n![Bottom bracket shell cleaned and ready. Internal threads are in good shape — no corrosion or cross-threading. Cable guide bolted underneath routes the derailleur cables.](https://hayorov.me/riverside-upgrade/bb-shell-empty.jpg)\n\n> **Note:** Before pulling the old cartridge, mark which side is drive and non-drive. The cups thread in opposite directions — left is standard, right is reverse. Cross-threading a BB shell is expensive to fix.\n\n---\n\n## 🛠️ Install\n\nThe Hollowtech II bottom bracket is a press-and-thread affair — grease the threads, thread the cups by hand, then torque with a BB tool.\n\n### Step 1: Bottom bracket cups\n\n![Drive-side bottom bracket cup installed with fresh green grease on the bearing interface. The hollow center is ready for the crank spindle.](https://hayorov.me/riverside-upgrade/bb-greased.jpg)\n\n![Tightening the bottom bracket cup with a TOOPRE BB wrench. The external splines engage cleanly — no hammering required.](https://hayorov.me/riverside-upgrade/bb-tool-install.jpg)\n\n### Step 2: Crankset\n\nOnce the bottom bracket is seated, the crankset slides through and the non-drive arm pinch-bolts lock everything in place:\n\n![Shimano CUES crankset installed — chainring on, chain routed, pedal not yet threaded. The matte black finish matches the fork and stem.](https://hayorov.me/riverside-upgrade/cues-crankset-installed.jpg)\n\n> **Tip:** Grease the pedal threads before installing. Aluminum crank arms and steel pedal spindles will seize if you skip this.\n\n### Torque specs\n\n| Fastener | Torque |\n|---|---|\n| BB cups | 35–50 Nm |\n| Crank arm pinch bolts | 12–14 Nm |\n| Pedals | 35 Nm |\n| Chainring bolts | 12–14 Nm |\n\n---\n\n## ✅ Result\n\n![The finished drivetrain — Shimano CUES crankset with 32T narrow-wide ring, bottle cage back on, and the chain tensioned. Clean and functional.](https://hayorov.me/riverside-upgrade/cues-final.jpg)\n\nThe difference is immediate. Pedaling feels direct — no flex, no creak, no play in the bottom bracket. The narrow-wide chainring grabs the chain with confidence, and the Hollowtech II spindle is noticeably stiffer than the old square taper. Combined with the rigid fork from Part 1, the Riverside now rides like a bike that costs twice what I paid for it.\n\n**What changed:**\n\n- ✅ Zero creak under load\n- ✅ No chain drops — narrow-wide ring holds firm\n- ✅ Stiffer pedaling platform\n- ✅ Cleaner look without the plastic chain guard\n\n---\n\n## 💰 Gear\n\n| Part | Link | Price |\n|---|---|---|\n| Shimano CUES FC-U4000 crankset | [Shimano](https://bike.shimano.com/en-US/product/component/cues-u4000.html) | ~65 SGD |\n| Shimano Hollowtech II BB | included with crankset | — |\n| TOOPRE BB wrench (BB-46/41/39) | [Shopee](https://shopee.sg/) | ~12 SGD |\n| Crank puller (square taper) | already owned | — |\n\n---\n\n## 🔮 What's Next\n\nThe drivetrain and fork are sorted. Next on the list: the rear derailleur and shifter. The stock B'Twin units still work, but they are the last pieces that feel out of place on a bike that is rapidly outgrowing its price tag.","content_text":"🚲 Bike: Decathlon Riverside hybrid\n🔧 Upgrade: Shimano CUES FC-U4000 crankset + Hollowtech II BB\n📍 Part 2 of the Riverside upgrade series\nIn Part 1 I swapped the heavy Zoom suspension fork for a TOSEEK carbon rigid. That shaved over a kilogram off the front end and transformed the steering. Naturally, once you fix one thing, the next weak link becomes impossible to ignore — and on the Riverside that was the drivetrain.\nThe stock drivetrain — B’Twin square-taper crankset with plastic chain guard, 11-36T cassette, and the original bottom bracket. Functional, but nothing more. 🔍 Why the Crankset Had to Go # The stock B’Twin crankset is a square-taper unit with a riveted plastic chain guard and a stamped steel chainring. It works, but the interface is loose after a few thousand kilometers, the chainring wears unevenly, and the whole assembly feels like it belongs on a department-store bike. The square-taper bottom bracket cartridge was also overdue — the bearings had developed a gritty feel that no amount of grease would fix.\nSymptoms that forced the swap:\nCreaking under load, especially climbing Visible play in the crank arms Chainring teeth worn into shark fins Bottom bracket bearings grinding on rotation 🆕 The Upgrade: Shimano CUES # Shimano’s CUES line is their answer to the “good enough for commuters, actually engineered properly” segment. I went with the FC-U4000 crankset and a matching Hollowtech II bottom bracket:\nShimano CUES crankset and Hollowtech II bottom bracket — still in factory wrapping. The 32T chainring with Dynamic Chain Engagement+ and external bearing cups with orange seals. Spec Stock B’Twin Shimano CUES Interface Square taper Hollowtech II Chainring Stamped steel, riveted 32T, Dynamic Chain Engagement+ Bottom bracket Cartridge, sealed External bearing cups Chain guard Plastic bolt-on None needed (narrow-wide ring) Feel Vague, creaky Solid, silent The narrow-wide chainring profile means no chain guard and no dropped chains. One less thing hanging off the bike.\n🔩 Teardown # First step — strip the old drivetrain down to the bare bottom bracket shell.\nThe old B’Twin crankset and square-taper cartridge bottom bracket laid out after removal. The crank bolts, chainring, and plastic guard all come off as one unit. Bottom bracket shell cleaned and ready. Internal threads are in good shape — no corrosion or cross-threading. Cable guide bolted underneath routes the derailleur cables. Note: Before pulling the old cartridge, mark which side is drive and non-drive. The cups thread in opposite directions — left is standard, right is reverse. Cross-threading a BB shell is expensive to fix.\n🛠️ Install # The Hollowtech II bottom bracket is a press-and-thread affair — grease the threads, thread the cups by hand, then torque with a BB tool.\nStep 1: Bottom bracket cups # Drive-side bottom bracket cup installed with fresh green grease on the bearing interface. The hollow center is ready for the crank spindle. Tightening the bottom bracket cup with a TOOPRE BB wrench. The external splines engage cleanly — no hammering required. Step 2: Crankset # Once the bottom bracket is seated, the crankset slides through and the non-drive arm pinch-bolts lock everything in place:\nShimano CUES crankset installed — chainring on, chain routed, pedal not yet threaded. The matte black finish matches the fork and stem. Tip: Grease the pedal threads before installing. Aluminum crank arms and steel pedal spindles will seize if you skip this.\nTorque specs # Fastener Torque BB cups 35–50 Nm Crank arm pinch bolts 12–14 Nm Pedals 35 Nm Chainring bolts 12–14 Nm ✅ Result # The finished drivetrain — Shimano CUES crankset with 32T narrow-wide ring, bottle cage back on, and the chain tensioned. Clean and functional. The difference is immediate. Pedaling feels direct — no flex, no creak, no play in the bottom bracket. The narrow-wide chainring grabs the chain with confidence, and the Hollowtech II spindle is noticeably stiffer than the old square taper. Combined with the rigid fork from Part 1, the Riverside now rides like a bike that costs twice what I paid for it.\nWhat changed:\n✅ Zero creak under load ✅ No chain drops — narrow-wide ring holds firm ✅ Stiffer pedaling platform ✅ Cleaner look without the plastic chain guard 💰 Gear # Part Link Price Shimano CUES FC-U4000 crankset Shimano ~65 SGD Shimano Hollowtech II BB included with crankset — TOOPRE BB wrench (BB-46/41/39) Shopee ~12 SGD Crank puller (square taper) already owned — 🔮 What’s Next # The drivetrain and fork are sorted. Next on the list: the rear derailleur and shifter. The stock B’Twin units still work, but they are the last pieces that feel out of place on a bike that is rapidly outgrowing its price tag.\n","date":"2026-04-13T00:00:00Z","description":"Part two of the Riverside upgrade — replacing the stock B'Twin square-taper crankset and bottom bracket with a Shimano CUES 1x setup for smoother shifting and a cleaner chainline.","json_url":"https://hayorov.me/posts/riverside-commuter-shimano-cues-drivetrain/index.json","language":"en","lastmod":"2026-04-14T00:49:31+08:00","markdown_url":"https://hayorov.me/posts/riverside-commuter-shimano-cues-drivetrain/index.md","reading_time_minutes":4,"section":"posts","tags":["cycling","gear","diy"],"title":"Riverside Commuter: Shimano CUES Drivetrain Swap","type":"article","url":"https://hayorov.me/posts/riverside-commuter-shimano-cues-drivetrain/","word_count":780}