Paris Roubaix Hardtail Rebuild: From Carbon MTB to Cobble Crusher (3-Part Series)
Introduction: The Ultimate Paris Roubaix Experiment
After 12 years riding the cobbles of Paris-Roubaix, I’ve tested almost everything: titanium touring bikes, carbon road bikes, cyclocross machines and dedicated gravel bikes.
But this time, I wanted something different.
This rebuild documents the transformation of a 2014 carbon hardtail mountain bike into a Paris Roubaix gravel-road hybrid — using mostly budget AliExpress components.
The big question:
Will it survive the Hell of the North?
And perhaps more importantly… will I?
This complete guide brings together all three episodes of the rebuild — from full stripdown to final hydraulic setup — so you can see exactly how the project evolved.
The Starting Point: A 2014 Carbon Hardtail
Original specification:
• Shimano Deore XT 10-speed groupset
• Mavic Crossride wheels
• Manitou 120mm fork
• Flat handlebars
• Quick-release style axles
The plan was simple in theory:
• Keep the fork and wheels
• Install 40mm gravel tyres
• Convert to a 1×11 drivetrain (44T front, 11–50 rear)
• Replace flat bars with drop bars
• Fit hydraulic road shifters
• Install a 3D-printed saddle
• Keep post-mount brake calipers to simplify compatibility
Simple… on paper.
Part 1: Full Stripdown – Preparing for the Conversion
The first phase was completely stripping the bike down to its bare essentials.
Removed:
• Crankset
• Chain
• Front and rear derailleurs
• Cassette
• Flat bars and controls
• Brake levers (hoses left intact initially)
• Wheels
• Tyres
• DIY chainstay protector
A full deep clean followed. Eight years of riding meant grime in every hidden corner.
This stage also revealed the first reminder that older bikes come with quirks: unusual axle standards and adapter systems that haven’t been common for years.
By the end of Part 1, the bike was:
• Completely stripped
• Cleaned
• Inspected
• Ready for transformation
At this stage, the suspense was real. The drivetrain hadn’t even arrived yet.
Part 2: Installing the Budget 1×11 Drivetrain
The first delivery: an 11–50 tooth cassette for €31.
Initial impressions were surprisingly positive. Clean machining, good finish, all 11 sprockets present and correct.
Drivetrain build included:
• 11–50T cassette installed with fresh grease
• Senicx 44T direct-mount 1x chainset
• Bottom bracket serviced and reinstalled
• Sensah SRX Pro rear derailleur installed
No clutch mechanism on the derailleur — a calculated gamble for cobbles.
Gearing Strategy for Paris Roubaix
A 44T front ring paired with a 50T rear cog provides serious climbing insurance while maintaining usable road speed between sectors.
It’s aggressive, unconventional, and possibly perfect for Roubaix’s brutal transitions between smooth tarmac and violent pavé.
Tyre Setup
• 40mm Arisun gravel tyres
• TPU inner tubes (36g each)
• Initial pressure: 40 PSI
Mounting was surprisingly easy. Both tyres seated quickly, which is always a good sign before cobbled abuse.
Saddle Upgrade
A 3D-printed lattice saddle was installed. Comfort remained a complete unknown — and Roubaix is not forgiving to bad saddle choices.
By the end of Part 2:
• Drivetrain installed
• Wheels mounted
• Gravel tyres fitted
• Bike beginning to look like a gravel-cobble hybrid
• Still waiting on hydraulic shifters stuck in French customs
The deadline was getting dangerously close.
Part 3: Hydraulic Setup, Chain Drama and Final Build
With one week until Paris Roubaix weekend, the final components finally arrived.
Sensah Hydraulic Shifters
After weeks in customs, the 1×11 hydraulic levers landed.
Installation involved:
• Mounting to drop bars
• Installing pre-filled rear brake hose
• Routing rear gear cable internally
• Securing housing with zip ties
Initial feel was promising — direct shifting, light lever action.
Chain Length Issue
The original 116-link chain was too short for the 44T x 50T combination.
Solution:
• New 118-link chain installed
• Quick links fitted (extremely tight)
• Full gear indexing completed
This is a key lesson when running wide-range gravel gearing: always calculate chain length carefully.
Front Brake Hose Problem
Switching from flat bars to drop bars meant the original front hose was too short.
Actions taken:
• New hose ordered
• Measured precisely before cutting
• Olive and pin installed
• Full front brake bleed completed
• New brake pads fitted
Bleeding involved:
• Reservoir setup
• Mineral oil fill
• Syringe pull-through
• Air removal
• Final pressure test
No leaks. Solid brake feel.
Finishing Touches
• Bar tape installed
• Shimano SPD pedals greased and mounted
• Stem flipped for lower front end
• Garmin mount and camera mount fitted
Final result:
A carbon hardtail reborn as a Paris Roubaix gravel-road hybrid.
High front end visually — but with 30% fork sag under rider weight.
Massive 11–50 cassette.
44T simplicity.
40mm gravel tyres.
Budget drivetrain.
The Five Fears Going Into Roubaix
- Would the components arrive in time?
- Would everything be compatible?
- Would the geometry still work?
- Would the bike survive both road and cobbles?
- Should I care what others think?
The truth is, Paris Roubaix exposes weaknesses instantly.
There is no hiding on the pavé.
Final Thoughts Before the Cobble Test
This rebuild wasn’t just about saving money.
It was about testing:
• Budget drivetrain performance
• Wide-range 1x gearing for cobbles
• Gravel tyre suitability for Roubaix
• MTB-to-gravel geometry conversion
• Hydraulic compatibility across brands
Next comes the real test: riding the sectors.
Carrefour de l’Arbre.
Trouée d’Arenberg.
The Roubaix velodrome.
Will the Sensah drivetrain hold indexing under vibration?
Will the tyres survive?
Will I regret trusting AliExpress on the Hell of the North?
That’s where the experiment truly begins.
If you’re considering your own Paris Roubaix bike setup or gravel conversion, this rebuild shows what’s possible — and what can go wrong — when you push equipment beyond its intended design.
The cobbles will decide the rest.