---

The Carrera Bike Project: The Second Upgrade: 1x Drivetrain Upgrade

In Phase 2 of the Carrera build, I upgraded the bike to a modern 1x drivetrain. The goal here was to simplify the ride, improve chain retention, and give the bike a cleaner, sleeker look — all while increasing the gear range with an 11-speed cassette.

Previously, the bike had a 3x drivetrain. It was overly complicated, added unnecessary weight, and frankly, felt outdated. The Carrera sits in that perfect window where the frame is still solid, but the original components were ready for an upgrade. With a bit of research, it was totally doable.

But the biggest reason for this conversion? I plan to add drop bars in the next phase. A clean 1x setup clears the way for future cockpit upgrades and lets me dial in a more aggressive, race-ready position. This drivetrain setup makes that next move possible.

If you’re planning a similar conversion, this guide walks you through the exact tools and parts I used, along with each step in the install process.

---

---

Tools Used for the Install

Here is a list of the basic tools needed for the install. Most of these tools are cheaper versions you can find on amazon. They work fine, but be aware that Park Tools is a good spot to look for quality tools. I did slide a premium Wera allen wrench set into the links. I ordered them when they were on sale and love them.

• Cassette lockring tool (FR-5.2 style) and chain whip tool
• Bottom bracket tool (Shimano Hollowtech II, TL-FC32 style)
• Allen wrenches (4mm, 5mm, 6mm, 8mm)
• Chain breaker tool & Master Link Pliers
• Cable cutters

---

Parts Installed in the Phase 2 Drivetrain Conversion

Here is the parts list of things I needed to make the install and conversions possible. Double-check your specific bike as it might be a bit different. I am upgrading a 2013 Trek Wahoo Mountain Bike.

• SunRace CSMX8 11-50T cassette
• Shimano M5100 rear derailleur (11-speed, clutch-style)
• Shimano M5100 shifter (11-speed trigger)
• KMC 11-speed chain
• Shimano M5100 crankset (32T narrow-wide chainring)
• Shimano MT501 bottom bracket

Total: $266.33

---

Step-by-Step Installation Guide

Step 1 – Strip the old drivetrain

Remove the existing chain, crankset, bottom bracket, cassette, derailleur, and shifter.

Buy the tools for this step:

• Cassette Lockring Tool
• Chain Whip
• Chain Breaker Tool
• Bottom Bracket Tool

---

Step 2 – Install the new bottom bracket

Thread in the Shimano MT501 bottom bracket using the Hollowtech II tool. Apply a bit of grease to the threads before tightening to spec.

Buy the part:

• Shimano MT501 Bottom Bracket

---

Step 3 – Add the M5100 crankset

Slide in the Shimano M5100 crankset (32T narrow-wide chainring) and torque down the crank bolts evenly. I did the assembly some months ago, and since then, I have upgraded to a 42T chainring.

Buy the part:

• Shimano M5100 Crankset
• Optional Torque Wrench

---

Step 4 – Mount the new cassette

If needed, drop a 1mm spacer on your freehub. Slide on the SunRace CSMX8 11-50T cassette and tighten it using the lockring tool.

Buy the part:

• SunRace 11-50T Cassette

---

Step 5 – Install the rear derailleur

Mount the Shimano M5100 derailleur to your hanger. Leave the clutch turned off for now to simplify cable setup.

Buy the part:

• Shimano M5100 Rear Derailleur

---

Step 6 – Add the new shifter and cable

Clamp the M5100 shifter onto your bars. Route the cable through the housing and out to the derailleur. Trim and crimp the end.

Buy the part:

• Shimano M5100 Shifter
• Cable Cutters

---

Step 7 – Size and install the chain

Use a KMC 11-speed chain, measure it to fit the largest cog, and snap it into place with the master link and quick-link pliers. I did not have to take any chain links off for my install.

Buy the part:

• KMC 11-Speed Chain
• Quick-Link Pliers

---

Step 8 – Final tuning and adjustments

Adjust the derailleur’s high/low limit screws, set your B-tension, and dial in the cable tension using the shifter’s barrel adjuster.

---

Phase 2 Complete

The Carrera now runs a clean, modern 1×11 drivetrain — no more front derailleur, no dropped chains, and way more gear range for city rides or light trail days. In the flat lands of the midest putting the 42T chainring on made it perfect, for the small inclines I do run across I can gear down and fly up then and and if I am lucky enough to get the wind at my back on some of my favorite stretches I can sustain 25-28 MPH according to my apple acticity that broadcasts live on my phone.

Up next: I’ll be dialing in cockpit upgrades like a set up drop bars so I can get in a few different riding positions, as well as a dropper seat post.

Stay tuned for Phase 3 of the Carrera Project, or check out Phase 1: Bike Base + Design Direction if you’re just starting the journey.