Zwift Racing League Week 6 Guide: Greatest London Loop (C/D Scratch Race)

The sixth and final race of Zwift Racing League 2025/26 Round 3 happens Tuesday, February 10, and we’re in London for a scratch race.

If you’re on a C or D team, you’ll be racing one lap of Greatest London Loop, and this guide is for you. A and B teams will be on two laps of London Loop (click here for that race guide).

There’s much to discuss, including crucial course segments, powerup usage, bike decisions, and strategic options. Let’s go!

Looking at the Route

The Greatest London Loop is 26.2km long with 360m of elevation gain. Here’s the course profile:

Clearly, there’s one big feature on this route: Leith Hill! This is where the big selection will happen. Don’t be fooled by the KOM leaderboard segment highlighted above, since it’s just a portion of what you’ll be climbing, and this is a scratch race, not a points race.

The actual climb is 6km long, with 252m of elevation gain, and the final 2km is the steepest part. Click to see the Veloviewer profile below in 2D to get a really good picture of how this climb lays out:

Here’s the Strava segment for the full Leith Hill climb, so you can analyze it further. It’s a long climb – the longest we’ll race in this round. Plan on 16 minutes minimum, but probably closer to 20 minutes for many C/D riders. It roughly breaks into four sections:

• First 1km: Quite flat and early, so I wouldn’t expect any big moves.
• 1-1.5km: Steep bit starts off the climbing in earnest. The pack will stretch here.
• 1.5-4.5km: Flatter, longer middle section. Sit in the wheels and draft here if you want to conserve energy for the final big kick.
• 4.5-6km: The pièce de résistance, averaging 8.3%. This is where the leading selection of riders will be finalized!

There are two small kickers on the circuit that deserve a mention as well. They may look small on the profile since they’re dwarfed by Leith Hill, but trust me – you’ll notice them in the race:

The first, Northumberland Avenue, comes early on as you turn right from the Thames and head up to Trafalgar Square. This is the first climb more than a few seconds long on the route, so expect the effort level to lift significantly for ~30 seconds, even though riders will be saving their big attack for Leith Hill up the road.

After the long descent from the top of Leith Hill (expect everyone to take a big rest here), you’ll enter the Underground tunnel and quickly hit the plywood-covered ramp back into the London sunshine. At 14%, this is the steepest climb of your race. But it’s short! You’ll want to enter it fast and keep your power high up and over the top.

From the top of the Underground ramp, you’ve got 1.6km to the finish line. Things often get cagey as riders cross Tower Bridge, and the final meters are slightly downhill and fast. It will take just the right mix of timing and strong legs to cross the line victorious. Good luck!

Read more about the Greatest London Loop route >

Powerups

Specific powerups will be given at each arch: the feather at the lap banner, and the anvil at the Leith Hill KOM banner.

Lightweight (feather): reduces your weight by 10% for 30 seconds.
Use on climbs, when weight matters the most. This is best saved for Leith Hill, particularly on the final section where the gradient is steepest and legs are burning.

Anvil: makes you heavier for up to 15 seconds, so you can descend faster. It won’t hurt you, as it only adds weight when the road is at a -1.5% decline or greater.
Use this when descending the backside of Leith Hill to make it even easier to sit in.

Bike Recommendations

This race’s decisive and long climb definitely makes me steer away from pure aero setups and look at climbing bikes and all-arounders instead. While a more aero setup has a pure time advantage on laps of the full course, that time advantage evaporates if you get dropped on Leith Hill!

My recommendation, then, is to use the new ENVE SES 4.5 PRO or DT Swiss ARC 1100 DICUT 65 wheels paired with one of these bikes:

• Specialized Aethos
• S-Works Tarmac SL8
• Cannondale SuperSix EVO LAB71
• Pinarello Dogma F 2024
• Canyon Aeroad 2024

Of course, your frame’s upgrade status should impact your decision. A fully upgraded Aethos will outclimb the other four frames, but that’s not the case when comparing un-upgraded versions.

Related: All About Zwift’s New “Bike Upgrades” Functionality >

See Speed Tests: Tron Bike vs Top Performers for more nerd-level detail on frame and wheel performance.

More Route Recons

Lots of recon events are scheduled on upcoming ZRL routes, led by various teams. See upcoming ZRL recons for this race at zwift.com/events/tag/zrlrecon.

Additionally, riders in the Zwift community do a great job every week creating recon videos that preview the courses and offer tips to help you perform your best on the day. Here are the recons I’ve found (comment if you find another!)

John Rice

J Dirom

Strategic Options

I predict riders will fall into three groups:

• Climbers: Lighter riders who can sustain high W/kg will surf wheels on the flats, then light it up on Leith Hill. Your goal: drop puncheurs/sprinters who have the pure watts to beat you in a pack finish.
• Puncheurs: You will struggle on Leith Hill thanks to the climb’s length, but if you can hold on, you’ll stand a good chance of finishing well. For you, surviving Leith Hill may require a combination of riding smart and praying the climbers don’t push the pace too high.
• Everyone Else: If you’re a pure sprinter, or simply a rider with lower fitness than most in the category, you’re going to struggle in this race, particularly up Leith Hill. Your best bet is to pace yourself well on Leith Hill, ride smart to bridge up to riders ahead on flats and descents, and simply finish as high in the list as possible. Remember: every point counts!

Your Thoughts

Any insights or further thoughts on this race? Share below!