TSOZ Closer Look: Zwift Racing Score Changes

In the Fall 2025 “This Season on Zwift” press release, Zwift revealed several upcoming changes to the Zwift Racing Score system which is used to group riders for most of the races on the platform. These changes will have a significant impact on rider scores, so let’s dive into the details…

Zwift Racing Score Decay

Launching mid-September

Zwift Racing Score decay was built into the early system, but the feature was turned off in October 2024 because feedback from Zwifters indicated it wasn’t making scoring more accurate. At that time, Zwift said, “We may turn this back on later after making some improvements to the mechanism.”

Zwift has now made those improvements, and they are reintroducing decay into the ZRS system. Zwift says, “This means that if you stop racing for a while, your displayed score will very gradually drift downward (after 30 days without a race), and the system’s uncertainty about your true level goes up – so when you return, you’re matched more fairly rather than a stale high score.”

Digging a little deeper, this change involves:

• 30‑day grace period: Your score will only begin decaying after 30 days without a scored race.
• Rising Uncertainty, Fairer Returns: After the 30-day grace period, the system’s uncertainty for your score will also increase, allowing your score to adjust more rapidly once you do race again. Or to put it another way: returning racers will adjust faster to their real level.
• Decay is Capped (or better, Floored): Your score will not drift infinitely downward.
• Discourages Rating Squatting: Built-in decay means riders can’t climb to a higher score and stay there without racing. It keeps rankings fresh.

In practical terms, Zwift says this is what you can expect if you take a break from racing:

• Short break (within grace period): No change; you won’t feel penalized for a holiday or training block.
• Moderate break: Slight downward adjustment; you may see a modest score dip that encourages re-engagement.
• Long break: You settle at a conservative plateau; when you come back, early results will move you faster than before.

Rewarding Personal Bests with Instant Score Updates

Launching mid-September

ZRS is a results-based algorithm where your score changes based on your finishing position in races. But the foundational component of the ZRS algorithm is your seed score, which is based on your 90-day power personal bests.

One crucial thing your seed score provides is a ZRS floor value – the lowest your score can drop to. Your ZRS floor is 15% below your seed score.

Currently, if you set a new power PB (in a free ride, workout, race, or any Zwift activity), your ZRS is only immediately changed if the updated floor value based on your new power PB is higher than your current ZRS. This means there are plenty of scenarios where riders will hit new power PBs outside of a race, but their scores don’t change. Here’s one example of how that could work…

Example 1 (current system):

• Current ZRS: 500
• New Seed Score Based on New Power PB: 540
• New Floor Value (85% of Seed Score): 459
• New ZRS: 500 (unchanged, because it is higher than the new floor value)

With the new system, when a rider achieves a 90-day power PB, their racing score will immediately be set to the new, higher “seed” value if that seed value is higher than their current ZRS.

Example 2 (new system):

• Current ZRS: 500
• New Seed Score Based on New Power PB: 540
• New ZRS: 540 (score instantly set to new seed score, since it was higher than the rider’s current score)

In simple terms, this change will lead to ZRS increases for more riders, which should mean more riders’ scores will accurately affect their current peak fitness. To be specific:

• Active Racers will see score boosts immediately when their power PB wasn’t in a race
• Active Non-Racers who are training but not racing will get their score adjusted upwards with new PB values, helping ensure their score is accurate once they race
• Returning Users coming back to Zwift after a break will have their scores adjusted more quickly as they set power PBs in any Zwift activity

30-Day Best Score for Race Categorization

Launching late September/early October

Soon, race organizers will have the option of categorizing riders based on 30-day best ZRS, as opposed to the current ZRS that all scored races use.

Why the change? Some racers have complained that riders are purposely tanking their score by riding hard enough to bypass Zwift’s anti-tanking measures while still finishing far down in the results. This is especially prevalent among racers who naturally sit near the cutoff lines for categories.

These racers may enter a “target” race with a score that places them near the top of their category, winning the race and receiving a ZRS result that would push them out of their category and into the next highest.

They will then purposely tank a race or two (or perhaps four, via our Tiny Races), dropping their ZRS so they can once again enter the lower category in their target race.

With this change, race organizers may enable “30-Day Max Score Enforcement” for their event, meaning even if a racer purposely tanked their score across multiple events, they would still be categorized based on their highest score in the past 30 days.

Simply put, this is an additional anti-tanking measure. And I think it’s a good one that many race organizers will use.

(For our Tiny Races in particular, this feature will have the added benefit of reducing how often a rider starts the set of four Tinies in one category, then gets forced into a higher category mid-set, eliminating their chance of a high overall placing since they raced in two different categories on the day.)

Displaying Score Deltas in Results

Launching mid-September

We published a post about the ZwiftPower ZRS browser plugin just 2 weeks ago. This fun little community-created add-on for ZwiftPower adds ZRS results to ZwiftPower pages, including a delta figure showing how much each rider’s ZRS changed in that race.

In that post, I asked Zwift to add the delta figure to race results found on event pages at zwift.com. Little did I know, Zwift already had that change in the works (which explains why the delta figure was available in the API data for the ZwiftPower ZRS plugin to access in the first place).

Anyway – this is a small change, but a welcome one. The deltas will also be visible in results on Zwift Companion.

Questions or Comments

That’s a pretty significant list of changes impacting Zwift Racing Score. What do you think of the changes? Share your thoughts below!