Pack dynamics? Sumer season? Something else?

For context, I joined Zwift at the end of 2020 and started in C cat, before eventually moving up to mid-B. After taking some time off at the end of 2021 for ankle surgery, I came back in as a C and I am now in the classic ‘High C / Low B’ no-man’s land: if I enter B I get dropped quickly, whereas I can be competitive in C. To complete the context, my minimum category enforcement is in C.

I remember when I joined in 2020 it was just pre-Covid. Between 2021 and 2022 I found that the average standards had noticeably jumped up in ZRL and general racing; in spite of getting fitter, I was finishing further down the pack. Our ZRL team finished 3rd in its category in 2021 but was way down the bottom of the league over the next 12 months.

Anyway, why do I bother say all this?

Well…and this is definitely not a humblebrag (well, maybe 1% it is) - even I’m getting suspicious of my own performance now, having just won a C category crit by around 2 minutes from the next place finisher. But, I’m doing it with the same level of performance as before. Somethings changed and it’s definitely not me (I wish it was!): but I’m getting narky comments from other riders during races and I can’t do anything about it.

So, my question is: are B and C races getting slower?

It would seem to me that the starts are much less brutal than they were 1 or 2 years ago and the average pack pace seems much more tolerable: less in the way of constant attacking? You can relax for a few seconds and not get dropped, whereas a year or so ago the slightest drop in concentration could have you off the back.

Definitely not here to brag - but something’s changed and I’m confident I’m not fitter than I was, so I’m keen to understand whether others are seeing it too and whether it’s related to the northern hemisphere warmer weather (more riders IRL), reduced rider numbers post-covid, pack dynamics or something else?

Yes Zwift now use Category enforcement so less sandbagging.

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Was it mass start race and you held onto the A/B’s longer than the others?
Or did just the C’s start together?

There is something odd going on there, you beat the quickest A cat racer by 30 seconds whilst averaging 3,3wkg.

I have no idea what caused it, not sure if you need to check height or weight… but your output looks normal, just the timing looks really odd.

The Cs started together; from the gun myself and two others rode away from the other Cs. The Bs then caught us and I jumped onto the Bs: the other two Cs must have failed to make it to the group as the group I was then in just pulled away.

Something is definitely odd. I am a good C, or a poor B, but I’m not good enough to win a C category event. I’m usually able to hold onto the leading C group but get dropped as they wind up for the final sprint. I am definitely, 100% not good enough to ride away and drop the entire pack and win by 2 minutes - no way!

As additional detail, quite a big group of the Bs then dropped me further, so in real-world terms there were definitely 10 - 20 (at least) B riders who physically finished before me. I suppose they must have started 1 or 2 minutes after the Cs (as otherwise they wouldn’t have caught us), but there is no way I beat the Bs, let alone the As!

It’s not just this race though; quite a few races recently have seemed a lot ‘easier’ than usual. Absolutely nothing to do with my fitness; from the starting gun, none of the usual intense sprinting. In fact, I’m having to ease off the starting sprint because otherwise I fly past everyone.

If you’re sure your fitness hasn’t improved (done an FTP test recently?), I’d start with obvious things like;
different (smart) trainer?
poor trainer calibration?
using a different power source (power pedals or cranks)?
accidentally changed your height value in Zwift?

I’m 100% certain that nothing has changed on my side, definitely.

My FTP is lower than it was at peak (I was around 308w in 2021, whereas I’m around 290w now).
My weight now is 87kg whereas it was 84kg previously.
Same smart trainer, same height, same calibration

It is not an isolated event though. It really feels as though B and C riders are not ‘pushing it’ in a way that they were previously, or in the same numbers.

For me, the starting sprint is a good indication of this. Usually, I would begin winding the power up around 5 or 6 seconds ahead of the bell so that I’m hitting around 470w to begin (around 5.4w/kg).

Now, 5.4w/kg sees me fly off and I’ll end up 20 - 40 metres ahead of the nearest rider. Even in the Cs there would always be a frenetic start, whereas now it’s just not there.

In the Bs, sprinting from the starting gun I would barely hang on to the leading riders and often would be outside the top 10, whereas now the same power/weight output sees me at the front.

I’m not complaining per se, except I am getting people comment in races accusing me of sandbagging, or entering the wrong category, when I’m not - and Zwift are also telling me I should race in C.

Looking at your Zwiftpower profile, it looks like you haven’t clicked the “refresh profile” under your photo since changes were made to Zwiftpower {last week???}, getting rid of the old pen allocation system and reverting to Category Enforcement.

Currently it shows “E” pen; zFTP of 317W and 87Kg (which is 3.64W/Kg and would put you lower-mid W/Kg for pen B, that starts at 3.36W/Kg or a ~6min zMAP of 4.2W/Kg).

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Are you racing many of the same races as before or have you changed your schedule?

Just a thought, but if you’re racing more on, say, Tuesdays during ZRL season, many of the usual (strong) suspects might be resting ahead of the big event. Same thing might apply to Thursdays when people might be taking time out ahead of the WTRL-TTT league etc.

Clutching at straws here :grin:

Thanks - I’ve just clicked refresh and it’s updated, but still saying I’m a C.

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That puts you at ~3.25W/Kg zFTP, what ZwiftHQ think you can do for 40mins+, right at the pointy end of C and in the mix for top 10% of many C races.

Category Enforcement has increased the ability range of pens B, C and D.

Under the old system, a three race average for 95% of 20mins > 3.2W/Kg would promote a C to B, now C riders can do ~3.36W/Kg for 40mins and not be promoted… Very roughly equivalent to doing 3.4-3.5W/Kg for 20mins.

To keep C pen ability the same under Category Enforcement as it was under the old Zwiftpower system, the W/Kg threshold would need to be ~3W/Kg zFTP.

Thanks for pointing that out Steve.

Is this a hangover from the original implementation of CE when there were seemingly daily complaints about unfair promotion under the new (CE) system and Zwift tweeked (increased) the values to placate them?


To be honest, I’m not sure that this explains it fully - on the basis that my power or weight hasn’t really changed, yet I’m still finding it easier to out-ride others in a way that I didn’t before. It appears that average paces / standards are slower slightly generally.

In terms of the category enforcement, it also sits awkwardly for me. 3.3 w/kg was enough to win a C category event by nearly 2 minutes earlier today; 3.5 w/kg is even higher.

I suppose the answer is to enter B events and just get spat out the back again…

IIRC a lot of us thought zFTP (or whatever Category Enforcement was using) for most of last year was predicting our 20min ability, so the “5%” buffer was introduced to make comparisons of the old Zwiftpower system “more fair.”

But towards the end of 2022, suddenly we were told zFTP was actually looking at 40min ability, but the 5% buffer stayed in place for some reason.

I think the main difference (as Gerry mentioned) is related to CE. It’s harder to sandbag with category enforcement, so you have fewer folks cruising at the top of C managing their 20 min power, so the races might feel a bit less like you’re trying to hang on to a bunch of Bs - because those Bs are more likely to be already promoted to B and forced into it. If you’re easily winning you’ll likely be promoted to B at some point.

It sounds like you mentally beat your C opposition way before the finish line in that recent race, when you were able to hold onto the Bs and make the break, so they gave up trying to chase you hard and so you won by quite a margin.

Some races attract the top pen racers and you might then get a better challenge, for instance in the often strong field Zwift Insider Tiny Races held at three times on Saturdays.

I’ve seen this a few times: races where someone gets away result in the remaining group not mounting a serious chase. Since groups traditionally catch solo riders with no real effort, it’s not unusual for people back in the group to gamble that they can sit in and still catch the break. That may be a little less true under PD4, but it’s not a huge difference and many people haven’t adapted their thinking to whatever that change will bring. People in the group behind may also be thinking that the solo artist will get a WKG DQ, which often happens in community events. Some of them are also feeling tired and conclude that they are now racing against the riders they can see. So there are several factors that can inhibit the chase.

EDIT: Looking at your race, it was a small field that was widely separated by the finish. They probably would have had a hard time chasing you down regardless of their intent.


Looking at the scores, it looks like the field was quite weak. I’m not surprised that you crushed them. If you compare it to a popular race I think you’ll see a much higher average ranking.

My guess its a number of different things all helping like CE. But also, have you gotten better at drafting? When I first started racing I was constantly killing myself to try to stay with the lead pack and was terrible at drafting so I would churn from the front of the group, to being spat out the back, to having to put an interval in to get back in, rinse and repeat. But now I am very effective (even before PD4) at holding exactly my desired position in a pack. I never see the front of the blob unless I’m purposefully attacking, and I rarely if ever see the back. I sit about a bike-length or two behind the front and the blob just looks like a churning mass around me (well, it did until PD4, now everyone is sort of doing the same thing as me). I’ve also gotten better at figuring out which moves are dangerous, and when a surge in the pack needs to be responded to or not. And I’ve gotten better at using momentum to get up and over hills with the group without spiking my power as much. Because of all this, at least in PD3 races, I was pretty regularly able to keep up with the next category up while not doing more work–finishing with the A’s (I’m a B) doing 4.2 wkg in the front pack with me at 3.5 wkg, for example. Maybe you have similarly gotten better.

Also, I think the starts of races have gotten a little tamer over the past few years. I think a lot of people figured out how to start well, which made the tactic of jumping hard off the line less useful / more pointless, so fewer people do it now. There’s still an initial surge, but I’ve found in B races it just needs to be around 5 wkg to stay with the front, where it used to be more like 6-7.