Confusion about categorisation

I’m a 65kg rider with an FTP of 209 according to ZP.

Only been using Zwift since mid January. Was only expecting to using it for ‘training rides’ but gave racing a go and loved it. After coming last in my first race, I’ve been pushing myself and seeing improvements.

I’ve been category C the past few weeks and have found the races I’ve done a real challenge. e.g. I took part in a Rhino Crash Chase Race last week where I was having to push really hard to stay with the group. I definitely felt like one of the weakest in the group (at least among those who finished)… and yet I’ve just seen I’ve been “promoted” to Category B.

I’m confused because although I feel in some ways I should be happy I feel quite disheartened because knowing how tough I’ve found “keeping up” with C riders I know there’s no chance I’ll keep up with B pace and once I’m dropped the lack of drafting will compound things massively!

Anyway, enough moaning I’ll get to my question: why is categorisation based on w/kg? From what I’ve read about w/kg, it’s a good measure of how someone will do on hills whereas on the flat watts are going to be the determining factor? Isn’t there a better measure that weighs up these two things?

Or am I looking at this all wrong? As a ~200W 65kg rider should I just accept that in Zwift, just as in the real world, I’m only suited to hills and should only enter races that are close to vertical???

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Hi @John_Puddephatt_BWCC

Welcome to the forum.

You did 16 minutes 3.81w/kg (244w) that is good B category power numbers.

The CE (category enforcement) algorithm is better than ZP it look at more than just 20min w/kg.

No you are not looking at it wrong. w/Kg is a poor indicator of ability, as is raw watts. There are better metrics that combine the two.

Changes are hopefully coming (zoon) to address the issues with Zwift categories.


W/kg is actually a decent measure of performance even on the flat in zwift due to the way weight is used to determine CdA, but it would be much better to use something closer to 3 min power rather than 20 min which really doesn’t matter much.

Of course the whole concept of categories based on physical performance is nuts to start with, but that’s zwift for you. uses a customised version of Compound Score (zrCS) which normalises for weight for 5m power.

This chart shows under performance (left of centre) / over performance (right of centre) versus expectation based on zrCS - as you can see it is extreeeemely reflective of capability across all weight ranges (all racers/races over couple of months)

Check it out - it may give you a much more rewarding Zwift racing experience as you try to rank up, and there are now a number of races from big organisers (like DiRT) using rankings to sort pens, and the feedback has been amazing.


thanks I’ll take a look

Chances are that with your level of power that you’re struggling to keep with a B pack for one of two reasons:

Not optimised drafting


Lack of punch to get over small climbs/surges

The draft is most likely I’d think. I’ve won quite a lot of B races and very rarely go above 3.6 w/kg for 20mins. And although I’m heavier, 76kg ish, that’s really not the main reason, I know the courses (or learn them before the race using ZwiftInsider) and sit at the back of the pack through all of the bits where a breakaway is unlikely to happen or unlikely to succeed, far from the finish, on the flat, before a descent…learn to hug wheels. And even if you don’t have much of a punch, you’ll find the punchier bits easier if you’ve being doing 3.1 up to that point rather than 3.8.

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Hi Gerrie,

"Good B category power number? " This is false. Category enforcement is out here.

244w for 16 mins is terrible for a B Cat Rider

In my last race as a C, the winner has a PB for 16 mins of 272Watts.

In my first race a B, the 15th place rider has a PB for 16 mins of 326Watts.

So our rider here will be a very very weak B Rider.

W/kg doesn’t matter because so many of the well attended races on Zwift have shorter races or very little elevation so pure power is all that matters.

The cat enforcement penalises lighter riders who are forced to move up cats very quickly.

If our lad is only 65Kilos he will be above 3.1 kilos just sitting in the draft.

Edited to 65 kilos

That is 3.81w/kg which is close the top of B category. Not good to win a B race but surely good to finish mid pack.

For most racers the drop between 16min and 20min is not a lot, less than 0.1w/kg (1-10w)

In CE as modified after the initial introduction, you frequently see people whose 20min power is 4.2-4.3, so 3.8 is not close to the top.

Ha I recognise that graph! That’s my power data!

Ah yes, our lad John, will be very much mid pack B. I think we can agree Average B rider is more appropriate than Good B category numbers.

Since I started Zwifting, I’ve packed the pounds on, Weight moves weight and in most situations in this game Power is everything. Big Meals and Big Snacks.

So John, my only tip to you is Eat Big, Get Big, your power will go up quick and then race hard. I’ve gone from 189 watts 20 min avg to 244watts in 10 weeks with a 3.1 kilo weight bump.

B category is Zftp 3.3w/kg to 4.2w/kg

so 3.81 is closer to the top 4.2w/kg.

The good thing is we all agree that the OP should be B category.

Are you not comparing CP value against raw watts value there?

In its current iteration of Category Enforcement OP meets the definition of B. I agree.

But that raises the question on how the current format for Category Enforcement is skewed and leans to a broken system. Heavy people in Cat C and Cat D can control races and rack up easy wins without moving up as lighter riders will consistently be catted up as soon as they approach competitiveness is those categories due to W/KG limits.

Again I will say this is from the perspective of racing the most popular events which are generally short and lack huge climbs. A light rider could win a race at 3 am in the morning against 5 other people…

Yup, too true.

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