Help understanding w/kg in a race (Event ID 2771206)

Hi, I did a race yesterday, entered in the A race as required by ZP (event ID is 2771206). My w/kg was 4.5+ ish the whole race , as was one other A grade who ended up in a group with me, but we were hugely dropped by/hanging on with guys with B beside their name after the first climb, and whose w/kg never rose above 4. I ended up finishing far behind a load of B’s - I’m ok with that but looking at their power data I can’t figure how. I’ve entered a few races previously under B and been UPG’d because I’ve had to put out this type of w/kg just to keep up.

Even on the climb, when I was hitting 5.5+ I couldn’t drop these guys who were doing 3. I’m no expert but assumed that w/kg was a big factor esp on climbs.

Appreciate any advice/comments you can provide.

The event ID is 4644529 (I think!).

Legsnapper is not a climb, it’s a punchy hill that takes 30secs-1min of hard effort. Look at the 1 minute and 30 sec power of the top B riders and compare them to yours. You will find your answer there.

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Yeah, I get that. But I was watching the w/kg while on the climb and there were no 30-sec/1min power increases - just a nice easy 3.5w/kg and dropping me while I pushed more… ah well, just interested really.

Hi Dean, thanks for the reply. This image doesn’t really show the full story as I know it’s a snapshot, but my w/kg was 4.5+ ish the whole race (I’m J.Sanderson (Buxton CC)), as was one other A grade you can see in the group with me, but we were hugely dropped by/racing/hanging on with guys with B beside their name, and whose w/kg never rose above 4. Even on the climb, when I was hitting 5.5+ I couldn’t drop these guys who were doing 3. I’m no expert but assumed that w/kg was a big factor esp on climbs.

The event ID is 4644529 (I think!).

“could not find event”

EDIT: here you are: ZwiftPower - Login

John, what bike are you using in the game? I can’t tell from the screen shot, but if it is a gravel bike that would explain a lot.

Oops - it’s 2771206

The bike is a Trek Emonda with DT Swiss ARC 62.

Ok, not a gravel bike, I think it is caused by your weight, you are very light at 59 kgs so you will need to put out a lot more power on flat roads to stay with the heavies. Comparing you to the winner, who is lighter than you, their 1 min, 30sec, and 15sec power is much higher than yours so they can respond better to surges and attacks.

This is where you should do some focused training to improve your VO2 max.

Thanks. The part I couldn’t figure out was on the climb, each time I was 5.5w/kg and struggling even to hold the wheel of 3.5w/kg. It goes up to 9% in parts and thought that weight was a help in that regard.

Yeah, you should have an edge there, and the Emonda is a good climbing bike… make sure you really are on the Emonda?

Yeah, I just did to check I am on it now, and I havent changed it since I got it 2-3 weeks ago. Should have been.

Suggest you check your power curve. How long a time did you really average 5.5 for? It’s easy to fool yourself by taking quick glances at just the right time. I suspect at 5.5 you were accelerating relative to the others, but maybe not for long enough to notice gaps changing.

Even on slopes lightweights need a bit more W/kg (your bike is a larger proportion of your weight) but it should only be about 0.2

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Your 15s, 30s power is by far the lowest in the race - on Innsbruckring with that pesky bump, that tells me people were hammering up there and you were staying steady. If you see the normalised power bars, the higher up you go the bigger the bar - that’s what seperates everyone on this course.

Next up is drafting. If you sit on the front doing 4.6 then lots of people will happily sit there below 4 behind you, and then scoot off when the hill comes. They are then drafting each other and heling each other down the hill.

Looks like you’d smash an iTT, but need to learn how to race on zwift for better results. Maybe next time purposely sit at the back and try to draft the whole time. Look out for surges and try to go with them. It takes time to learn

@John_Sanderson_7330 here is your power curve (black line) compared to the winner. Let me know if you want me to delete this picture if you aren’t ok with me sharing the data (but anyone can look at it on zwiftpower, so…) Notice how flat your line is.

More importantly for the climb, this is in w/kg (there’s a button on the top of the plot)

This is the top ten and John. The climb is about a minute. It doesn’t look that surprising to me!

Wow - that’s all really useful. Thanks for taking the time to look into it.

I’ve come to race Zwift only in the last month or two, and guess the difference to real world racing is what I need to learn.

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There are a lot of strong riders for sure. I go up that climb about 6.5w/kg which is just about ok in B cat but nowhere near in A.

All of which begs the question why am I being asked to race in cat A!

Because, currently, Zwiftpower uses 95% of your best 20 minute power to categorize you, average of your top 3 in the past 90 days:


Which puts you firmly in A.

Check out the new test races next week, you might still be in A, or maybe allowed to race in B?

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Yeah I read that. Are these races called Category Enforcement or something?

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Yes they are