Anti-sandbagging is unfair for lightweight riders or young


Some comments about the anti-sandbagging feature. I am all for more fair races. I do some races, I have to say that I am not serious about it, but I understand that for some competitors it is important. My son is 10 years old and he was doing crits with a lot of fun. He does them in the D category and he performs pretty well for his age. His best finish is third. He usually finishes among the last of the first tier. He only weighs 32 kg but pushes usually around 3.3 watts per kg. He did some races at 4 watts per kg. Now, he is penalized by the anti-sanbagging feature. At his weight, even if he has a B. cat power, he does not have the speed. Races are screwed for him by the anti-sandbagging feature. If he races in the B. cat, he will ride alone and finish at the last place. If, he races in the D. cat, he will only have the choice between being flagged and slowed or voluntarily diminish is power (again not really doing a race). Anti-sandbagging as a solution to control race fairness is unfair for him. It will be unfair for other rides too, not just the young, but all lightweight.

At zwiftinsider, there is an article about the weight impact on speed. Just search ‘Why You’re Getting Beat by Riders with Lower w/kg’.

I’ll post in the feature request another solution to control races cheating or unfair categorization. Anti-sanbagging seems complicated, unfair and not required to me.


Zwift use more than just w/kg for races categories. They have a minimum wattage as well.

This is how Zwiftpower use w/kg and watt.

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You’d appreciate Zwift’s having junior races so your son can enjoy the competition against his peers. The numbers you’ve supplied say he’s averaging 105 to 128 watts. Outside, that might get him to 32 km/h or so, solo. Pretty good.

If racing against adults, he might want to select from the many races that do not incorporate anti-sandbagging. As-is, anti-sandbagging is not ideal for every Zwifter.

If he’s racing in D and finishing in the first tier, is he finishing with adults who are cruising and sandbagging? The top adult finishers in D are often riders who should be in C category if not higher.


Based on what I have heard, I think the anti-sandbagging logic does not recognize the minimum wattages. You will probably get the warning already when entering the event.

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Yes, this is a big problem for me, I am pushing over 4 during C races and have won once(when there were only 10 riders) I have tried B but get dropped after a few minutes

Those minimums are used by ZwiftPower though. The anti-sandbagging is core Zwift though, so that’s different and I don’t think that it uses those minimums for outright power.

Just don’t ride the races with anti-sandbagging controls. There are many more races without the controls than with them.


This follows the line of so many similar discussion on this forum coming down to race categories, and unfortunately Zwift’ point of-view is remaining a mystery. The issue is both delicate and difficult, too.

Depending on race results only - as often suggested - has its disadvantages with so many people jumping in and out depending on season and weather. The focus on 20min wkg, while it arguably does reasonably well, has obvious disadvantages due to the impact of riders weight and cruising. I don’t completely understand the emphasis on 20min power either, telling a time-trialist to upgrade and work on 1-5min power, whilst not ever telling the sprinter/pursuiter/cruiser at a certain point to upgrade and work on 20min power output. I do believe the anti-sandbagging was designed to include a bigger spectrum of the power-curve, but it may not be quite there yet. Again, it would be nice to hear if it is still in development. Perhaps a race rank could just be designed as an additional layer to upgrade those that somehow manage to perform exceptionally well without ever upgrading.

Back on topic: In my opinion you are absolutely right that not accounting for raw power output in race categories is of disadvantage to light riders. On the other hand the ZwiftPower race results also show that their Wkg + ‘hard’ absolute limit favors the very light and the very heavy - understandably. In that regard, the suggestion that was made in another threat to first normalize riders weight to an average weight seems worth investigating.

I can do other races, it’s just I can’t do any races run by zwift, all races run by zwift now have the anti sandbagging on… so that makes it so that I pretty much can’t do crit city…

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There are other races in Crit City, not just ZHQ’s anti-sandbagging races. I can see a few in the next 24 hours, for example. Look on somewhere like ZwiftPower to make it much easier to find races.

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This is my favorite platform for selecting events:

Zwiftpower is a close second:

I still don’t understand why Zwift or ZwiftPower don’t introduce promotion/relegation. Is is the most simple and fair solution. Race on your race level.

ps. the minimum watts used by ZwiftPower is just enormous b*st

I’ll second this: my 12 year old got flagged today in the ZHQ FutureWorks Circuit Race in the C’s on the Champs (zwiftpower zid=1305154). He was barely hanging on to the front group for most of the race despite doing almost 4w/kg (171w). Going into the finish he sprinted and the anti-sandbagging feature kicked in and slowed him down. Very disappointing for him and clearly unfair as he was really just hanging on for most of the race despite his higher w/kg.

So anyway here’s my vote for doing something to scale the algorithm so that a lighter rider who isn’t crushing everyone doesn’t get flagged.

To be honest I think that someone who is really sand-bagging isn’t going to get flagged because well they just sit in cruising well below threshold for the entire race and then unleash a crazy hard sprint at the end (or do a big 30-60 sec effort and ride away from everyone). Just looking at average w/kg seems like it catches the wrong people. The algorithm should factor in whether or not the rider is OTF or consistently attacking. Put another way, who cares if someone is at 4w/kg and sitting in the middle of the pack on a flat-ish race?

Anyway I hope that some attention can be given to this. My son really felt robbed of a potentially good finish and didn’t feel at all that he was sandbagging (and to be fair, when he did an Alpe du Zwift race he did enter the B’s as his w/kg on the climb put him in that category).



Actually, This is not true.
Your children should be categorized according to their W/K just like everyone else.
They will not finish last.
This idea of finishing last is a myth that incorrectly keeps getting used as an excuse to continue breaking the rules.

Your children (and everyone else) finishes with the other riders that can ride at the same pace.

Most races on Zwift are mass start races.
Yes, you start in a certain pen but we all go at the same time.

You put out the power that you can put out and you ride with and draft the other riders around you.
You ABCD class has nothing to do with the actual race.
It only affects the post race standings.
You (and everyone else) still get the same Zwift race experience.

The ABCD categories only affect Handicapped races and races where you only see your class.

And sand bagging is not cheating.
It is making use of understanding the rules.

4 W/K entering a C race IS cheating.


I do not think it is cheating because us lightweight riders have to put out 4wpk to keep up, any less and we get dropped from the group.

you shouldn’t be trying to keep up with the cheaters who are B riders in the C class… that’s a common mistake

the lead group in the race is full of miscategorized riders who you should not be able to keep up with.


Then what about a 100kg guy having to do 400w just to hang on the climbs?

Yes the w/kg system is not perfect but that is all we have.
Pick a route that suite your ability. Like the volcano climb race.


That is a very good point. Never thought about that… You are right.

The light weight riders are not cheating but they are asking to be given a pass to race in a lower category.
In real life, it is unlikely that a 10-15 year old is going to place anywhere near the top of a cat C or B race against adults.
Everyone is so thrilled that their Zwifting children are doing well in races.
We all know that in a real race, it would not happen.
The problem is zwifts algorithm for calculating speed based on a calculated frontal area.
The relationship must not be linear.
Very small people push the calculation into an unrealistic realm and their speed is too high.

That’s a short coming of the game.
But claiming you can’t race in your appropriate category because you won’t place as well is absurd.

Allowing small people to race in a lower category makes their race the same giving a participation trophy.


Why were my posts deleted? Two of them.


Also just as @Twoshihtzu said the front riders in the category are usually cheating/sandbagging and won’t be included in the end results.