Anti-sandbagging is unfair for lightweight riders or young

A good example here - last night’s C race. I’m designated B but wanted to race with a mate - he is 100kg and I am 62kg. He wins the race @ 3.1w/kg (305w) I’m DQ at 3.8w/kg(237w), but finish just behind him. Volcano circuit for reference.

Yes, you are a B rider and should not enter as a C rider in a C race.
You can still ride with your friend
B’s and C’s ride together all the time.
If your friend was female, would you sing up as female?

The race cataegories have nothing to do with how well you place or how fast you are.

I’m not sure why you think you are giving a good example.
You are not setting a good example at all.


Thanks Tim. Not sure how this is setting a bad example - I knew I would be DQ on ZP, there is no way around this. But I’m damned either way - shelled out the back of most B races or DQd from Cs. At least the latter allows me the enjoyment of keeping with a speed/group I can mange and to race with a mate - both of which help maintain interest and motivation to keep training over winter.

Forgive me for being naive but what are the race categories for if not to group similarly paced riders together?

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Hi @Chris_Beags_Moonglu

It look like you are a solid B rider.



This is my point - on paper it does - but B races require me to output far higher w/kg than most other riders in order to keep up and generally result in me blowing up early.


And that is why we are asking for race ranking.
Rankings based matchmaking (get rid of cats!)?


Isn’t that the truth, and it appears that you are unaware of how ridiculous that situation is. I think any sane person would agree that a category system should be set up to place riders of similar ability together, ie: can complete a ride in about the same time. This is how every other sport does it.

Having a system based on w/kg means that riders are kept apart even though they are the same ability. The most frustrating part is that Zwifters have been clamoring for a better system for years but Zwift has done essentially nothing about it, even though they already have a metric that DOES separate people based on relative performance in the same race, but choose not to use it.


I don’t see why you can’t register into the correct category and just ride with your friend.
Misrepresenting yourself as a C does not help you ride with your friend.


Sorry, but but this is simply not true.

If it would be like this IRL only the best sprinters could win the cycling races, there would be no time gaps and the sport would be not interesting at all. Someone must be the winner - and (many) more are the losers…

I am on the boarder D/C, racing only in C cat - claiming not to finish in the last 1/3 of the finishers. Should I ask for another category? Perhaps because of my age?


Zwift will improve the current system, either by modifying the current system or try a new one.
Right now, there is only 1 rule.

Enter the correct category.

I see no reason ever to do otherwise.

Sure, there are inaccurate miscalibrated trainers, people sandbagging but they are still following the 1 rule.


Milan, I don’t think you understand what I’m suggesting. Imagine a TT being used to set categories rather than the height, weight, chest size etc of the riders. Take the riders finish time as their rank and then put the top 25% in A, the next 25% in B and so on. Then when the C race happens you have put riders of similar ability together. In practice, some will have better race craft and will consistently do better, and that quartile also includes quite a wide range of fitness/ability anyway, so some are better Cs than others. So there will always be a spread of finish times in every cat no matter how carefully you set them up.

In the current w/kg system those who are labeled as C includes some who could compete in B (fitter, but heavier riders who can therefore stay below the 3.2 threshold), some who are real C (average weight and ability) and some who should still be in D (weaker riders, but because they are so light they still exceed the 2.5 threshold for D). Similarly, some of the Bs should still be in C, and some of the Ds should be in C. So riders who should be having a very competitive race (ie broadly similar finish times) in C end up being artificially separated into three different races.

I know this scenario happens from personal experience as a lighter rider (67/68 kg) who got promoted out of D and C before I was even halfway up the field in those cats. A cat system that is working properly should never promote someone unless they are consistently winning/on the podium in their current cat. The w/kg system doesn’t get close to that basic truth.

Finally, I’m not suggesting we use TT races to set race cats (although if people gave 100% it would be far better than the w/kg system), a system based on relative performance against other riders during racing would better, and Zwift actually maintains that metric already. It’s just easier explain the problem with a TT example.

Edit: here’s a link to a post I did back in May, where you can see the amount of overlap in times between riders in different races. They should have been in the same category and racing together:

Detailed comparison of ABCD groups within 4 different races


I am just going to chip in on this that I don’t mind either way, but some consistency would be good.

Zwiftpower says my son is a ‘D’ 3.7 w/kg @124 watts. Therefore with his new sterzo he is naturally disappointed to be DQ’ed from the steering race when he chose to ride as a ‘C’ with Zwift saying is he actually a ‘B’.

Given Zwift and Zwiftpower are now combined, surely matching these two up is needed?

He will race wherever the rules say and yes, it isn’t easy to set the rules - he will dominate the 'D’s and never see the 'B’s - but one set of rules is should be the starting point.


It is difficult.
Your son is 33 kg or 73 lbs.
This is an average ideal wt of a 9 year old.
You probably don’t ride with your son in real life on sporting rides because he is too slow.
He is an “unsupported rider” and should be capped in some way.
Perhaps cap speed to 13-15 mph.
Fast enough to have fun but won’t win any races.

Paying customers have a legitimate complaint when a free user is spoiling their experience.
In real life, a 33 kg, 9 year old would not keep up with the vast majority of the D group and definitely not with the C group.
It is as wrong as a wheel on unsupported ZP trainer.

Zwift could alter the algorithm but it takes time and paying customers want other things fixed first.

Don’t get me wrong, I’m glad your son is riding and indoor riding seems to have a good future but it’s not ready for all things to all people yet.


i tried for a long time to get the minimum weight lowered as when we first joined zwift the penalty for very light weight riders was extreme. they have now reduced that. there was always a concern that the cheating adult population would cheat even further lol, so the zwift response was to penalise light female riders and kids to prevent weight doping adults, it never made sense to me. Tim just to let you know my 15 yr old son because he is light 51kg still is ranked at B as his FTP is under 250w so legitimately he could race there however he races in A cat minimum as he would destroy a B field. he wins most of the A cat races he enters so kids can compete very well at the top level, a lot of zwift racing its racing smart and hiding for as long as possible

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I know that is the case but the issue is the program is not designed for light riders.
I’m not saying light people are breaking any rules.
Previously, light riders were penalized.
Now they have an unfair advantage.
117 watts should never best 250 watts.
It never happens IRL.
I know Zwift is not real life but this example demonstrates a place for improvement.


I am a female rider who is cat C for women’s races and cat D for men’s / mixed according to ZP. I joined a crit race this evening that was anti sandbagging. I joined the D cat as that is what I believe is the correct cat for a mixed race. Within 5 minutes I received the message that I was in the wrong cat race, was flagged and the brakes were put on, I quit the race as that is not fun. My average watts are below 150. The system is not taking account of light riders and I certainly won’t join one of those races again. I resent being flagged as cheating when I have done nothing wrong.

Send a message to the bugs forum so they will fix the problem of applying the cone to people who are in the appropriate catagory.

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Thanks I will do that.

I found this thread out of frustration following the 3R Volcano Climb race I rode in yesterday. The race was won by an 11 year old, with a 10 year old in second place - both of whom weighed 26-28kg.

Initially I was impressed but when I looked at the performance numbers I saw that both had put out an average of 4.4w/kg in a Cat C group. When I looked at the winner’s profile I saw that he had placed first in almost every race he had entered but all were either C or D and yet his average w/kg had never fallen below 4.2w/kg in any of these.

The rest of the line up in the Volcano race had all finished with w/kg power outputs that broadly sat within the Cat C bracket and it had been a very competitive race with quite a tight spread of timings. The only exception being 1 & 2 who basically stood out like a sore thumb.

I accept the points made by the original poster on this thread and can imagine how frustrating it must be if the Zwift algorithms create challenges for younger riders here. However, I can’t see a great deal of value in having a young rider win every race they enter because their w/kg output is consistently 40% above the upper limit of the catergory they are entering?!


IT’s a tough one. If my boy races in a Zwift race (he’s 12) and does a ZHQ anti-sandbagging race we have to change his weight from his actual 45kg up to 55kg, in simple terms he has great 20-30s power and can stick out 200+w to hold a bunch for a bit, but then as soon as he does that, he gets the cone of shame and is throttled back. If he does the 200w power, he then drops quickly back down to 130w or so, averaging 146w in his last race. But if we put him in at 55kg he seems to just about manage to not get DQ’d.
It’s not about him winning or beating his D cat peers, it’s simply about him being able to ride and enjoy Zwifting. There’s no fun in getting the cone of shame, i’ve been there too.

I guess what i’d like to see, is the time period the anti-sandbagging is configured for to be increased maybe ? I don’t know how long you have to exceed their figures for, but maybe if that was longer it would help even things out.

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