Anti-sandbagging is unfair for lightweight riders or young

Looking at the times for the whole field these two lads would have placed very well in the Cat B group and would even have picked up a few places in amongst the Cat A riders. I guess you could introduce lightweight or junior categories but then it starts getting complicated and I suspect you wouldn’t have a big enough field of riders in the classes to make it much fun.
I think the real solution is probably for people like me to chill out - I’m only ever really competing with myself in these events so provided I’ve beaten last week’s Scott then I’m generally happy!

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Tim camden Alot of good points.
People should look at speed weight calculators for cycling irl. At a constant power ( 300watts ) a much heavier rider ( 200lbs ) will not go much slower ( .2mph ) then a lighter rider (150lbs). On Flats that is. But the zwift algorithm benefits the lighter rider by giving them considerably more speed in this situation. In the outside world speed is not calculated by w/kg.

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Are there test results that show Zwift unfairly gives signifignantly more speed to a lower weight, higher wkg, rider on the flats at the same power output?

I would love to read into this further.

As an overarching statement I do see many comments about “being dropped right away”, or “can’t stay with the lead group” etc. Everyone needs to understand that not everyone is able to stay in the lead group every race. Not everyone is able to contend for the win every race. There should not be this expectation by the racers. This is especially true when you first move up a Cat and your fitness is not up to the level of the best in Cat.

There is only 1 winner and that is hard to come by. It is already an accomplishment to be contending for the win and make the selections that occur during the race.

I have not made the lead group for my Cat (used to be D, now C) many times. Maybe the start was too hard, maybe the small hill was too much for me 15 minutes in, maybe I simply lost concentration and didn’t see what was happening in front of me, etc. Whatever it is, I missed out when a gap formed and I was on the wrong side of it and therefore I missed the opportunity to contend for a win. Be it my fitness or otherwise.

Point is that there is the expectation that “the right Cat for me is one in which I am competing with the leaders to win the Cat” and I must disagree.


I’m not sure if the kids are benefitting from a light weight or from a short height.
We need to make sure we don’t group our responses to the kids in with category cheats and sandbagging.
These are 3 different issues and sand baggers and kids are not breaking rules.
The kids are just riding and the program is not capable of being realistic.
It’s ridiculous telling a 12 year old he must race B because he wins to much.
The B group doesn’t reflect his true ability.
A sand baggers, on the other hand, should be told to race B, because it does reflect his ability.

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Here is zwift insider test strange thing is they did not discuss the difference between weight but sifference between calculations.

  • ***150 watts, 75kg rider
    Specialized Venge S-Works, Zipp 858 wheels: **31.4kph
    BikeCalculator **30.55kph

  • ***150 watts, 50kg rider
    Specialized Venge S-Works, Zipp 858 wheels: **34.4kph
    BikeCalculator **31.44kph

This shows a 1.3 mph advantage on zwift compared to outside riding that is a huge difference

Links are not allowed

Now its also ovious because of the discussion above about 10 year okds putting out 130 watts are not gona stay in a outside peloton putting out 300 watts not gona happen . I also can soeak from experience with riding outside with guys who are 25lbs less then me cannot do what i can but on zwift they would drop me in a heart beat
Also understand thats at only 150watts if 300watts that difference will be greater


Thank you for the data. I am not following along with the two speeds for each. What does the 31.4 and the 30.55 (kph) for the 75kg rider represent? Is the 31.4 the Zwiftinsider test result in Zwift and BikeCalculator a different program all together? Let me know if I have it correct.

Can you post link with a coupke spaces added in? I can remove the spaces and find the page.

Thanks again.

Just slip a space or two into url’s and paste until you get enough posts to be able to directly paste.

Thanks. It looks like the difference between 75kg and 50kg on the same bike at 150W is 3kph then in Zwift. This was using the same rider height if I read this correctly. That speed difference would be even greater for a shorter 50kg rider.

I would love to see them compare a 225W 75kg 175cm vs 150W 50kg and say 168cm. It would be reasonable to assume less power from smaller rider and that smaller rider would also be a little bit shorter.

zwiftinsider .com / zwift-speeds

I calculated 75kg rider would go 2.04mph faster then a 100kg rider at 300watts which is alot. Now imagine if it was totally flip floped that would really show how off this whole thing is. Get in zwift use erg mode at 200lbs and see what your speed is at 300watts then do same thing for 150lbs its like 2mph on flats It should not be anywhere near that

Same problem for me!!! I hope ZHQ finally does something about this to make it more fun for kids