And I totally agree with you, as a lighter rider myself I too struggle a little on the descents, although not to the point that it’s an issue if I’m diligent. We need to balance that with the fact that lighter riders do have the advantage on the climbs so I’m OK with a little back and forth with difficulties up and down.
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Hold zFTP for long terms instead of expiring it. You’re ignoring an obvious and useful metric and ignoring useful feedback.
Then you need a better metric. 5% is noise.
I don’t understand this statement… can you explain how holding long term FTP fixes this?
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He said someone might not have ridden recently so they might not have a zFTP number. If someone hasn’t ridden in six months use their zFTP number from six months ago. It’s one person who might have a metric that’s off by a few watts, it won’t have any significant effect on a group.
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The 5% may sound like noise but only if you are comparing it to the previous power instead of the power you would need to maintain the same speed when your nose actually hits the wind (say 30–50% more depending on the speed).
How is it useful in the context of pack churn? My FTP is 300w, I can be riding in a pack at 200w. If I back off to 180w to avoid hitting the front, that’s a 10% reduction of my current output but only 6% of my FTP. How is that useful?
Edit: my quote on mobile didn’t work…
I said make the threshold 50% of zFTP. That would be 150w hard not relative numbers.
Absolute watts. Not reduction from previous X seconds.
So I have to back off from 200w to 50w before it would think I was reducing my power?
No. To 150w. Read what I wrote.
Alright, so im riding in a pack at 275w. I have to back off 125w before it thinks I’m easing? Pack churn is all about what’s going on now, not what I am capable of.
Yes. If I’m in the pack pushing at 300w and back off to 284w I am by no means trying to ease up. “Easing up” is absolutely based on what you are capable of. If you back off from 450w to 300w are you indicating that you’re trying to not pass anyone? Or are you just fading?
Totally agree, and I’ve been making these kind of comments whenever the opportunity arises (to the point that I sound like a broken record). On the face of it, it sounds like a fairly easy problem to address.
Even if the “corner auto-braking” feature isn’t ready for implementation (apparently it’s being “worked on”), a change in the speed-weight relationship for descending could easily be employed.
I’ve never had any kind of (positive) response from ZHQ when myself, and others, have raised these issues on here. However, you almost always get the disingenuous quip from someone about lighter riders being advantaged going uphill, so it’s only fair that heavier riders are advantaged going downhill 
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The churn issue is a huge contributor to the descending problem because the extra effective “free” power a tightly-packed group gets is close to the draft power savings in the group and that is proportional to the cube of the group speed. It is effectively several hundred watts that the group is getting free because of the churn that the solo rider does not and so has to put in to try and stay away. If the group all stay in the draft, the churn can add over 10kph to the overall group speed on a 10% drop at minimal non-supertuck power. As James and RC Ivany said, fixing the churn should make a big difference to group descending speeds.
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This looks really promising, thank you. Regarding the power test, did you consider making it a test vs. increasing power rather than a decrease from the 3 second average? e.g. Power is less than 105% of the last 3 second average power. The reasons for suggesting this is that the churn still takes place for 2 identical riders holding the same power constantly. It would also help with the descending/supertucking situation that Stian Lersveen raised, which is a special case of the same average power problem.
Let’s hope so 
But it still wouldn’t address the situation where the lightweight descender can be fairly easily reeled back in by one or two (or three 
) heavier riders descending at unrealistic speeds just by the sheer dint of their weight.
If we’re trying to make Zwift racing more exciting, dynamic (realistic?) and promote more breakaway attempts etc (PD4) then addressing unrealistic descending speeds could be a big part of that?
You’re missing the point. It’s possible riders don’t have a zFTP, for example brand new riders. You can’t base a core mechanic on a data point that isn’t universally available.
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Yes. that and other aspects like:
% of FTP at the end vs. beginning of race (if a long one) will feel different. if doing let’s say 280w at the beginning of the race feel Ok to one rider, at the end of a race it might not feel that good 
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No it is not possible, unless a rider’s very first ride ever is in a race, in which case just use some multiplier against their weight for that one instance (e.g. 3 x kg). zFTP is calculated based off all rides. It may not be accurate if it’s someone’s second ride but there will be a value.
Then make it a smaller fraction of zFTP than 50%. Fiddle around with the numbers until it doesn’t feel broken - like you’re trying to do with X% reduction of power vs last Y seconds.