Zwift, Kickr, ERG and Speed/Distance issues

[mikees]

Morning folks. Hopefully someone can help with some issues I have with the above.

On some occasions when using Zwift with Kickr, the speed reading thus the distance is wrong. I can be peddling like fk and it claims its 4 kph usually up hill. If I stop peddling its stops ERG and when I start peddling it comes back but still no resistance and slow speed reading. Similarly, (last night the route was NY High Road) when coming down hill I peaked at 80 KPH down hill which is crazy

Without doing extensive testing it appears more likely when running a workout rather than just riding a route.

Anyone seen similar or have any ideas what I might be experiencing?

I might be misunderstanding how the Zwift/Kicker speed curve (power, RPM, gradient) work but even so, even on a 15% gradient, the gear/cadence I was peddling at wasn't 4 KPH

Cheers
Mike

TLDR: I'm a ZWIFT noob and a bit dim :-)

[ukbabz]

I've a Kickr Core, but I've noticed it doesn't do ERG so well with ant+ and prefers bluetooth.

Is it reading the power correctly? As I believe zwift would use your power to calculate how fast you're going. Might be worth checking your Zwift profile and you've not added your weight in lbs as the weight in KG (would explain the slow up and fast down)

[frisbee]

There are some reasonably steep hills in Zwift.

In the real world on a 20%+ gradient I drop down to 5-6kph and have to do 250+W to keep moving.

If you put even a little effort in on a decent downhill you should be able to hit 75+kph.

[mikees]

Thanks guys. Also I was 10kg to heavy !

[mikees]

Issue is also erg isn’t making the hills hard ie off the saddle stamping in the pedals. Shouldn’t it?

[frisbee]

mikees said:

Issue is also erg isn’t making the hills hard ie off the saddle stamping in the pedals. Shouldn’t it?

In erg mode your effort is just determined by the set power, the effects of the terrain is completely ignored from an effort point of view.

To experience the terrain you want to turn off erg mode. Increasing the difficulty will let you experience the terrain "more".

Your speed in world, erg mode on or off, is determined by your power, the gradient, your height, weight and other factors.

[mikees]

frisbee said:

mikees said:

Issue is also erg isn’t making the hills hard ie off the saddle stamping in the pedals. Shouldn’t it?

In erg mode your effort is just determined by the set power, the effects of the terrain is completely ignored from an effort point of view.

To experience the terrain you want to turn off erg mode. Increasing the difficulty will let you experience the terrain "more".

Your speed in world, erg mode on or off, is determined by your power, the gradient, your height, weight and other factors.

Thanks mate. So is it better to have erg on or off?

[frisbee]

mikees said:

Thanks mate. So is it better to have erg on or off?

Dunno, I've never actually tried doing a workout with erg off!

I have a sort of love hate relationship with the workouts and erg mode. They can be an effective way of getting fit but they often feel too easy or too hard and do getting boring after a while.

Racing, route badges and pace partners are good ways of passing the time in Zwift.

[mikees]

So ERG on for rides races etc?

[defblade]

ERG is only for workouts, really. It means you can go through a given set of hold-this-power-for-that-time without having to modulate the effort or gears yourself to hit those targets - you pedal, the trainer worries about giving you appropriate resistance so you are pushing the correct power for that interval.

Turn it off for all normal riding, and things get harder going uphill and easier going down, somewhat (but not exactly!) like RealLife.

Then there's the "trainer difficulty" setting... lots of macho rubbish talked about this, it's really mis-named... it should be called "gear ratio setting" or something like that. It's set to 50% by default as lots of smart trainers can not replicate the full percentage slopes found in Zwift. 100% "difficulty" gives 100% of the slope "feel" - if your trainer can do it. Lowering the slider is like fitting lower gears to your bike - at the end of the day, you still have to put out the same power/time to get up a hill - if you're set to easier, it'll take longer... just like RealLife again.


The slightly weird speeds you're seeing in ERG mode are due to the maths and feel of how Zwift works - uphill, your speed will be a function of slope steepness, your weight and height, bike weight, which wheels you're using, any draft from other riders, etc... and there's a fair chance that the power the workout is asking for is lower than you'd actually ride up that hill at. So you end up with a very low speed.
Oddly, due to the way Zwift requires you to keep pedalling to keep moving (except in supertuck), it's somewhat harder to hit high speeds downhill in Zwift, especially if you have a high trainer difficulty, as it removes the pressure you need to pedal against to give high power figures (it's still possible, but more difficult)... in ERG, your power output on an interval stays constant, so it's much easier to hit high speeds downhill than when you're not in ERG mode. Also, no braking for corners etc means your speed builds unrealistically.

So in ERG, the power you put out is controlled by the workout programme; what you see your avatar do is a result of how that power is applied by the game to the slightly weird physics of Zwift, but this has no influence back to you, you're still just going through what's set on the workout.

[gl20]

mikees said:

So ERG on for rides races etc?

I think you might be misunderstanding ERG (as was I when I first got my Kickr). For a race or any other group activity or a free ride, you want it left off. That way the turbo is simply simulating resistance based as though you were riding the road for real (ie it factors in wind resistance, drafting and gradient). Speed/distance should be accurate if ERG is off.

ERG is there to help you hold a specific amount of watts. So you only need use it in interval training. Let’s say you’re heading into a 200 watt interval. If you hold your pedalling steady as you enter the interval, the turbo will adjust the resistance to get you to 200 watts. If you then start pedalling a bit faster your watts will rise a bit so the turbo will slacken the resistance a bit to get you back to 200 watts (and vice versa if you slow your cadence). So for intervals it’s great. Just focus on your cadence and it will adjust to help you maintain your interval watts. Throughout this, I’d ignore speed. In theory the speed will be based on the watts per your interval and the gradient you happen to be on but it’s not important. What this also means is however fast or slow you pedal watts stay the same so, using it in a normal ride, makes it feel like the turbo is broken and not responding to your effort!

With all that said I’d agree with the comment above that it’s often easier to get fit faster by getting in some races or other events. Just seems more motivational.

[okgo]

I find erg horrible on Zwift with kickr (though I am using ant+ powermeter, interesting that may not help). So I never use it, even for workouts I turn it off.

[Gin and Ultrasonic]

mikees said:

Morning folks. Hopefully someone can help with some issues I have with the above.

On some occasions when using Zwift with Kickr, the speed reading thus the distance is wrong. I can be peddling like fk and it claims its 4 kph usually up hill. If I stop peddling its stops ERG and when I start peddling it comes back but still no resistance and slow speed reading. Similarly, (last night the route was NY High Road) when coming down hill I peaked at 80 KPH down hill which is crazy

Without doing extensive testing it appears more likely when running a workout rather than just riding a route.

Anyone seen similar or have any ideas what I might be experiencing?

I might be misunderstanding how the Zwift/Kicker speed curve (power, RPM, gradient) work but even so, even on a 15% gradient, the gear/cadence I was peddling at wasn't 4 KPH

Cheers
Mike

TLDR: I'm a ZWIFT noob and a bit dim :-)

Are you doing a group workout or a solo workout? The Group workouts slow you down a lot (some of us more than others!!) as they go at the pace of the slowest people to keep everyone together, so your power output won't correspond with your speed.