Kickr Descent

(Daniel Connor WBR A) #1

I can’t seem to get up a great deal of speed on descents. I’m using the Wahoo kickr.

it doesn’t seem to make much difference whether I’m putting out 150watts or 300watts. My speed will be around 25-30 mph (although my top speed in the ride may be 36 or 42 mph)

I understand that the speed should be lower in corners, but I can’t seem to influence my speed much on strings descents by increasing my power. Compared to in real life I could coast down a hill at 25 or pedal and get a fair amount more speed.

anyone see experience this?


and if there is a cap on decent speed (which I know I am not close to as I see other riders with similar average speeds but much higher top speeds) the. Is there some way to show this so that I don’t bother gunning it on descents and getting no extra speed, and can save energy for climbs.


Im also finding I’m pushing very high gears throughout just to get enough resistance


(Eric C. (Zwift HQ)) #2

Hi Daniel,

Are you getting changing resistance while riding on the island?

(Jonathan Pait (X)) #3

I’m with Daniel on this one. Perhaps we are not having the same problem, but I am definitely having an issue on descents. During a recent Friday Training Race on Zwift, I would find myself in the group. I would try to find a reasonable pace to stay with them, but I would begin to drop back. Then I was off the back with a gap! I had to increase wattage significantly to get back to the group where I would then go flying through them, but as soon as I got to the front, it was as if I was hitting a wall. I’d start the whole process over again. It was very frustrating to be putting out 500 to 600 watts on the climb to stay up with the skinny guys and then having to put out 350 to 450 watts to stay with them on the downhill! Judging from what I am seeing on social media, Daniel and I are not the only ones. I think you have over compensated for weight. I weigh 173 pounds.

(David Sack 50+) #4

To me it used to be too much in the other direction. Being a heavy rider I would fly down the hills with no effort.  Since the last change it seems to be better but maybe a bit too far as I now have to put out more effort going down hill than seems accurate.


(Daniel Connor WBR A) #5

Hi there,


yes the resistance changes throughout the course of my ride. The resistance seems to correspond to the road (ie the big screen view) rather than the % readout which seems to lag (I think I have this the correct way round)


I seem to have perhaps a similar situation to Jonathon where I can catch a rider on a climb - the power output here feels proportionate. And say I come level with them at the top, I will simply not be able to get enough speed on the descent to match them - here my watts don’t seem to have much effect. In this case - if my effort wil make no difference to the speed Id rather have a lower resistance and not waste my effort here.


im sure it’s all in the works, and entirely possible, so hopefully things will get a bit smoother with regard to changes in resitance vs wattage vs ride speed


(Seb Barrett (U19) AUS) #6

i have to agree with above comment from Daniel.  at first i thought it was just my fitness - but i think now it’s just a fine tuning thing for the kickr.

(Casey Schumm [X]) #7

I have seen this too but I don’t think it is as much about kickr speed but power.   Prior to me having the kickr going fast downhill was easier because I could still hold a steady high power over the top of the hill.  Now with the kicker you have to accelerate/shift and push hard before you get the watts back up in the games once resistance drops out.   By the time you do that a group holding a steady power has gapped 6+ meters and then they are gone.  On the long downhills this is tough because the ultimate speed going downhill is so much greater in the drafting group.   By the bottom of the hill you have a couple seconds to try and cover.    


From watching the kickr power vs. my PM power I think allot of these small kickr nuances could be improved if zwift could read my PM for game speed calculations but still run sim mode on the kickr for resistance changes.   This would eliminate the lag in power changes created by the kickr.  Obviously this doesn’t solve anything for the people that don’t have a PM to us with the kickr.  


FYI - while the kickr sim has a disadvantage cresting it has an advantage starting a climb - the draft doesn’t play a big role climbing so it isn’t as noticeable.   Starting a climb at say 250 watts and holding my PM steady by shifting you can watch the kickr power spike for a few seconds while it is still decelerating to match your speed/power. So starting a climb I could see a 100-150 watts spike for 2-3 seconds on the game when the PM stays steady.  This is a kickr advantage but not as significant as the opposite impact on the downhhill because of the lose of the draft.  I used to think Pait was attacking me in the rollers but it is really the yo-yo of the kickr power that would cause big/short spikes in power on the short uphill bursts.  


I don’t see these as flaws as much as differing traits of the setups.  Once you know them it is easier to adjust for them but some them do make different setups more difficult and it would be nice if they could be adjusted somewhat.