# wahoo speed vs Zwift speed and also effective power

(dale heiler) #1

hi guys,
had my first ride tonight, few things I noticed,

first the speed reported in Zwift does not match the speed reported by the garmin

sitting at 9-10mph on the zwift software I was at 25-28kmh on the wahoo, now zwift told me my max speed was 41mph or so but my true top speed was only 45.4kmh,

now I have a Giant ridesence speed/cadence sensor but only using for cadence, would that play up with the speed readings?

also is there a way to increase the rider weight? as climbing the 8% odd hill on zwift island I was sitting comfy on high 200w when in reality im usually sitting at 400w going up a hill that steep

(Gary Randolph(BTC)) #2

I had similar questions. The speed reported by Kickr is NOT used by Zwift. Zwift calculates speed based on power (read from Kickr). (This is based on feedback I have received.)

(dale heiler) #3

yeh got ya, seems a little strange to do when the data is there ready to go…

(Gary Randolph(BTC)) #4

I agree, Dale. I think they are trying to make a uniform result for everyone based on power only.

(Eric C. (Zwift HQ)) #5

There is currently no way to modify weight. We’ll be adding that in as we continue to test other aspects of the Beta. That will definitely affect your speed.

A lot of these things aren’t final (hence the Beta) but all the reports from you guys are helping us for sure

(daniel sekera) #6

unknowingly i asked a very similar question. my answer was speed from the trainer means nothing the only thing that matters is watts. I guess there is a rational for that however the point I was trying to make is a revolution of the wheel is a revolution. If i am using my trainer set at a zero percent slope and I am pedaling at 20 mph then it is supposed to replicate 20 mph in real life on a flat road. I can verify this as the wattage is relatively close as the trainers algorithm is taking into account or trying to simulate wind resistance, rolling resistance, rider weight (which I set including bike weight) etc. so all things being equal 20 mph is 20 mph. however on swift because it is only looking at wattage it will show me much slower. same with the uphills or downhills on swift. I’m spinning zero slope at 130 rpm cadence in a 53/12 which in real live on a down slope like deliverance hill and i’m well over 40 mph. however swift is saying yea well you’re only putting out 200 ish watts so you’re only doing 28 or whatever. Uphill my 400 watts at 10 percent in real life is 5mph at my weight. with swift I’m 10+. so until it can take into account rider and bike weight it is not going to be close

it will probably be really super awesome someday and its cool to be in on the ground floor so it is what it is for now. every day its getting better

(Andrew Cichello) #7

How come my kickr speed and distance don’t match up with Zwift. What data is correct?