I have a Polar Pacer watch that I use in addition to my Wahoo Tickr. I had to do a factory reset on it today. Not able to find the correct wheel size to use anywhere. Anyone have any recommendations? Set it at 2000 mm just now just to get my workout started, but the speed differential between the watch and Wahoo SYSTM is SYSTM +1.5 MPH or so.
Thanks
This might help. You may have to try a couple and see. The default for what I use is often 2096 (I don’t have a Bike Shift)but you can make it whatever most closely matches the bike you actually ride.
Thanks mate!
That’s Sir Mate, Sir 
I have the same question, did the wheel size he suggest work out? Or did you figure out a different number? I have the Wahoo kicker shift bike and I’m looking for the number for Trainer Road.
I settled on something that isn’t entirely accurate and not be the most accurate size available. Sorta gave up just cause I don’t really even care that much about the speed my watch reads. I’m more concerned between the speed discrepancies between Wahoo SYSTM and Training Peaks Virtual, which aren’t going to be reconciled by me finding the correct wheel size.
All the apps use their own speed calculations. Zwift and TPV also include environmental factors like wind (TPV) and gradient, while SYSTM assumes no wind and a level gradient. Even removing the wind and gradient from TPV, the speed calculations would likely still be different. Add in the extra factors and it’s unlikely the speed and distance will ever fully match between platforms.
And even recently with the updates to the SYSTM video player, the Wahoo SYSTM speed and distance calculations are different from what they used to be in the SYSTM app itself.
So, yeah, unlikely you’ll get an exact match between any of the apps regardless of your wheel size selection.
Yeah, was sorta hoping to find the closest to what SYSTM shows doing the same wattage for the same duration, assuming no wind, in TPV… realized it wasn’t worth my time though.