I have plumped for a power tap to run on my winter bike this year. This is so that I can run compact and normal chain sets as the rides dictate as I live in a very hill area. Over winter I tend to take rides a bit easier and spinning up big long climbs is good sometimes. I also want to avoid putting lots of hard wet and dirty miles on my other power meters for a change.
I own a Riken and an old SRM and have been using power for about 4 years, so not new to the game.
Will I see any differences on my garmin from the powertap? Is there anything that I should look out for or be a bit unfamiliar to me you folks are aware of? Are there any useful tips to owning a powertap? I don’t imagine there will be but I thought I would ask the ST collective as you just never know 
Thanks for any replies.
I switch between the two (Quarq to PT) frequently. On my crank PMs I prefer 3s power averages, and I haven’t found it’s needed with the PT. I also find that the cadence reporting in the PT is sub-optimal, so I run an external GSC-10.
I also find that the cadence reporting in the PT is sub-optimal, so I run an external GSC-10.
Thanks! That is good to know. I have a spare garmin cadence sensor I can put on the bike before the new wheel arrives. Appreciate the post
I have plumped for a power tap to run on my winter bike this year. This is so that I can run compact and normal chain sets as the rides dictate as I live in a very hill area. Over winter I tend to take rides a bit easier and spinning up big long climbs is good sometimes. I also want to avoid putting lots of hard wet and dirty miles on my other power meters for a change.
I own a Riken and an old SRM and have been using power for about 4 years, so not new to the game.
Will I see any differences on my garmin from the powertap? Is there anything that I should look out for or be a bit unfamiliar to me you folks are aware of? Are there any useful tips to owning a powertap? I don’t imagine there will be but I thought I would ask the ST collective as you just never know
Thanks for any replies.
Something to be aware of if you’re comparing power numbers from the different power meters: Assuming all the power meters are accurately calibrated (slope and offset), the PowerTap should read a little lower than the crank-based power meters, all else equal. The reason is that PowerTap measures power “downstream” of frictional losses in the drivetrain, unlike crank-based power meters.
A squeaky clean drivetrain with good chain lube and without excessive wear can be ~98% efficient. In that case, you wouldn’t really notice a 2% difference in power. But drivetrain frictional losses can increase significantly due to dirt/grit, wear, not enough lube, crappy lube, rust, etc. So if you want consistent, accurate power data from your PowerTap, keep your drivetrain well maintained.
I switched from an older SRM V to a G3 and the only thing I noticed was not having to sit at the bottom of my driveway zeroing out my SRM every ride.
The G3 surprisingly doesn’t seem to noticeably differ at all wattage wise compared to my SRM and I set quite a few CP prs after just using the G3. I was expecting it to read a bit lower but that hasn’t been the case.
They are very similar in wattage reading, in fact my max 5 and 10sec power numbers are from the PT not the Quarq, go figure. Assuming they are both zeroed you will notice no difference at all. I have ridden with both frequently just to make sure i can mix the data and i have seen no issues. PT is a set it and forget it kind of PM without the water damage issues that plague the Quarq’s.