I just built up my new bike with SRAM Red22 and a Red22 Quarq. My old bike has a Dura Ace 7800 SRM. Both bikes have Rotor Q-Rings 50x36. I last calibrated the SRM in the late summer/early fall time period. I did my normal trainer workout on the Quarq and my watts were around 20-25 watts higher for the same gear/speed/cadence on the same trainer with the same rear wheel. So I set the slope on my Quarq using the Qalvin app with the McMaster certified 20kg weight (same weight I used on the SRM). The slope changed slightly and the power numbers moved slightly towards the SRM numbers, but not a whole lot. The chainring bolts have been torqued to 12Nm.
I’ve heard rumors that the Quarqs come in hot and then “settle in”. At the moment I’m going to just ride with it for a while to see what happens, but I’m curious if anybody has any thoughts to explain this.
I’ve been using SRM’s for years and have been doing the same trainer workout for years so I’ve got a pretty good handle on where the watts should fall. What I’m seeing now is just too high. I’m willing to consider that the SRM’s have been low for the last 6 or 7 years, but I think that’s unlikely.
maybe your quarq just overestimates your q-rings more than your srm does
my quarqs seem to need the slope higher than factory setting, as factory setting on one is over 4% low per same 20kg as you use. that said I was told recently by quarq I should use the factory settings, but I will not being doing that as I prefer numbers closer to reality.
I will ask if you have done a few hard jumps on the quarq? or…
“Do you follow The Process (carbon paste, torque, jump to seat the bolts, retorque)?” which was sent to me by a buddy again last night. seems some of us even with the newer quarqs still need to do this to get the zero offsets to stay put.
edit…I should add that I tried a comparison the other day to see the difference between 280 and 300w on my trainer in same gear. turns out, the cadence given by the quarq varied so little between the two, that I could not tell anything as I had no speed sensor and the data I got was the same rpm, but one was subjectively harder
I’ll try the carbon paste thing. I remember seeing that in the past but it slipped my mind. I wish I would have remembered that when I had the rings off…
I’ve looked at the power files and my average cadence for the 20’ intervals I’ve done are down an rpm or so compared to the past, but the power is higher so they are certainly different. I might take the time to recalibrate the SRM, but I’m kind of lazy and I’m going to sell it anyway so maybe I won’t.
