Focus Paralane: Switching to 105 R7000 Power Meter

It was not long ago when I completed upgrading the Focus Paralane to a full Dura-Ace Di2 groupset. However, on that groupset, there was one component which is not from the latest R9200 groupset, and that is the left crank arm.

I was still using the older R9100 left crank arm with 4iiii power meter, as it is useful to have power readings even though I am not training with the help of a power meter.

When I was using the Dura-Ace R9100 2x11 speed crankset, the right and left crank arms were matched as a set. Then, when I changed to 12 speeds, I only swapped the right crank to R9200, leaving the left crank arm still as R9100 with power meter.

Now, I plan to install the unused R9100 crankset on another bike, and I would like to move the R9100 left crank arm with power meter over as well. Therefore, I need a left crank arm for the Focus Paralane.

I actually have many spare left crank arms, as I have two different left crank arm power meters, the R9100 and also a cheaper 105 R7000 version. In fact, the R7000 power meter was on the Focus Paralane previously, when it was a 1x11 speed setup.

The 105 R7000 left crank arm with power meter is currently on the Cervelo Aspero, but I think it would be more useful on the Focus Paralane, given that I ride it more often and on the road, where power readings are more useful than when riding on gravel.

This gives me a rare chance to have both the Dura-Ace R9100 and 105 R7000 power meter left crank arms off the bikes, for a side by side comparison.

105 R7000 crank arm on top, Dura-Ace R9100 crank arm below. 

They are both of 165 mm crank arm length.

Different surface treatment, and the R9100 crank arm looks more well used given that it has been in use since it was first installed on the Canyon Endurace.

R9100 has a bonded 2 piece hollow construction, while the R7000 is a hollow forged design.

Bond line on the R9100 crank arm can be seen. The R7000 crank arm is also slightly larger.

Note that the orientation of the two clamp bolts are opposite between R9100 and R7000.

No idea what is the reason for the difference.

R9100 left crank arm with 4iiii power meter is 182 grams.

R7000 left crank arm with 4iiii power meter is 200 grams.

Dropping down from Dura-Ace to 105 left crank arm only adds 18 grams of weight, which is very little in exchange for a much cheaper crank arm. In terms of cost to weight ratio, both 105 and Ultegra give very good value, as compared to Dura-Ace.

Finally, some pictures of the 105 R7000 left crank arm on the Focus Paralane.

R7000 left crank arm with power meter, with XTR PD-M9120 pedals used previously.

A mixture of components from different groupsets, with Dura-Ace, XTR and 105 all seen in just one photo.

It doesn't bother me that the left and right crank arms are not from the same series, as the appearance is close enough that they can match. In fact, it is not possible to see both the left and right sides of the bike at the same time, so it is OK even if they don't quite look the same.

With this latest setup, the Cervelo Aspero does not have a power meter, just a complete R8000 crank arms on left and right sides.

The Focus Paralane now has Dura-Ace R9200 on the right side, and 105 R7000 on the left side.

Finally, the R9100 crankset with 4iiii power meter is now available for the new bike project.