New Bike Day

Got a new bike and had a few questions that I was hoping some people here would have answers to.

  1. new bike has a new crank based power meter. Comparing to my old pedal PM in identical activities it maybe reads a touch higher. Guessing no issue for Xert as a BT will update to the new PM as it’s higher?

  2. Seeking any mechanics :sweat_smile: as I’ve reached my limits…putting new bike on the trainer the Rear Derailleur seemed to need adjusting because of a ticking sound. All good, done in Di2 app, sound reduced to almost gone. Putting the wheel back in though it shifts fine without undoing that adjustment. Seems counterintuitive to me so should I be worried/ double checking something or just happy it works and I won’t need to adjust every time?

Alongside this was going from 10-speed QR on trainer to 12 speed thru axle, all compatible but mention in case it’s in that change I should be looking.


  1. How much higher along your power curve? If a touch higher, no big deal. But if 10 watts higher than trainer at your TP wattage that will raise signature value on your next BT. That BT will also be relatively easy to achieve.

  2. How different is the cassette model on the trainer from the one on the bike?
    If no ticking and shifts fine indoors and out, I’d leave it as is.
    If off enough to warrant readjusting each time, a shim should help assuming the cassette on the trainer is a bit further in than the bike’s.
    If necessary, are you familiar with making micro-adjustments on a ride without the app?
    12-speed Rear Derailleur installation and adjustment guide (

You can’t start a new thread called “New Bike Day” and not have a picture of it! C’mon - let’s see it! :smiley:


Exactly what I was to say!

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Still running comparisons using the ZwiftPower comparison using Vector 3 Pedals vs The new PM. Seems to run ~3% higher but for some
Time points like 5 min power the difference can be greater.

Next step is to dual record on the Tacx Neo to see what’s going on for both power meters. I imagine power match can solve some issues too?

They’re both 12-speed shimano. Only difference is I got the cheaper 105 version for the trainer while an Ultegra is on the wheel.
Know how to adjust on the move without the app so can get myself out of a pinch.
Seems like if it’s all good just run with it. I’ll mention it at the first service anyway and see.


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What brand/model is the new PM?

Dual recording and verifying results with DCR Analyzer or Compare the Watts is the way to go for an accurate delta %.
You can also play with Powermatch on EBC while riding some steady blocks under ERG control (AUTO) on the trainer. During each block pull up Sensors and switch Power from trainer to meter and back again. RPE alone will tell you if the difference is significant.

FWIW I get a ticking sound in one gear with my out-of-spec 11-36T 12spd 105 cassette running on a DA 9200 rear derailleur. I’ve futzed with it enough times now to leave it alone. Shifts fine. :man_shrugging:
I figure it has something to do with the ramps on the cassette cogs or some other tolerance issue between 105 and DA cassettes. May be applicable between 105 and Ultegra too.

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:star_struck: Wow - look at that colour! How do you like the Ultegra Di2? I had the option on my bike, but had originally passed on it to save some $. I already feel like I’m out of the times with my mechanical 2x11sp :sweat_smile:

Which power meter came with the bike?

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Thanks for the Compare the Watts website! Was looking for a free option with smoothing and it is great.
Interesting idea on using Powermatch to pair PM and ERG. I was going to record PM across different devices without outside impacts like traffic lights to see. But RPE is a good move.

The Power Meter is OEM “Giant Power Pro” claiming +/- 2% accuracy, so a downgrade over Vector 3 pedals, but more cost-effective and rechargeable is a factor and does another 1% accuracy really matter to what I’m doing and if I really need accuracy for something I’ll use the trainer. (If you get a SRAM version of the bike you do get Quarq).

Good to know on derailleur compatibility, I’m hoping its all sorted anyway and triple checked the cassettes should be compatible.

@ManofSteele I’m coming from eTap so mostly finding Di2 means shifting down when I wanted to go up :sweat_smile: but it has been great otherwise, it feels like all you get is a 34 on top of your 11-30 and swapping cable maintenance for recharging and firmware, but then you start to use the autoshifting and realise there is autotrim and it adds up.