I’ve got maybe 3mm between the Di2 battery and 4iiii battery cover on my Merida - my thinking is … I probably don’t have enough watts to make things bend far enough for them to actually touch.
If you have less clearance than that I guess that’d be an issue though.
I’ve got the Stages left only power meter (gen3, R8000, 172.5mm crank) on my Domane SL. Fits fine, no issues with clearance. The 4iiii power meter pod appears to have a pretty similar size as Stages.
Just got my Stages crank installed.
Pros: It seems to work.
Cons: I feel anxious about having to look at power data all the time now.
My crank won’t support it - I have 50/34 and they support 50/36
How did you test whether your Stages L-only was good or bad? I have a Kickr as my only reference.
Here is what I’d recommend, if you can put your bike with the Stages on the Kickr:
This isn’t perfect since the Kickr might be off as well, but it at least gives you a sense of how close they are. My Stages was over-reading by 20-25 watts 
Some thoughts on single-sided from the Fast Talk guys (ff to 33:33 if the link doesn’t take you directly there):
Fast Talk #62
I’m in the same boat as you and a bunch of other posters on this thread. I had to look over my 2018 data and found I am about 53/47 on flats and the trainer, but that will switch to more heavily favoring my right leg when standing - it can go as far as 46/54. Rides that combine long flat and long climbing sessions can average out to 50/50. I don’t actually feel like my left leg is stronger. I am right-dominant otherwise.
The only thing is, my only recent usage for this data was actually figuring out that I needed to be more consistent in calibration when the balance shifted to right-dominant. This was a major source of recent confusion for me - my power numbers were going up and I thought I was getting stronger… I was, just not quite to the absolute number that was being reported. (I figured this out after a lot of puzzling over last years’ workouts and wondering why I was getting annihilated by “threshold” workouts; unfortunately there was about a month of rejecting reality there 
) I feel the information cannot be used to guide my training otherwise.
Your unit was definitely whack. Similar to DCRainmaker recent reviews, I’ve now had two Stages (L gen2 and LR gen3) that have been within roughly 3-5W of the Kickr. Assuming the strain gauge on Stages is more accurate, I’ve actually seen the Kickr 2017 wheel-off optical sensor wander up and down during some tests. In other tests the Kickr has shown a stable offset, sometimes a little high, sometimes a little low. When discussing with Wahoo support, they recommended I do a spindown 10 minutes into every workout.
Hi There,
I work at 4iiii and I was hoping you could contact me directly at jerold@4iiii.com It looks like we are waiting on that photo we asked for. I look forward to hearing from you soon.
Cheers,
Jerold
Thanks Jerold - have just forwarded you the email 
Forgot to mention that I don’t have a GPS unit. I use Zwift Companion App on my iPhone 6 to run Zwift on my Apple TV I run TrainerRoad on the iPhone itself.
I have the option of running TrainerRoad on my notebook and a different cycling computer app on my cellphone.
Following this thread for a while. Impressed that a guy from 4iiii’s jumped in to help Baron.
Did some more research on stages vs 4iiii’s and found gp Lamas recent reviews.
Stages.
4iiii’s
I know Gp’s review is on a higher end 4iiii’s but I think I’ll pick up my first power meter from 4iiii’s.
@FatBoySlim go read the DCRainmaker review. In the 2018-2019 Power Meter Guide he mentions using it for testing. I picked up a gen3 LR and not seeing any issues. If I had a do over, would save $75 over what I paid for new Ultegra 8000/Stages LR and buy the Power2max NGeco and use with my Shimano chain rings. Because I don’t mind the aesthetics and would rather save $.
I can pick up a 4iiii’s 105 left for 360.00. I have a 2018 roubaix with shimano 105 on it. By the looks of it I have to spend 490 and then buy cranks on top of it? I don’t think its going to be close in price but I really cannot figure it out.
@FatBoySlim For my Trek Domane with a BB90 bottom bracket, I will need Rotor3D24 cranks ($150), and the corresponding tool ($30) along with the NGEco power meter. Both are available from Power2Max’s website. That brings the total to $640-$670 range, which is reasonable for a 2-sided power meter. (You will need the 4-bolt Shimano version of the NGEco).
You can reuse Shimano chainrings, but not the Shimano cranks.
Do keep in mind that you will need to pay $50 extra to get the breakdown of L\R power, which unlocks for both Bluetooth and ANT+, so that’s $720. This is done through Power2Max’s app.
I only learned this after 2 emails to Power2Max, and 1 to PowerMeterCity. Best confirm before buying.
great price to buy into left only. Like @anirudh I have a Domane and his breakdown is for total (left+right) power. The power2max is a great deal for total power. I’m a data geek and upgraded to left/right power, but would have been happy with total power.
Hi @Jerold_Hoshowatiuk did you get the photo ok? Cheers.
Exactly what I bought a few weeks ago (4iiii 105 5800).
So far, the device seems to work, although it reads a bit too high compared to my Tacx Neo: approx. +30W at 200W output.
I’ll need to collect more data and do a proper comparison - could be L/R imbalance. At least this can easily be corrected via the 4iiii app.
Isn’t it rare for power meters to read high? If they’re faulty, they almost always - if not always - read low?
