4iiii or Stages Gen2 or Gen3 Power Meter

About to be impulsive and order a power meter and have narrowed it to lh 105 crank from 4iii or gen 2 stages.

Both review well but I have heard of issues with stages but not sure if that’s interweb over stating it.

Prices are similar (~£280), which way would folks swing or is there a left field option I missed?

Less issues with 4iiii, from what I’ve read. Got one myself - no issues.


I also have had a 4iiii left only PM since September. Zero issues for me, just one battery change recently.


Stages G3 in 5800 105 is apparently in budget (£10 difference).

Now I am back to confused! I presume gen 3 being newer is better than the 4iii which is a couple years back in design.

I use both 4iiii and Stages on my different bikes. 4iiii reads more accurately according to my Tacx Neo and it supports adjusting power scaling up/down so you can calibrate it yourself or against another PM if you so wish.


I wouldn’t presume that. Quite the opposite even.

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I’m a big fan of my 4iiii precision. I’ve got one good anecdote and one weird. I crashed in the first third of a gravel ride (gnarly rock garden, probably should have walked it) this past spring and somehow, somewhere popped the battery cap off. I rode the rest of the ride with no cap with plenty of dust and a little bit of water splashing here and there. Got home, got in touch with 4iiii and they sent me a new cap for no charge, popped it on and everything worked like nothing happened so it seems to be pretty resilient . The weird is that a couple months ago I got some random drop out and the battery levels weren’t reading properly, basically would drop out for a second then read 255% battery. At the same time when the battery read normal it fluctuated between 99-97% for no reason. Got in touch with them again and got a very detailed troubleshooting protocol to follow, but after just popping in a new battery I didn’t have to follow any of it because it just started working normally again and the battery is now around 76%. I also make sure to turn off sources of interference during workouts which may be helping as well. So weird, but better than a real issue. As it stands I’m getting a new bike this year and planning on getting another 4iiii, probably the podiiiium.


4iiii make the Specialized PMs. If it is good enough for them…


I have both 4iiii defo!


This, I would go for an established product that has a few firmware updates behind it.

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You can play that both ways… If Stages gen3 is good enough for DCRainmaker as part of standard testing… And Sky… I don’t see DCRainmaker pointing out problems with his store bought gen3.

Would have bought 4iii if dual was available in Nov 2018. Ended up buying Stages Gen3 LR at a discount. No issues.

If I had to do over, would skip both 4iii/Stages and go with Power2Max NG Eco Rotor 3D24 and reuse my bottom bracket and Shimano chainrings. Full L+R power for $670.


another +1 for 4iiii precision. Have had it for about 6 weeks but it’s been solid and accurate from the get-go as others have indicated. I must be pretty balanced because my power #'s are inline with my indoor powertap I use.

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Was going to say pass on gen2 Stages as well but Gen3 Stages seem to have the issues sorted. I have nothing but good things to say about my Gen3 and have found it very reliable and easy to live with.

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A friend had problems with a G2 Stages 105.

First one battery died within 2 days, no water ingress that was from new. It was replaced and on second on power sometimes would steadily rise over a few mins to approx 3000watts (when doing nearer 150w on a club ride).

He took it back again and got a 4iii, never had a single issue since. Probably been a couple of years now

I have the Stage LH 105 Gen 3 (May 2018) and have had zero issues with one battery change.

For the record I’m on my 5th 4iiii Precision 5800. The first one just started giving me bad readings out of the blue mid-ride. The second just didn’t turn on straight out of the box. My third gave me a calibration error after washing my bike. The 4th gave me a calibration error after sitting in direct summer sun for a lengthy time. My fifth is going strong, came from a different supplier in the UK.

Have to say support from 4iiii has been excellent and with that said I thought my luck had to be in sooner or later so I stuck with the company.

My takeaways for 4iiii are don’t hose the crank arm directly and also keep the o ring lubed up and don’t subject it to extreme temperatures.

I have 2 bikes set up for 4iiii, both with 5800. I swap these around in November and April. :metal:

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I recognize this is an old thread, but want to add +1 for the 4iiii because of the excellent support I recently got when I finally did have a problem with my 105 left-only after almost 2 completely trouble-free years. They had me check a couple things and when those were eliminated had me send it back for repair / replacement. I was technically out of warranty, but they have extended warranties to 2 years since I bought mine and just included me in and installed a new meter at no charge. No hassle, no quibble. Five stars.


Revisiting this, I had a PM failure last week.

My head unit was giving very weird readings and then eventually power just said 0 the whole time. Re-calibration on the head unit and 4iiii app both gave error messages. Emailed their support who were pretty quick to reply with some troubleshooting steps which didn’t help.

Thankfully, it’s still within a couple of weeks of the 1 year warranty period. I’ve seen others online outside of warranty period and they only offer a discount on a new PM at that point.

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Agree with the other’s that are recommending the 4iiii unit. However…

I will say that after updating my FW to V3.2.0 on my Precision Pro, I get regularly scheduled dropouts on TR. I do NOT get these dropouts on Garmin or Zwift, so there’s something going on between the PM and the TR application. TR support was initially helpful, but I’ve been weeks now without an update. I really think that they (TR) need to get 4iiii on the phone and suss out what’s going on.

Looking to pick up a GRX crankset and looking at a factory install of either a Stages Gen 3 or 4iiii. Stages is cheaper with the USAC discount by $60. The other option is a Power2Max but that’s about double the price. What is the current thought about Stages vs. 4iiii vs. P2M? I can get a GRX crankset for $120 at REI with my dividend/discount, so around $360 total for the Stages, $420 to go the 4iiii route, or $670 for P2M (with chainrings).