Curious what the collective opinion here is. I’ve been looking at getting a 4iiii Precision Pro install on my 105 crankset (currently $650). Seems like 4iiii has a solid reputation. But I’ve also seen some Gen 3 stages LR Ultegra sets for $500, lightly used (allegedly). So 2 questions, 1) Is Stages Gen 3 reliable? It sounds like they’ve fixed the issues from Gen 2 from the little I’ve heard. 2) Would you be concerned about a used PM from eBay/FB marketplace/etc?
EDIT: Updated the title to be more specific.
I have been happy with my Gen 3 Stages.
Don’t know about Gen 2 or 3, but my Gen 1 has been great and still is years later, and the +/-2% accuracy is plenty good for all but the most serious riders.
Only reason I mention is you could probably find some Gen 1’s somewhere brand new for a $150 or so, rather than buy used… FWIW
My stages Gen2 was good to me for over 2 years and 11,000 miles, but stay away from the 8000/9100 dual sided versions (stages, pioneer, etc) cause apparently the cranks are asymmetric which messes with readings. I think older 6800/9000 groups are better. L only will be fine regardless of generation, and people do seem happy with the 4iiii and single sided pioneer also.
If bought for the right price I think they’re a bargain. I sold my mint Ultegra based Gen2 for 280
Left only are fine if you’re happy with left x2 = total power. Stick with Gen 3 (or higher if ever released) with Stages as they’re a LOT better for signal strength.
L/R wise I’d keep away from anything on a Shimano crank. The numbers just don’t line up. I can’t use ANY Shimano based power meter to compare power numbers against trainers or other power meters. This is a problem.
I have two stages units. Both purchased used off eBay or Facebook. Both are fine. Neither are the reason I’m not faster.
I’m very happy with my 3rd gen stages.
Having been a Stages owner for many years I think it is very much a lottery.
Had a Gen1 that never worked for more than 10months at a time. At which point Stages refused to replace as it was over the two warranty; I was not best pleased.
Own two Gen2’s. One was replaced after six months, the other is still going strong apart from eating batteries during the cold.
Have a Gen3 that has only lasted four rides and is now suffering from random offset values and looks like it will be going back.
This info has really thrown me for a loop…haha. I wasn’t aware of these issues, but it theoretically makes sense. Interesting that some users don’t seem to see these issues though (Obviously, not many users do comparison testing, as you mention, but DCR review for Stages LR Gen 3 seems to show L/R readings are sane when compared with Garmin Vector L/R readings, for example).
Maybe the Shimano would still be ok for me. It would indeed be the only source of power, and I could probably bring myself to ignore the balance figures. I’m only riding outside and on a dumb trainer (so no ERG mode), so maybe the issues wouldn’t be as pronounced. Just hard to shell out $500-650 for an instrument that could be out by as much as 10%, but if it’s consistent with itself, that’s all that really matters for training.
I’m not sure where to go from here if Shimano isn’t the answer. I don’t want to go pedal based because I’m on Speedplay pedals that seem to have helped alleviate some knee issues I’ve had and don’t want to switch cleats again. I don’t want to go hub based because I use a different wheel on the trainer vs outdoors and don’t want to lose power if I swap wheels during a race. I’m concerned if I go left-only crank-based, it will get in my head and I’ll develop a power imbalance (I’m a classic overthinker about everything). Maybe if no Shimano, either look at SRAM cranksets or just forget about adding a power meter altogether.
I have a Gen 3 Stages DA crank and it has been excellent…after the first one got replaced under warranty. I don’t do the exact comparison tests that GP Lama or DCR do, but based on my trainer rides with my Direto, the numbers are very much inline with each other.
That said, here is a great option for you…Quarq crank that is 50% off, so roughly the same cost as you were considering for a used Stages. Other BB options are also available if you aren’t running a GXP BB.
I think your best solution is an L only arm
The thing is, why fork out for dual sided when you know it will be wrong…? Just get the left only and save the money. Then at least there is some chance it will be accurate, plus a lot cheaper.
You won’t know if a left side-only meter is “accurate”, either…people’s power balance varies throughout their different effort levels.
Left-sde only meters can be great options if cost is the voerriding factor and you are only looking for general data (average power for a ride, power over longer intervals, etc). But a dual-sided PM is always a better option if you can afford it.
That DFour looks great. I have R7000 chainrings though. Looks like the DFour91 would be the compatible product. I’ll have to look more into this option. Thanks!
Those chainrings would be compatible with the DFour. It is a 4-bolt chainring pattern.
Not a shimano crank based one, that will be inaccurate… Have a look at Shane’s Post above, he has done a lot of work on this.
I am not necessarily advocating for a Shimano-based option, hence the links I provided for the Quarq options.
But a single-sided PM is not necessarily “accurate” or even “consistent” as I noted above. Again, it can be a great option for those who can’t drop the $$ for a dual-sided PM, but its limiters need to be understood.