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ROTOR introduces new ROTOR Power LT power meter

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ROTOR has officially announced their newest power meter offering, the ROTOR Power LT.  The LT stands for ‘lite’, but it could also actually stand for ‘Left’, which is because unlike their higher end power meter the LT is a left-leg only system.  This makes it identical in functionality to that of the Stages Power Meter that was announced just under 2 years ago.

I’ll dive through the basics, the pro team usage in the Tour de France, why it’s important to understand left-only power, the models available, and my thoughts on the offering.

The Basics:

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The ROTOR Power LT is at its simplest merely half of the full ROTOR Power system.  The full (non-LT) system has two crank arms (one for each side) that both have strain gauges to measure power output.  Each of those arms then transmits power data using ANT+, which is then combined on a single crank arm and then transmitted to a head unit such as a Garmin Edge or other ANT+ capable device.  Where the full system differs from that of this new LT system is that they’ve removed the right side (drive side) of the equation, effectively becoming a single-sided power meter just like Stages.

By going to a single-sided system they’re able to reduce the platform price by cutting in half the required hardware.  Though, in actuality the drive side tends to cost more, so they’ve likely reduced their raw costs by more than half.  Of course, as you’ll see the end-price didn’t quite get the cut that folks would have expected.

Pro Team Usage:

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The Power LT is already being tested and used by a pro team today, where it’s installed on the bikes of Team Lampre Merida.

There however the units are actually used in conjunction with a Power2Max power meter on the spider, which you can see below on the flip side of the same bike:

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This has allowed them to reference against a ‘known good’ when need be.  In talking with one of the Team Lampre Merida mechanics on Tuesday during setup he noted that the vast majority of the time they were using the ROTOR LT as their primary power meter.

In their case, they were pairing the ROTOR LT to Garmin Edge 510’s.  The Edge 510 (like all Garmin devices) can only record and display a single power meter at one time.  So they are unable to concurrently record both streams to compare later but have to simply decide ahead of a given ride.  However, the rider could have both power meters configured as different ‘bike profiles’ on the Edge 510 and simply change bike profiles as needed if they were seeing issues.

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Still, seeing a new power meter product being used in the Tour de France is certainly promising – even if it’s just half of an existing product.  And ironically, it’s also a pretty interesting show of confidence by ROTOR to use Power2Max (a competitor) as a known good, as the president of ROTOR told Bike Radar’s Ben Delaney that it (Power2Max) was “100 percent accurate”.

Understanding Left-Leg:

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So why do I keep mentioning left-leg only?  And why’s it important?

Power meters measure torque (basically your output) via strain gauges.  These gauges are placed in various locations depending on the model of the power meter.  For example, a PowerTap has this in the rear wheel hub, whereas Garmin Vector has it in the pedals.  Power meters like Quarq, SRM and Power2Max place these inside the spider under your chainrings.

The full version of ROTOR Power places two of them, one on each crank arm.  Whereas the ROTOR LT, like Stages Power, only has a single set of strain gauges on the left crank arm (riders left).  This means that it’s only able to capture the power from the left leg.  In the case of Stages, they simply double the power value to give you total power.  You’ll often see Stages note that they are within 1.5% accuracy “as measured”, which means that they don’t claim that it’s 100% accurate to your actual power, but rather just the measurement point.

In my testing of the Stages system I found that in the vast majority of cases, this works out just fine.  It’s not 100% perfect though.  For example, most people have biases to either a slightly stronger left or right leg (which is totally normal).  If you have a 5% bias to a single leg 100% of the time, then one could argue things would always be consistent.  The challenge here though is that some people (including myself) tend to have shifts in bias depending on power output level and factors like fatigue.

For example, my balance is pretty good and consistent up until my FTP point (about 315 watts).  Beyond that though my balance shifts quite significantly.  On the flip side, for myself as a triathlete I rarely have a ‘sprint’ effort.  So it’s of less concern to me personally in most of my normal training.  Whereas a road cyclist doing lots of hard sprints may see a bigger impact (if they follow a similar trend as me).  This could either inflate or deflate values, again, remembering it varies on the person and many other factors.

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(Above, an example of power balance on my Sunday ride, you’ll notice the gradual shift from start till end)

You can’t easily test to understand your bias because it does indeed generally shift based on a variety of factors.  For example fatigue (such as a 4-6 hour ride), or power output level, fit changes, or injury.  As one that has a lot of historical power meter data to look at (often 3-4 power meters at once, including left/right capabilities) it’s easier for me to understand my own patterns.  Whereas most riders wouldn’t have a vast library of data to reference with multiple power meters over long periods of time to develop patterns.

The point here being to simply understand the limitations.  It doesn’t mean I wouldn’t recommend such a system – as I certainly do in specific price/functional scenarios (such as in the case of Stages at that price point depending on how you plan to use it).

Pricing and Availability:

The ROTOR LT is scheduled to be available in the coming weeks.  Given the unit is basically just half the existing ROTOR system with a slightly different firmware – this is a reasonable timeframe in terms of them being able to deliver.  The unit will be available in the following models:

- Crank length: 170, 172, 175mm
– Chainring Sizes Compatibility: 110BCD, 130BCD
– Both 10 & 11 speed oval and round rings available/compatible

From a price standpoint the ROTOR LT will be US$1,490/€990/£799, which does however include crank arms but not chainrings.

My Thoughts:

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I think it’s definitely interesting that ROTOR is getting into additional models of their power meter line.  More selection is great for consumers.  Further, I don’t have any particular issue with left-only power meters as long as one understands the product, I think offering more choice is good and in many situations I don’t have any particular issues with recommending left-only power meters.

However, with that said – I don’t get the pricing.  It makes approximately zero sense.  Why on earth would I pay $1,490US for a single-sided power meter when there are plenty of very good options that accurately capture both sides for the same price (or even lower)?

While their existing full ROTOR Power system is priced very high at $2,350, at least it was in the ballpark of other similar system (albeit the high end of that ballpark).  In the case of the LT though, it’s basically double the price of the Stages Power Meter ($699).  And also in the case of the ROTOR LT, there’s nothing it really offers beyond what Stages can do.  In fact, one could (easily) argue it does less.  For example, ROTOR doesn’t dual-transmit ANT+ and Bluetooth Smart like Stages does.  Nor does it include Stages new high-speed data mode (targeted at track athletes).  Nor can you install it on 3rd party cranks like Stages can  be.

From a weight standpoint Stages only adds 20g, while ROTOR has previously stated 30g additional for their dual-system (it’s unclear if the single system is exactly half the weight, thus 15g).  Note that it’s very difficult to exactly compare weight differences because of the way the two companies sell the products.  So at most you’re looking at a 5g difference.

But ultimately the problem for ROTOR is that they aren’t actually competing with Stages at this price point.  Rather, they’re competing with everyone but Stages.  And in that race, they lose horribly on price.  First, you’ve got Garmin Vector priced slightly higher at $1699 (but with a $200 rebate down to $1,499).  Then you have the SRAM Quarq RIKEN at $1,200US.  Next is Power2Max at $1,099.  And finally, the veteran PowerTap at $789.  And all of those accurately capture power from both legs, and all of them have far more flexibility in cranks/chainrings than ROTOR.

So in summary while it’s great that ROTOR is adding products to the market, I’m just entirely unclear who their target market is.  But, as I’ve long ago learned in cycling – there’s a buyer for just about everything.

Thanks for reading!

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51 Comments

  1. Happy runner

    It costs that much because it is difficult to get that much ugly in a single product. Is that supposed to be a lightening bolt? Someone needs to check the graphics department for child labor law violations.

    Reply
  2. Pete

    Just a quick note on the price comparison to the Stages meter, over here in the UK, the price is £699 for an Ultegra 6800 meter, essentially, they've taken the US$ price and stuck a GBP £ on the start. That makes it only £100 cheaper than this new ROTOR.

    I'm going to be in the market for a meter towards the end of the year, and these two fit my budget perfectly.

    Reply
    • TheBigYin replied

      exactly my thoughts Pete - and if you were in the market for a full Ultegra crankset, not just the left arm to fit an existing one, the price is almost the same, even allowing for buying chainrings for the Rotor...

      Reply
    • Jonathan replied

      Even in the U.S., $699 is only the price for some Stages models. For Ultegra (6700 or 6800) its $799, and for Dura Ace its $899.

      Reply
  3. Dan

    Ray,

    Is this the first PM that supports oval chainrings?

    Reply
    • Rainmaker replied

      First crank-based one, yes. Things like the PowerTap do without issues of course.

      It's a valid point, but IMHO, since it's left only, you kinda wash away the theoretical accuracy gains by understanding the oval rings in place of only measuring half-way.

      For those curious about oval rings and what Dan is asking about in reference to power meters - check out Tom's post here on it: link to bikeblather.blogspot.com

      Reply
    • Dan replied

      Agreed re: Left-Right metrics. Certainly seeing some useful information from my Vectors - at least identifying fluctuations which I'd miss using left only.

      I guess that technically speaking, there are no obstacles to bringing non-round support to the existing Rotor power meter. I've not seen this capability confirmed to date (Ray?), but it would certainly give them a (temporary and marginal) USP.

      Reply
    • Tom Anhalt replied

      Ray, although the oval rings may be "compatible" in the sense they are able to be mounted, what confirmation is there that it doesn't suffer from artificial inflation? Do you have any insight into how the rotational velocity is measured/calculated and how that's combined with the torque values? The answer to that will tell us how likely it will suffer from the inflation.

      Reply
    • Rainmaker replied

      When I chatted with them at Eurobike last year in person, they confirmed that they were oval-aware in their calculations. I'll triple-check with them via e-mail here in a moment and validate the LT still retains that.

      Reply
    • Tom Anhalt replied

      Can you (or they) expand on what "oval aware" means? The devil is in the details, of course ;-) Thanks.

      Reply
    • Dan Connelly replied

      "Oval-aware" could simply mean sampling cadence (pedal velocity) sufficiently rapidly. Power2Max makes that claim: there should be only insignificant anomaly with Power2Max.

      Reply
    • Tom Anhalt replied

      Dan...how would they do that with accels? Sure, you can sample a lot, but if they just look at the gravity vector sweeping through the signal and look for time between peaks, that's really no different operationally than a reed switch "trigger", no? Like I said, "the devil is on the details". The question that should be put to all PM manufacturers to answer this question about non-round rings is: "do you assume a constant rotational velocity within a pedal cycle in your power calculations?" I don't care what hardware is used or how it's sampled, if the answer is "yes", then that PM will have artificial inflation issues with non-round rings. If they refuse to answer, then the only safe assumption that can be made is that it most likely will.

      Reply
    • Keith Wakeham replied

      I don't think company is going to refuse to answer that question. They all stand behind their products. It's pretty obvious. If you put a magnet on a bike then you have a reed switch (or 5, in the case of Quarq). So suffice to say it has to be done with another sensor type.

      Lots of way to do it. Gyro + Accel + Kalman or complementary filtering techniques. Or could use a multiple magnets and field sensors. It's just a lot of expensive, time consuming hardware or algorithm development where as a reed switch has proven reliable (except 1/5 in my used Quarq which is stuck -- it's old, I forgave it long ago).

      Reply
  4. H M

    I think what you are missing is that £799 is exactly the same price as Stages in the UK, and if you buy a Stages you still have to buy a Right-hand crankarm whereas this Rotor LT one includes the RH arm IIRC.

    If you are in the US you get slated by exactly the same import taxes that we pay on stages in the EU, so its not a good option. However if you are in the UK / EU it looks very attractive if you are currently considering stages.

    However, an extra £100 or so to get a Power2max is a better option....

    Reply
    • Rainmaker replied

      There are no import taxes into the US. The prices are as-is retail prices in USD.

      I agree it's odd that the UK/EU Stages prices are nearly double. Usually it's just equiv amount in euros. Still however, Stages is more functional.

      Reply
  5. Mathew

    Thanks for the helpful review.

    Minor typo (unless they've adapted a new standard), for crank length - surely it should read 172.5mm

    Reply
  6. Lex

    I own 2 Rotor 3d+ cranks, one is fitted with a power2max, if I could purchase just the rotor crank arm, with power meter, rather than the whole crank, for close to the stages price, my order would be in right a way.

    Reply
  7. Madrigal

    When you are comparing the prices between Stages vs Power LT you are comparing a left crank arm (Stages) vs left+right crank arms (Power LT). You should plus to stages the price of the right crank arm. Right Dura-Ace crank arm isn´t free ;)

    Reply
    • Rainmaker replied

      The price of the base costed Staged drive side crank arm (Shimano 105) is about $150. Which makes it still just over half the total coat in the US.

      Keeping in mins though that a key point of the Stages platform is that you don't need to rebuy that since they have a wide selection.

      Reply
    • Madrigal replied

      Yes of course! But so then you also should have in consideration the weight of the crankset in the comparative. Because the different in the weight between Shimano 105 cranks and Rotor cranks are so big. I think the comparative with Power LT should be with Dura-Ace cranks+Stages. It´s only my opinión...

      Reply
    • Rainmaker replied

      No doubt. Though, the cost diff is only a few hundred buckets (far less than the $800US).

      Reply
  8. I'm surprised of ROTOR's endoremsent of the Power2max. Considering the retail prices in Europe, ROTOR may have a market. But if I were to purchase a PM through my US mail forwarding address, it wouldn't be a ROTOR LT.

    Ray, I wonder if you have an opinion about Garmin-Sharp's use of SRM?

    Cheers

    Reply
    • Rainmaker replied

      I've asked for some comment from Garmin on the reasoning behind use of SRM's. Fear not, will definitely report back there.

      Reply
    • Dan Connelly replied

      Do you think it may be that Vector is relatively high maintenance? It certainly seems accurate enough, excepting perhaps the occasional power spike. SRM is pretty much install-and-forget.

      Reply
    • Rainmaker replied

      Here's the official answer:

      "In regard to the pictures posted – as part of our partnership with Slipstream Sports, Garmin works with the athletes, mechanics and head of Sport Science to continue to develop our products, including Vector. By doing so, we are able to make improvements and enhancements before these products are made available to the general public. As such, it is not at all uncommon to see different combinations of Vector, pedals, and other power meters on team bikes. We are committed to the constant improvement of our products, including our Vector power meters."

      I'd agree that installing Vector repeatedly can be a PITA, but honestly for a team mechanic of that caliber, it's pretty easy to get nailed down.

      Reply
  9. LVbob

    In general, it's surprising to see that there has been little to no downward pricing pressure in the power meter market.

    This particular PM is a non-starter from my perspective (at least here in the US. I'm looking for a PM now and would never consider paying this for left-only power when for just a bit more I can have L/R power with either the Quarq Elsa of Vectors. I also have the option of a PowerTap if moving the PM is a priority. Finally, the Stages provides left only power at a fraction of the cost (even with Dura-Ace).

    Reply
    • Rainmaker replied

      I think we're about to start seeing downward pricing pressure by Interbike timeframe. I suspect the bubble and price race is about to begin. Stages is very much driving that and the Team Sky sponsorship was a brilliant PR move from them, resulting in a lot of pressure on the industry right now. Simply ask any LBS what they're selling the most of...

      Reply
    • Richard replied

      I think downward pricing is starting to happen, just look at the Vector rebate and the way that power tap have decreased prices. Stages started to at least cause some waves in pricing. At the end of the day, the market is still not quite saturated enough for them to start worrying about pricing yet I guess.

      I have a Dura-Ace Stages which although was good value at $899 (compared to the rest at the time), its questionable once you look at Garmins Vector perhaps as a bigger picture when the rebate, discount (from clever training etc) and not having to buy pedals that may cost $250 (DA9000 for instance) are thrown in.

      If I had to do it again then I would go with the Vectors for the added functionality of left right since the total outlay (if not buying pedals) is $1330 after discount and rebate, whereas stages for DA9000 is $1150 if you had to buy pedals also.

      Reply
  10. I get paid to do pricing - that's my job. And I agree with Ray 100% - looks like Rotor scored an own goal with the price here. And it's a classic error of launching a product; overly focusing on your own product and worrying about 'cannibalization' rather than going out and putting together a compelling package for the market. I can see the conversation between the brand folks and management in my head right now...

    Alternatively it could be a Euro/Dollar issue as mentioned by a previous comment above - but it is typical in biking things to use the facial price and put whatever currency in front - $100 US becomes 100 Pounds and 100 Euros, though at 1.7 for Cable that's a real high price to pay for the Brits...planning a trip to the U.S. for shopping are we?

    But on the flip side of the Atlantic, this product is priced out of the market and thus isn't really relevant - shame too.

    Reply
  11. Hoss

    So I would definitely consider the Rotor LT — but not at $1,500. Stages is, unfortunately, incompatible with my BB30 unless I retrofit (which I'm not interested in doing and, at any case, would bump up my total cost considerably). I'd love to have power, and would be willing to spend around $700-$800, but for twice that much money I expect more than half the metrics. Next!

    Reply
  12. Squeegy

    I know your main focus is on tri based activities and road bikes but can you offer any comments on which power meters could be used with mountain bikes.

    Are there any reasons you could not use any of the currently available power meters for mountain biking?

    Thanks!

    Reply
    • Mayhem replied

      Mountain bikes normally have a wider bottom bracket than road bikes do, thus requiring a longer crank axle. Mountain bike chain rings also require a smaller bolt circle diameter, even a compact road crankset with 110 mm BCD cannot fit smaller chainrings than 34T. To use a power meter with a mountain bike you really are better off using one developed specifically for MTBs. At least Stages, SRM and PowerTap have suitable options.

      Reply
  13. Robin

    I think the important "apples to apples" comparison is between the Rotor LT and Power2Max's Rotor 3D Plus offering which comes in at a list price of $1449, $41 cheaper than the LT. The Power2Max of course measures power from both sides, so it's difficult to see what the benefit would be in choosing the Rotor LT given the base cranksets are the same.

    Reply
  14. Ben Richards

    I know it's been on the quiet front for a long time, but don't forget about Pioneer's Athlete Lite!

    I've been waiting to see others try it out first, but the price is appealing to me at $1550 for direct measure L/R power + a new Ultegra crankset. Unless I'm mistaken, that's almost less than any other meter that measures both left and right leg power directly. With the rebate, the Vector is $50 cheaper, but of course, with the Vector you're only getting new pedals with your power meter, while with the Pioneer you're getting a whole new crankset.

    Reply
  15. Ray

    Ray,

    Have you heard anything more from Brim Brothers. A few weeks ago they had a competition so you could help test their product. I'm guessing that they won't be making their August target date. That said I rather they get their product right.

    Reply
    • Rainmaker replied

      The point of said competition was to get beta testers to help make said "product right". Quite honestly, that's awesome - and would have saved other companies headaches with initial launches had they down that. :)

      Reply
  16. Mr Nofish

    "Me too" product:

    - your power meter is nice but it's too expensive. If only you had a cheaper option like your competitors...
    - but we an entry level too
    - sold!

    It also works the other way:

    - we have this power meter here for only $xxx
    - that's nice, and it doesn't cost an arm and a leg ...I think I'm getting it!
    - of course it's not as accurate as our top of the line model, and you only want the best, right?

    Can you not see all of this playing out in the typical LBS setting? Online, things might be a little different, but I still see a lot of commenters who, despite Ray's detailed explanations, still seem overly confused - which is probably a clue they simply skim the posts because the only other explanation that would make sense to me is their reading comprehension skills are next to 0.

    FTR there's a shop in my bookmarks selling the cheaper Stages (Rival) for slightly less than 600€, so if you're in Europe it probably doesn't make a lot of sense buying direct from Stages...

    Reply
  17. Jose I

    I curious - why are power meters (crank arm and pedal versions) so expensive? Is it the small manufacturing quantities? The cost of research?

    While they have come down in price, there are sill up there. The main component themselves appears to be industrial strain gauges which are widely uses and not expensive.

    Reply
    • Rainmaker replied

      It's primarily the R&D costs, which typically take 2-4 years to get from zero to hero (even for established players). Many iterations, very high costs and in the grand scheme of production - fairly low volumes.

      Reply
  18. Thanks for the review Ray.

    Reply
  19. Matteo

    Ray, any chance LT can be offered as stand alone unit? From photos it seems less "built in" than Stages, kinda "clip on"
    Met

    Reply
    • Rainmaker replied

      I don't believe there's any way for them to offer it that way and be able to validate the installation onto the back of the crank arm end.

      Reply
  20. Matteo

    Oh, that's a pity. I think that's the real missing opportunity. All of us is already well equipped with his crank arms: why do I have to change them? We're still far away from popular access to powermeter IMHO

    Reply
    • Rainmaker replied

      It's really for the same reason as Stages. Getting strain gauges permanently attached to something in an accurate manner is not easy. Since the strain is measured on the crank arm, it has to be rock-solid perfect - otherwise it'll have inaccurate measurements.

      Reply
  21. adam

    He, just trying to get my head around this.This and stages are classed as Left only measurments. Is the likes of the spider based crank measurments not the same thing but on the right hand side? For example looking at the LT, if that strain gauge was attached to the right hand side would it be classed as a spider based measuring tool? Maybe I'm missing somethin?

    Reply
    • TheBigYin replied

      Adam, my reading of this is that the "Single Sided" ones - Stages/Rotor - measure power by measuring micro-deflections in the arm of the crank. If you were measuring from the spider, you'd get deflections from the drive side crank directly - down the crank arm and into the spider, and deflections in the spider from the non-drive side transmitted through the torque imparted on the spider via the bb-axle.

      If the strain gauge was on the drive-side crank, it'd still really only be measuring the deflection in that crank arm. To measure both cranks, it really needs to be measured at some point that's more central (or, in the case of Vectors/Polars, via seperate units for each foot)

      Of course, this may well be completely over-simplifying things and I look forward to hearing an explanation from someone competent...

      Reply
    • Adam replied

      What I'm thinking is, like a simple speed sensor on a wheel, it doesn't matter how high or low the magnet is on the spoke, as long as the sensor lines up it reads the same. Would be very interested in an detailed article about how different cranks measure in different places and why some are seen to be more accurate than others.

      Reply
  22. MikeD

    I ordered a quarq riken with Red chainrings from Amazon prime for under $1100 a few weeks ago. Hard to imagine buying this over that.

    Reply
  23. Tim Grose

    Yes in the UK the Stages and this "LT" one aren't priced that differently. I had wanted to get a Stages Dura Ace 9000 for my new Cervelo P3 but it does not fit so rather than a less than satisfactory option of using the 7900 for the left crank only (which may have fit - we did not actually test in the end) opted for the full Rotor Power in the end - mainly as Rotor cranks and Cervelo bikes seem setup to work together. Did you ever manage to complete the full Rotor Power review? Hopefully will be taking delivery very soon so will able to see for myself.

    I use Speedplay pedals so that ruled out the Vector and so the Rotor seemed the next cheapest as well (in the loosest sense) although I see some cheaper options are now being discussed even if they look a bit "Heath Robinson" to me with wires and clips and stuff.

    Reply
  24. Abraham

    Long time ago, you said you were going to review the rotor power, but I cant see it. Do you have it still on mind?

    Reply

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