Elite Zumo Trainer

Yes, of course. Using the Elite myE Training App and after about 10min warmup.

That was my initial experience, after the 2nd JSON file the divergence seemed to stay consistent.

Thought you will have done (I would have) but also wondered what would happen if you didn’t do a spin down?

At least power match shouldn’t have any bother at all with a consistent 10w offset - I think trainerroad even lets you apply a constant offset?

I have a Zumo and so far I’m not suspicious of any readings but I am going to attempt to use the DCR analyzer tomorrow. I have an Edge 520, Assioma pedals and a laptop in my garage. So, to get 2 files to compare what should I do? Pair the Edge 520 to the pedals and pair the Zumo to TrainerRoad. Do my session which I have just created and save my Garmin recording and the TR session. Obviously I then have a .fit file from the Garmin but what shall I do about the TR file? Use the download option from the ride analysis page I guess?

Is this correct?

I’m about to watch the how to YouTube video.

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Hi, yes that will do it. The TR download will be a tcx but that is supported.
Other things to do I’d suggest would be
Ensure the clocks are accurate on your devices
Warmup your trainer before starting the recording
Calibrate both trainer and power meters before recording
Disable auto pause on both garmin and TrainerRoad
Try and keep to a consistent testing protocol.

Good luck and I do hope your trainer is a good one.

Regards, Dave.

As I’m sure you know, the value the Zumo spits out doesn’t really matter for training purposes - But there are three other reasons I want to ensure it’s reasonably correct;

  1. So I can connect simultaneously to TR and Zwift and have a representative output in Zwift.

—This is totally mitigated if using Meet-up setting that keeps everyone together anyway

  1. To validate the mechanical efficiency of my drivechain

— Some time ago I felt I was losing something significant from pedal to tarmac, which I since believe to be resolved. But it would be nice to know how many what’s are lost anyway :slight_smile:

  1. If you plan to use BestBikeSplit to plan your races, unlike training, you need a reasonably true value so that power output does relate to tone on the course.

—It could be that my pedals are wrong, the Zumo is right, and my FTP is 30W less than I think it is.

All three are interesting but truth be told, they’re “nice to haves”.

Well that was a disaster. I’ve been using the Zumo almost daily since November and for the very first time ever I had an Ant+ dropout, unbelievable. Plus, now I’ve saved my Garmin file and got the TR file and put them into the analyser it turns out the files are identical. So annoying. What’s happened here?

I definitely had the pedals paired to the Garmin. :rage: :rage: :rage:

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To me the value that the Zumo spits out is fundamentally important to my training. In my case, I bought the trainer as a cheaper alternative to use when travelling so that i didn’t have to cart my Kickr around the place. The bike I want to use on it doesn’t have a PM and I don’t want to use PML in anycase even if it did.
I did an initial test with it and though everything was all ok (~150W-200W). Then when I tried Striped +1 as part of my CX training plan the damn thing tried to kill me (was more like 500W when the target was supposed to be 420W). Try that and see how you get on.
Everyone has different requirements i guess. Mine is simply to get what I paid for and that was supposed to be ±3%.

Sure, I was replying to Vale who has a more similar use case to me.

What is similar between you and I is that we’ve paid £££ for something that has essentially interfered with our training…not helped it!

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OK I’ve sussed out the files and calmed down a bit now.

Looks like mine is under reading too against my Assioma pedals. So from anyone who has reported this to Elite, what evidence did you send and to where?

What is the official accuracy of the zumo stated as and how does yours compare?

@ValeCyclist honestly that doesn’t look too bad. I logged a ticket with Elite Support. If mine looked like that I might be temped to put up with it. At least it is consistent across the power range.
@scotscyclist65 ±3% is the stated accuracy. But ± against what? It’s always a bit of a game comparing power meters.

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@ValeCyclist
That actually looks pretty good considering that even if both power meters were perfect then the zumo should report less due to drive train losses.

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OK thanks for looking and the replies. Here’s a sample of discrepancies over various time points.Differences

Hard to get a definitive answer but this is the kind of thing you would find on the internet regarding drive train losses.

“Chain
The main source of resistance in the drivetrain is the chain. Even a new, well-oiled chain will lose about 3% of the power that is put into the pedals. This is in the typical bikepacker range of 150-200 watts; efficiency is slightly better at higher levels of power. If the chain is dry, for instance after riding through a rainstorm that has washed away the oil, then this could cause a further 1% of power to be lost. If the chain is so old that it has become elongated then another 1% of the power could be lost.”
source: Mechanical Resistance on Bikes: Drivetrain Efficiency & Hub Bearings – Ride Far

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Here’s the actual power trace.

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There should be some difference between your PM and your Zumo, neither will be perfectly accurate and there are watt losses in the drivechain. I’d suggest 10W wouldn’t concern me.

Where I’ve seen up to a 30W discrepancy is why I’ve raised a ticket with Elite support.

They asked me to run a particular protocol using their app, and I recorded the output from my pedals in TR at the same time and emailed the files back to the support staff who contacted me.

It’s not clear to me whether they can tell the distinction of something wrong being with the Zumo, my pedals, or my drivechain, but they have cast no aspersions so far and I expect to get a firmware update.

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It does sound like mine isn’t too bad. I’m going to modify my test workout later and repeat it later today, hopefullybthis time without dropouts. I’ll give mybchain some attention beforehand too but it is on a bike which hasn’t been outdoors for many months.
My most recent ramp test I did in erg mode and this finding does make me wonder if this is the reason I felt I had underperformed. When you’re up at those final steps 10 or 15W has a proportionately greater effect.

It could also explain why SSBHV1 left my legs in tatters.

OK I got home, cleaned the chain, did the pedal offset check and had another go. Apart from one minor blip for some reason I’m more content with this. For some reason the Zumo did have a drop out just before the final 30 second interval, I’m wondering whether it just doesn’t like having the pedal close by also on Ant+, I don’t know. The 2 files were lined up on the HR chart as recommended.

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Yup, they finally emailed me - not even asking if I had an Android device BTW - telling me to go through the routine you described. When I politely informed them I don’t have an Android device they told me to borrow one.

I’m getting a little cheesed off with Elite, I have to say. But packing it up and returning it is even more hassle, so I’m probably going to await the iOS release that allows us to update the trainer.