KayakPro Speedstroke Gym for sale

4 weeks 16 hours ago - 3 weeks 4 days ago #37931 by jsapan
Hi -- I have an old but working Speedstroke Gym kayaking erg.  The only problem is that it does not have a performance monitor.  I tried the KayakPro bluetooth solution ("GenesisPort") and I could get the machine to measure distance, but it would miss strokes, making the cadence data wonky. See below for full details.  My goal is to get enough to get me at least halfway to an another erg, like the Paddlesport Training adapter with the Concept2 SkiErg.

$1200 OBO.  Located in AZ.  Can figure out shipping if there's serious interest.

Original adjustable aluminum shaft included.  Needs one replacement adjuster ($25 from KayakPro + shipping) OR buy a Length Lock 1 adjuster from Epic for $9.90.

Shown with a custom-made carbon fiber paddle rod.  I took the pull bar off the footrest, but it screws back on.

The electronics issues can probably -- but not definitely -- be fixed, but I'm fed up with dealing with KayakPro.  They are either unwilling or unable to help troubleshoot if it does not involve buying more parts from them at extortionate prices.  I know other folks have had good experiences with them, but evidently if you haven't already given them $3000, you're not worth their time.  The problems would certainly be solved by replacing the flywheel and sensor ($500 for flywheel).

If you were to try to fix the electronics, you'd need a performance monitor (~$250 after shipping from KayakPro) and a new pickup ($40 + $20 shipping from KayakPro).  Note that the "pickup" is actually a $1 inductor, so you can save some money by soldering a 3.5mm aux cable to the right inductor.

I *think* but do not know, that the problems might be solved by positioning the pickup closer to the flywheel OR replacing the magnets on the flywheel.  There are also various cheap alternatives to the KayakPro electronics, but none I'm aware of will do flywheel calibration.
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3 weeks 1 day ago - 3 weeks 1 day ago #37934 by graysonhugh
Hi Jonathan,
I saw your post and wanted to reply, as your negative references to us are not fair. Whilst we note your frustration, a second hand, used 13-year-old ergometer does not always have a low-cost resolution in order to make it “like new” or return it to its original functionality. …Rather like say a 13 year old car.... especially if it has not been well stored, well maintained and generally well looked after. Electronics are particularly susceptible to unsympathetic treatment. It is simply not right to say we have been unwilling to help to get to a low-cost resolution for you, as the 10 emails sent to you on the subject should attest.  As the chain of low costs fixes has run out, the likely resolution is a replacement flywheel.

As I had advised, the Genesis Port- Bluetooth interactive portal is not designed to be a console replacement but rather to run in tandem with the on-board console.Despite the Genesis Port you bought being well over the return policy period – we will still continue to maintain the previous offer to give you your money back.

However as previously advised, the new pick-up cable that was sent to you and has been broken, we cannot offer a return refund on this. I think none of this is unreasonable, extortionate nor shows an unwillingness to help.I recall you had said the repositioning of the pickup did not work.

We no longer make the full flywheel for this model, [Formerly $ 1000] but the flywheel internals can be made available. The replacement onboard console is $240 + shipping.

Or alternative a new SpeedStroke PRO is $ 2150.00 USD. 

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3 weeks 1 day ago - 3 weeks 1 day ago #37935 by jsapan
Hi Grayson,

I don't intend to start some sort of flame-war and perhaps I had overly high expectations, but I'm not some sort of crank.  I wish I had been told from the get go that you were unable or unwilling to provide any support for an old machine beyond selling parts.  I would have been disappointed, but saved a lot of time and grief.  Separately, the prices charged for parts feel excessive across the board.  You're obviously welcome to charge what you like, but you run the risk of people feeling like they're being taken advantage of. ( I will happily detail, for anyone interested, various Speedstroke parts which can be purchased elsewhere for 1/3 to 1/4 of the prices charged by KayakPro.)

My frame of reference here is Concept2.  Like KayakPro, they make a great product. Concept2 also provides ample support, which is not conditional on being the first owner, or even on buying their parts.  They even post schematics of their machines.  And they have made sure that their new monitors can be retrofitted to machines they don't even sell any more. Their prices for parts and shipping are completely reasonable. 

I'm an electrical engineer and physicist by training.  I told KayakPro I was hesitant to buy a new monitor because it seemed likely that the sensor or something else was faulty.  I initially asked for help verifying the output from the sensor with an oscilloscope I had connected (literally just what the output signal should look like for a working sensor).  They were either unable or unwilling to assist and steered me instead toward purchasing a new monitor.  I took a leap of faith and bought the GenesisPort.  When that did not work, I agreed to purchase a new sensor.  I was assured by Steve Tingay that I would be allowed to return both if the problem was not solved and that the return window would be extended to accommodate this.  

When the replacement sensor did not resolve the problem, I still had hopes of fixing things.  I last e-mailed Grayson and Steve on 12/7.  Neither replied so I e-mailed again on 12/23 saying I would be returning the sensor.  I still had hopes of getting things working, so I disassembled the flywheel because they would provide zero information about the workings of the machine.  Unfortunately, I broke the new sensor in the process of removing it from the flywheel to return.  At this point, I decided to return the GenesisPort (as promised I could) and stop trying to work with KayakPro.  I told them directly I had no expectation of a refund for the sensor since I broke it.

For those interested, I'll be replacing the sensor and installing a generic performance monitor for now.  It won't do spindown calibration, but c'est la vie.  Haven taken the Speedstroke apart, I now know how it works.  Shame it's treated like a state secret.  There are a set of 6 magnets mounted to the flwheel... as above, the sensor is a simple inductor that passes through the flywheel housing to face the magnets as they pass by.  If I'm super ambitious, I might try to jury rig machine to work with a Concept2 monitor which would provide force curves.

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3 weeks 1 day ago #37936 by tve
In the off-chance you're interested in building your own performance monitor, I just built one for a water rower. Doesn't do force calculations yet, but that could be added if one is interested in working through the physics and calibration. The current input is the hall switch that detects water wheel rotations. Sounds like a hall switch to count 1/6th turns of the flywheel would work the same. The whole thing is based on an esp32 microcontroller with a very common 2.8" TFT display and programmed in micropython. (It also sends the data to my little home server over wifi so I can plot workouts, etc.) If you're into this sort of thing I can help you get started, if you've never worked with embedded microcontrollers, it's probably too high a barrier for just a performance monitor.

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3 weeks 1 day ago #37937 by jsapan
Hello, kind sir.  That's awesome!  I'd been considering the DIY route.  I've done some embedded programming and I know enough python to be dangerous, so it probably wouldn't be totally beyond me.  I'll be honest -- I'm not sure how likely I'll be to follow through, but I'd love any info/help you can share.  Maybe I can get spindown calibration and force curves working or help you with it.

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2 weeks 3 days ago - 2 weeks 3 days ago #37944 by tve
Quick follow-up, the prototype system I have looks like this (the screen looks a lot better in real life):

The "real" system's electronics are almost complete:

A few more mods and that's all for the hardware (<$40 in parts).
Software is shaping up nicely. The core dealing with the rower pulses is one page. Most of the work goes into the screen driver and the whole font rendering and layout... I can make the code available in a few days, right now I'm reorganizing some stuff... The off-line processing allows me to chart stuff like:


Edit: I forgot to add that I'm somewhat tempted to add an S load cell into the pull rope to measure pulling force. At that point I'd forego tracking the water wheel revolutions and essentially write a physical simulation of a rowing shell based on force input, or more likely, just integrate the force to get power and track raw power. You could probably do the same, although you'd need two load cells. Overall it's more challenging 'cause beyond a proof of concept which could use wires to hook up the load cells one would need a little BLE transmitter in the handle / paddle stick. (The set-up I have already tracks heart rate via BLE, so the RX side is pretty much covered.) Dunno whether I'll go there 'cause the rower is not me and she's not that deep into tracking performance...

For direct msgs you can use my screen name here at voneicken.com
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2 weeks 2 days ago #37948 by jsapan
That looks amazing!  Seems to me that tracking the flywheel would get you a very good idea of the forces... Perhaps with a kayak stroke the reduced dead time might complicate things...

As I understand it, Concept2 calculates drag after each stroke.  The KayakPro monitor has a function to do "spindown calibration" which I think is basically the same thing, but done once at the start of a session.  You ramp up the flywheel, stop paddling, and watch the decay starting from below a preset speed threshold.

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2 weeks 2 days ago - 2 weeks 2 days ago #37949 by jsapan
Know you've got me thinking.  What do you think of this?
smartloadcell.com/slc-force/tension/rope-tension-sesor.html .  
Edit: eek!  over $1700 ea.

Would be easy to simply insert this in line with the rope near the ends of the paddle.

Personally, I'd still like something that would only need to use the flywheeel since that's getting measured anyhow, but I might experiment with one these suckers for stroke analysis.

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2 weeks 2 days ago #37951 by tve
Yup, that type of load cell is what I mean, just without that price tag! 500 tons is also a bit overkill, haha!

There are <$10 modules that can be configured with some serial-line commands to transmit simple sensor values, e.g. Microchip RN4871.

The problem with the "spindown calibration" is that you need a known value for the moment of inertia. For your erg you may be able to get that but in my case, for a water rower, go figure... I'm not even sure how constant the moment of inertia is with the way the water slushes around...

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