Power measuring turbo trainer - any recommendations?
KAR
Posts: 24
I am looking to buy a turbo trainer with a power measuring facility but do not want to go to the expense of virtual reality machines. I am considering the Tacx 1680 Flow Ergotrainer as it seemed quite simple had the basic functions I think I need for over the winter. Just wondering if anyone had used this type or could recommend another?
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Powertap elite+ rear wheel, cheap turbo. fan and pen paper/diary.
Everything else will be a compromise.0 -
I know this question may seem a bit silly but it really is important:
Why do YOU want to measure power on a turbo?0 -
I hate to tell you this, but Chrisw12 is correct. The power reading on the Tacx Flow is a bit 'variable'. Those who have used powermeters as a comparison report the Flow over-reads. The other main gripe is that the reading is not very linear (e.g. 300W + 10% does not read 330W)
My observation is that unless I keep the roller and turbo tyre clean my readings are very out, by as much as 30 to 40 watts.0 -
Get one of these. http://www.windstreampower.com/Bike_Power_Generator.php
The free electricity you gain from it will eventually pay you back.
Hook it up to a digital wattmeter and you've got yourself a power measurement.
That turbo trainer is very expensive though. With a bit of simple electronics knowledge, you could probably make your own electricity-generating turbo, using motors.0 -
Bhima wrote:Get one of these. http://www.windstreampower.com/Bike_Power_Generator.php
The free electricity you gain from it will eventually pay you back.
Hook it up to a digital wattmeter and you've got yourself a power measurement.
That turbo trainer is very expensive though. With a bit of simple electronics knowledge, you could probably make your own electricity-generating turbo, using motors.
Gold."In many ways, my story was that of a raging, Christ-like figure who hauled himself off the cross, looked up at the Romans with blood in his eyes and said 'My turn, sock cookers'"
@gietvangent0 -
:evil: Will it matter if it is a compromise? (We don't know do we?)chrisw12 wrote:Powertap elite+ rear wheel, cheap turbo. fan and pen paper/diary.
Everything else will be a compromise.
Geez - now you've got a powermeter you've joined the "nothing less will do" brigade!
Ruth0 -
KAR - they are right about the accuracy. Fairly cheap turbo trainers are not going to be accurately calibrated and possibly won't provide accurately repeatable power readings, although with a lot of care and a permanently set-up turbo+bike, you may manage to get good enough repeatablity to still train pretty well. It's just that you'll always have a nagging doubt in the back of your mind as to whether observed increases/decreases in power are really true. And you won't be able to compare your power readings with anyone else's.
But to EH's point, it really depends on what use you intend to make of it. I don't think accuracy is all that essential for many cyclists who use turbo trainers.......... but it depends on your view as to the importance of accuracy and repeatability.
Ruth0 -
The reason for wanting to measure power is simply to show if I am progressing throughout the winter. My tt bike will be permanently set up on the turbo with just the tyre pressure as a variable.
I wont be trying to compare outputs to anyone else or to any possible wattages I want to project on to the road next season - I also feel that training 'zones' would be more accurate with a power set up as opposed to the drifting that can occur for different reasons when I only rely on my heart rate monitor.
Any further comments would be most appreciated.0 -
If it's permanently set up, and the trainer has a published known resistance curve, you can calculate the power differences between workouts from speed info. Given that all you care about are relative changes rather than absolute numbers you can save quite a bit of cash that way - which can go to buying a PowerTap wheel so you get the accuracy later
Look at SportTracks GPS2PowerTrack plugin, or some of the many spreadsheet based options that calculate power from speed data on trainers... If you can borrow a powermeter to calibrate it, even better.Jibbering Sports Stuff: http://jibbering.com/sports/0 -
The reason for wanting to measure power is simply to show if I am progressing throughout the winter.
You can do that without ever knowing a figure for power output on an indoor trainer. Assuming everything else remains the same, then for instance 5 minutes at a cadence of 90 in a gear of 53x17 means you are putting out more power than 5 minutes at a cedence of 90 in a gear of 53x19.
I do wonder if for most of us time restrained people once you consider the time spent trying to understand power, the data analysis and the modifying your program, you wouldn't have just be better off just bunging in a few more cycling/turbo/race sessions.0 -
BeaconRuth wrote:
:evil: Will it matter if it is a compromise? (We don't know do we?)chrisw12 wrote:Powertap elite+ rear wheel, cheap turbo. fan and pen paper/diary.
Everything else will be a compromise.
Geez - now you've got a powermeter you've joined the "nothing less will do" brigade!
Ruth
Sorry, I held off for as long as I could but in the end the Welsh tt scene had moved on and I hadn't moved with it so I gave in.
Now (as I guessed would happen) I am totally obsessed with the thing.
Back on track, I tried using av. speed on the turbo and I just couldn't get motivated with it and in the end just gave up. It just seemed so meaningless. At lest now with a powertap these trainer numbers will have some significance to the road.
Interestingly (or not) I had a plan to increase av speed by 0.5 mph every <insert time> and this worked fine, then one day I changed the chain and all of a sudden I got something like an extra mph (or something significantly large). I honestly can't explain what happened but I now keep a close eye on any forum studies done on new chain efficiency and note with interest that Hutch puts a new chain on for important races (apparently)
At the end of the day you are spending ,money on what is the most boring, stupid punishing things ever invented by man. You may as well spend your money on something that will reward you, you owe that to yourself if you're going to turbo in the winter.0 -
BeaconRuth wrote:
:evil: Will it matter if it is a compromise? (We don't know do we?)chrisw12 wrote:Powertap elite+ rear wheel, cheap turbo. fan and pen paper/diary.
Everything else will be a compromise.
Geez - now you've got a powermeter you've joined the "nothing less will do" brigade!
Ruth --
"Because the cycling is pain. The cycling is soul crushing pain."0 -
Predicition: give it another 3 years and Powermeters will be as common as HRM's and we'll all be talking about how much time we're spending in the wind tunnel 0
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I'll be signing up for the first PowerTap road hub with disc brake compatibility
Le Blaireau (1)0 -
Bhima wrote:
No it wont, you dont get free electric.0 -
freehub wrote:Bhima wrote:
No it wont, you dont get free electric.
Ok, fair enough, you have to buy the fuel for your body, but it's food you would have bought & burned off on the turbo anyway, so it's negligible.
I know someone who has one of these devices. It's incredible how much electricity you can generate with it. :shock:0 -
Ummm, 250 W for an hour would be a pretty reasonable workout. It'd power, what, 5 light bulbs if you were lucky?Le Blaireau (1)0
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Accuracy helps motivation.0
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Surely results help motivation, little else.0
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eh wrote:Surely results help motivation, little else.
and surely results that you will be able to relate directly to the road will help motivation even more.
I know now that to reach next years targets I need to get a certain power, I can work towards that magic number all winter. How can I ever work out what speed I'll need to be doing on my turbo to reach those targets.
I'm talking motivation issues here by the way, if you don't have motivation issues then I suppose it isn't going to matter either way.0 -
Back to the OP, I have both a computrainer and an srm. I'd highly recommend getting an on-bike power meter like the SRMs, a cheap turbo and a spare wheel with a turbo tyre. That way you can use the PM indoors and outdoors.
I had a PT before but couldn't be bothered to change tyres every time I went on the turbo. Of course, if you do most of your winter riding indoors then maybe changing tyres on a PT isn't such a hassle becase you'll do it less frequently.
The no compromise option is to get a velotron for indoors and SRM for outdoors. But then that is 10 grand of kit. :shock:--
Obsessed is just a word elephants use to describe the dedicated. http://markliversedge.blogspot.com0 -
Definitely agree on changing the PowerTap wheel tyre is a pain! I have resigned myself to it though and tell myself it is all good practice for fixing punctures quickly out on the road... And now I've changed the Conti turbo tyre so many times that I can actually get it on the wheel without using tyre levers!
Still thinking about getting a PT Elite as a turbo wheel though - but I would prefer to have one for my MTB first!Le Blaireau (1)0 -
eh wrote:Surely results help motivation, little else.
Often results are a factor of things you can't control as well as those you can control. That means results are a double edged sword wrt motivation.0 -
Alex_Simmons/RST wrote:eh wrote:Surely results help motivation, little else.
Often results are a factor of things you can't control as well as those you can control. That means results are a double edged sword wrt motivation.
Indeed... I've started measuring my race goals by performance rather than result, especially road races. You can only master your own performance, after all. Tony Smith taught me that, and he's just got us to the Challenge Cup Final!!!"In many ways, my story was that of a raging, Christ-like figure who hauled himself off the cross, looked up at the Romans with blood in his eyes and said 'My turn, sock cookers'"
@gietvangent0
