Do I really need power stats on a turbo trainer ?

kmcd21

Surely I can have very productive training session, using my exisiting bike computer with speed and cadence, without having to buy a separate power sensor ?

SBezza

You can do, I am guessing you have a rear wheel speed sensor fitted. Power isn't neccesary, but it makes training a whole lot more accurate for the measurement of fitness and progress.

Most important thing though IMO is repeatability, so if you train with speed and cadence the turbo needs to be setup exactly the same each time, and the tyre and tyre pressure needs to be the same each session. Ideally you would do a coast down check eacg session to make sure turbo is setup the same.

kmcd21

In that case the kurt kinetic road machine may be the right choice as there is no computer with this.

My other choice was a Tacx flow- It is expensive and some reviews consider the stats to be inaccurate. Forgive me for being picky but if I were to spend that much I would like it to provide stats that were reliable. It does not have lifetime warranty and one has to plug it into mains power supply.

rdt

By many accounts, the KK road machine has a pretty stable relationship between speed and power (once it's warmed up). See this thread, as an example:-
http://www.cyclingforums.com/t/380967/t ... st_3160616

So if you ensure consistency of setup for each session (SBezza's repeatability), your rear wheel speed should act as a good proxy for power, enabling you to perform targeted training sessions, as you suggest. You'll not know your actual wattage, but that shouldn't make any difference for what you have in mind.

The majority of turbos don't appear to have such a stable speed/power relationship. For example it seems to be common with magnetic trainers for the power required to maintain a given speed to reduce over time (ie. the resistance falls) - likely due to a build up of heat in the unit. The KK seems to be a cut above at dumping heat and therefore maintaining consistent resistance.

brettjmcc

kmcd21 wrote:

IMy other choice was a Tacx flow- It is expensive and some reviews consider the stats to be inaccurate. Forgive me for being picky but if I were to spend that much I would like it to provide stats that were reliable. It does not have lifetime warranty and one has to plug it into mains power supply.

I think the issue people have with the Tacx Flow though is that it reads a different reading to Powermeters? Assuming you haven't got one on your road bike, why is this a problem? As SBezza says it about repeatability, so the reading will give you datum points to measure against. It should read the same.

I noticed in my local Decthlon tonight (whilst picking a longsleeve baselayer up for £7 [65% off]) that the Flow's are only £250; however, next to it was this: http://www.decathlon.co.uk/hometrainer- ... 64387.html £50 cheaper and appeared to read power as well. I see you are in NI, they apparently have a store in Belfast if that helps.

B

P_Tucker

brettjmcc wrote:

kmcd21 wrote:

IMy other choice was a Tacx flow- It is expensive and some reviews consider the stats to be inaccurate. Forgive me for being picky but if I were to spend that much I would like it to provide stats that were reliable. It does not have lifetime warranty and one has to plug it into mains power supply.

I think the issue people have with the Tacx Flow though is that it reads a different reading to Powermeters? Assuming you haven't got one on your road bike, why is this a problem? As SBezza says it about repeatability, so the reading will give you datum points to measure against. It should read the same.

It should, but word has it it doesn't. So its basically an expensive random number generator, like that contraption they use to draw the lottery.

brettjmcc

P_Tucker wrote:

It should, but word has it it doesn't. So its basically an expensive random number generator, like that contraption they use to draw the lottery.

I can't speak for the Flow, but I can confirm my Fortius reads pretty close to my P/T. OK different motor, but just saying.

kmcd21

Yes Brett, There is a Decathlon nearby, and that is such a good price for a Tacx flow as I am watching one on ebay right now '2nd hand' about to go for same price!!

Its great to read some of these interesting comments on this subject.

Tacx is at a great price, more I think of it,the KK is just a no nonsense trainer great for purpose and probably regret not getting it 3-4yrs down the line when most other trainers wilt when the guarantee expires.

andyrr

KK IS a good trainer - the older model (mine, a std not a fancy Rock Road thing) has stood me oin good stead for about 4 years regular use. It came with a power computer but it's fairly poor in that they are known to fail and I've been through 3 of them. The newer ones do/can (optional extra ?) have a power computer and these look a bit fancier than mine.

twotyred

I had many productive sessions last winter on my KK Road Machine with a speed and cadence sensor on my back wheel.

Keep the rear tyre pumped to the same pressure and keep the same roller pressure on the back wheel and I've found speed is a pretty good approximation for power.

izzy Eviel

So i've got a Turbo Trainer, can I just put a normal computer on the rear wheel? Is there anything special I need to do or would I just set it up like normal? Would the results be the same as if I was on the road?

Bronzie

izzy Eviel wrote:

can I just put a normal computer on the rear wheel?

Any speedo that works off rear wheel will do

izzy Eviel wrote:

Is there anything special I need to do or would I just set it up like normal?

No, just try and keep tyre pressure, roller pressure the same each session

izzy Eviel wrote:

Would the results be the same as if I was on the road?

No. Riding a turbo with zero moving mass is a different feel and encourages a slightly different pedalling technique to real riding. It's more like riding an MTB in mud to my mind.

Some torbos are better at simulating road feel than others though - the bigger the flywheel the better, but makes unit very heavy

bahzob

I have a kurt kinetic trainer, I train with it using a powertap wheel. From this I can say that its a very good product that is robust and reliable. (I also bought their cycle computer and afraid to report it doesn't work too well in terms of its estimation of power compared to reality)

Only thing is, as above, if you are planning on using speed and not power as independent variable you need to be quite finicky about setup, small things like a change in tyre pressure and especially roller tension can result in large differences in the power needed to hit a given speed.

SBezza

The Tacx Flow might not be accurate, but mine is pretty repeatable. As long as you set it up exactly the same each time, ie roller pressure, slope, tyre pressure, do the same warm up amd calibrate, it stays fairly constant. It might fluctuate a little but for training purposes and being in a zone rather than a set power figure, it is a good choice.

That is measured against my powertap as well.

ajmitchell

I also use powertap on the turbo and can honestly say that if you keep the set up the same the output graphs prove there is a tight relationship between speed and power for a specific resistance. As mentioned above magnetic trainers warm up over the first 5-10minutes (depending on the load) loose a little resistance. you can see this effect in the powertap graph as after the trainer warm up phase it takes less watts to increase speed (but only about 10% less) and once its warm (ie hot to touch!) its stable.

However mag turbos generally give linear relationship between speed and resistance (=power). This is different to normal road riding (at speeds over 15mph) which has a exponential relationship (becuase of the wind resistance of course)....hence some people prefer wind or fluid trainers that try and match this. I actually don;t mind the linear resistance as speed is more closely linked with effort. The bottom line is that you can train successfully without power on the turbo but power is a usual but expensive addition. HR monitor is also a useful but cheap addition.

ut_och_cykla

SBezza wrote:

The Tacx Flow might not be accurate, but mine is pretty repeatable. As long as you set it up exactly the same each time, ie roller pressure, slope, tyre pressure, do the same warm up amd calibrate, it stays fairly constant. It might fluctuate a little but for training purposes and being in a zone rather than a set power figure, it is a good choice.

That is measured against my powertap as well.

+1 ( i have no powertap but have experienced flow as reliable & repeatable at least.

phreak

P_Tucker wrote:

brettjmcc wrote:

kmcd21 wrote:

IMy other choice was a Tacx flow- It is expensive and some reviews consider the stats to be inaccurate. Forgive me for being picky but if I were to spend that much I would like it to provide stats that were reliable. It does not have lifetime warranty and one has to plug it into mains power supply.

I think the issue people have with the Tacx Flow though is that it reads a different reading to Powermeters? Assuming you haven't got one on your road bike, why is this a problem? As SBezza says it about repeatability, so the reading will give you datum points to measure against. It should read the same.

It should, but word has it it doesn't. So its basically an expensive random number generator, like that contraption they use to draw the lottery.

I've got a Tacx Flow and it's been absolutely fine. I use it in conjunction with the speedo on my normal computer and the power readings correlate nicely with the speed readings. So whilst I can't vouch for the accuracy of the power, they do seem to remain constant every time I use the device.

bahzob

By coincidence another thread here references this article http://jibbering.com/sports/power2max-review.html

Mid way down it uses the KK as a standard measure for comparing two different power meters, which illustrates how reliable it can be as training aid. There is some set up advice along with some actual power>speed data

It also shows that power meters themselves can vary both between brands and during a given session. So at the end of the day if you train predominantly on the KK and use speed along with some reliable RPE measure you are very likely to obtain results as good as if you had a powermeter. The only issue comes if you want to transfer this to the road in some way, which is when having a power meter really scores.

kmcd21

bahzob wrote:

By coincidence another thread here references this article http://jibbering.com/sports/power2max-review.html

What a huge amount of research and information there is on this subject. I look forward to reading through this article. thanks.

Hearing form the tacx flow users there is little doubt that this is a product is much liked by the masses.
Best option for me is to try and get an opportunity to try both trainers.

Getting a powertap would solve this too, but the expense is unjustified, considering I am a novice road racer.

BeaconRuth

It's sometimes worth remembering that it's how hard you train, not how accurately you measure it, which determines how good you get. Ask yourself how accurately you NEED to measure your training in order to make progress.

Ruth

Alex_Simmons/RST

BeaconRuth wrote:

It's sometimes worth remembering that it's how hard you train, not how accurately you measure it, which determines how good you get. Ask yourself how accurately you NEED to measure your training in order to make progress.

Ruth

True, although at some stage of development (i.e.when you start getting pretty fit), the progress one is measuring is less than the resolution of any turbo sans accurate power measurement.

BeaconRuth

Alex_Simmons/RST wrote:

True, although at some stage of development (i.e.when you start getting pretty fit), the progress one is measuring is less than the resolution of any turbo sans accurate power measurement.

Erm, yes, obviously.

But the OP is a novice road racer. My guess is that he doesn't need to measure his power output to +/- a few % in order to make a great deal of progress.

Ruth

kmcd21

My LBS is willing to lend me a KK power computer for a while and see how it goes.

The Kurt Kinetic Road Machine seems the best option to progress over winter as its as close to road feel as your likely to get from a static trainer..

I heard a rumour that KK are developing a new power meter for spring next yr, fingers crossed it is at a good price and works effectively.

Alex_Simmons/RST

BeaconRuth wrote:

Alex_Simmons/RST wrote:

True, although at some stage of development (i.e.when you start getting pretty fit), the progress one is measuring is less than the resolution of any turbo sans accurate power measurement.

Erm, yes, obviously.

But the OP is a novice road racer. My guess is that he doesn't need to measure his power output to +/- a few % in order to make a great deal of progress.

Ruth

I only make the point:

(i) to say +1 to what you said (IOW the OP just really needs to train more and do some hard work in order to improve and the power stuff isn't super important, it's the training that matters) and

(ii) it's not actually obvious to many that measuring progress on a turbo has limitations (sometimes quite big limitations depending on the set up and user knowledge of all the variables). If it were obvious, then we probably wouldn't have the multitude of threads on turbo training and power measurement every month on here and elsewhere.

RChung

SBezza wrote:

The Tacx Flow might not be accurate, but mine is pretty repeatable. As long as you set it up exactly the same each time, ie roller pressure, slope, tyre pressure, do the same warm up amd calibrate, it stays fairly constant. It might fluctuate a little but for training purposes and being in a zone rather than a set power figure, it is a good choice.

That is measured against my powertap as well.

My Flow was very repeatable. The problem is that when measured against a PT, it was very much off, especially in ergo mode. Repeatably, though.

bahzob

lol @Alex and Ruth, just popped back here to see if much has changed. Not much has it seems.

Just one off topic note on comments here. Powertap seems to synonymous with power meter.

One thing I would say is do NOT buy a Powertap. I have 5. The fact I need so many illustrates one problem with them. If you are serious about training with power you need real race data and this means either compromising event performance or spending a lot of money.

Of the 5 ALL have broken, some within 12 months others after 2/3 years. When broken it costs several hundred pounds to repair them. This makes them prohibitively expensive. * edit * if they break within 2 years they get fixed on warranty, it just takes weeks to happen.

I was a relatively early adopter of power training when there was little product choice. There is more now and will be yet more soon. Powertaps would be at the bottom of my list of choices sadly.

SBezza

RChung wrote:

SBezza wrote:

The Tacx Flow might not be accurate, but mine is pretty repeatable. As long as you set it up exactly the same each time, ie roller pressure, slope, tyre pressure, do the same warm up amd calibrate, it stays fairly constant. It might fluctuate a little but for training purposes and being in a zone rather than a set power figure, it is a good choice.

That is measured against my powertap as well.

My Flow was very repeatable. The problem is that when measured against a PT, it was very much off, especially in ergo mode. Repeatably, though.

Ah, I never used mine in ergo mode though, like as you say it is woeful in ergo mode. If you are training within a zone however, it is a perfectly usable tool if you do not have a powermeter, though I will accept a powermeter is a far superior tool for training.

SBezza

bahzob wrote:

If you are serious about training with power you need real race data and this means either compromising event performance or spending a lot of money.
.

Not true depending on what you race. I bought some wheel covers for my Elite+ on Open Pro's for TT's and have set numerous very good times on them. For me wheels make little impact and although the weight of the wheel is heavy, it doesn't affect me that much. I even did a few hilly events early season with good results, not bad with a wheel that weighed nearly 2kgs.

If you are road racing, then yes you want the lightest wheel possible, but I can still only see the need for 2 wheels, one training and one racing wheel.

Not every event is going to be umcompromised however, surely if you are training as well as racing there are going to be quite a few races compromised by just racing tired.

I do agree that a crank based PM might be a better option, but then again ideally would need 2 or 3 of them, as no matter how quick they are to swap bikes I wouldn't want to keep swapping between bikes, that would work out even more expensive.

doyler78

bahzob wrote:

lol @Alex and Ruth, just popped back here to see if much has changed. Not much has it seems.

Just one off topic note on comments here. Powertap seems to synonymous with power meter.

One thing I would say is do NOT buy a Powertap. I have 5. The fact I need so many illustrates one problem with them. If you are serious about training with power you need real race data and this means either compromising event performance or spending a lot of money.

Of the 5 ALL have broken, some within 12 months others after 2/3 years. When broken it costs several hundred pounds to repair them. This makes them prohibitively expensive. * edit * if they break within 2 years they get fixed on warranty, it just takes weeks to happen.

I was a relatively early adopter of power training when there was little product choice. There is more now and will be yet more soon. Powertaps would be at the bottom of my list of choices sadly.

One other annoyance is that when you do get your powertap fixed out of warranty and pay heavily for the privlege you get a 1 year warranty on the new torque tube. Mine cost me over £400 so if you assume it breaks down yearly out of warranty that locks you into near £900 per 2 years. It's like buying a new hub every couple fo years. Very unsatisfactory.

amaferanga

I only have one PowerTap that I use for training and racing. It was previously laced to a IRD Cadence Aero, but is now laced to a 50mm carbon clincher. Weight-wise my wheelset comes in at less than a set of Cosmic Carbones so it's certainly good enough for most amateur racing. Having a carbon wheel for training isn't ideal, but I swap out the front carbon wheel for an alloy clincher for training so any braking issues in the wet are less significant. Through the winter the PowerTap will live on the turbo anyway since my road riding will be endurance/tempo rides where I don't need a power meter.

So I disagree that you need at least two Powertaps - one is enough though two or more might be desirable.

doyler78

amaferanga wrote:

I only have one PowerTap that I use for training and racing. It was previously laced to a IRD Cadence Aero, but is now laced to a 50mm carbon clincher. Weight-wise my wheelset comes in at less than a set of Cosmic Carbones so it's certainly good enough for most amateur racing. Having a carbon wheel for training isn't ideal, but I swap out the front carbon wheel for an alloy clincher for training so any braking issues in the wet are less significant. Through the winter the PowerTap will live on the turbo anyway since my road riding will be endurance/tempo rides where I don't need a power meter.

So I disagree that you need at least two Powertaps - one is enough though two or more might be desirable.

Depends I guess on how much you rely on feedback from your PMC and how good you are at fudging the figures going into it from your non metered rides