FTP Turbo Vrs Road tests

wellboss

Hi All,

Just looking for some information on FTP testing, Recently I have done two tests
1) Indoor, the 1Hr protocol with 20 mins all out (Avg x 0.95) and then

2) Joe friels outdoor 30 minute time trial average as recommended in his power meter handbook.

Over the course of the 6 weeks between the two I have have a large consistent increase in my training load and am getting back to some level of fitness so I was happy to see my FTP jump from 262 to 315, I am aware that it was tested over two different protocols so probably not the most accurate way to do it.

Having reset my FTP level and calculated my zones accordingly I was doing a turbo session this am and was finding it hard to stay in the middle of Zone 4, I was only doing 5 x 4 mins, However outdoor I was able to average slightly higher wattage for 30 minutes. There was no way I could have held this mornings set for 30 mins at watts that were just below my FTP. Maybe its fatigue but I dont feel overly tired.

My main question is, is there a difference between FTP on the turbo vrs outdoor? I thought power was power so it shouldnt matter. A cyclist I was out riding with recently told me he takes 30 watts off his FTP when on the turbo

Apologies if it's a silly question, I am new to the power game and still figuring it out, thankfully with the help of Joe Friels Knowledge

Thanks in advance

fat bloke

You can't compare turbo power to out on the road power. No one seems to be quite sure why! Some reckon it's to do with the pedal rotation dead spot deceleration on the turbo which is not comparable to what happens out on the road.

So you can either repeat your tests on the turbo to get a turbo specific ftp and calculate turbo specific zones, OR (easier) just reduce the watts yourself to what feels right or comfortable and comparable to out on the road. - in my experience roughly 30 - 50 watts less is what you'd be talking about in a difference.

mossym

not joking, but do you have a fan when you are on the turbo?

godtabh

mossym wrote: »

not joking, but do you have a fan when you are on the turbo?

I've read your body core temp can have a significant impact on power output

Raam

mossym wrote: »

not joking, but do you have a fan when you are on the turbo?

Hell yes, unless you are training to ride somewhere hot!

mossym

Raam wrote: »

Hell yes, unless you are training to ride somewhere hot!

i was asking the OP, not a general question I'm fully aware/experienced of the necessity of a fan for turbos, my shed is a non heated steel shed and i think there has only been one/two turbo where the fan wasn't on, and for those it was so cold in the shed i had gloves on.

fat bloke

Nothing to do with fans or temperatures. The difference is immediately apparent to anyone who has used a power metre on the road and then tried it on the turbo. It's nothing to be concerned about, you're not suddenly weaker. Just accept it and adjust your zones accordingly.

magicbastarder

fat bloke wrote: »

Some reckon it's to do with the pedal rotation dead spot deceleration on the turbo which is not comparable to what happens out on the road.

is this because the turbo doesn't benefit from the momentum of the bike that being on the road does?

mossym

fat bloke wrote: »

You can't compare turbo power to out on the road power. No one seems to be quite sure why! Some reckon it's to do with the pedal rotation dead spot deceleration on the turbo which is not comparable to what happens out on the road.

.

fat bloke wrote: »

Nothing to do with fans or temperatures. The difference is immediately apparent to anyone who has used a power metre on the road and then tried it on the turbo.

3 years of working/training with power on both road and trainer. i'll stick with the fans

harringtonp

There are a combination of reasons for the difference and overheating is one of them. I never use a fan but that's because I'm always outdoor on the turbo and hail, rain or snow always end up bare chested with a pool of sweat below me.

fat bloke

mossym wrote: »

3 years of working/training with power on both road and trainer. i'll stick with the fans

Cripes I must get myself one of those 50W fans

Beasty

Up to 20 mins my power output is pretty similar indoors and outdoors, road, track and turbo/WB. Much longer on the WB and I may lose the will to live, but certainly over that 20 mins or so I don't see any drop off with the turbo I do have a large fan as well:



:pac:

Arthurdaly

I find it difficult to hit the same wattage on the turbo towards outdoors also but it is nowhere near 50 watts. Most people do their FTP test and intervals on drags or hills which by nature are easier to maintain higher wattage.

A good comparison to a turbo would be a flat out and back rather than drag/hill and see how your numbers compare.

I found a fan didn't make much difference it terms of the wattage numbers but it did make the session a little easier and definitely helped recovery.

harringtonp

Does your turbo allow lateral movement by any chance ?

Beasty wrote: »

Up to 20 mins my power output is pretty similar indoors and outdoors, road, track and turbo/WB. Much longer on the WB and I may lose the will to live, but certainly over that 20 mins or so I don't see any drop off with the turbo I do have a large fan as well:



:pac:

Beasty

harringtonp wrote: »

Does your turbo allow lateral movement by any chance ?

Mainly use the WattBike which is completely rigid. Over shorter/sprint efforts I can put out more on the WB.

wellboss

Thanks guys, Good to now its not just me. Will go on feel and try and get a rough difference between the two. Nope dont use a fan but do plan on getting one as i do overheat quickly

Bambaata

fat bloke wrote: »

in my experience roughly 30 - 50 watts less is what you'd be talking about in a difference.

30-50W!!! That's an entire zone. I don't very little difference. Having had a turbo based FTP of 339 I averaged 340 in an actual hour TT on the road. Beware the 0.95 multiplier too, many can't hold the figures and wonder why they struggle over longer reps

Does your turbo suffer from temperature calibration issues like old style power2max?

fat bloke

I've only ever used a very basic magnetic turbo so maybe that's for something to do with it. More expensive trainers maybe mimic road conditions better. For me, hill intervals on the road at say 260w were (by heart rate and by feel) equivalent to 220-230w on the turbo.

It hasn't been an issue for me really cos tbh most of my training is in the turbo and it's too much hassle to switch my power meter from my turbo bike to the road bike and back again.

Bambaata

Doesn't really matter in the difference so long as it's consistent and that you know both I suppose

I've a tacx flow turbo and when I was bothered calibrating it I'd find that kind of difference between the tacx reading and actual power meter

mossym

Doing FTP tests on an incline will inflate your numbers . Comparing those to a turbo is pretty much meaningless.

And surely comparing power levers by HR and feel breaks the reason for using a pm, which is to remove variances in HR and feel for a given power level

Koobcam

I've never actually done an FTP test but was planning on one next week. From what I've seen, isn't it best to stick with the same source for all of your tests? So, pick a hill, turbo, whatever, but do all your subsequent testing there so as to have the same conditions for each test. Actually, thinking about that, wouldn't an indoor session be best as it removes weather from the equation?

tunney

Koobcam wrote: »

I've never actually done an FTP test but was planning on one next week. From what I've seen, isn't it best to stick with the same source for all of your tests? So, pick a hill, turbo, whatever, but do all your subsequent testing there so as to have the same conditions for each test. Actually, thinking about that, wouldn't an indoor session be best as it removes weather from the equation?

Just don't forget to use 0.95 as your multiplier for indoor FTP and then add 20% to get a figure for outdoor FTP. This should be the figure you quote.

harringtonp

Koobcam wrote: »

I've never actually done an FTP test but was planning on one next week. From what I've seen, isn't it best to stick with the same source for all of your tests? So, pick a hill, turbo, whatever, but do all your subsequent testing there so as to have the same conditions for each test. Actually, thinking about that, wouldn't an indoor session be best as it removes weather from the equation?

Ideally test in the environment where you will be doing most of your training.

dahat

I'm currently using Traineroad with a Tacx Smart Satori using Virtual Power as a method of calculating the targets for each session. My FTP seems quite low at just 215 with a small reduction in intensity for VO2 max intervals to allow me complete the session.

I'm hoping to get a Stages Power Meter once my b2w is approved so it will be interesting to see if there is a difference. There is a long stretch of road near Kilcoran Lodge which should be suitable.

My gut is my FTP should be higher than what I'm currently getting but as I can't seem to calibrate the unit for some reason.