[Closed] One for the roadies...what is my FTP?

Based on what you’ve written I would guess at 200-220w

It's quite common for turbo ftp to vary quite a bit from outside - usually it's lower. So you did 220 solid for 20 mins indoors, that might be 250 emptying the tank, which in turn might be 275 outside with a number on your jersey, and could be even higher on a mountain time trial. FTP is then 95% of these numbers IIRC - Sounds like you're around the 225 mark, give or take?

So it can vary quite a bit, if you mix training inside and out you might need two values.

I don't know about crank PMs but I have a bepro pedal PM which although it's well-rated as a reliable device, does seem to be a bit flattering on the climbs - dishing out bestial Watts. FTP efforts on slight inclines to work against are good, but I don't think a steep pitch will give very accurate number.

The thing about FTP is that it's a threshold. Under it, as long as you keep fuel going in you can keep going ''indefinitely" .  Above it and it becomes hard quite quickly. So trying to estimate based on a road ride can be hazardous, estimating high and being slightly the wrong side of threshold and as you say, you wouldn't be able to hold it for longer periods.

I'd say 200-220 as well.

If you head over to somewhere like Timetrialling forum, there is plenty of discussion on how FTP is NOT 95% of 20minute power.  It could be, but it's just as likely not to be.  Why not just ride for 1 hour at a hard pace, that will give you a nearer idea rather than guessing you went fairly hard for 20mins and then carried on riding and then ....

"Normalised power is roughly FTP plus 5%"

If that is correct then FTP is lower than normalised power. 220 minus 5% is 209.

Im not sure sure your ftp is 220 as you say youve never emptied the tank.  You need to do that.  You need a steady paced 20mins with nothing left after.

It’s also worth mentioning that if you decide to do a 20 minutes FTP make sure you do the prescribed 5 minute all-out pre-fatiguing (followed by 5 minutes recovery) effort first.  This reduces the anaerobic contribution to the 20 minute effort and will give you a truer estimate of your sustainable power.  I think a lot of people skip the pre-fatiguing effort to get better numbers...

Based on what you’ve written I would guess at 200-220w

Crikey thats lower than expected. FTP is meant to be lower than normalised power according to training peaks no? And if I can hold 220 for 2 and a half hours on the road normalised surely for an hour that equates to more than 220 ftp!!? Surely!!! 🙁

FYI I have regularly achieved an average of 220 actual watts during a 20 min section of a ride but that includes  downhills, and flat where I am free wheeling, on rides well over 90 min. In fact I did that today. Surely taking that as a base I must be well in excess of 200 no?

Perhaps I'm just much slower than I thought.....

I can send you a free month pass to trainer road if you want, you can do a proper ftp test then. Only way you’ll really know for sure

Rough guess I’d say 230 ish everyone’s different...the more you test the more you’ll get familiar with the process and results, the more you’ll be able to estimate your FTP with greater accuracy.

Think just do a test to be sure, this time of year I’d be testing on the turbo as most of my intervals will be indoors.

I definitely get a lower value from the turbo so will typically re-test outdoors around March when the majority of training turns to outdoors.

Don’t forget FTP is just a reference point to work off in training or racing.  If you are not using it in a planned way it’s pretty irrelevant

I can send you a free month pass to trainer road if you want, you can do a proper ftp test then. Only way you’ll really know for sure

Cheers fella thats a really kind offer, however as I know for a fact that im quite a bit lower indoors (as many are) its probably not going to give me a realistic number for outside, which is what I'm curious about. Useful for training inside as others have pointed out however as I'm not planning to do any structured training this side of chrimbo it would be wasted on me!

The question was really asked more out of interest than anything else. Will probably resubscribe to trainer road in the new year, I found that using it with sufferfest vids really added speed previously - interestingly i use to use it with a elite wheel on trainer, and my FTP was set at 300!!! Then I raced and realised it was nothing of the sort, and when I started using a stages it dropped to around 220! This was years ago however.

is a free add-on to Strava and will tell you your estimated FTP based on your best 20min effort in the last six weeks, along with some other power stats.

cricklesorg.wordpress.com is another freebie that will estimate your power, along with other useful stats like your heart rate zones and lthr.

This year, I've found the 95% 20min power ftp does not match my best power riding for a full hour over undulating terrain, ~271W vs ~255W respectively. But then the hills in Hampshire aren't that long, the longest being Bell Hill near Petersfield, riding at high power on flat and especially downhill isn't easy or even possible with 50/11 on steep descents.

Normalised power becomes more different from average power the hillier the ride, it’s taking into account that an hour of hilly riding with its associated hard efforts will have more impact on the body than an hour at steady state.

If you want a good approximation of your ftp then put aside 45mins and do a proper test on the turbo. 10 mins warm up followed by 30mins all out effort (recording the last 20mins average power). Pace it sensibly, can I recommend starting at 200w then building to 220w after ten mins. After that listen to your body for clues. Your breathing should be tipping into panting but not getting ragged. The last ten mins should be eyes shut, sweat dripping onto the floor, total focus to the task. Stop looking at the numbers and wring the very last drop out of your body.

Go on, do it! We’ve all had to at some point or other. Let us know the result. I’m going to predict 250w.

P.s. turbo might feel harder than outside but it’s safer and easier to maintain the effort. The results won’t be wildly different from outside anyway.

Isn't it the difference between the two numbers that is the most significant and worth paying attention to:

Ftp at beginning of winter training.

Ftp at end of winter training.

At least if its out by 10w it will be consistently out by 10w?

is this a game of pin the tail on the donkey ?

an awful lot of spurious numbers being thrown about.

I don't get the thing of, "my ftp is different outside to inside" sounds like bs to me, unless anyone can tell me a genuine reason why it would be different.

You have a turbo and a power meter, take a test. Its the most accurate way to get a number.

And the answer is ........ Power Meter cc. Link it to your Strava and it will estimate your FTP, 3 minute power etc from the recent rides you’ve uploaded.

Turbo power tests are great for setting figures to train with on the turbo but your looking for real world outside power.

I don’t get the thing of, “my ftp is different outside to inside” sounds like bs to me, unless anyone can tell me a genuine reason why it would be different.

Real world vs artificial 'pressure' to perform I guess. Like the difference between how long someone could hold on hanging off a pole in a lab test vs how long they could hold on over a thousand foot drop. It is very hard for most people to be able give it everything on a turbo, even if they think they are. Does not mean your FTP is different indoors, just your ability to demonstrate it is diminished.

That and maybe overcooking with heat indoors with a fan in comparison to the larger cooling effect of the airstream over your body. Less convinced about this one as you could be climbing a steep hill at slow speed in the alps in summer and be just as hot if not hotter.

FTP is meant to be lower than normalised power according to training peaks no

Not correct. Average power, not ftp, will be lower than normalised power for a ride, with the difference getting larger if the route is hilly and you smash it up the hills. It deliberately overemphasises the power output you put in over your current FTP as the 'damage' you are doing becomes exponentially more significant. Ten reps of 10 seconds sprints at 600W with freewheeling in between over ten minutes will have a far greater destructive influence than the ten minutes of riding at 100W your average would indicate you are generating.

In 'theory' in a one hour all out effort your ftp measured on a turbo or flat road will be the same as your normalised power over the same hour with a more fluctuating power output.

Real world vs artificial ‘pressure’ to perform I guess. Like the difference between how long someone could hold on hanging off a pole in a lab test vs how long they could hold on over a thousand foot drop.
That and maybe overcooking with heat indoors with a fan in comparison to the larger cooling effect of the airstream over your body. Less convinced about this one as you could be climbing a steep hill at slow speed in the alps in summer and be just as hot if not hotter.

I have just done some googling and read a few articles, as this is something I had not heard of before. It seems there are people who claim a difference in favour of outside ftp, but also quite a few that claim the reverse.

Personally I would trust my indoor ftp much more as its a more consistent controlled environment. There are just too many variables outside.

Also OP, it would be better to judge your outdoor ftp on a flat consistent stretch of road, rather than up a hill.

I thought turbo trainers generally flattered with higher numbers as

A) You could go flat out for 20min, even in the fens no road is straight enough or flat enough to let you do that consistent an effort.

B) You can actually ride on the threshold of pukeing. On the road you would fall off and get run over by a car, on the turbo you just keep turning the pedals through that last 5 minutes.

C) You're not wasting energy in your upper body, so it's all going through the power meter.

If you've just got the power meter then you need more data than just one ride. I got mine from 220 to about 280 just by realising that actually I could pedal that hard for 20min (im a fat bastard, 280 would only begin to look impressive if i lost 4 stone).

I thought turbo trainers generally flattered with higher numbers as

A) You could go flat out for 20min, even in the fens no road is straight enough or flat enough to let you do that consistent an effort.

B) You can actually ride on the threshold of pukeing. On the road you would fall off and get run over by a car, on the turbo you just keep turning the pedals through that last 5 minutes.

C) You’re not wasting energy in your upper body, so it’s all going through the power meter.

If you’ve just got the power meter then you need more data than just one ride. I got mine from 220 to about 280 just by realising that actually I could pedal that hard for 20min (im a fat bastard, 280 would only begin to look impressive if i lost 4 stone).

But....enter a 25 mile TT on a relatively flat course and get your pacing right. You have a minute man behind you you are desperate never to see, a minute man ahead of you and another ahead of that you really want to catch and your results will be published on a great big board for everyone to laugh at. The only time I have ever worked harder was in a road race trying to chase down a breakaway or in a breakaway trying to stay away on the last lap. I have passed out at the end of TTs, thrown up, had a nose bleed and even on one occasion bled out of my ears. You are right the 'lab' environment theoretically gives you the best chance to perform but the 'human' factor will always surpass that in my opinion. Your idiotic competitive juices might not flow so freely however...

I have passed out at the end of TTs, thrown up, had a nose bleed and even on one occasion bled out of my ears

Competitive !

If you want a number grab the TR free month and do the ramp test. Idiot proof as you basically ride until you can't turn the pedals anymore. Set your FTP to 220 and start pedaling. It'll only take 20 to 30 minutes depending if you far exceed the 220 watts.

It'll be close enough for outdoor use generally but if your not using it to do structured interval work it's just a number as has been said above. Mine's been static since April but I've enjoyed my rides. Back to the hard work now until next April trying to bump it up before Spring events.

Strava seems to spit out a pretty good number on the power curve if you're a premium member.

I've left my Zwfit FTP to bump itself up as and when it sees fit normally when racing.

My indoor and outdoor ftp varies. The outdoor one is normally done as part of a local 10 mile time trial where nothing is left on the table. It’s still not 100% accurate as I drop a few watts at road junctions. Indoor is lower but more consistent. I don’t think it’s really worth trying to take an estimate from power achieved on normal rides. An ftp is an evil undertaking if done properly. It’s more about your mind than your body. I don’t consider that I have given it 100% unless I’m sick at the end. I keep a bucket by me know when I’m testing.

I have just done some googling and read a few articles, as this is something I had not heard of before. It seems there are people who claim a difference in favour of outside ftp, but also quite a few that claim the reverse.

Personally I would trust my indoor ftp much more as its a more consistent controlled environment. There are just too many variables outside.

Also the physical biomechanics of pedalling the turbo are just different, there's something about how you're always intrinsically balancing the bike outside that makes a difference to your output, and how this effects its consistency. I cannot hold position on the TT bike indoors at all - find it intolerable after a couple of minutes. But I can do a 25 (ie about an hour) outside no problem - it's not what you'd call comfortable but there's no question of coming out of position.

 It’s still not 100% accurate as I drop a few watts at road junctions.

But, those few seconds of recovery are no doubt repaid with extra effort accelerating back away. If you cross the line in a condition where you would be unable to ride at the same pace any further I suspect you've got very close to your max.

Ten reps of 10 seconds sprints at 600W

600w over 10s?  Is that all?

The main reason for turbo numbers being lower is all to do with mechanics and efficiency which I don't understand completely but for example, you'll be overheating massively on a turbo, and there is a wasted economy somewhere in loss of momentum etc....  on both those counts you are working harder for less.

But, those few seconds of recovery are no doubt repaid with extra effort accelerating back away.

Conjecture. which is why a controlled FTP test indoors is always the best option if you want accuracy and repeatability.

The main reason for turbo numbers being lower is all to do with mechanics and efficiency which I don’t understand completely but for example, you’ll be overheating massively on a turbo, and there is a wasted economy somewhere in loss of momentum etc…. on both those counts you are working harder for less.

But surely indoors is more accurate. No head wind, tail wind or side wind. No coasting, no junctions, no potholes, no uphills, no downhills. No rain, no sun, no effort to keep the bike upright.

I get the overheating bit, but loss of economy I don't get. The aim in an FTP test is to keep as consistent an effort as possible is it not? I don't get how you can do that outdoors, you will put in less effort downhill (even slight gradients), more effort uphill, and are guaranteed during a twenty minute effort to stop pedalling at some point unless you are extremely lucky.

but loss of economy I don’t get

My understanding is that you are working harder through the pedal stroke(s), using more energy, glycogen and producing more heat/lactic acid this reducing the overall economy over the given period vs road e.g working harder.   Thats not to say it isn't accurate or better than the road which it is, but something changes which makes turbo'ing harder.

FWIW I can 750w average over 30s on the road, but indoors so far I can only manage 628, I've often wondered why , there are so many factors.

This is akin to "marginal gains" IMO, its small but it impacts your ability to work as hard toward the end of the effort.  There are many variations that could do the same indoors & outdoors, this is just one small set amongst many.

My understanding is that you are working harder through the pedal stroke(s), using more energy, glycogen and producing more heat/lactic acid this reducing the overall economy over the given period vs road e.g working harder. Thats not to say it isn’t accurate or better than the road which it is, but something changes which makes turbo’ing harder.

Im still unsure. If its about power output then you only work as hard as you need to to generate the watts. Resistance, drag, and any other factor will only effect how far you travel for the given power output (which is irrelevant in a test).

Its beyond my level of knowledge / will to live to discuss further, sorry Trailwagger.   I do what I'm told.

Its beyond my level of knowledge / will to live to discuss further, sorry Trailwagger. I do what I’m told.

You OK hun?

Strangely enough my turbo FTP was always much higher than my road FTP. Could never get the same watts out on a time trial probably due to micro breaks corners, gradients etc or possibly not putting enough effort in to make my ears bleed.

I always understood it that you fatigue sooner since you're working throughout the pedal stroke, so you're fresher toward the end of an outdoor test.

You OK hun?

Yep.  Sorry that may have come across incorrectly - as much as I love a discussion its entered in the realms of what I don't know, so I can't really contribute any further, sorry.

I am reading with interest though...

Yep. Sorry that may have come across incorrectly – as much as I love a discussion its entered in the realms of what I don’t know, so I can’t really contribute any further, sorry.
I am reading with interest though…

Didn't come across badly, just poking fun at the internet.

<span style="display: inline !important; float: none; background-color: transparent; color: #222222; font-family: 'Open Sans'; font-size: 16px; font-style: normal; font-variant: normal; font-weight: 400; letter-spacing: normal; line-height: 22.4px; orphans: 2; text-align: left; text-decoration: none; text-indent: 0px; text-transform: none; -webkit-text-stroke-width: 0px; white-space: normal; word-spacing: 0px;">I always understood it that you fatigue sooner since you’re working throughout the pedal stroke, so you’re fresher toward the end of an outdoor test.</span>

I believe this is why its bad to do an outdoor test on a hill.

Still cant manage a double quote, sigh

Slight incline probably best, helps you keep the power on.

I think which type of test you'd do best on depends on what you're used to, and your natural physiology.

Take four different tests with two different protocols:
- An indoor ramp test to establish Maximal Aerobic Power
- An indoor 20 minute test
- An outdoor 20 minute test on a flat road
- An outdoor 20 minute test on a long hill

I've done quite a few of the first three, and keep meaning to try a proper test on a hill when I'm somewhere mountainous. My experience is of getting a result about 15w higher from an outdoor 20min test or MAP derived FTP estimation (70-85% of MAP) than an indoor 20 minute test.
Interestingly this gap has dropped over the past couple of years, as I've gotten older and started focusing more on endurance racing rather than short XCO.

The outdoor test has a lot more potential for variability. Whether this is a good thing depends on your physiology. I always found I'd perform better if I could alternate between seated and standing, so my 'ideal' testing road would be a hill that goes up in gentle ramps. I also respond well to 'micro rests', like corners.
I also know people who perform better on fast flat roads; or people who can put out much more power while standing, so would perform best on a long steep hill.

However, the end goal isn't really to find the highest power you can do for 20 minutes, it's to estimate your functional threshold. So by taking micro rests or changing position a lot you're not really following a test protocol that will find an aerobic threshold. For instance, I could probably get pretty close to my max steady 20 minute power by doing 30 second efforts with short recoveries for 20 minutes. But the physiological pathways used to do this are so totally different from steady aerobic work.

Physiologically speaking the best thing to do is an hour maximal effort on a turbo or velodrome, but this would be so horrible that there'd be a significant loss of power due to lack of motivation. Plus a regular hour effort is annoying to work into a busy training plan as it causes quite a lot of stress without massive adaptation.

And if you want to win at comparing your power data with people on the internet you're best off buying a Stages.