20k TT training and target Watts

Thinking about a 20k TT ( over 60 do half the normal 40k) in Mid May. Is the 40k TT program still the best option and what power %FTP would people target for a 20k tt ? This is TX state championship and pretty much a flat course.

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20k TT… I’d probably be shooting for 95-98% of FTP in the first half, and then try and slowly open the taps in the 2nd half. Gonna be a half hour or so effort, so you can make yourself hurt!

The 20 min FTP test takes 95% of the 20 min average. Seems like 103% to 105% would be a range and agree going out slightly below the target would be the strategy. Anyone done one of these and if so what did you target?


I think the guys talked about this on a recent podcast. The answer is almost always “not as far above FTP as you think”. The curve between 20min and 60min power is very gentle.

I do 10 mile TTs, which is - let me just calculate - 16km, and I do that at around 104-5% FTP for 21-23 minutes depending on course.

The other thing to factor in is, how fast will you actually go at or just above FTP? What is your expected time? If you go at 40kph then it’ll take you 30 minutes, which you’d never hold at 105%.

I think this is a good pacing strategy, but as it’s under an hour, I’d just go at 100% FTP for the first half, and then see if you can push it a bit more for the last 10km.

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As above, depends on how fast you’ll be going. In the past when I’ve done short TTs of about 15km that take sub 20min I’d go out at 105% ish and then ramp it up towards the finish.

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Thanks, that helps. I would not be above 40kph so something just under 30 minutes is more likely. Never done a stand-alone TT before. Typical 40k tri pace is 22mph or less so assuming I could go faster without worrying about the run.

I stand by my proposal of going out sub-FTP… because you’ll get over excited and overshoot it by 5% anyway :wink: No matter how clever I think I am, and how in tune to my training I am, at the start of 90% of the TT’s I do I start off and think “oh shit, turns out I’m superman today, my FTP is obviously about 50W higher than I thought…”. What a douche. Then I fall apart :smiley: My negative split pacing strategy helps me keep a lid on it a bit better.


Fair point!

I’ve never done that of course :innocent::innocent::innocent:

Something to consider might be that if you’re only riding for 30ish minutes rather than 60+, could you manage to get in a more aero position for that duration?

Only do it if you’ve tested it on the turbo with a couple of 15 minute intervals of course and found you can still get the power out, but worth a try.


I will be on a TT bike and striving to stay in my most aero position. Will need to do a ramp test to see what my FTP is in that position of course.

How to race a TT in 3 easy steps.

  1. Get all hyped up on caffeine and general excitement.
  2. Go out at 400w and think gosh this feels easy today.
  3. Die a slow painful death.

I train for 25km TT’s and use the 40km plan. My advice is to practice your target distance regularly. You’ll then know how hard you can go. Apart from that it’s also good practice at staying aero. I’m 57 and compete at regional and national level in TT’s.

For a 20km TT I’d be looking at doing it pretty much at FTP then if you have any gas in the tank for the last 5 minutes you go 105%ish.


Thanks, I much appreciate the advice from someone who regularly races this sort of distance. Should be fun in a painful way😀

I target a 22.5 km TT each year. Target wattage very much depends on the course. Mine is an out and back with an lumpy 1-2% grade on the out leg and usually a slight cross tailwind. Last year going into it my 20 minute (-.95) TT bike power was 310. Looking at WKO+ I averaged 327w out and 313w back. Not saying this right or wrong but, it is pretty close to what Best Bike Split recommends. Check out Best Bike Split by the way…

edit: so roughly 105% out and 99% back.


I do 2-4 20k tt’s per year around fiesta island in San Diego (3 laps = 20k, you get every angle of wind and there is always wind. About 10 feet of elevation change per lap). Here are a couple of things I have learned over the years.

Know yourself:
I can go out and do a 300 watt 40k then recover for a week and only throw up an ftp of 285watts ftp on a ramp test on the indoor trainer.

When I talk Pacing power I am going off that known outdoor number or approximate outdoor number based on ramp test. I know if I pace a 20-40k TT with my raw indoor ramp number I will leave something in the tank. YMMV.

General Pacing:
First 10-30seconds get up to speed, don’t lay down a 1500 watt Sprint but go above ftp. I generally aim for 20-30% more than ftp (vo2 ish effort)

Next 2-4 minutes, get into a grove. This is where you tell yourself over and over the calm down, keep the watts at or just below calculated ftp. This is where no matter how good you feel you want to keep it where you know it is sustainable.

For the next 2/3ish of the race I mostly go on feel and wind conditions.
If it is a calm day I will settle into a pace and check in with my power meter every 30-60secs, if I am running low I will push a bit harder, if I am bit high I will assess how sustainable it feels and either stay there or drop the power a little.
If it is a windy day (5mph+) then I try to push 10-15 watts more into the wind and 10-15 watts less when going with the wind. The goal here is to “lose the least amount of speed” Here is where targeting an average speed can help. If you know you want 25mph average try to find a wattage that is 26 when going with the wind and 23-24 when going into the wind. If the wind pushes you down to 19mph you are going to lose way more time than you will gain pushing mega watts to 27mph with the wind.

20 - 25 min in I start thinking about emptying the tank. I will start to push just a little bit more, 1-5%. At this point it hurts like no end but you have to push yourself.

Last 1-3 minutes, all you got, I generally bring it up to 350-400 watts gain a bit of speed (there is a tiny downhill and usually a tailwind at this section of my course) then just keep the watts as high as I can through the finish shoot. I am generally making some form of war cry/audible pain grunt at this point. Once across the line it should be near impossible to turn the pedals with any force.

With some mental gymnastics I can generally eek out 10-20 watts above target.

Also realize if this is your A race you should be coming out of a taper so you can probably muscle out more than in any previous test.

I guess the short answer is do a couple live practice runs of as similar a course as you can. The nice thing about a 20k for me is that it is not such a huge effort that I need more than 2 days to resume full training.