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adamrice 03-15-21 03:41 PM

Estimating TSS in advance
For my weekend ride, I plotted a route in Ride with GPS, and then rode it. It turned out to be a lot harder than I was counting on.

It seems that given course and weather information, and a target pace, it should be possible to come up with a TSS estimate. I'm wondering if anyone has come up with a formula for this. If I'd known what I was signing myself up for, I probably would have done a different ride.

In the past, I've categorized my rides as "hilly" or "flat" and figured out average TSS/mile in both categories for estimating. But this resulted in a drastically low estimate on my last ride.

atwl77 03-15-21 10:07 PM

Usually I start by estimating the average power I want to ride at (e.g. Z2 endurance, Z3 tempo, etc). That'll give me a rough/estimate IF.

Then based on the effort, I make a rough guess on the ride duration. Often this will be in terms of average speed (e.g. flat route, avg 30km/h, hilly route, 25km/h, etc), so distance / speed gives duration. With IF and duration, I can roughly estimate TSS as IF * IF / duration (yes, I know the actual formula involves NP/FTP but IF * IF, for me, is close enough, for "rough estimate" purposes, and also easier to do it in my head).

pdlamb 03-16-21 10:18 AM

It'd be tough to estimate TSS ahead of time, unless you can also (correctly) estimate your efforts -- especially on climbs.

For example, one of my favorite rides has a 1,000', 3.5 mile climb near the start. A few weeks ago I attacked that ridge. Kicked my CP right up. Burned too many matches, finished the ride just beat. Last weekend I did a similar route, but decided I'd stay in endurance mode going up the ridge. Didn't make much difference in climbing time, but I had some energy left at the end of the ride for cleaning out the garage. My TSS ratio was 2:1 for the two rides.

Can you look at grades and lengths of climbs on a new route and make projections as to how hard you're going to ride up them? Or are you running a series of (flattish) intervals where you can predict your effort? That kind of detail is what you'd need to develop to make a good estimate of TSS. A simple calculation probably won't do it.

Carbonfiberboy 03-16-21 10:44 AM

First, I plot the route in RWGPS. I notice the estimated riding time. I then look back at previous rides in TrainingPeaks, looking for a similar ride in terms of feet per mile and then notice its TSS/hr. I multiply that times the estimated time for the new ride. When I create the new ride in TP, I click on Build Workout, choose Threshold HR or FTP, Duration, and Target. Then I drag down an Active block and then enter the estimated elapsed time, guess at an effort number, and then manipulate that until I see the desired TSS. I add a ride title and save it. If it's a ride I'll do again, I often drag the completed proposed ride or workout over into my Library of workouts.

I do this with all my workouts, a couple weeks in advance, so I can plan my CTL and TSB progression. Of course things never work exactly as planned, so I edit, add, or subtract as I move through the week(s).

The above assumes that you'll ride the new route with the same intensity you used on the route from which you got your TSS. You'll see the power or HR average necessary to do that when you create the new ride or workout. Mess with that number if your want to change the intensity for the proposed ride or workout, then try to ride to that intensity.

Takes practice, but experience begins when you start.

adamrice 03-16-21 01:27 PM

Carbonfiberboy—that's an interesting technique. Will try that next time.
pdlamb—in this case, I was going for a long ride in the Texas hill country. RwGPS only identifies 8 climbs, but the elevation profile looks like a crosscut saw. I try to stay well within Zone 2 on my long rides, but I tend to forget those plans on steep grades. I know what you mean about the level of detail.

pdlamb 03-16-21 05:39 PM

Adam, glancing at the profile I thought, "Neat, rollers!" Then I saw the distance -- that's going to be a slog. Looks like the flat parts are where the uphill turns into a downhill, or vice versa.

rubiksoval 03-17-21 03:27 PM

TSS is based on normalized power. Choose a normalized power and just stick to it, just the same way as you would based on average power.

There's a workout called a TAN tempo or something like that in which you ride to normalized power, much the same as you would a regular tempo, except you can hit the uphills harder and downhills easier if you're so inclined. Feels more fartlek-esque at that point.

adamrice 03-17-21 03:39 PM

It also occurred to me that, as I'm increasing the distance of my long rides, small errors in TSS/mile get magnified when multiplied by a lot of miles. An error that multiplied out to 30 TSS would be no big deal. An error that multiplies out to 110 TSS feels like a bigger deal.

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