Home > Cycling > Estimating your Etape du Tour time

Estimating your Etape du Tour time


The 2010 Etape du Tour is from Pau to the summit of the Tourmalet.

I’ve produced a spreadsheet that allows you to estimate your time. I’ve ridden the Etape three times myself (2003, 2004, and 2006) and used a similar spreadsheet to estimate my time. It has proven accurate to within about 10 minutes. In 2003 and 2004 I placed just outside the top 1000 riders, and was about 20 minutes short of gold standard time.

To estimate your time you need to provide 6 pieces of information:

  1. Weight (rider + equipment) (kg). This is the total weight of everything, including clothes, shoes, food, water, tools etc. The easiest way to measure it is to set up the bike as you will ride it (including full waterbottles, tools, pump, food etc), put on the gear you will wear when riding the etape (including shoes and any spare clothing or food in pockets), pick up your laden bicycle and weigh yourself on the bathroom scales.
  2. Power (when climbing). This the power output you can sustain over a long climb of about an hour. I’ll give you a way of estimating this later.
  3. Slight incline speed (km/h). This is the speed you can sustain on a slight incline (1%-3%)
  4. Flat speed (km/h). This is the speed you can sustain on the flat in a group of riders.
  5. Slight descent speed (km/h). This is your speed on a slight downhill. (1%-5%)
  6. Descent speed (km/h). This is your speed on a steepish (more than 5%) downhill. Note that it is not your maximum speed, it is your average speed and takes into account the corners.

The spreadsheet

The spreadsheet is at: Etape 2010 spreadsheet. You’ll need to download the spreadsheet to use it.

As well as allowing you to estimate your time, it allows you to ask What if? questions about how you ride the course.

  • What if I reduce my weight by 1kg? Depending on your power output, your time will improve by about 2 to 3 minutes for each kilogram of weight saved.
  • What if I go 10km/h faster on the steep downhills? Surprisingly this only shaves about 3 minutes from your time.
  • What if I go 5km/h faster on the flats? This improves your time by about 10 minutes.

Why does the spreadsheet work?

The spreadsheet works because, for the Etape, the climbs dominate the stage. Differences in speed on the flats and on the descents make relatively little difference to your overall time, so you don’t to estimate these speeds very accurately. The climbs are steep enough that wind resistance does not really come into play, so your speed is determined pretty well by your overall weight and your sustainable power output – if you know these two things, you can make a pretty good estimate of your overall time.

How do I estimate my climbing power output?

You can estimate your time either using an ergometer (say at a gym) or by doing a timed climb. For either method you need to warm up and then start riding at a heart rate that you can sustain comfortably for several hours – if you know what your lactate threshold rate is, it will be slightly below this rate. On an ergometer read off the power rating for this heartrate – make sure you have been riding long enough for the heartrate and power to settle. If you use a timed climb (ideally this should have a steady gradient) then ride the climb at this heartrate. Enter the total weight of you and your equipment, the length of the climb, and the altitude gained into the spreadsheet and it will give you an estimate for your power output.

The route profile

I obtained the route profile from http://www.letour.fr/ augmented with climb profiles from http://www.climbbybike.com/

Col de Marie Blanque steep climb with over 3km at or near 11% gradient

Col du Soulor steady climb, mostly at at around 8%

Col du Tourmalet mostly at around 8% with last kilometer at 10%

Advice on riding the Etape

Below are some words of advice. They are mainly intended for riders not experienced in riding long mountainous courses. If you know what works for you, then use that.

What gears should I use?

The choice of gears is determined by the steepest parts of the course. You need a gear low enough to allow you to ride at a comfortable cadence on the steepest parts of the course. This year the Etape has some steep sections, so you’ll need low gears.

There is a section on the spreadsheet that calculates your cadence on the steepest part of the course. If you want to keep your cadence above 50rpm on the steepest sections, then you can see you’ll need low gears. I advise the largest possible sprocket, normally 27 or 28 teeth. This means something like an 11-28 or a 12-27 rear cassette. To go with this you’ll need either a triple chainring with a 30-tooth inner chainring or a compact chainring with a 34 tooth inner chainring. A standard chainring (with an inner chainring of 37 or 38 teeth) just won’t cut it. (For the record, I’ve always used a triple chainring when I’ve ridden the Etape, even though I hate triple chainrings.) A 30×28 gear is not overkill for this course. Every year that I did the Etape I saw riders who got off their bikes and walked. They did not have a low enough gear.

But the pros don’t use such low gears, I hear you say. That’s true, but they are pros. A top professional might weigh 65kg and have a power output of 400W while climbing. Add 10kg for bike and equipment and put the figures in the spreadsheet. You’ll see that a top pro can maintain a good cadence riding a 37×21 or a 37×23 gear.

How should I ride the course?

Assuming you have trained well, you need to do four things to get a good time:

Climb well. This means keeping a good pace on the climbs. It also means riding on your own: unless you are experienced it’s easy to either get behind a rider who is going a bit too slow or a bit too fast. My strategy is to climb by heartrate and cadence, for me this means something like: “keep the heartrate at 145bpm and the cadence at 85rpm”. You’ll need to find the figures that work for you. The heartrate needs to be a rate that you can sustain for several hours, it will be below your lactate threshold rate. The cadence is what is comfortable for you for long climbs.

Eat and drink well. Make sure you don’t dehydrate or bonk. Talk to other riders and get experience of how much to eat and drink on long rides.

Descend well. First and foremost this means don’t crash. Don’t take risks on the descent. From the spreadsheet you can see that even going 10km/h faster on the descents won’t make much difference to your time. It also means don’t brake too much. Too much braking tires you out – you need to be reasonably relaxed on the descents. If you’ve never done long descents you need to get some practice in before the Etape.

Get into a group on the flats. On the flat parts of the course try and ride with a group. Save your energy for the climbs.

Good luck!

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  1. Joth Dixon
    Jan 8, 2010 at 17:00

    Nice article Martin, lots of tips in there besides predicting time. I’m not entering Etape but will be attempting some pretty serious long & hilly audaxes this year, so useful stuff.

    Just one thing – looks like the spreadsheet has been flattened and formulas removed, both in google docs and when I download it as XLS.

    • Martin Budden
      Jan 9, 2010 at 10:58

      Joth, thanks for pointing out the flattening. I’ve now corrected this. (The original spreadsheet was a OpenOffice sheet saved as .xls, GoogleDocs flattened this (without telling me). Uploading the .ods file directly seems to have solved the problem.)

      I intend to write at least one more post with tips for riding the Etape. I probably won’t do it for a month or so though. So watch this space.

  2. Feb 2, 2010 at 12:21

    Excellent stuff Martin thanks, I have been focusing on getting my wife fit so she can finish the Etape and this info is just what I needed to give myself some real context and meaning to my own training. I have been doind Tri’s for 3 years but this is my first foray into proper cycling. I shall set about calculating the inputs shortly to see how I am doing. (not that I hae riden further than 45 miles yet!)Can you tell me any more about the gold and silver certificate times? Usually when I ride a flatish w/i race 40k I av 32/33kph but this longer distance hill stuff is a whole new challenge…
    Miles
    -team Milomania-

    • Martin Budden
      Feb 4, 2010 at 20:56

      Miles, the gold and silver times are set by the race organisers. Unfortunately they tend not to publish them before the event – they are normally available on noticeboards near where you pick up your number. The silver time is achievable by a committed club-level cyclist, but the gold time is normally pretty tough – if I remember correctly only a few hundred riders get gold each year. For women the silver time is the same as the cut-off time – if you complete the event you get silver (or at least it has been in the past).

  3. Matt DAY
    Feb 6, 2010 at 19:45

    This looks a great piece of software …. would you mind clarifying the unit of measure for the weight , Thanks !

    • Martin Budden
      Feb 7, 2010 at 18:38

      Matt, the units of weight are kg. I’ve updated the post to clarify this, thanks.

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