Checking my estimate of Arctic Rally Finland pace

The first ever Arctic Rally Finland just ended. Before the rally I posted my estimate of the average speed of each stage (and through that, the whole event). Let’s see how that turned out.

Cover Image by Taneli Niinimäki / AKK

The original post Estimating the pace of Arctic Rally Finland

Stage times

StageLengthEstimateReal paceDifference
Sarriojärvi 131.05 km119.81 km/h116.70 km/h3.11 km/h
Sarriojärvi 231.05 km119.81 km/h117.30 km/h2.51 km/h
Mustalampi 124.43 km100.17 km/h105.40 km/h-5.23 km/h
Kaihuavaara 119.91 km129.15 km/h131.10 km/h-1.95 km/h
Siikakämä 127.68 km130.77 km/h132.80 km/h-2.03 km/h
Mustalampi 224.43 km100.17 km/h105.00 km/h-4.83 km/h
Kaihuavaara 219.91 km129.15 km/h130.60 km/h-1.45 km/h
Siikakämä 227.68 km130.77 km/h130.40 km/h0.37 km/h
Aittajärvi 122.47 km135.27 km/h133.20 km/h2.07 km/h
Aittajärvi 222.47 km135.27 km/h134.30 km/h0.97 km/h

In my prediction I didn’t predict any difference on how the stages would change from first pass to second. Based on Rally Swedens, I saw that they sometimes became faster, sometimes slower. It was well foreseen, since we also saw both happening in Arctic Rally Finland. The Friday and Sunday stages became faster, the Saturday stages slower on second passes.

All of my predictions were off 5 km/h at most. The biggest difference came from the Mustalampi stage which hadn’t been driven in the national Arctic Lapland rally, so the estimation was merely pulled from a hat, based on similar stage paces from Rally Sweden. The closest I got was Siikakämä 2, where my estimate was only 0.37 km/h faster than it actually turned out (this means roughly 10 seconds in the stage time).

The ratios

To form my estimations, I was only able to get data from Rally2 cars on the national Arctic Lapland Rally. Thus I needed to calculate ratios from different stages in Rally Sweden to see how much faster WRC car is compared to Rally2 car on snow.

StageEstimated Rally2 stage winRatioEstimated WRC stage win
Sarriojärvi114.10 km/h1.05119.81 km/h
Kaihuavaara122.00 km/h1.06129.32 km/h
Siikakämä123.40 km/h1.06130.80 km/h
Aittajärvi126.40 km/h1.07135.25 km/h

When we add the actual data and get the real ratios, we see that most of them were chosen correctly, although the ratios changed between runs (I chose 1.06 for Siikakämä, whereas the real ratios were 1.05 and 1.07). The only incorrect ratio seemed to be Kaihuavaara, where I should have clearly chosen 1.05. However, the Rally2 cars in the WRC event were also faster than in the national event, so my WRC stage win was still quite spot-on. A lucky double error.

StageRally2 stage winWRC stage winReal ratio
Sarriojärvi 1111.70 km/h116.70 km/h1.045
Sarriojärvi 2112.00 km/h117.30 km/h1.047
Mustalampi 1101.10 km/h105.40 km/h1.043
Kaihuavaara 1124.40 km/h131.10 km/h1.054
Siikakämä 1126.20 km/h132.80 km/h1.052
Mustalampi 2101.50 km/h105.00 km/h1.034
Kaihuavaara 2124.90 km/h130.60 km/h1.046
Siikakämä 2121.60 km/h130.40 km/h1.072
Aittajärvi 1124.10 km/h133.20 km/h1.073
Aittajärvi 2126.20 km/h134.30 km/h1.064

This data also supports the values from Rally Sweden – the ratios vary from 1.04 to 1.07 depending on how technical or fast the stage is.

The whole rally

The winner Ott Tänak finished the rally with average speed of 121.7 km/h. My prediction stated 121 km/h with no decimals, so I got pretty close! My stage time predictions were sometimes too fast and sometimes too slow, but together they canceled their error margins and gave a pretty accurate prediction.

Tänak won half of the stages. My estimate of 121 km/h assumed the unlikely situation that the rally winner wins all the stages, which is quite rare. In fact, if you put together all the actual stage wins from the rally, you got 122.12 km/h.

As I said, the biggest difference in my estimates was from the Mustalampi stage. However, my blog post also stated  if [the Mustalampi stage average speed is] 105 km/h, the whole rally is up to 122.6 km/h. This is also quite close to the aforementioned 122.12 km/h, the average speed of all the stage wins of the event.

This was a fun experiment to do, and I was happy with the results. It was interesting to anticipate the rally and see people naming their candidates for the fastest stage of the rally or how fast the rally will be or if this will be the fastest ever WRC event. At least I had some science behind my guess!

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