Ultracycling

It’s the number of standard deviations from the mean. So he thought it would be +1.3 but was +0.7. So it was worse than he expected and not much better than mean. Michael has done analysis on historic weather to create a bell curve. And probably all other statistical analysis methods available.

@wheels_of_fire perhaps no perfect. But the higher the z value the closer to perfect!

As @skinny says above...

Very roughly Gethin's day was a z-value of +1.8, which you would expect to turn up every 25/30 days. Which shows why this is a silly game to get into!

One whole z-value is about 1hr45 difference over the End to End route

That’s a big time difference.

May 5th 2015, when the men's tandem record was sent has a z value of +2.85, 5 hours quicker than the mean (for a set power output)

A day that you would expect roughly every 450 days!

Thanks for that, very interesting.

Oh, so it's not microbial thermal death time? How disappointing. ;)

Once a month sounds reasonable, your support crew might get a bit tetchy waiting 450 days...

I guess the other factor is how reliably the great days can be predicted
eg Ian clearly ended up with a less good day than he thought he would get. So you could wait for a month, get what looks like a great day, then find it is just a goodish day.

...or reject a day for not being good enough and find out it was quite good (eg 1st May 2018)

this z-value stuff sound interesting, where do I read more about it? what's the equation?

just google statistics z value.

maths flashbacks

POC

yeah I know what a z-value is, just wondering what the maths is to get a z value from the weather?

oh okay. Same as anything else, you'd collect all the individual data for each day, probably available to dowload in excel spreadsheet from somewhere, then run the calculations. You could also then cross compare wind speed, temperature, pressure against each other to see if there was a relationship

cool, thanks. given me some good ideas!

I’m guessing it’ll be (temperature - the mean temperature)/standard deviation.

So if you had historically temperature for 5 days — let’s say 24, 25, 26, 26, 25. That’ll give you an average of 25.2 and a standard deviation of 0.7. Therefore if they had a 30 degree day that’d give a z-stat of (30-25.2)/0.7 = 6.9.

But isn’t this just a long winded way of saying it’s warm and the conditions will be good?

allows you to quantify how good.

And gives a number for whatever the formula michael create to determine time saved due to weather.

I'm talking about wind conditions rather than temperature... using mywindsock.com along the entire route.

I have had considerable assistance from Ben Norbury (himself an accomplished long distance TTer) who runs that most excellent website. Unfortunately he doesn't actually control the wind, which would be even more helpful.

time saved due to weather.

That's the interesting bit, not the z-values.

Any of these help?

Ian To
3 hrs ·
Beaten by the weather ☁️ Having celebrated the successes of our LEJOG attempt, especially the great amount we raised for the National Autistic Society, here is the short version!

The current record is so tight (and was taken with a raging tailwind) 🌪️that the winds are critical to success. All of the other obstacles encountered were overcome, although a lot of time was lost stopping: stomach bug (with 8x Loperamide tablets!), crash (Ibuprofen), heatstroke 🌡️☀️(iced water and ice lollies), hayfever (Cetirizine), gravel rash and left hand fracture from being run-off the road 3 weeks pre-event.

During the day, it was much hotter than expected. During the night, it was much colder ❄️ The tailwind, forecast past Bristol (after 200mi), never materialised, and I chased further north in still air. The promised 17mph tailwind at 0400hrs was but a gnat's fart. In Kendal, chimney smoke was rising straight up and not a tree's leaf moved - demoralising. I climbed Shap⛰️ to see if the wind was to be found on the other side, but it wasn't there. To stay ahead of the record, I had exhausted myself. Tailwinds were forecast further north, but it was too little, too late. In order to break the record, I would have to maintain over 21mph average for 380mi.

Many small lessons have been learned, and more will be discussed as a team, but we were beaten by the weather. Too little, too late.

However, Project 44 lives on... watch this space 😉

@wheels_of_fire was it a raging tailwind?

yeah but how was eating only milk and sausages for 400 miles

He didn't.

Seems like a lot of excuses. Be better to say it wasn't going to happen on the day and called it off and will be back again to try it. It's not the first time that people haven't succeeded at what they try. I do find it funny they never mention TCR 2017 when talking about previous riding.

TCR 2017

Refresh my memory, what happened there?