Monthly Archives: July 2013

Fernwood to Saddle Segment Change

I’ve had several problems with the Fernwood to Saddle segment that the challenge has used for the last two years and finally changed it to a new segment today. The old segment¬†ended in the parking lot, but sometimes it would stretch a little until the end of the parking lot almost to the start of the Stunt descent.

Capture

This meant that if you stopped somewhere in the parking lot to rest you would end up with a much longer time than expected since your rest would be included. The new segment ends before the parking lot begins so there should be fewer issues of people getting stuck with resting time.

Capture1

For the top 15 places, the times dropped an average of 11 seconds. For the people who I knew had an issue with this their times dropped between 9 and 14 minutes (not seconds).

Time vs. Average Speed

If you look at the segment leaderboards on the SMMT Challenge website, you may notice in some cases that some efforts may have a longer time but a higher average speed. For example, if we look at the current leaderboard for the Mulholland segment it looks like this:

Note the time vs. average speed

Note the time vs. average speed

Scott has posted the fastest time while Gareth has posted the fastest speed. How is this possible?

A look at the underlying data shows that Scott’s effort on the Mulholland segment was 6.96 miles while Gareth logged a full 7.04 miles. So while Scott’s time was lower, he didn’t ride as far as Gareth did. These types of minor discrepancies happen because of a variety of reasons.

First, our GPS devices do not constantly record our locations. Rather, they take a measurement every few seconds. So you most likely do not have a GPS reading exactly on the start or end of the segment. That measurement is also not an exact measurement.

Another reason is just due to the inexact nature of the segments themselves. The start and end point depend on the ride the segment was created from. GPS is not an exact science, so the original ride may have been off and the segment might start off the road.

The result is that when it comes to Strava segments, it is an inexact science which means that luck is involved to some degree. As another example, my time on Fernwood was faster that Jon Woodbury’s time, but he posted a faster average speed. When I compared the endings of both of our efforts together, you can see why. I got lucky (or Jon got unlucky) and my segment ended before his did giving me the time advantage.

bryantvsjon

 

Normally the Fernwood segment ends where mine did, but for some reason Strava has Jon’s ending later.

So that is why you may see some discrepancies in the times vs average speed.