How to time a complex wave-start race

This article describes the considerations involved in timing a complex wave-start race

A customer emailed us with the following scenario, which serves as a good example to describe how to time a complex wave-start race:

 In our race, we’ll have a mass start of approximately 80 racers on a 10-mile lap, for 40 miles. We’ll later release a wave of teams/duo who race the same course for 40 miles. Later, we release a wave of racers racing the same 10-mile lap for 20 miles (two laps). Here’s the schedule:

  • 9:30am—40 mile solo men, duo men and solo women
  • 10:00am—40 mile duo women, duo coed, duo team
  • 11:00am—20 mile solo women, duo coed
  • 11:30am—20 mile solo men, duo men

How can we time this race with RaceSplitter?

And here was our response:


Inconsistent wave start

We notice that your waves aren’t evenly spaced in time; you have 30 minutes separating the first, but then an hour between the second and third. RaceSplitter requires the same time between each wave. You can work around this by creating a wave race with 30 minutes between waves and leaving the third wave empty, i.e.

  • Wave 1, 9:30am
  • Wave 2, 10:00am
  • Wave 3, 10:30am (empty)
  • Wave 4, 11:00am
  • Wave 5, 11:30am


Timing teams

We notice that you’ll have duos and teams participating. Each member of a given team should have the same bib number, so that RaceSplitter sees them as a single unit for the purpose of timing.


Whether to time with multiple devices

You asked whether to setup the event as a single race, and time with a single device, or whether to set it up as multiple races. And if you set it up as multiple races, would that require multiple devices?


Option 1— Ideally use two devices

Ideally, you would use two devices, and setup and time a distinct race on each:

  1. Device 1—40 mile, wave start, 9:30am, 30 minute interval.
  2. Device 2—20 mile, wave start, 11:00am, 30 minute interval.

Note that as long as each device is logged into the same iTunes account, you can download RaceSplitter without having to make an additional purchase.

Option 2 — Single device, multiple races

In theory, you can run multiple races in parallel in RaceSplitter. If racers between the various races will be arriving together, this mode of operation would be error prone, as you’d have to frequently switch between races.

If you did choose this direction, you’d need colored bibs, or some other way for the timer to distinguish which race a given participant belongs to.

Option 3 — Single device, single race

If you wish to operate a single race in RaceSplitter on a single device you can do this with creative definition of your categories, i.e.

  • 40M-Men-Solo
  • 40M-Men-Duo
  • 40M-Women-Solo
  • 20M-Men-Solo
  • 20M-Women-Solo
  • etc.

In this case, if you want to see the results within a particular category, you just switch to that category in RaceSplitter.

The RaceSplitter app can only show the results of one category at a time. If you wanted to see general results of the 40 mile race, you can do that by publishing results to, since our website lets you sort by combinations of categories.


Potential gotchas

In your particular race, there are two potential gotchas to watch out for:


Missed laps

In each of your races, you’ll be timing participants multiple times as they circle the 10 mile loop. Note that if you happen to miss a particular racer on, say, Lap 1, and then you time them on Lap 2, RaceSplitter will insert that time in Lap 1.

If this happens, you can correct such timing entries either during the race, or after.


Wrong wave start

It’s very important that each racer begins in the wave in which they are assigned. If a racer assigned to wave 5 actually runs in wave 2, then when they are timed by RaceSplitter you could have a situation in which RaceSplitter would calculate a negative time — since it subtracts their start delay from their recorded time based on the wave in which RaceSplitter believes they started.

Since negative times can’t exist in the real world, RaceSplitter can only assume you started the race clock at the wrong time, and will adjust the race start time so that the racer’s negative time becomes zero. This will then shift the recorded times of all other racers.

So if by chance in your race it seems like RaceSplitter has mysteriously added, say, 45 minutes to all racers’s times, it would be because somebody ran in a wave different than that which was specified in the start list.


Practice makes perfect!

We strongly encourage race organizers like yourself to practice/simulate your race at least once before the real race, so that you are familiar with everything—timing, correcting mistakes, publishing results live to, printing results, etc.

When organizers practice at least once beforehand, problems are rarely experienced!

Scenarios & examples


This article explains how to use RaceSplitter to time a triathlon.

Timing 5k and 10k races together

This article discusses the considerations involved in a common timing scenario—5k and 10k running races, ran together in a single event.

Variable start races

This article explains how to time races in which the start interval between participants or waves is variable.

Complex Multi-Race Event

This blog article explains how we organized the timing of a multi-day, multi-race and multi-split ultra event using RaceSplitter.

How to time ties & groups

This blog article explains how we organized the timing of a multi-day, multi-race and multi-split ultra event using RaceSplitter.

Complex Wave Starts

This article explains how we helped a customer setup timing for a complex wave-start event.

Relay Races & Team Events

This article discusses considerations related to timing relay races and team events.

Multi-heat regatta

This article discusses timing of a multi-heat boat regatta.

We’re here to help!

If you’ve been unable to find what you’re looking for, don’t hesitate to contact us, and we’ll get back to you shortly.

Support Email: [email protected]