TriPacing is a Triathlon Pace Calculator that helps triathletes get accurate predictions and personalized training zones to optimize your triathlon performance. For Ironman or Challenge events I have included list of races so you can get course details like hilly, lake, rolling etc.
Triathlon Calculator to Personal Race Planner & TRacker
I started vibe coding TriPacing as a simple calculator to learn. Then as technology got better I wanted it to be more. The next logical step was to save my pacing plans to review later vs actual results. Other triathlon pacing calculators don’t do this.. I currently do this via a notion table as seen below or Results.
I’m pretty proud when I negative split a race. It shows I had a good pacing plan in place and was able to stick to it and control the result that is why I have iterated to build NegatievSplits.com.
Update 19th August – Prototype v4
The hardest part of saving race results or pacing plans is the manual data entry of the race details. To combat this wanted to build a database of all triathlon races but also include solo races such as road races or gran fondos as they are what I have in my notion page.
Big change was integrating with Mapbox to display the races. Bigger problem though was that Base44 ai agent that I’m using to build the app has just been iterating on previous builds. Really a prototype should start from scratch again with new design so I had a lot of tech debt cleaning up the data entities to manage the events in a scalable way. Now I understand why people say start with the model.
Next I want start piloting with people but from speaking to a few members of the triathlon club it might not be common practice to save results, pacing plans and set race goals. Might be a bit more difficult to find some users so might just be building a over engineered spreadsheet that nobody else will use but as they say if you build it they will come.
Update 17th July – Prototype v3
This prototype was really happy with the smashing homepage. Things kinda lost track though. I was thinking of it as a hub for my ai tools to help negative split. example of this is the Running Form AI GAIT Analysis tool – which did bring in my first registered user.
Also, added a race chat feature to find new races and see old results etc. Logged in users had a different experience. Spent a bit of work on public profile and showing bibs and result pages.
Update: 4th May 2026 Prototype v2
Vibe coding has come a along way since I started with Lovable and recently discovered Base44 a app made to deploy websites without having connect databases and worry about security.
I went ahead and built out my new version in a handful of prompts vs all the effort for v1.
Unknown to myself let the domain name tripacing expire and frustratingly some fucker bought it and I refuse to buy it off them. I really liked that domain name.
It did get me thinking though – about do I want to actually build.
Its really a race results tool. The triathlon calculator is really just a lead magnet so it should be embeddable. You can see the version below; to save results you need do it on main site https://negativespilts.com/
Maybe the next version looks at my training data set and creates predictions or pacing charts that could be used to predict performance or recommend what should be achievable.
TriPacing Triathlon Calculator Prototype v1
URL: triathlon calculator | Negative Splits
Target: Triathletes with 2+ years experience
Problem: Trying to predict finish times without data
Insight: Calculators don’t combine athlete data with pacing
Motivation:
- Have a side project to learn how to use no code solutions like Lovable
- Create a niche website that Google results can’t match
- Have used calculators in past and building for myself.
Competition:
- Triathlon Calculator — Race Time and Pace Calculator Top of Google
- Triathlon Race Pace Calculator | MyProCoach™ Best calculators
- Triathlon Pace Calculator – Calculate your race pacing
Problem Statement:
v0.1: Shane is a triathlete who needs to understand the speed to achieve a time in each area of a triathlon because he wants to improve his total time to get PB.
v0.2: Shane is a triathlete who wants to predict his finishing time at a Ironman race by guessing his finishing times in each area of the triathlon because he wants to improve his total time to get PB.
v0.2: Shane is a triathlete who wants to use his threshold paces predict his finish time at a Ironman race because he wants to improve his total time to get PB.
How could I improve on pre-AI calculators?
- Select Course for Ironman / 70.3 Events (Data on IM.com Website)
- Average Times per Age Group
- Total Time Last Year Placing
- Prediction vs Actual
- Personal Race Time Tracker
Notes on Building Triathlon Pace Calculator
- Using free version of Lovable so limited number of chats. Still can use other features such as restore which is because trying to do too much especially around styling has lead to errors which you need chat to fix. Seems to be issues with naming and calling libraries.
- Using free version is limiting me to spending 15-30 minutes per day on the project which will help keep it as a side project.
v0.1 Select Race and Input Times
create a triathlon calculator in kms inputs – triathlon distance (sprint, Olympic, 70.3 or full ironman) – set swim CSS pace – expected t1 time – bike threshold pace – expected t2 time – run threshold pace output – total time
make t1 and t2 drop downs of 1-10
lets make design more fun Add more personality to questions add icons, colour, animation add welcome page
For the code present, I get the error below…
no need for icons
revert back to version 2 with no errors and one page but dropdowns
v0.2 Single Tile and 2 Columns
Total Edits: 12
v0.3 Imperial or Metric Option
Total Edits: 19
v0.4 Slides & Restyle
Edits: 23
Slider was interesting as it created an error when changing. Took two attempts to fix this but it got there. Styling I checked out their templates and then referenced start-up. Also, added animations.
Feels ready to do some user testing.
Next
- Add share button
- Need update distance selections:
Possible Next Steps Add More Calculators
- Heart Rate Zones
- Age
- Swim CSS Calculator
- Time for 200 & 400m
- Enter CSS or Calculate
- Output times for Easy, Steady, Moderate Hard. Hard, Very Hard
- Pace Calculator
- Enter Threshold Running Pace
- Time for 5km
- Select Miles/KMs
- FTP Calculator
- Average power for 20min test
- Enter Threshold Power in Watts
- Race Pace Calculator
- Insert Distance Times vs Pace
- Use per my Thresholds
- Give feedback when setting unrealistic targets
v0.5 Thresholds Calulator
Uploaded screenshot for basis and asked created new screen.
Noticed errors calculating CSS and Run Paces. It refactored and gave option to preview the changes in the code:
This is how it looks now:
v0.6 Restored Twice
Gave it too much information and got lost on what I actually wanted the tool to do. Wanted to use thresholds to create a race time prediction but became neither so reverted back to it being just a training zone calculator. Thought I fixed run pacing calculations but didn’t.
v0.7 Finished Training Zones
- Couple of bug fixes for run pace use the input to calculate the average pace from their 5km time trial
- Refactored code into components as suggested but not sure of benefit besides best practice.
- Added download pdf version which works well for training zones but broken for race planner
v0.8 Elapsed Time & Suggestions
I
MVP Complete
- Calculate total time for variety of distance with UX at forefront
- Download predictions to a pdf with race name and date
- Calculate training zones based on thresholds
- Simple feedback area of feature suggestions
Added New Calculator
Wanted added a FTP calculator but it seemed to update the other pages too, lost a homepage and change the navigation while also giving new page its own style.
It took 10 or so prompts but got it working. Introduced new style of table for displaying plan which used on Time Based Calculator too.
Update Deploy Style using GitHub & Hosting to avoid introducing breaking changes to production.
At this point I got slightly distracted by the possibilities of AI and started researching AI generated training plans that could help hit the target pace and based off training zones.
Some Live Testing – Coogee Sprint Tri
I’m competing in Coogee Beach Triathlon — Fremantle Triathlon Club tomorrow and want to predict my times or set some targets. This a sprint and local race so no gpx. file available but relatively flat course.
My usual process
- Lookup previous sprint races
- Set some targets per area
- Record the final results with notes
Have my legacy data to know what is my PR to beat is usually my goal, or see what I did previously on same race previously or check out notes.
My archive looks like this. I’m manually copying the data from race results website.
This is what it looks like without the filter
What actually would be even better to figure out my pacing for the race would be load my PB or last race.
Key Features
- Save previous results (scrape from website)
- Save race prediction
Save Predictions
This is where it has got frustrating as it turns out my two calculators were doing their own thing so I had do a lot of refactoring and troubleshooting. Which has been slow.
Found this excellent video which I wish I knew about earlier.
Added a homepage
Simplified options to change pace
FTP based made look closer to time based and added a FAQ
Profile page with a prediction table
Version 2 – Running Calculator
I added this and was ready to start changing but its a critical data model change when I try extend to other sports and think its better to create a new version or start over with information I now have.
So I restored back to version prior running.
Some final testing around saving and then it would be ready to get some user feedback and track how people use it. In particular testing needed saving with sign-up involved. The saving without signing up works well by itself.