Mark Philo

The Inferno Triathlon – a mountain too far

Event : Inferno Triathlon

I made a statement back in 2015 that I would not be doing long course events again.  The Inferno triathlon in Switzerland measures up as a 2-mile swim, 60-mile road bike, 20-mile mountain bike and 15-mile run.  So not a full IM at around ¾ the distance.  What is difficult to comprehend however is what they stuff into those distances.

The 2-mile swim is a point to point across the Thun Lake.  Then the road bike with 2 demanding climbs of 8600 ft of climbing (2800 + 6000 for each with a 30 mile ‘rest’ between them).  Then to the mountain bike with 4000 ft of climbing and finally the run with 6500 ft of up to reach the finish at the top of the Schilthorn.

I spent a year preparing for this.  I hammered all 3 disciplines and lost 6 kilos to aid the climbs. Everything I did for focused for this event and I find it a great mode of incentive to have a goal to look to.

A quick note so say my close friend Warwick from Yorkshire talked me into this event and we were to be on the start line together, but only a week out, his wife became seriously ill, and he had to bail.  So, I was left to carry the flag as it were.

Day before the race is a logistical nightmare.  Register at swim exit (T1) and dump road bike gear there.  Over to T2 in Grindelwald to dump MTB and gear there, over to T3 to dump run gear.  These are all miles from each other with things like lakes and mountains in the way, so that was an 11-hour day by itself.

Race day: up at 3:30 am to drive to T3 and dump the car for a 90 min bus ride to the swim start.  Race starts at 06:30 with just enough light to swim directly across the lake using a castle as sighting.  Water is 20°C and goes well getting out on the hour.  Loads of bikes in transition so I’m doing well!  Morning is still cool, so I start the bike and straight into that first climb.  I plan to do nothing stupid and sit in the saddle to not overdo it.  The first climbs go well, and I’m eventually rewarded with some sweet descending with a new speed record of 51.8 mph.  Then onto the 30 miles of flat which I keep easy despite being constantly overtaken.  Sun is out now, and the temperature is rapidly rising as I hit the big 11-mile climb.  I keep spinning and things are going OK. Then out of nowhere, 8 miles into the climb things go bad.  Cramp in the upper thigh so I stop and have a stretch.  Manage another half mile and there is a real kicker of 17%.  Others are walking that bit and I don’t need a second invitation to do the same.  Difference is they get back on and continue riding, I remount and manage only a short distance before I’m out of breath and have to stop for multiple walk/rests.  I realise I’m in real trouble.  I’m really losing places now, not that that matters.  I’ve got to get to the top of the hill for that rest downhill.  I manage the summit and keen for the descent.  I was wrong.  This descent was a steep narrow road with tight switchbacks …… for 9 miles.  You couldn’t really get any speed up and I was hanging on the brakes relentlessly such that I had to stop for a rest as my triceps were killing me. I’m glad I have disc brakes on that bike!

I limp into T2 thinking I will sit and contemplate whether I can actually carry on.  After all, my hotel is only a few hundred yards away so I could finish just here.  But as I get into T2, I’m shouted at.  I need to get through T2 in the next 2 minutes to avoid the cut-off!  I found myself frog-marched out of T2 and sent on my way on the mountain bike.  Well, hopefully, the lower gearing will let be just spin up the next climb.  I get 2.5 miles into the climb and the cramps are back.  A course first aid guy turns up out of nowhere on a moped and gives me a leg rub and some dextrose and I manage another ½ mile.  It’s 35°C now and I’m really wheezing.  A car approaches from the rear, stops just ahead of me and is taking down the course signage.  I catch up as ask if I’m at the back.  He says yes and that there’s no way I’ll make the T3 cut off.  I can’t face another 7 miles of climbing (or pushing) so I surrender my chip and withdraw from the race, then throw up.  I think I’ve had enough.  Even though I’m out of the race, he drives me up to the top of Kleine Scheidegg so I can do the descent down to my car at T3.  Again, I thought this would be fun, but it was 35 mins of a 7-mile descent on loose gravel switchbacks.  Every time I needed to brake, I was at risk of the wheels locking and I overshot or took a tactical fall at a couple of turns.  The lower section was through woods with lumpy root drop-offs (with the switchbacks) until you finally got to tarmac, and a couple mile run into T3 where Kitty was waiting.  I was done as was my rear brake: the almost new pads had completely gone.  Then just the small matter of a cable car to the top of the Schilthorn (instead of running it) to get my personal things (car keys) where I was able to take in the fabulous views and watch some of the much fitter athletes finish the course while I was one of the 30% of DNFs on the day.


In summary, it is one heck of a race.  You need to be more that ironman fit for this one and well adept at hills (up and down).  I will not be going back to retry (more the expense than anything!) as I know I put everything I had into this course.  But the landscape was stunning, and I have no regrets stepping way over my comfort and ability zone.

If I had my time again, I would put a few more teeth on my rear cassettes and time the trip so the race was at the end of my stay to take in a few rides beforehand and get altitude and heat acclimatised.  And may sneak an e-motor in there somewhere!


Mark Philo




The MTB descent:


Published on 30th August 2023

One comment on “The Inferno Triathlon – a mountain too far

  • Bernd Rechel
    Bernd Rechel — September 2, 2023 11:16 am

    Great report! Sounds like a hell of a race!

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