HEVER: Castle Triathlon Series - 2x FREE places up for grabs

OK there’s really no catches here. 2 free tickets up for grabs for ONE lucky winner. IE one for you and one for a fellow sufferer.

At £162 for an entry for the Gauntlet that’s potentially worth £324.

first up: I have absolutely no interest in your email address for mailing purposes. I just don’t do that for me or anyone else I don’t have an email database and I don’t want one.

TO ENTER

ALL YOU HAVE TO DO: give me some way to contact you if you win. And you can enter by any and all of

leaving your name as a comment against this post or
tweeting @the5krunner or
re-tweeting this post and/or using the hashtag #castlecomp5k. (The heading of this post should also appear on twitter) OR
by commenting against this post as it appears on www.facebook.com/the5krunner.
Finally I will probably link to this post on tritalk.co.uk so you can comment on that and/or
confidentially PM me through tritalk’s messaging system.

Phew! ie enter 6 times if you really want to.

WARNING: The Half Iron-distance Gauntlet is quite a hard race. The lake swim at the start is safe and spectacular with an interesting mass swim down a canal section leading from the lake. the bike is HILLY. The run is mostly over estate land and is slightly undulating and quite pretty in places.

There are videos and other resources on the main site as shown below and late September weather is often pretty good for this sort of thing. Here are the race distances, check which race is on which day:

24/25 sept. https://www.castletriathlonseries.co.uk/races/

The Gauntlet – Half iron distance
Olympic Triathlon (best triathlon watch for this is the Garmin Forerunner 955)
Sprint Plus Triathlon
Super Sprint Triathlon
Starter Sprint Triathlon

ENTRIES CLOSE: 8th May 2016 – plenty of time to train afterwards…

Last Updated on 13 January 2026 by the5krunner

Small things I always use

Garmin 90-degree charging adapter: Charges your Garmin from any USB-C cable. Essential when travelling. I use one.
Body Glide: The blue anti-chafe stick swimmers and runners carry. I use it.
Speedo earplugs: Fewer ear infections and no cold-water dizziness. I use them.
Dryrobe Advance: My winter changing robe for open-water swims. I use one. A cheaper option is the AONYIYI changing robe.
Maurten: Race fuel that stays easy on the stomach. I use them.
Beet It Sport nitrate shots: Beetroot shots I take in the days before a race. I use them.
Garmin charging puck: The quickest way to top up before a session. I use one.
Injinji: Toe socks that stop rubbing, so you run more. I use them.
Ultimate toe protectors: Stop black toenails on long runs. They work. I use them.
Compressport R2 v2 calf sleeves: My calf sleeves of choice. I use them.
Cellucor C4: My pre-workout before hard sessions.
TPU tubes: Schwalbe Aerothan, Tubolito and Pirelli SmarTube. Light, tiny spares. I use all three.
G8 insoles: Adjustable insoles that are good. I use them.
Cycplus Cube: A 97g electric pump that gets a road tyre rideable in two minutes. I carry one. 5% off with code THE5KRUNNER.

Watches and sensors

Polar H10: My daily driver for waking HRV.
Polar Verity Sense: My backup arm-worn HR sensor.
Nomad bedside charger: Charges my iPhone and Apple Watch overnight. I use it, and many of their bands.
Train.Red: The best muscle oxygen sensor I’ve used.
Tymewear: Accurate heart rate and reliable ventilatory zones. I use it to pace endurance rides over an hour.
Garmin Forerunner 970: A pro-grade triathlon watch. I use this.
Apple Watch Ultra 4: My daily smartwatch. No phone needed on rides.
Garmin Fenix 9 Pro: I’ve just bought one.

On the bike

Continental GP5000 for everyday riding, and Aero 111 on the front for special occasions.
Helmets: Specialized S-Works Evade 3 for road riding, and Rudy Project Wing for TT-style races. I use both.
Ravemen FR300: A front light that mounts under your Garmin or Wahoo. I use one.
Wahoo TRACKR Radar: I use it on one bike and Varia on the other. They perform the same.
Garmin Varia RTL515: Radar that warns you of cars from behind. I use this model.
Wahoo ELEMNT Roam 3: The bike computer that’s easy to use. I use mine on most rides.
Favero Assioma Pro RS2: Accurate power pedals that swap easily between bikes. I use this model.

Home and indoor training

NPE Runn: Makes my basic treadmill smart, sending more accurate speed and distance to my watch and Zwift. I use it.
Google Wifi: Keeps Zwift connected in my pain cave. I use it.
Apple TV 4K: Zwift on the big screen. I use two.
Google Nest Doorbell (wired, 2nd gen): My video doorbell, running in both Google Home and Apple Home. I use it.

Health, recovery and sleep

FreeStyle Libre 3 Plus: Shows how my blood sugar responds to diet.
hDrop: Measures my sweat loss in summer and indoors.
Fourth Frontier Zone: Checks my heart under load in hard sessions.
Oura Ring 5: My partner’s recovery tracker of choice.
Eight Sleep: A cooling mattress cover my partner and I use nightly.

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tfk the5krunner

tfk is the founder and author of the5krunner, an independent endurance sports technology publication. With 20 years of hands-on testing of GPS watches and wearables, and competing in triathlons at an international age-group level, tfk provides in-depth expert analysis of fitness technology for serious athletes and endurance sport competitors. See the gear tfk uses. ID