A Weekend on the Ironman Wales Bike Course

I opened the curtains in our Tenby apartment to be greeted by a bright and sunny morning, the air was still and the sea was calm, I could only hope for conditions like this on race day, in seven months time. We were lucky, many a childhood summer has been spent on British beaches, sheltering behind a windbreaker under grey skies, but this late February weekend was unseasonably mild; perfect for exploring the Ironman Wales bike course. Assuming we could find it – in my haste I’d forgotten maps or GPS files – a scribbled diagram and terse notes taken from the web site were all we had to guide us. Success was dependent on my girlfriend’s cartographic skills and given the momentarily heated debate we’d had on the previous weekend’s ride, I had my concerns. Wholly unfounded, during the two days we took one wrong turn.

The bike course comprises two laps – the first incorporating both a western loop out to Angle and a northern loop to Narbeth, and the second repeating only the northern loop. For our reconnaissance rides we reversed the order – prioritising the more challenging northern loop by riding it on the Saturday, followed by a trip to Angle on the Sunday. With the exception of a short out and back into the centre of Pembroke and the one turning we missed, we covered every section of the course in those two days.

It’s challenging. The undulating terrain and constantly changing gradient makes pacing difficult, each hill draws you out of that comfortable Ironman steady-state and tempts you to push harder. Red line once or twice and perhaps you’ll get away with it, do it too often over 112 miles and it will be a different story.

Details of the Ironman Wales Bike Course

While it’s the bottom-gear-grinding hills or the out-of-the-saddle walls that are easily remembered, the good news is much of the course simply undulates, gradually climbing or descending, but under the right conditions fast. Should race day replicate last weekend there will be many opportunities to regain time lost to the hills. But those steep, slow climbs that divide these, potentially, fast sections define Ironman Wales – none are very long and few are very steep, they punctuate the course and sap energy; even cruising round in training they take their toll. After Lanzarote I was glad I’d left the TT bike at home, the standard gearing of my road bike was kinder on my legs, but a 27 cog on the back would have been a nice touch. I am under no illusion that this course is quick.

It feels premature to propose race strategies this early in the season and the relaxed pace of my trip leaves me unsure how hard I could ride. It’s clearly a tough race, but then I’ve not encountered an easy Ironman – whatever the terrain if you push yourself enough you will suffer; a course like this simply makes the process of pacing more challenging. How hard can you push the hills? How much can you recover on the limited flats? For now I’ll adopt one of my prepackaged strategies: two power caps, one for flats and one for proper hills; hold back during the first lap and save something for the second time up those climbs. It has broadly worked before, but a course like Wales will test the approach and my discipline to the limits. I think I’d like to ride it again in anger before I decide how I feel about this race.

Whatever equipment I choose and strategy I adopt one thing I’m certain of – I need to be very bike fit in September. Because when I enter T2, legs shot from every out-of-the-saddle climb, the run that follows is far from flat.

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  • Grant Smith

    Great article, I to am doing IM Wales, and long course which is probably the first time I will get to ride the course? I was thinking of putting a bigger cassette on the back, and I think you have just confirmed this for me!

  • Thanks Grant,

    No shame in putting a bigger cassette on. I can’t see there being many sections I’d be using an 11 cog, and while I can get up the hills in a 25, I think a 27 would just go a little easier in a few places, so likely a 27-12 on the back with a standard 53-39 up front; a compact could be good on this course too, with an 25-11 that would give a good range. Of course there are a few points on the course where any gear will feel hard: the climb into Narbeth, the 16% hill out of Wisemans Bridge and the 12% hill out of Saundersfoot. All three will be ridden twice as they fall in the northern loop. As with any Ironman, it comes down to pacing in the end, it’s just when there’s as much up-and-down it’s much harder to get that pacing right.


  • Grant Smith

    Pacing over hills is an area I need to train on. I’m an above avg. climber, being pretty small and light, but I find myself in a very high HR whilst climbing. Any tips on pacing whilst climbing would be very welcome, although I think it might just be a case of restraining one self?

  • For any race I tend to operate to a HR (or power) cap, I aim to keep my HR below that figure throughout the race. Actually it’s two caps really, one for the majority of flat riding and a second for harder sections – climbs and strong winds for example. I could certainly climb harder in isolation, and probably early in the race I’d feel fine about it, but too many spikes of power up a hill sap energy and will ultimately slow you more later on; only so many matches to burn in the race.

    No harm working climbs hard in training, but on race day it is a case of being able to hold back and slow yourself down. If you’re creeping over the cap, ease back in the gears and take your time. I’ve been overtaken on hills a lot in races, only a few of the people doing it stay ahead till the end.


  • good luck russ be good to see you racing again fit and ready to take on the race :O) , think i might be doing the 10km swim at reading 5th june not sure yet

  • Mob O’Brien

    Road Bike or TT Bike? What you think for this course Russ?

  • Kit Stokes

    Good read Russ. Time trial bike all the way. Be a bit wary of wheels with carbon braking surface with a good chance of rain.

  • Thinking about it now, I’d agree with Kit, it’s a TT bike course really. There are a few uphills and a couple of steep ones, but then lots of fairly rolling and straight terrain too – certainly nothing hugely technical. A road bike isn’t going to give you enough advantage on the climbs to outweigh a TT bike on the course overall.

    So I’d say TT bike with a decent gear range so you’ve got comfortable options for the steep moments.


  • Nick B

    Did the race last year on the TT bike and did not regret it for a second. I know you like to push a big gear with a lower cadence Russ. I like to spin and was horribly over geared last year with a 39×25. This year I will be fitting a compact paired with a 28T on the back otherwise its too much time grinding and out of the saddle. If I don’t need the 28, guess I won’t use it! Also the crosswinds were nasty last year on the loop out to angle so would recommend having the option of not riding anything deeper than a 404 or equivalent if it’s the same. Glad I left the disk back at the hotel last year.

  • Nick,

    I won’t have any worry about going any deeper than a 404, that’s as deep as I go! I’ll likely take the TT and have a 42×27 on the back to get me up the steep bits, compares reasonably with a 39×25 and they got me up the hills fine on the test ride.

    Not sure on disk, will take Powertap with wheel cover in case, but likely go with 404 front and back.


  • phil orr

    hi, doing ironman wales, my first and concerned about the hills. i have a powerglide 50/34t chain ring set, will this be ok as i no nothing about gearing etc. your advice would be greatly appreciated. cheers

  • Phil,

    That’s a compact setup on the front which will be ideal, all you need to do is combine it with the right cassette on the back to give a good range of gears. The course is mostly rolling with a handful of particularly steep hills which is where the lowest gears really come into their own. Generally with a compact an 11-25 will more than cover your needs, but if you’re a weaker climber then opting for a 12-27 or better an 11-28 might be a sensible choice.

    Do you know what cassette you have on your rear wheel at the moment? If not count the teeth on the biggest and smallest cogs. How do you find that with local climbs? If you struggle out of the saddle on the biggest cog and smallest chain ring at the front then you may want a bigger rear cassette, so one that goes down to 28. If you have no issues with hills, even those over 10% then you’ll be fine.


  • phil orr

    cheers will check but i think i have one of the ones you mentioned. was just concerned with all the chat about this hilly course and was getting a bit paranoid , but that gives me peace of mind. are there any pictures of this monster hills to be found anywhere?thanks for coming back to me.

  • No problem Phil. The course is hilly and there are some steep sections, but with suitable gearing it’s all about pacing those hills. You’ll work harder on the uphills, but if you don’t over do it, you’ll be fine. I would practice some steep climbs in your rides and make sure you’r comfortable with them. The steepest parts tend to be fairly short, but given they occur later in the race you’ll notice them.

    I don’t have any pictures I’m afraid, the Wisemans Hill 16% climb is a narrow, tree-lined lane, and the Saundersfoot climb is on a bigger road with a bit more variation in gradient, it averages lower, but possibly has slightly steeper pitches in there. You get a nice downhill back into Tenby after that though.


  • phil

    thanks for the peace of mind, counted teeth (on back cogs that is) 12-32 so should be fine. are you doing it again? if so i owe you a pint, we are staying till tuesday so we can have a few beers on the monday(rugby mentality)
    all the best

  • Phil,

    With that gearing you’ll be fine.

    I’m doing it, but this will be my first time racing the course. I’ve ridden it in training and I’ve coached a few athletes who raced it last year, as well as coaching a few racing it this year. I’ll be there at least till the awards ceremony on the Monday, assuming everything goes to plan finishing this will mean I’ve completed the Endurance Challenge set up by Ironman UK and completed all 4 of their events.

    See you there


  • phil

    good , piss up on monday if we are able.

  • phil orr

    did the belfast marathon in 4h 49mins 31 secs, bloody sore today , next one will be in wales, some serious trianing ahead of me to do one after a swim and bike ride. but not to worry this guinness and red wine seems to be working.

  • Full of antioxidants I believe.

    Few months to go yet and a marathon at the end of the Ironman is different to one on its own. Not to say it’s easier, but the pacing is a different matter. The whole day at Ironman is about balancing your pace and managing your effort to ensure you’ve got the energy left for the run.


  • Regarding HR, how high would you let it get on a hill – a) a short steep climb, b) something longer – over 3-5 miles say, @5-6%

    as a % of MAX HR or % Threshold (or maybe number above target average for the race)

    I’m doing France, not Wales, so different course, but similar concerns.

  • Sean,

    As I understand it (I’ve yet to race there) Ironman France mainly has the longer, steadier climbs and fortunately not the short, steep pitches of Wales. This makes the pacing of them slightly easier with heart rate. One of the issues you face with very short, steep pitches is the lag in HR response means you can be a fair way in, or even over the brow before you realise the full impact. When I guide an athlete with power I have very clear instructions to avoid surging over threshold wattage, and they will see immediately if they do. You can spend a good minute getting over threshold HR on a hill, by which time some damage is done.

    That noted my advice would be –

    a) Anything short and steep should still be controlled, HR cap for climbing in an Ironman should be kept around the 90-95% of Threshold HR mark. This gives a buffer against unintentionally crossing threshold, but enables you to work hard. Of course if you hit a 20% pitch and you’re out of the saddle you just have to take what comes.

    b) For longer climbs you could potentially stretch up towards 90% of threshold HR, say 85-90% so a definite tempo effort. The longer it is the more cost associated with this of course, so bear that in mind; on the other side there’s plenty of descending for all the climbing and this does allow some recovery. On an alpine course you can potentially work a little harder for longer, but recover on the descents. However it remains true that crossing threshold is damaging, those spikes in effort if too frequent cost the legs on the run however much recovery you have on descents.

    For comparison the majority of the ride would be an endurance effort and held at around 80-83% of threshold HR.

    That’s my general approach on it. I’ll be racing Lanzarote in a couple of days and with my power meter I’ll be focussing on a controlled effort on the climbs, probably aiming for around 85% of FTP as my maximum. There are one or two points where the terrain may simply make this impossible, but otherwise I’ll choose my gearing and moderate my effort to keep with that bound.

    Hope that helps,


  • Thanks Russ, this helps heaps.
    You are right, France is mostly long steady climbs – the steepest I think is the first 500 meters@10%,, where I reckon I’ll try to go really easy to avoid going over threshold and then after that I’ll be looking to keep below 90% threshold HR on the long climbs.
    Initially I was planning on staying lower than this throughout, but I think if I do that I’ll be way too long out there, and as you say there is plenty of long descents to recover on.

    I am starting to think that a power meter may be worth all the expense. HR just lags too much to be a good indicator.

    Good luck in Lanz, it sounds like a tough course!


  • Stick it in the lowest gear for the 500m at 10%, it’s not the place to be making time on the course anyway. With prolonged climbs and descents I’d definitely opt for a more flexible approach, use the descents as a good opportunity to recover. Also, as I was reminded in Lanzarote this weekend, make sure you keep eating on the climbs, don’t delay that.

    HR will be a reasonable indicator over long periods, but power is better. Not having it for the Ironman Lanzarote on Saturday was disappointing, not just for the difficulty of pacing, but it is much harder to analyse what happened in that race. My HR was low throughout, but I have no idea what was actually happening in terms of the work I was doing. The pair together would give me a better picture of the condition I was in and if there were unusual discrepancies that might indicate something wrong.