Ironman Wales 2016 is just around the corner, so I thought I would share some thoughts (I'll refrain from calling them 'tips' in case it turns out to be terrible advice...) about how to nail/smash/rip up/destroy/just ride the bike course. I have ridden it quite a few times now (both in practice and racing at 2012 and 2014 events) with the fastest being 5hr 22mins 31sec, which was the 5th fastest bike split of the day.
Course overview (strava segment here)
The course is 'only' 110.6miles long according to my garmin. Don't worry you won't feel like you got it easy, as it also takes in 2500m of total elevation gain along the way, with short and (very) sharp climbs (some >15%) together with technical descents with some fairly sharp corners making it difficult to carry speed.
I would recommend riding the course (or key parts of the course) before race day so you know exactly what to expect. If riding it isn't possible, then driving the course is a good substitute, although if doing this really try and take in what the course would be like if you were riding it.
Also, as with any Ironman ride, make sure you know where the feeds stops are located. Possibly write them on a mini stickey note and sellotape to your top tube. It makes deciding whether to stop at a particular feed station during the race easier if you know when the next one will be.
Due to the challenging elevation profile of the course, a lot of people seem to debate whether to use a full on TT rig or a road bike with clip on aerobars. I have used both, and would pick the TT rig every time. This would definitely depend on how comfortable you are on a TT bike though - you need to be confident descending the technical downhill sections whilst on the TT extensions and feel comfortable climbing the short, steep hills, probably out of the saddle (I try and stay in aero position for as many climbs as possible).
Good brakes are essential, not just for safety but to maximise speed in the technical sections. Also bare in mind that this is Ironman Wales, in Wales(!), where it always rains. So if you are using carbon wheels maybe make sure the brake blocks work well in the wet.
In terms of gearing, I have previously used a compact 50/34 and standard 53/39, but always with an 11-28 cassette. Again this probably comes down to personal preference and whether you like to spin or grind out big gears. I would definitely recommend having an 'easy' gear option though to save your legs when those sharp steep climbs keep coming at you.
To disc or not to disc
Another thing to agonise over is whether to use a disc or a deep section rim on the rear. Previously, I have used 65mm deep sections on the front and rear, opting for lightness over the aerodynamics of a disc. It can also be windy in Wales so this should influence selection.
There will be a 'tipping point' speed where it would become detrimental to pick a disc wheel over a lighter non disc option, so you need to be honest with yourself and pick appropriately.
However If there is favourable wind forecast, and your disc is a fancy lightweight one, it may be worthwhile picking a disc over a shallow or deep section wheel.
Ride the hills hard (ish)
The conventional wisdom of the ironman triathlete is to ride smoothly, keeping the variability index as low as possible, to minimise fatigue on the legs. In my opinion, this doesn't work so well on the Wales course. The reason being that because of the technical descents, you end up freewheeling more than usual. All the time you spend freewheeling, you are doing exactly no watts. So if you then ride up the hills conservatively, you'll end up just riding the whole course under powered and a bit slow. (On the other hand, riding a course such as Lanzarote which has a similar amount of climbing, but with much longer, straight descents, you can still lay the power down descending and so keep power variability low).
So although it carries a higher risk, it may be worth thinking about going slightly harder up the climbs than you would like to, and then using the descents to recover while concentrating on carrying speed.
heartbreak hill (aka St Brides hill)
This is a highlight of the ride for me, and some good news; you do this climb twice! (as it is in the second loop of the course). In the past there have been huge crowds here, all goading you to light the fuse and go ballistic up the climb. It's like a scene from a mountain stage in the TdF.
he advice here would probably be stick to your race plan and avoid going too much in to the red (i.e high heart rate).
Some alternative advice would be to make the most of the atmosphere and go mental up the climb.... I did this (well, tried to) and the reaction from the spectators was worth it.
Save some leg!
You need to remember that the run course is not flat either. According to my Garmin, it has ~400m of elevation gain over 4 laps. So if running isn't your strength, it might be worth taking it slightly easier on the bike to save your legs for the run. Otherwise it may be a very miserable, long, experience...