Differnce between a 2k and a 4k road bike in terms of outright speed is pretty minimal.

A 2k road bike is more than adequate for most road riding needs. A 2k TT bike will be quicker than a 4k road bike

I priced up a TT bike earlier in the week – Planet X Stealth frame for £300, Ultegra group set for £500 (or £1k for Di2), FarSports carbon wheels and some reasonable finishing kit. You can do it for £1500 or £2k with di2. Definitely be my choice.

£1k gets you the full Di2 Ultegra TT group, £500 for mechanical. Big jump, but I think di2 is particularly useful on TT bikes as you can shift from the brake levers or the extensions and it avoids convoluted cable routing – through aerobars/stems etc.

Mmm, that was why it appealed, but no idea on routing etc I’m afraid!

I was originally thinking of a Flyxii or something Chinese, which would have Di2 compatibility, but the Stealth at £300 was rather tempting!

Interesting, thank you. I’m not likely to buy until spring anyway.

Sorry OP, sort of hijacked – but I’d still do a build like that for the TT bike, and spend more on the road, but it depends a bit on how much/how seriously you’re planning to use the TT bike.

2 x £2k for me. Bit of a Planet-X love in, but this

http://www.planetx.co.uk/i/q/CBPXEXO6800/planet-x-exocet-2-shimano-ultegra-6800-time-trial-bike
And this
http://www.planetx.co.uk/i/q/CBPXNANO6800/planet-x-nanolight-shimano-ultegra-6800-road-bike

Would get my penny’s I think.

Do you want a fast time in the Iron Man or enjoy riding Sportives? If it is Iron Man then I’d spend:

£500 on a wetsuit – you’ll save more time in a transition taking off a well-fitting smooth wetsuit than you will with the bike 😉

£2500 on a good TT bike – Cervelo S2 looks like a lot of bike for the money

£1000 on a road bike for training.

Di2 Ultegra looks good for TT, but if sticking to a budget, really won’t make you faster. A skin suit and some decent deep profile wheels will save you most time on the bike.

If you want to really ride Sportives and dabble in tri, spend more on a decent road bike. I like my Defy Advanced SL and it is a joy to ride long distances. Decide on your priorities and adjust accordingly.

There is no reason why a Giant Propel aero bike, with Di2 and TT clip on bars could not be used for Tri, then unclip the TT bars, unplug the remote shifters and switch wheels and you have a nice road bike. That is probably a reasonable balance if undecided and would cost about £4000 (including an extra set of wheels). I think most people can’t be bothered to do the shifter conversion, but that to me is the read advanced of Di2.

Lucky guess. I rode our club sporting 25 on it without clipons and was a lot faster than last year – and fitter.

But I do think that an aero road bike with Di2 and clip-ons and 80mm deep section spare wheels would serve the OP well for all duties, so that would be my recommendation.

If you do go that route can recommend the Zipp Vuka poles, loads of adjustment which you’ll probably need if you’re trying to get a good TT position on your road bike.

The aeroad is lovely, and like the Giant, has an integrated cockpit on some models. The downside is the the bars aren’t round at the top, so clamping those Zipp Vukas will not be possible. I’d personally still go that route with some Zipp bars to match.

1) I can’t see why not, they are a standard diameter
2) Yes, neat aren’t they
3) Almost certainly yes, my Propel takes them easily (and could take a 28)
4). You’ll need to sit on one to really check, particularly if you go down the route of the fashionably trendy cut-off saddles.

Since you say your first love is road riding, get a good bike for the road 😀

One extra point – the Di” junction box will need replacing for a five port from a three. If it is under the stem, then this is trivial.

+1 cynic-al. Munqe chick did a 14hr Wales (hillier than Bolton and club mates who did both were an hour slower compared to their Bolton times) on a ~£1k ally framed, heavy fulcrum R7 wheeled bike. Spending big on a TT bike will have a minimal effect on your time compared to spending it elsewhere, but don’t let that stop you justifying it if that’s what you want (not meant sarcastically).

MC reckons her best investment was in a swim analysis coaching session (filmed in an endless pool) and an open water coaching session. She smashed her Tenby sea swim, only 4 minutes off her best pool time for that distance in conditions where RNLI were pulling people out and a former Kona qualifier mate quit after the first ‘lap’.

Dont blow all your IM/tri kit/prep budget on a bike if you’re serious about getting a performance return on your investment.

drag proportional to v^2

I would echo the above about making sure your swimming is up to par. Probably a lot easier to lose time and tire yourself out with bad swimming.

Unless you after an excuse for a shiny new expensive bike 😀

Yes, looks like cynic-al has done his sums…

And that fabled figure is probably from a wind tunnel at just the right yaw angle, and probably rarely achieved on the road. Throw in hills and an assumption that your speed will be considerably less than 25mph over ironman distance. Still even if it saves you a minute off the bike ride and you come in say 30 seconds under an hour barrier then it may be all worth it 🙂

May sound obvious but it’s more the position that the aero bars allow you to get into. I’ve seen people clip aero bars to a standard road bike and go slower either because their position ended up being less aero, or because they couldn’t make power.

Well worth doing some proper timed testing with them to see what sort of benefit you are getting. Also have a look at the BikeFastFit app to help record and tweak your position (can also measure frontal area which may be useful in guestimating drag.) You may need to make quite a few changes to setup to get a good position, may not be a case of just popping on some bars. Riding in an aero position is also something you need to work on lots (especially for that sort of distance) and what’s sustainable should evolve as you get more comfortable/stronger in a position.

is a power meter in the budget?