OK, I know you’re all hardcore MTBers and probably not interested, but just in case..

Looking to do a 70.3 event next year and hopefully full Ironman the following. Now starting to check out options for a TT bike and getting confused with all the variations in sizing/geometr!

I’ve seen different manufacturers offering large frames with a huge variation in top tube length (e.g. Planet X vs Giant), ranging from around 530mm up to 570mm. Head tubes, too, seem similar, from 100 up to 150ish.

I’m 6 foot and mostly feel comfy on a 570 (top tube) road bike, 170 or thereabouts head tube.

I realise position is completely different and TT bikes generally need to be shorter and lower.

Be good to hear from anyone who may have both a road and a TT bike. What kind differences in frame measurements do you have? Basically, wondering if there’s any kind of +/- rule I can follow as a reasonable guide.

Anyone?

You do realise that TT bikes and triathlon bikes are totally different bikes dont you?

No.

But I think this looks awesome!!

http://www.cycleexif.com/english-cycles-naked-tt

Its true. You need to go smaller. Im 5’11 and ride a medium Planet X wich is about 53cm tt, a good couple of inches smaller than my equivalnet road bikes.

Its not meant to be comfy, more aerodynamic to assist in the tuck position.

Here’s mine (Hello sailor!) * kicks heel up touches ankle*

OK, I’m after a bike for triathlon. It’s just most sites I’m looking at list the bikes as TT/triathlon.. 😳

They look bloody uncomfortable 😯

If your TT bike is uncomfortable then it’s either the wrong size or it’s set up wrong. I had a long term loan of a TT bike, in roughly the same frame size as my road bike and it was very comfortable and fast too.

Just chuck a set of £30 aero bars on your road bike especially if its your first event. I’m a serial bike buyer but normally try out the event type before committing to buying!!

My road bike has a set of aero bars on it for TTs, found it much easier out on my own. Flipping the stem and moving spacers about might get them a bit lower too.

Small frame is a throw back from when you just adapted a road frame into a tt bike and. You needed a shorter top tube to give the correct cockpit

I ride a 58 giant ocr and a large planet x stealth – its the one glupton had actually ive done 200k rides on mine as i was supposed to be racing uk24 – only i forgot to enter i was so caught up in training and entries had closed …… Didnt realise you had to enter quite a bit in advance :/ school boy.

My mate the same height as me said it was too big for him , bought a 56 scott plasma…. Guess what – wrong size sold it pretty sharpish and got a bigger un

For most triathlons a tt bike will do but doing a half and then a full iron man id be looking for a propper triathlon bike …. Less hard on the legs for the run – seats further forward and everythings adjusted for it rather than a bodge.

Fit is even more important in a tt than a road bike as guess what you have only one position and infact as suggested above id rather a well fittinf road bike i could get comfy on than an ill fitting too small spine curving non aero position tr bike

Stand and watch any tt race….. The fast guys are on. Bikes that fit with nice flat backs and a fluid pedaling position

glupton1976 – Member
You do realise that TT bikes and triathlon bikes are totally different bikes dont you?

An MTB and a recumbent are completely different. A TT bike and tri bike are virtually the same save a few tweaks.

Fourbanger totally agree in the same way my 456 in full downhill build is just an xc race bike with a few tweaks.

Tools for jobs etc.

Tt bike fine for most but if yor goin to do a full iron man might as well make it easy for yer self . Although notice at taupo ironman that mostly it was road bikes and clips ons . Was a rolling hilly route though

An MTB and a recumbent are completely different. A TT bike and tri bike are virtually the same save a few tweaks.

Tell me what the tweaks are.

They look bloody uncomfortable

There is nothing pleasant about a time trail.

An extreme example for you.
http://www.youtube.com/watch?v=Tix9iF3reSE

Thanks for the input and education. So, I take it the big differences in geometry I’ve seen are because the bikes are either TT or tri specific.

I’ve completed a couple of Olympic distance events on my road bike and would like to treat myself to something new for the bigger distances I have planned.

Looks like I need to do more research and probably get professionally fitted.. although would like to take advantage of deals that the likes of Planet X, Canyon and Rose can offer–yet these aren’t easy to have test rides on 🙁

Tell me why they’re “totally different”.

I’d say fourbanger is right. Save a tweak in seat angle because of the change in the not having to meet the UCI BB rule a TT bike set up for a long distance time trial (100 mile or 12hr for example) and a “tri” bike set up for IM look pretty similar.

IMO knowing you want to do an IM eventually isn’t enough as terrain makes so much difference. I’m pretty sure I’d take my road bike with a pair of clips to Norseman or Celtman for example where my P3 was ace in Austria and Hawaii. Setting my P3 up for a non drafting standard distance race, it didn’t look that different to how I’d set it up for a 25m TT.

Saddles quite a bit further forward on a true tri bike to save your legs . This has a knock on effect to most of the other angles and locations of other componants, angles are usually less sharp to prevent fatigue from constant correction.

This is why not to many full on tt bikes around and most are adapted tt bikes . Most it not all tri bikes are jot uci compliant due to where the bars have to be and the saddle being infront of the center line of the bb . So dont pop down your local sanctioned tt on your tri bike.

How many triathletes do you think could handle a tt bike without falling off? Slacker angles keep the things a bit more triathlete friendly, different seating position to bias which muscles you use – tri bikes have no uci rules to bother about either.

So fairly big differences.

So dont pop down your local sanctioned tt on your tri bike.

To be fair your local tt would have to be the national champs for it to be an issue. UCI rules don’t apply on normal club or open tts – hence why you still see the odd corima fox, lotus or giant mcr knocking around.

Just chuck a set of £30 aero bars on your road bike especially if its your first event.

This
Most of the aeroness comes from your position, then your helmet, clothes, shoe covers. Wheels make very little difference at all. There’s a great article on bike radar where they tested various permutations from standard road bike to full TT with trispoke/disc rear wheel and all the aero kit.

I have a mate who came 14th in this year’s celtman on a low-spec allez with clip ons and a helmet.

My sister did an iron man on a £800 road bike with a set of aero bars so you don’t need the kit.

If you are going to spend a lot then I would try some. TT bikes can be hard to ride and uncomfortable so I’d want proper fitting advice.

Personally for a 100mile ride i’d want something with a generous nod to comfort as well as speed. Would be brutal if you haven’t built up to it.

Convert – you want to try some of the jobsworths at some of the locals round ere

Ok ive never had my bike checked but i dont doubt they wouldnt if it was out of ordinary.

Hope you have a plane white cycling top if yor not in team kit ( im between teams – that is im no longer local to my home team and the few ive tried round here i didnt really gel with)

I’s are dotted and the ts are crossed

There is certainly a very special breed of person who sets their heart on running TTs. Bless ’em!

I have a mate who came 14th in this year’s celtman on a low-spec allez with clip ons and a helmet.

To be fair, the guy who won it was riding a road bike with clip ons. Sometimes a course is just more suited to a road bike with clip ons than a tt or tri bike.

How many triathletes do you think could handle a tt bike without falling off? Slacker angles keep the things a bit more triathlete friendly, different seating position to bias which muscles you use – tri bikes have no uci rules to bother about either.

So fairly big differences.

Sorry mate but you are talking complete cobblers. Triathletes pioneered the use of steeper seat tube angles, not slacker, and these have now been adopted by most of the UK TT scene (where there are also no UCI rules to worry about).

To the OP, almost everyone uses “TT bike” and “Tri bike” interchangeably so don’t worry about that. This article will tell you most of what you need to know about fitting a Tri/TT bike. The key point is that you are rotating your whole body forward so that the hip angle stays the same as on a road bike.

http://www.slowtwitch.com/mainheadings/techctr/bikefit.html

The planet x is a good bike popular amongst tt’ers (Mrs kilo has one) and I use the Ribble cheapo alloy frame. Disc wheels and deeps section fronts & occasionaly frames can be picked up from the classifieds on Timetrial forum. i can’t help with sizing but i would say don’t go for the most radical low front end straight away. I did a course pb this year simply by going back to a higher front end on my tt bike. When Mrs Kilo had a bike fit the guy was saying they ofte had problems where people couldn’t get the bars high enough having gone for some micro fit front end and cut the steerer tube short, adam topham in his tt book goes on about how people drop the bars thinking it’s more aero but in doing so actually expose more of their back and therefore increase resistance.

. So dont pop down your local sanctioned tt on your tri bike.

As mentioned above uci frame rules play no part in tt’s in England and wales run by CTT, they would only effect BC events and these are very, very few and far between (except in scotland). There are a few rules about tri bar positioning and a big no no re very deep section front wheels such as the zipp 1080.

There are certainly a very special breed of person who sets their heart on running TTs. Bless ’em!

That’ll be me 😀 I run club 10’s and an open HC. Club tt’s – keeps the sport going. You can pretty much wear anything, even sleevless tops to encourage triathletes!! Open tt’s no sleeveless and there are rules about advertising / team tops all can be found here:

http://www.cyclingtimetrials.org.uk/Information/Procedure/Regulations/tabid/79/Default.aspx

@trebord – which events are you thinking of doing? I’ve done UK 70.3 and IMUK and would be happy doing either on a standard road bike. The Wimbleball 70.3 in particular is seriously hilly and the climbing is much easier on a road bike.
I did the IM on a TT/Tri bike and found it started to get rather uncomfortable towards the end as you don’t get such a variety of positions to help stretch you out a bit. Clip-ons are OK but it’s tricky to get the arm rests low enough and close enough to get comfy – which is why TT/Tri bikes are shorter and lower.
(I’m also happy using the term TT and Tri interchangeably too as bar UCI regs that control things like how deep you’re allowed to make the tubing, we are pretty much talking about the same thing).
If you’d like more info on how I worked out the sizing for mine have a peek over here:
http://www.spanner.org.uk/2011/05/gallery-ws01-carbon-time-trial-frame-and-wheels-from-gotobike/
TT are great fun for shorter events though, I hit my target of a sub 2:30 Olympic this year at London which would have been much tougher on a road bike.

Cos I’m well ‘ard I TT on fixed. Although you’ve got a few more ‘ard points for considering an Ironman.

Now has a -25° stem for extra rad points and I’ve pushed the saddle forward a bit

Where did you get that from? 😀

That English is stunning.

EDIT: That Andy Wilkinson vid. 541 miles. 😯

The UCI technical rules do not affect TTs in Scotland. Effectively the only TT event where the UCI rules come into play is the British Circuit TT champs.

If you are aiming at an Ironman, that’s quite a specialised sort of time trial. For a short course time trial, you can afford to compromise comfort for aerodynamics, but for Ironman distance, with a marathon to follow, you may find it more effective to compromise aerodynamics for comfort. If you therefore end up riding a less aggressive position, the advantages of using a TT specific bike over a road bike with clip ons may not be so great.
So I would think carefully about whether there is actually much advantage in purchasing a TT specific bike if your target is a longer (and possibly hilly) Ironman course.

Have been known to take part in a few 😉

My frame is the same length top tube as my road bike (540mm) and TBH could be a smidge shorter, but after much fiddling with position it is for a TT bike fairly comfortable.