Building a TT bike

lackofgrip

I am looking at building a TT bike and was wondering if I can use any frame, or are the geomterys vastly different?
I can get hold of a nice road frame at a good price but was wondering if I can just adjust the handlebar height saddle fore/aft to compensate?

chrisvanderkaap

it'll become a little bit of a franken-bike if you ask me. Apart from its aero-distinct shape the geometry of a true tt-tri bike is very different. This difference is mainly noticeable in the seat tube angle. There are specially kinked seat masts that correct for the difference in angled but somehow I've only seen this used in the nineties. I think the sloping toptube of modern bikes is to account for that. Even with less than perfect clip on aero extensions you won't really be able to position your upper body over the steerer, so as to lean on your bone structure and instead be hanging and pulling yourself onto the bars. Of course it all depends on how many TT's you're actually going to do. Give it a good try at your LBS!

lackofgrip

Thanks for the advice, off to Planet X it is then lol

markos1963

The geometry is paramount if you are going to have a dedicated TT bike. A steep seat tube angle is needed to get your body as far over the BB as allowed to be able to put down the power. Then obviously a short head tube to then allow you to get a good aero position. It's unlikely you'd be able to achieve this with a standard road frame(especially with all the 'sportive' type frames out there). Aero tubes, internal cable runs and hidden brakes are all desirable but not essential so you don't have to pay big bucks for a frame get the one you fit the best first and foremost.

lackofgrip

markos1963 wrote:

The geometry is paramount if you are going to have a dedicated TT bike. A steep seat tube angle is needed to get your body as far over the BB as allowed to be able to put down the power. Then obviously a short head tube to then allow you to get a good aero position. It's unlikely you'd be able to achieve this with a standard road frame(especially with all the 'sportive' type frames out there). Aero tubes, internal cable runs and hidden brakes are all desirable but not essential so you don't have to pay big bucks for a frame get the one you fit the best first and foremost.

Where's best for a frame? I'm 6ft 6"

markos1963

lackofgrip wrote:

markos1963 wrote:

The geometry is paramount if you are going to have a dedicated TT bike. A steep seat tube angle is needed to get your body as far over the BB as allowed to be able to put down the power. Then obviously a short head tube to then allow you to get a good aero position. It's unlikely you'd be able to achieve this with a standard road frame(especially with all the 'sportive' type frames out there). Aero tubes, internal cable runs and hidden brakes are all desirable but not essential so you don't have to pay big bucks for a frame get the one you fit the best first and foremost.

Where's best for a frame? I'm 6ft 6"

Best to find a LBS who stock TT frames and have the time and expertise to fit you to the frame. You can use on line companies like PlanetX if you know what you want size wise. A general rule of thumb is if you think you are between sizes then go smaller for a TT bike. Personally I would go to a shop for my first TT bike.

lackofgrip

Cheers will do, I live near Planet X anyway

danlikesbikes

chrisvanderkaap wrote:

it'll become a little bit of a franken-bike if you ask me. Apart from its aero-distinct shape the geometry of a true tt-tri bike is very different. This difference is mainly noticeable in the seat tube angle. There are specially kinked seat masts that correct for the difference in angled but somehow I've only seen this used in the nineties. I think the sloping toptube of modern bikes is to account for that. Even with less than perfect clip on aero extensions you won't really be able to position your upper body over the steerer, so as to lean on your bone structure and instead be hanging and pulling yourself onto the bars. Of course it all depends on how many TT's you're actually going to do. Give it a good try at your LBS!

Phillip Graves rides an S5 frame as a full TT set up & has been setting some impressive records since last year on it.

chrisvanderkaap

Danlikesbikes wrote:

chrisvanderkaap wrote:

it'll become a little bit of a franken-bike if you ask me. Apart from its aero-distinct shape the geometry of a true tt-tri bike is very different. This difference is mainly noticeable in the seat tube angle. There are specially kinked seat masts that correct for the difference in angled but somehow I've only seen this used in the nineties. I think the sloping toptube of modern bikes is to account for that. Even with less than perfect clip on aero extensions you won't really be able to position your upper body over the steerer, so as to lean on your bone structure and instead be hanging and pulling yourself onto the bars. Of course it all depends on how many TT's you're actually going to do. Give it a good try at your LBS!

Phillip Graves rides an S5 frame as a full TT set up & has been setting some impressive records since last year on it.

I think it's his talent that brought him that. The s5 however not a typical road bike in the sense that it's specially designed for wind cheating aerodynamics and has a seatpost (with two slots) that allows for a much more forward position. It's really up to personal preference and the special needs of your body that'll make a bike fit or not. Not a sales pitch by a rider who's heavily sponsored or a brand's cunning marketing.

Planet X is a great place to start if you can find it! I heard it's somewhere near Krypton.

danlikesbikes

I know I was just using it as an example (was reading his blog the other day & it reminded me he uses a road frame for his TT's). The amount of biking & TT races he does I think he would be setting records on a tricycle from Argos!!!!

I do agree that it is partly about geometry but also the areo design of the frame I recently saw a semi- pro fellow competitor and asked about their set up & they advised they need a TT style bike for longer races, TT bike for specific races & road for standard drafting distances and who use the Blue AC1 frame as he cant afford to run 2/3 different bike set ups.

It can be done, but you do need to consider your bike & its frame carefully.

John.T

It is quite possible to get a good TT position on a road frame but it moves the weight forward which affects the handling. TT frames tend to be a bit longer in front of the BB and also have slacker head angles. Even then they are not as 'lively' as a road bike.
Aero frames are all very well if you are trying to save fractions of seconds but a good position and handling on a less aero one will pay dividends for the average rider.