The equipment you need to take part in a TT can be as basic as a normal road bike preferably with clip on aero bars (forward pointing bars that clip on either side of the stem that allow you to assume the aero position) right up to a full top Johnny banana aero TT machine… and anything in between.
The most important/effective aspect of you and your equipment is to be in the aero position. This is achieved by leaning on aero bars on your elbows with your torso as parallel to the road as possible. The main difference to road bars here is that you will need separate brake levers and gear levers. The bar end brake levers are mounted onto the handlebars and the bar end shifters are mounted forward on the end of the aero bars with pads to lean on around the head of the stem.
The next most important part of the package is wheels and tyres. A lot of TT bikes have rear disc wheels, these help with the aerodynamics as there is less turbulence and a greater gyroscopic effect than with a normal spoke wheel, they are also a lot stiffer. You will eventually want to run tubular tyres instead of clinchers. These allow for a higher pressure and are thinner therefore give a smaller contact patch with the road and a lesser rolling resistance and faster times…
The frame: a normal road frame will have a slightly slacker geometry, a TT bike will have a more upright geometry and will be a lot stiffer than a road frame, much like a track frame. This allows for more of your precious effort to go un wasted and get transmitted to the road.
Drive train: these days compact chain rings are common place, front chain rings will be 50/34 with 25/12 rear cassette. As most TT’s are preferably run on a flat ish course, a larger front chain ring say 53/36 and a smaller rear cassette of 25/11 is more desirable, this gives you more power/length on the flat/downhill parts of the course. There is also a current trend for asymmetric chain rings like Rotor Q-rings or Osymetrics.
The set up of the bike is different to that of a road bike as well. A TT bike will be set up with the bars being as low as possible to help with the aero position, sometimes the stem points downward at 24 degrees. The saddle is further forward than that of a road bike as the power (you) needs to be positioned more over the bottom bracket, watch a TT race see the riders “on the rivet” that is their bums forward most on the saddle. Try it, it’s very effective…
Then we come to the clothing etc. Close-fitting skinsuits shave off a surprising amount of time. The right helmet will channel the air over your head and down your back saving energy and time. Even small accessories like shoe covers and aero gloves do their bit to save precious seconds, as will shaving your legs (probably!)
TTist, MTBer, Roadie