Sizing Question

catweazle

Not ideal I know but I am looking at a TT bike online which is a good deal for the price- no more than me hes no expert on sizing - we are working it out that both of us are 5'9 and he says it fits him fine. The measurements I am getting aren't what I normally try and work it our from. Would anyone know what the below would equate to approx

The floor to the seat measure's approx 37"
The pedal's axle to the seat measure's approx 26"
The handle bar axle to the seat measure's approx 20"
The handle bar axle to the pedal axle measure's approx 24"

Zippe

catweazle wrote: »

Not ideal I know but I am looking at a TT bike online which is a good deal for the price- no more than me hes no expert on sizing - we are working it out that both of us are 5'9 and he says it fits him fine. The measurements I am getting aren't what I normally try and work it our from. Would anyone know what the below would equate to approx

The floor to the seat measure's approx 37"
The pedal's axle to the seat measure's approx 26"
The handle bar axle to the seat measure's approx 20"
The handle bar axle to the pedal axle measure's approx 24"

Hey,
Not sure what hight you are but you need to get the these measurement's of the bike your looking at,and then work out how it needs to be set up for you,
(1) Center of bb 2 center of top tube where the seat post enters the frame
(2) Center of seat tube to Center of steering tube

Then you will need to find out what these measurement's need to be for you,if the other guy your buying off is the same hight as you and if he has longer legs shorter body or shorter legs and longer body,this is something you need to look at,tt bikes are ridden a size smaller than your road bike for most people,

(1) Tip of saddle to tip of tri bars (tt shifters)
(2) Center of bb to top of saddle
(3) Tip of saddle behind bb
(4) Stack hight (top of elbow pads to Center of bb)

The sizes you have from the ground up are not the right way to work out if it suits you need to work off the bb,a bike fit is the best way to get set up and well worth the money,if your setting the bike up for UCI regs your saddle needs to b 5cm behind the bb,

Cheers zip,

eoglyn

This is bizarre i was coming on here to ask the same question abou the sizing of TT bikes. I currently have a 56cm frame road bike and am 180cm in height (5'11'' in old money). I am in the market for a second hand TT bike and i am thinking that, based on what's on sale that a 54cm frame might suit me best. What do people think - would you get a more comfortable or better aero set up with a slightly smaller frame, is it possible to get both?

catweazle

Heres my answer from that - hes a yank so I assume he is working off inches so I have converted his measurements and rounded them off to the nearest cm. I assume the most important one is the 51cm - given that I ride a 54cm road bike and that TT bikes usually fit smaller I wonder is it worth the chance?

Center of the bottom bracket (in between the U & J) to the bottom of the seat post near the frame is approx 15" (38 cm)
Center of the bottom bracket (in between the U & J) to the seat is approx 20" (51cm)
Center of the seat tube to the center of the steering tube is approx 22" (56cm)