[DRLski]

Typically how much shorter is the top tube length of a time trial bike compared to what you would normally use for a road bike? I ride a 54cm top tube on my road bike right now, if I get a time trial bike with a seat tube angle of like 74.5-75 degrees and say a 250mm length bar extenders, would I be looking for a 53cm top tube? Would I want to go shorter than that?

 

[Tri Slow Poke]

Time trial bikes are funny in that they are all measured differently. The general rule of thumb is to get a TT bike with a top tube a few centimenters shorter than what you ride in a road bike. Otherwise, you may find your arms too stretched out in the aero bars and have shoulder/upper neck pain.

 

[sscooterguy]

Yes, time trial geometry can get funky. Definitely go to at least one or two stores and check it out. I personally ride a medium Giant OCR series road bike with a virtual top tube of 55 cm and ride other brands 53-55's. My cervelo p2sl time trial bike was a 51, which is a small once everything else was appropriately adjusted (stem, aerobars, seat).

Good luck.

 

[CurbDestroyer]

Find what your position needs are, then find a frame to fit those needs.