Greetings one and all and Happy New Year...
My question is a straight forward one concerning Trek and their sizing. I have heard that Treks run a little small...does anyone here have any information about that...? If so where does the information come from...? I'm thinking of getting a new bike and I want to be sure before I leap. Thanks.

Compared to the most typical center to center or center to top methods of measurement, a Trek frame of a given size will be vertically smaller than most other brands, because they use the entire seat tube length as the "frame size". A 58cm frame, for instance, might only measure 54.5cm c-c.

What you really need to look at is the head tube, with the headset to determine vertical size. The new Madone uses an integrated headset (typically 15mm tall) , while older models use a taller conventional headset with a 25-30mm height.

Treks tend to be a bit long in TT length compared to most other brands, although you must also consider the seat tube angle to determine frame reach. Steeper STAs increase the reach by about 1cm per degree.

When looking at 2008 Treks, keep in mind that some road performance models are measured differently for nominal frame size than they were last year.

Madone 5.1 through 6.9 are now measured (both for nominal frame size and effective top tube length) to a "v" dot on the seat mast. The dot marks the spot where a virtual horizontal top tube would intersect that mast. Madone 4.5 and 4.7, Series 1, Series 2 and Pilot are measured to where a virtual horizontal top tube would intersect the seatpost. The TI track (except for the 62 cm) and FX is measured by actual seat tube length, with FX nominal frame sizes given in inches.

Accordingly, most of the 2008 Trek road bikes may no longer "run small." But even with the new sizing scheme, nominal frame size isn't the important fit dimension, as explained in C-40's reply.

Trek's latest geometry drawing actually shows one endpoint for the horizontal TT length to be at the top-center of the head tube. While unusual, it doesn't create much difference in the TT length mesurement, even if the STA and HTA differ by 2.5 degrees. The Trek frame with a 120mm head tube length is called a 54cm, while my LOOK frame, which is measured by the traditional c-c method, having the same head tube length is called a 51cm. The Trek frame has about 6mm more reach. To get the same reach as my LOOK, I'd have to drop down to the 52cm frame and settle for a 10-15mm shorter head tube.

Whether the horizontal line crosses the seat post or seat mast makes no difference, but it's nice that they marked the point on the seat mast. Trek also lists a stack height and reach mesurement, just like Cervelo. The concept of reach is useful, but still has a major drawback. To compare the reach of two frames, they must have the same stack height, otherwise there can be significant errors in the comparison - about 3mm for each centimer of stack height sifference. If you're trying to decide between two frames sizes, you still have to add 3mm per centimeter of stack height to the reach of the larger frame to figure the difference in stem length.

The Trek frame with a 120mm head tube length is called a 54cm

True for the 5.2 Pro through 6.9 Pro Madone 54 cm frames. The plain 4.5 through 6.9 Madone 54 cm frames have a 15 cm headtube.

Nothing to do with the topic, but I posted that older photo. The recently improved seat cap clamp appears dark grey or black, not silver. The seat cap was also modified. A dark clamp is the identifier for both modifications.

Thanks for the info so far...actually what I'm looking to do is go FROM my 2006 Trek 5200 to a 2008 Orbea Orca the Orca comes in a 57 and I am currently riding a 58...

Thanks again...

Thanks for the info so far...actually what I'm looking to do is go FROM my 2006 Trek 5200 to a 2008 Orbea Orca the Orca comes in a 57 and I am currently riding a 58...

Thanks again...

Well, here I was trying to unload a new Madone on you :D

To just briefly answer your original questions: yes, all Treks ran small vertically, and C-40 explained why. A good case in point is your 58 cm 5200 with its short 14 cm head tube. The 57 cm Orca you're looking at has an 18.2 cm head tube, so the bars will be coming up to meet you.

That the slightly smaller Orbea will not be really noticed. I can't seem to find the geometry specs for the 06 Trek anymore it would be nice to know the TT length and STA to compare to the Orbea...but me-thinks i'll be comfortable on the 57...

Thanks...

but me-thinks i'll be comfortable on the 57...

Thanks...

If you're at least reasonably comfortable on the 5200 now, I agree. Enjoy the new bike :)