GT bike sizing question
 

Hey, I'm new to this forum, so sorry ahead of time if I posted this in the wrong place. Anyway, I was planning on getting a GT GTR series 5 or 4 online, but the sizes are unusual. It says Large is 53cm and XLarge is 55cm. I'm 6'2", and I fit perfectly on a 58cm Trek 1.1(2012 model). I also drove a 2003 caad5 r800 that was 60cm and I felt pretty comfortable on that as well. From what I understand, the sizing with GT's GTR series is a little strange(like for the large it says 53cm). I couldn't find any bike shops near my house that carry gt road bikes to see what fits me. Basically, would either a Large or XLarge fit me properly, and if so which one would be better? All help and advice would be appreciated. Thank you.

The sizes numbers on today's frames are meaningless. What you need to compare is the head tube length or stack height of the frame and the TT length (with the proper correction for any difference in the seat tube angle) or the reach. For example, note that the XXL has a 20mm taller head tube than the XL. Although the TT on the XXL is 15mm longer, the reach is not 15mm longer, since the STA is a little less, at 72.5 degrees. That reduces the reach difference beween the two to only 10mm.

The proper size would either be an XL or XXL, but which one would depend on your body proportions and the type of fit that you desire. People of the same height can have much different leg and torso lengths, so posting your height is only on part of the story.

If you've been riding and know your saddle height, from the center of the crank to the top of the saddle, along the seat tube centerline, that would tell even more than your leg length.

http://www.gtbicycles.com/media/pdf/...atalog_GEO.pdf

ftr - I fit comfortably on a Tarmac @ sz 56, I'm ~6-1 and ride a Large GT Series 2 comfortably.

I'm 6'2" and I ride comfortably on an XL GT frame. If I remember correctly, the owner's manual actually specifies that the XL is a 58cm frame, not a 55.

Thanks for the quick replies.

!'m 6'2" and got a 58CM GT GTR (how's that for on point?) from eBay and it was too damn small. The fitter said so at the LBS and the responders said so in this forum after I posted pictures. Perfectly nice bike other than that, but that's obviously a deal killer.

Impossible! I had been fitted at my LBS prior to testing a 58CM Specialized Roubaix which fit perfectly. "Oh," my LBS tells me, "the Roubaix is special and it's probably the only 58CM that would fit you."

After a month I got a 58CM Roubaix. Ironically I got the bike on Thursday of a week between my first two centuries. I averaged 15.3 MPH on the GT and then a week later averaged 15.3 on the Roubaix after a single, short test ride the day before the century.