How big is a Mediium Giant?

samoff

I'm about to upgrade my old Giant OCR, which is sized simply as 'M', to a Trek 1.7.
Is it safe to read of the tube length of the Giant to size the Trek?

I reckon I want a 56 or a 58, but I can't try one out because buying through CycleToWork. Our HR has signed up with Halfrauds who, in my area at least, don't actually sell bikes.

All I know for sure is that my Medium-sized Giant fitted me fine. If it was a matter of choosing slightly bigger or slightly smaller, I reckon I'd go for the bigger one.

Compton77

I've recently sold a FCR1 2007 in Large, that seemed a bit big for me though I am 5'11". I had a Lemond Versailles which was a 57 which, again, felt a bit big. This has been sold! I am now the custodian of a Cervelo RS in 54 which is fantastic. My advise would be to go smaller frame-wise, you can always add length by swapping the stem for a longer item. Your a bit limited with shorter stems, unless you start with a 140mm of course..!

meanwhile

samoff wrote:

I'm about to upgrade my old Giant OCR, which is sized simply as 'M', to a Trek 1.7.
Is it safe to read of the tube length of the Giant to size the Trek?

I'd go to Trke's own UK forum -

http://www.trekbikes.com/uk/en/general/terms_of_use/

- give my inside leg and height, and see what they say. There's usually someone official around on most manufacturer forums to give guidance. And most bike co's have them these days.

Pirahna

As I'm a bit bored, a quick look on the relevant websites shows:

A medium OCR has a 55cm top tube and 170mm head tube

A meduim Trek 1.7 has a 55.7 top tube with no head tube measurement given.

The Giant has a tall head tube. Modern compact geometries tend towards shorter head tubes, and I'd guess that to get a similar riding position on the Trek you'll need a stack of spacers as well as a shorter stem.

To compare Giants, the medium TCR has a 20mm shorter head tube which is probably closer to the Trek sizing. I'd go into a shop and measure them.

samoff

Thanks for the replies. All these oddball geometries really are confusing to your average layman.

I've actually done the sensible thing for a change and gone to my LBS for a fitting. Just as well, as it turns out I'm a bit of a freak: body that would suit a 52 but legs best fitted to a 60. It's going to take another visit to decide between a 54 & a 56.

Pirahna

My wifes bike would be a perfect fit for you, but I had the frame custom built. The only off the peg frame I've found that came close to fitting properly, tall with a short top tube, is the older Scott cyclocross. She uses one as a winter bike.

JesseD

I have both a medium Giant and a 56cm trek.

The medium Giant is a little small for me and the Trek is OK but the head tube is too low.

I would aliken the medium Giant to a 54cm Trek personally.