Giant Defy - Size

[bpsmith]

That is largely marketing bs now as so many other brands use sloping top tubes too. Giants don't slope significantly more than the other slopists.

The dimensions are way transferable, I don't really get what you mean. Simple cross referencing of the different geometry charts shows which have dimensions similar to a giant defy of a given size, regardless of the number or capital letter on the frame. BB

Yes, other brands have also followed suit with the sloping tubes, but it doesn't necessarily follow that they use Compact Frame geometry.

A brief Google, shows the following link further explaining some example frame sizing for Giant.

https://www.cyclestore.co.uk/contentPages.asp?pageID=61

For example, you cannot compare the TCR to other bikes by simply taking a measurement of any part of the bike. A Medium is a 50cm frame, which measures 55.5cm at the top tube, but equates to a 54cm frame with other brands which suits someone 5' 6" to 5' 9" tall. There's no Marketing BS there.

 

[bpsmith]

I still have no idea what they are actually measuring - centre to centre or centre to top?

As above, which further emphasizes the need to seek guidance from the Brand and/or a Dealer for expert fitting advice.

 

[tincaman]

Defy Advanced 2 here, small size @ 5ft 7

 

[youngoldbloke]

I think they are being deliberately abstruse, making it difficult to compare with other manufacturers frames. I have a Ribble 7005SL - sloping top tube. Seat tube 44cm centre to centre, ACTUAL top tube (c to c) 510mm, Virtual top tube (c to c) 535mm. I don't know the frame angles or head tube dimensions off hand, but it sounds pretty close to 'compact frame geometry' to me. IF I wanted to buy a Giant I would like to be able to compare the frame geometry BEFORE making a (for me) long journey to the nearest Giant dealer. Their (and others) refusal to give bike weights is likewise annoying.

 

[bonsaibilly]

Yes, other brands have also followed suit with the sloping tubes, but it doesn't necessarily follow that they use Compact Frame geometry.

A brief Google, shows the following link further explaining some example frame sizing for Giant.

https://www.cyclestore.co.uk/contentPages.asp?pageID=61

For example, you cannot compare the TCR to other bikes by simply taking a measurement of any part of the bike. A Medium is a 50cm frame, which measures 55.5cm at the top tube, but equates to a 54cm frame with other brands which suits someone 5' 6" to 5' 9" tall. There's no Marketing BS there.

My opinion on the example above would differ from yours then, because a top tube that measures 55.5 cm on one brand isn't equivalent to one that measures (and gives its published "size" as) 54 cm on another. The TCR's Medium is somewhere around a 56 in eg the Specialized Tarmac which is a roughly equivalent type of bike - both have around a 56 cm effective top tube. In fact the TCR (and Defy) in a Medium is slightly smaller than a 56 cm Tarmac (which the geometry does tell you quite clearly) which is why a lot of Giant riders hover between the M and the M-L where an equivalent Tarmac rider would ride the 56.

The only observation I was making was that Giant's stated "size" is based on the seat tube length whereas several other brands stated "size" is based on the effective top tube length. But that the effective top tube length on the Giant is (give or take) the same as that on those other brands, thus the bikes are in rough terms the same size, regardless of the fact that one calls itself a 46.5 and the other a 52. This should be obvious by checking the respective geometry charts, at a basic level the median-sized bike of equivalent type across brands will have roughly equivalent dimensions; it's self-evident.

I accept that every bike is *slightly* different both geometrically and proportionally and try before buy is the best approach, but it isn't mutually exclusive that they will be of similar size and proportion for a given size (whatever the brands choose to call each size).

The marketing BS I was referring to is around Giant's sloping geometry being somehow unique (it isn't any more) and/or inherently more sloping than other slopies (it isn't). BB

 

[bpsmith]

I believe we are pretty much saying similar things @bonsaibilly. I ride a Medium at 5' 9" tall with a 32" inseam. Giant shop equates the Medium to being a 54cm bike in other brands. I ride a 55cm on my Bianchi. Just shows that top tube or seat tube measurements for sizing means nothing, basically. There's a bigger picture to consider.

 

[mrbikerboy73]

@Glasgow44 I could have written this thread as I'm also 5'6" with a 29" inside leg. I have two Defy's and they're both size Small and they are spot on. Not sure why they came with different length stems but that doesn't matter, I've sorted that and they are perfect.

 

[Dave7]

Hi there
I’ve made a few postings about getting my first road bike Anyway, I have narrowed it down to this bike:
http://www.giant-bicycles.com/en-gb/bikes/model/defy.2/24964/90519/#geometry
I have put down a deposit and ordered this in a small frame size. The bike shop I went to in Glasgow has said that a small frame with this bike would be the correct size.
I’m a bit confused because, according to the chart, a small size frame on this bike is only 46.5cm – see below:
http://www.giant-bicycles.com/en-gb/bikes/model/defy.2/24964/90519/#geometry
On other road bikes I have tried for size, it has been a 51cm but I was told that this particular bike has different geometry and that a small (46.5cm) size is correct. I do know that different manufacturers size their bikes differently (cm, inches, S, M, etc).
I’m 5’6 with a 29 in inside leg if that helps.

I am also 5'6" and 29" inside leg. I got the Defy in small and it is just about OK. It was the only one left with 40% so I took it. I have the seat post extended to the absolute maximum***. So my advice would be........next size up if possible but small will do if that's all they have.
***Allow me to amend that statement as I have just re-checked. It is my Giant hard-tail that is fully extended.........the Defy 'small' is indeed fine for me.
Sorry If I caused any confusion.