I notice that the chain stays on my Giant Defy don't intersect with the seat and top tubes like they do on most other bikes. As you can see in the image, they intersect the seat tube well below where the top tube does. What purpose does this serve? I looked at other relaxed geometry bikes like the Specialized Secteur and did not notice the same construction.

I think if you compared the Secteur frames from size to size, you'd find that they do the same thing Giant does -- they use the same rear triangle geometry on all sizes. Specialized varies the slope of the top tube to flow into the seatstays. It's probably more an aesthetic choice than anything to have the tubes line up.

All the Secteurs on the website have a rear triangle that meets the top tube at the seat tube:

https://www.specialized.com/us/en/bc/...?sid=10Secteur

I have a Defy3 and have always had the same question (well, after realizing that other people's bikes were different).

I figured that's what made it "relaxed," but I don't know how or why.

I called a bike shop this afternoon which is a Giant dealer to discuss what they had in stock and what kind of road bike I'm looking for and that I wanted to test ride a Giant before I pulled the trigger on another brand. I was googling an image search of the Defy and I noticed that and figured I'd try my luck and see if the bike tech on the other end of the line knew the answer.

He said Giant does that because it helps eliminate road vibration that occurs from the rear wheel. When the vibration travels up the seat stays and they directly intersect to the top tube/seat tube, it transfers vibration to the seat post and ultimately the saddle. By dropping the point of intersect of the seat stays it helps eliminate road vibration since it's not directly transferring it to the top tube/seat post area.

I have a Giant Rapid which has somewhat the same geometry. I am trying to think how moving the seat stay below the seatpost really helps? I can tell you that I get enough of a butt-kicking on the ALUXX frame that I like riding the Rapid out of the seat a lot. As per climbing hills...the Rapid geometry is far less conducive to climbing than the Tarmac. I really struggle with the Rapid whereas the Tarmac is like a little goat in it's enthusiasm to climb. That being said - total weight is a factor here as the difference between the Tarmac and Rapid is probably a good 10-11 pounds.

Cheers,

Essex

Just going by what I was told. Logically (to be honest) it makes sense, because it's not transferring vibration directly to where your seat post is located. I test rode the Defy tonight and the parking lot had a solid ripple to it and the bike felt great to me in the 20 mins I test rode it. But hey, just going by what little I've seen and what I was told.

I can see how there may be more of a transfer of vibration to other joints than to the rear end/up the seat post. I am now wondering if I should experiment by removing the Tarmac carbon seatpost (has an Zertz elastomer insert in there) and giving it a shot on the Rapid? Maybe I get less rattled around? One thing I like about the Rapid is that I can take it anywhere and it seems to take a lickin' and keeps on a tickin.' Best with your new bike purchase.

Cheers,

Essex

giant defy advanced 2.

its the carbon fiber version of the regular defy but the geo is the same.

marn - SWEET photo man. I love that action shot. What size bike is that? Did you by chance find that the Giant bikes run a bit larger in size? The 53.5 I tried out felt bigger to me than the 56cm Trek 2.1 did (in some regards).

Essex - Nothing has been purchased... yet. I'm tempted. MAN it was hard to walk away...

those pics are badass.

are you asian? I was having a discussion with a friend today about asian body types on frames. we've always felt that the short leg/long torso combo of most asian bodies makes it look like a frame is too small for us.

Giant uses compact geometry on many of their models. A M/L or 53.5 has an effective top tube length of 56 for the defy and 57 for a TCR. So the 53.5 Giant could be bigger than the trek 2.1

Yeah - I was just looking at the Defy 1 vs Trek 2.1 spec sheets.

Defy 53.5 TT - 560
Trek 56 H2 TT - 560

Defy 53.5 HT - 185
Trek 56 H2 HT - 170

Defy 53.5 Standover - 78.7
Trek 56 H2 Standover - 76.7

The Defy definitely felt a little bigger to me overall, which is strange considering I'm referring to the 53.5 Defy vs the 56 Trek. I can see comparing the 55.5 Defy and 56 Trek being more on par but I was really surprised how "big" the 53.5 felt. I guess I had assumed it would be on the much smaller side for me. I sat on a 55.5 Defy and I almost felt like it was too big for me. Perhaps it was the 575 TT (15mm longer than the 53.5 Defy I was on) and the stem was 10mm longer on the particular 55.5 I rode, making the entire bike 25mm longer (aka, 1 inch) than the setup on the 53.5 Defy I had just gotten done test riding.

I'm beginning to give serious thought about grabbing the Defy 1... But the above brings up a question in which size to get. With a 100mm stem flipped down, I felt as though the 53.5 was solid for me. Likewise, I probably could get away with the 55.5 and a 90mm stem. I still have standover... not much... but I have about a half inch or so of standover. My inseam is right around 32.5, and the "standover" for the 55.5 is considered 32.0. Too close for comfort?? Whatcha think guys - 53.5? 55.5?

thanks for the compliments on the photo. me and my friend are photographers and the action picture is a staged shot with me doing multiple passes at slow shutter speeds.

i'm 5'7" and the frame is a SMALL with a 100mm stem dropped to the bottom of the steerer tube.

giant suggest 5'4"-5'7" for small and 5'7"-5'10" for medium.

i went with the smaller frame because i can use a longer steam, the headtube is shorter than the medium for a bigger saddle to bar drop, and the frame supposedly lighter and stiffer than the bigger medium.

here's a link for the sizes

https://www.giant-bicycles.com/en-us/...ompactroad/45/

i'm filipino. i think im fairly proportional with a 32" inseam.

Thanks for the link bro. Yeah that makes a little more sense looking over this chart. It looks like Giant's suggestions for frame sizes go along the lines of indicating that these frame sizes indeed run a little bigger than other brands. I'm 5'10" and according to Giant, they spec 5'10" to be right in between the 50 and 53.5. That being said, perhaps I don't need to look into the 55.5.

your height is right on the border of a M and a M/L

its all personal preference but if you go with the medium you can use a longer stem.

i was on the border of two sizes and went with the smaller option because i like the stem to be longer for a more stable ride. (also lighter and stiffer frame)

there are some really steep and long descents all over so cal and i prefer the stability the longer stems give.

if you go with the bigger frame with the longer stem you could end stretched out.

if you are able to test ride both frame sizes try to get the store to put the correct length stem on each bike so you can see how the handling changes.

get opinions from the store because even despite the height recommendations peoples proportions could change things quite a bit.

I hear ya man. I had test ridden the Defy 1 tonight in the 53.5cm size. It came stock with a 100mm stem. The stem was at the top of the spacer stack and flipped up. I rode it for about 20 minutes on their test course and liked it a lot, but I knew I would want to drop the bars just a bit if I bought it. I brought that up with the bike tech and he happily flipped the stem for me, making it horizontal to the ground. Blam! Winner! I was a fan, and SOMEHOW had the balls to leave without the bike. (darnit, I hate paycheck-waiting). I think I'll be going back for it though...

I didn't test ride any other size bikes, but I did sit on the 55.5 in the store. I was weary of it, and decided not to bother riding it. Quite honestly I've ridden several bikes recently from other brands, and the 53.5cm Defy was a sure-fire winner for me. I'm anxious to get paid so I can go pick the darn thing up...

Good info. Thanks guys. When I was shopping for my Defy, the LBS initially put me on a M frame. I'm 5'7.5 with a 31" inseam, but I've also got short arms for a guy my size. I felt a bit stretched out on the M, so tried a S and felt more comfortable on that frame. However, my seat is slammed back as far as it can go. Now that my body has gained more flexibility from riding, I sometimes wonder if I should've just gone with the M frame instead. Then again, I suppose I could also try flipping my stem and removing some spacers to effectively lengthen my reach.

Marn - pinoy rin ako. Bring on Mayweather!