are giant sizes different to others?

llywmog

looking into getting the cube agree gtc race.

currently ride a giant defy 1 in medium. checked giant's site for geometry and they pretty much match those of a cube agree 58cm.

that doesn't sound quite right to me, as I would expect to ride a 56cm as I'm 5"10 with 33" inside legs.

Unfortunately there are no cube agrees for me to try out for size around here.

are giant's geometry a little different to other manufacturers and should I go for the56cm, or should I go for the same geometry and opt for the 58cm?

Cheers

ALaPlage

Bike fit constant is you with the variable being the bike make. As Bike Geometries differ by manufacturer and bike type there are differences so one 56cm bike may feel completely different to ride.

Definitely worth try before you buy however where a manufacturer gives height and inside leg guidance then I would say thats the safest way to go if you can't get to sit on your bike of choice before ordering it.

I'm 5'11" with a 32" inside leg and fit a 56cm Trek however a colleague at work with the same measurements as me rides a 54cm Ridley. When I tried his bike and he mine we found the riding position to be perfect for each of us.

aspender

I test rode a 58 GTC Race today as I'm also planning a purchase of one. I'm 5'10" and 32 trouser leg.

I went expecting to need a 56 as that's what I ride currently (Specialized Secteur) I sat on a 56 Litening and it was tiny. Tried the 58 GTC after they built it up for me and took it for a ride. It was perfect. Looking at the geometry info on the 58 GTC and my 56 Secteur confirms that Cubes seem to size one smaller than most other manufacturers.

night_porter

The most important measurement is the top tube length or in the case of compact frames the virtual/horizontal top tube length. This is because it is a constant for the size of the bike whereas all saddles can be raised or lowered to suit the rider.

I too own a Giant Defy 1 and although my M/L frame has a 53.5cm size the virtual top tube is 56cm. According to Giants website the M is 50cm with a 54.5cm virtual top tube.

I just checked out Cube's website and it says (if you translate it) that a 58cm frame has a 56cm horizontal top tube so I would guess that it is more like the M/L of the Defy range.

It is of course possible to change the stem length but this is harder than raising the seatpost and there is a limit to the changes you can make. If a frame is too small it is easier than if a frame is too large but you will also have the problem that the bars may be too low so getting the right size to "tweak" from is relatively important.

I don't know the Cube but a quick look would suggest you need to investigate the figures yourself because it looks like a 56cm (with a horizontal top tube of 545mm) looks the same as your Giant to me.

Of course the geometry only tells you so much and an actual test ride will tell you so much more providing the bike has been "tweaked" to suit your needs or confort.

llywmog

thanks all for your input.

after reading aspender's comments, i've taken a gamble on a 58cm.

the medium giant is comfortable to ride but I'm sure i can fit a larger bike.

worse scenario i'll have to pay the return delivery costs so no big problem.

fingers crossed it's all ok.

anto164

Giant's geo is compact, so the sizes seem smaller.

BTW, the 58 will be way too big.

I'm 5'11", and i ride a 53.3 ML. (The large felt too stretched, and the L is 55).

Mate rides a 58cm, and he's 6'7"

thescouselander

Just a bit is extra info. I'm 5'11" with a 31' inside leg and my Defy is the M/L. It fits quite well but I had to move the seat all the way forward on account of my stubby legs.

llywmog

aspender. you were right. the 58cm was spot on. the seat is right at the bottom limit to be exactly right for my legs but arm length is perfect.

can't wait to get out on her now.