Confused about frame size

annekcm

Hi all,

I've got my heart set on a Cannondale Caad8 so I went to my LBS and they quickly told me that a frame size 58 was the one for me. I have no experience of road bikes so thought nothing of it and it felt comfortable enough to me but then again I don't really know what it's supposed to feel like!

Then I began looking it up online, and people of similar dimensions to me are talking about having 56s and even 54s. So I really don't know what to go for.

I'm 184cm(slightly over 6ft)
My inside leg is 85cm(33.5")
My ape index is 1, ie my arm span(fingertips to fingertips) is the same as my height.

Do those sort of dimensions sound right for a cannondale 58?

Thanks.

Grill

Possibly. Realistically anywhere from 54-58 could be right for you (54 is the least likely unless you have severe flexibility issues). You should try a 56 and 58 to see which one you're more comfortable on, or go to a shop that has a proper fitting service.

petej07

Having just gone through the same process you describe, you must try for size in a shop. After weeks of research I tried a Caad8 58cm but it was way too big. I am 6ft 33in leg and 1" + on ape index. The shop didnt have a 56cm so couldnt try one.
I also asked a web shop what size I would need in a Raleigh revenio 3 given my dimensions above. They said without doubt 56cm. I went to a shop who had one 56cm in stock and it was too small.
The bottom line is that you must try for size and fit before you buy. In my experience the sizes of bikes are all different and to get the right size you must physically sit on the thing to determine if it is right for you.

kajjal

PeteJ07 wrote:

Having just gone through the same process you describe, you must try for size in a shop. After weeks of research I tried a Caad8 58cm but it was way too big. I am 6ft 33in leg and 1" + on ape index. The shop didnt have a 56cm so couldnt try one.
I also asked a web shop what size I would need in a Raleigh revenio 3 given my dimensions above. They said without doubt 56cm. I went to a shop who had one 56cm in stock and it was too small.
The bottom line is that you must try for size and fit before you buy. In my experience the sizes of bikes are all different and to get the right size you must physically sit on the thing to determine if it is right for you.

This is the best advice. Frame size is only a guide. I am over 6ft6 and ride a 62cm framed trek which after a few setup adjustments is great for my riding needs. You need to ride a few bikes to find the right one. Don't forget if a bike is too big there is little you can do. Slightly too small and there is a lot of room for adjustment.

mattsccm

Too many people want to be labelled an exact size and then expect that to fit.
It's the same as shoes. Your measurements are fixed. (well relatively) but every manufacturer makes their product in a different way so one will not be the same as another. Your own known measurements give you a guide to roughly what size to try on but then you try different sizes, bigger or smaller until it fits. When you then try a different make you start again. Its the same for shoes, clothes, in fact anything that goes with the human body.
Like shoes you wouldn't buy an unknown make without trying them on would you? In fact you would be unwise to buy another model from the same manufacturer without trying them on.
Of course you may be lucky and with a 5 quid pair of sock it may not matter. With a bike you try it on.
Where you worry is when different shops recommend different sizes of the same bike. I would then be asking them to qualify their advice. An experienced shop will be in a position to give advice based on experience about what will probably fit but no more.