An ongoing question we receive from customers is what size frame am I?
There seems to be some confusion going around and I would like to try and make sense of it as best i can from our experience.
So as you may or may not be aware all of the frame now except for the steel models are sloping, and for some time now Colnago have used a relatively moderate 4cm of slope, so what does this mean for your frame size? Simply take the slope away to find your traditional size, for instance i have always ridden a 58cm (c-top) Colnago frame, which means i now ride a 54cm Slope. Seems simple? Not always! We receive quite a few Bike Fit charts from customers and they can be great and also can be very confusing. A recent example was for a customer ordering a C64 Disc and although at first glance the bike fit seemed pretty spot on, they had based it on a 7cm stem....The smallest possible on the C64 Disc is 9cm. After pondering through the sizing charts and talking with the customer the overall reach was possible with the 9cm stem and a size 50cm slope. Basing your frame size on reach or the top tube length can cause problems but has become very fashionable lately. The end result for the frame size was the same but it often seems a backward way of finding this out. And more often than not we are asked to find the frame based on a stem length.
Frame sizing can be over complicated and frustrating for people especially if you are not able to go in for a full bike fit that can be adjusted in real time but there are simple ways of finding your frame size and a method we have used over the decades for our Pro riders and amateur customers alike. Starting from a point of your optimum saddle height you can work backwards from this to find the frame size and trusting the frame builders Geometry the overall reach (Tip of saddle to centre of bars) can be adjusted with the stem size and not the other way around. The biggest issue we have found in the past with some fits is they tend not to take into account the overall geometry of the frame and how you sit on the bike which really needs to be adjusted on an individual basis. And very rarely take into account the frames head angle, a vital point on how you will sit on the bike. There are some super fancy computer controlled jigs out there that don't have adjustable seat and head angles, this doesn't seem right?
Now once this starts to make sense we can throw in the High Geometry option, which again has caused quite a lot of confusion for people. We witnessed this recently after supplying and building up a C64 for a customer in the winter. We received an email a few weeks ago explaining that although he loved the frame he just couldn't adjust to the sloping aesthetics and had ordered a traditional size from a UK Distributor after discussing it with them....After a couple of emails back and forth it became clear he was talking about the High Geometry Option and had been led to believe that it was a non sloping frame. After we explained these were still sloping frames just with an extended head tube for riders needing more stack height he quickly cancelled the order, wether this was a genuine mistake by the shop or not we don't know but it seemed to fuel the confusion over sizing.
It doesn't need to be over complicated and at the end of the day all Bike Fits and frame sizing are opinions and the most important thing is they need to be right for the customer.