Colnago K-Zero Geometry

The announcement of the new K-Zero bike has caused a bit of a stir as it looks like Colnago are taking TT/Tri development seriously. I’ve done a bit of work on extracting useful information from the sparse geometry data that’s offered and figured I’d share what I’ve learned for anyone who might be considering this bike.

One of the services I offer is matching a riders position from an existing bike (or from the fit bike) to a potential new bike. Which means that I maintain an extensive database of frame geometry so that I can compare the fit and handling of the different options.

Some brands offer all the information I (or any other advanced fitter) need. Others are a bit more frugal in what they provide. Colnago are a brand that plays their cards close to the chest geometry wise – they think their steering geometry is the magic sauce that differentiates them…

For road bikes this still seems to work for them, but for TT/Tri bikes the market is used to Reach & Stack data so that clear comparisons can be made.


The chart to the left is colour coded – black numbers are what Colnago provide. Red numbers are assumptions and blue numbers are calculated figures.

First the assumptions:

Colnago always use (afaik) 43mm rake forks, so that’s a logical figure to use.

The fork length is clearly higher than normal in order to fit the rear mounted brake caliper (notice the gap above the tyre). Using a graphics program I measured the length at just over 380mm (I was able to measure the 108mm Headtube to within half a mm so the method is pretty good) but used 380 as a conservative guess. For reference – most forks are 368-372mm.

And Colnago typically use BB drop of 68mm plus or minus a couple of mm (and measuring on the picture indicates that this is the case here).

For the calculated figures:

The head tube angle is derived from the Front-Centre and Top Tube measurements.

Trail uses the Head Tube Angle and Fork Rake.

Wheelbase is a combination of Front-Centre and Chainstays (with BB drop thrown in too)

Finally the Reach and Stack use most of the other measurements to define the fit of the frame. I offer no guarantees but these calculations should be within a few mm of reality and are enough to know whether the K-Zero is a possibility for matching your current position.

Of course, the next piece of the puzzle is the dimensions for those integrated bars, which appear to have a stack of at least 50mm, but we’re just going to have to wait and hope that Colnago feel like giving some info when the bike becomes available.

Bike image is from the Colnago website




Leave a Reply

Your email address will not be published. Required fields are marked *