A bike fitting first: Angular head pin on an X/Y fit bike
Written by: Dan Empfield
Date: Thu Jun 12 2008
It's one small step for man, one giant leap for bike fitters. Ves Mandaric (pictured with his new angular head pin), former master framebuilder for Quintana Roo (when I owned it), is now offering for sale an angular head pin for his otherwise X/Y adjustable fit bike.
The fit simulator, which Mandaric calls the Kobila (which means something in Serbian, but I keep forgetting what) generates as an output "stack" and "reach," the metrics used by F.I.S.T. tri bike fitters when generating custom geometries, or finding production bikes that match the fit coordinates of their customers.
The benefit of fit simulators like the Kobila, as well as Serotta's fit bike, and simulators made by Tiemeyer and Bikefitting.com, the Rob King fit bike, as well as the Waterford Fitmaster after completion of certain simple retrofits, is that a fitter can change the length of the aerobars without affecting the height, and vice versa. Certain of these bikes (Tiemeyer, Serotta) go further, and calculate the X and Y measures from the bottom bracket to the handlebar clamp. The Kobila measures X and Y to the head tube top.
The fit simulator, which Mandaric calls the Kobila (which means something in Serbian, but I keep forgetting what) generates as an output "stack" and "reach," the metrics used by F.I.S.T. tri bike fitters when generating custom geometries, or finding production bikes that match the fit coordinates of their customers.
The benefit of fit simulators like the Kobila, as well as Serotta's fit bike, and simulators made by Tiemeyer and Bikefitting.com, the Rob King fit bike, as well as the Waterford Fitmaster after completion of certain simple retrofits, is that a fitter can change the length of the aerobars without affecting the height, and vice versa. Certain of these bikes (Tiemeyer, Serotta) go further, and calculate the X and Y measures from the bottom bracket to the handlebar clamp. The Kobila measures X and Y to the head tube top.
But the problem has been the need to calculate the "negative reach" when using the Kobila, a process explained in an earlier article. The new angular pin makes the Kobila the first bike to adjust in an X/Y axis while also pitching the stem back at a traditional 73 degree head angle.
Fitters using the Kobila may now put the actual stem on the fit bike that will go on the bike the customer intends to ride, along with any spacers under the stem that the fitter thinks should be on the subject's bike. Then, after the fit process is complete, the fitter reads the stack and reach measures off the Kobila and compares these to the specs of all the tri-specific production bikes found in the stack and reach database.
The other alternative available to fitters is to use stack and reach metrics to "back into" custom bike geometry. Slowtwitch.com has just finished its online geometry calculator, and will unveil it to its F.I.S.T. trained fitters within the week.
Fitters using the Kobila may now put the actual stem on the fit bike that will go on the bike the customer intends to ride, along with any spacers under the stem that the fitter thinks should be on the subject's bike. Then, after the fit process is complete, the fitter reads the stack and reach measures off the Kobila and compares these to the specs of all the tri-specific production bikes found in the stack and reach database.
The other alternative available to fitters is to use stack and reach metrics to "back into" custom bike geometry. Slowtwitch.com has just finished its online geometry calculator, and will unveil it to its F.I.S.T. trained fitters within the week.
Information on Exit Cycling's fit bike can be found by calling 760-736-4427, or via email at sales@mandaric.com
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