John has noticed that top tubes or crossbars are now running down. From the head tube to the seat tube, unlike the more traditional frame designs where the top tube is horizontal. Does he want to know why this is? These are the reasons:
Question:
Why does the cross bar on bikes are not straight like the originals. but at a slope or off lower down the down tube?
Answer:
Hi John,
The slopping down tube or crossbar was a design that originally appeared on Giant bikes quite a few years ago.
There are a few different reasons for this design:
First, it makes the main triangle and the rear triangle smaller. So that it will be lighter and stiffer than the more traditional frame design.
Secondly, it cuts down the number of different frame sizes that the manufacturer has to produce. Now they need only small, medium and large and then possibly an extra small and an extra-large. This is great for carbon frame production as mold has to be made for each size and they are very expensive.
The handling of the frame is very similar to the original designs and some frames feel more “lively” with the compact design. Is this what you needed to know, John?
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