I’ve been spending a lot of time on the Trek 770 of late, after spending a lot of time on my Madone this summer. I’m amazed by how quick handling the 770 feels, and had initially planned on writing this blog post about the huge differences that happen in bike geometry over the course of 25 years. In all honesty, the 770 was the pinnacle of Trek road bikes in 1985, and the Madone 7 is the pinnacle of today, so it’s apples to apples, even though one is lugged steel and the other is carbon-fiber.
I got out the tape measure and started doing some measurement. Much to my amazement, the wheelbase on the two bikes is within 1/2cm. In fact, if you slide the wheels in the dropouts on the 770, the wheelbase is identical. Rather shockingly, the chain stay length is also within a hair, to my tape measure. According to their published specs,
The Madone has a 52.5cm seat tube length; the 770 is 54.9cm.
The Madone has 4.5cm of fork offset; the 770 is 3.8cm.
The Madone has a 99.3cm wheelbase; the 770 has a 97.1cm wheelbase (at the shortest setting. When pushed back in the dropouts, the wheelbase is about identical).
The Madone has a 56.4cm “effective” top tube length; the 770 is 55.5cm.
The Madone has a 40.7cm chain stay length; the 770 is 41.2cm.
The Madone has 7cm of bottom bracket drop; the 770 is 7.2cm.
The Madone has a 73.5 degree head tube angle; the 770 is identical.
Accordingly, the top tube on the 770 is a bit higher than on the Madone, which throws some of the measurements (such as seat tube length, etc.) off a bit, but the geometry is pretty remarkably similar.
I’ve come to appreciate that the 15% reduction in fork offset, coupled with super-narrow, skinny handlebars, is likely what makes the 770 feel so much more lively/nervous (depending on whether you want a compliment or a pejorative). (If you want a better explanation of fork offset and its significance, click-through to this older post about the Vaya).
Nonetheless, I’m amazed at how close the geometry on the two bikes is, notwithstanding the 2.5 decades between their construction, not to mention their different materials.