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29er / Re: Carbonda fm936 Thoughts
« on: July 10, 2020, 09:41:39 PM »
I have a hard time of trusting any of the Chiner geometry drawings. Not because they are trying to deceive or are just getting it wrong. These open mold frames go through so many iterations that the one we see posted might not be the final iteration or at least the drawing is not updated to the most current geo numbers.
Having said that, you need to at least have a starting point to begin with. Without having a frame here in front of me to measure I have no choice but to reference the drawing. If I were to assume the drawing as listed on their site is accurate at 100mm travel, then according to my calculations shock travels would be as follows:
40mm shock = 101mm travel
42.5mm shock = 105mm travel
45mm shock = 112mm travel
My calculations come from a CAD program that has been used in Motorsports for years to model suspension kinematics and is dead nuts on!
Could you model the NS frame dimensions as well? Curious how it stacks up b/c the rear triangle measurements look the same to me, just visually different.
I've modeled the NS frame. Their rear triangle is different than the 936. You can tell straight away from looking at the interface at the seatstay rocker link. The results are as follows:
37.5mm = 100mm travel
42.5mm = 112mm travel
45mm = 120mm travel
The frame has an average leverage ration of 2.66, a little higher than the 936. That accounts some for the travel differences. I feel the 936 has a more progressive ratio, should work well with this style of frame.