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Discussion Starter · #1 · (Edited)
I'm older than dirt so you will have to bare with me. I don't know how to put a picture up of this f/s frame which I just bought from aliexpress. Rear is 100mm travel. The first 50mm or so are free moving, but as it gets farther in the stroke it gets stiffer and stiffer. What is happening is the seat stays are flexing about 1 inch to compensate for the last 50mm of travel. Is this normal? Is this some way to help slow pedal bob? It looks like the frame would eventually self-destruct. I have noticed some frames have a pivot point where the seat > chain stay meet, this frame does not. The more I learn about bikes the more I want to stick a hot pocker in my eye.:eekster:
 

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Looks like a single pivot. Progressive suspension is designed to have less resistance in the beginning stroke to soak up bumps and get progressively harder to compress so the shock doesn't bottom out harshly. If in fact your seat stays are flexing so visibly as you state, one reason could be inferior layup of the carbon fiber. Designers that understand the properties of the material can fine tune strength-to-weight ratios which allow the designer to ensure extra strength is applied where need and weight is reduced where appropriate.

To answer your questions: No, the amount of distortion you mention is not normal, it is not a "design element". Yes, this frame may very well fail if you are accurately describing the amount of flex you are observing.

I would find out what the torque recommendations are for this frame, get my torque wrench, and double check all connections, as well as rear wheel to frame. If your shock is not properly installed, your rear end will flex.

Another possible and very probable explanation is misalignment of the frame.

Lastly, your shock may be faulty, resulting in your rear frame getting jacked up as it attempts to cycle through its travel but meeting resistance. But I don't believe the rear triangle should distort like you describe.

Take your bike to a trusted bike mechanic, have him or her check the alignment of your frame. I'm guessing this is an alignment issue. Be safe.
 

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Interested to hear how this frame is holding up as I may build one up at some point. With regards to the chain stays flexing, this can be a design feature, like in my 2015 canyon Lux CF. They call it a flex pivot.

Have you ridden the bike yet?
 

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Discussion Starter · #5 ·
Wow, I haven't looked at this post in weeks. Just happened to see this. Yes I have been riding the bike for over a month now. Just started back riding this year, so I'm not up on all the latest and greatest. Yes I believe this is a design feature, it sort of thru me for a loop at first. I have not completely bottomed the rear suspension yet, maybe 3/4 travel. I love the frame and have had no problems at all. I had it painted and it turned out better than I expected. It weighted 2300G large frame. I think it would have weighted around 2050G unpainted. I'm 5' 9" large frame seemed to be a good fit.
 
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