NDS Seatstay/Chainstay reinforcement

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I’m going to add a 12 (?) mm OD reinforcement tube in the rear triangle on the NDS like this Chumba frame (I’m also using Paragon sliders):

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is there a rule of thumb in terms of the exact placement of this tube? Looking at the picture it is something like 40mm from the SS edge, 60mm from the CS edge.

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Is the brace needed?

My understanding is that traditionally a CS/SS brace is there to brace against braking loads from a SS mounted IS tab. With Paragon sliders the braking force is transfered to the dropout through the insert. So correct me if I’m wrong but I can’t see what that brace is really doing.

I have a hardtail with Paragon sliders that doesn’t have a brace. I’ve hit the rear tyre hard enough to dent rims but am yet to have any structural issues with the frame. Also you can look at production bikes like the Kona Unit that don’t feature that brace either.

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The most important part is allowing clearance for getting an Allen key on the adjuster bolt.

My other consideration is making it parallel the edge of rotor. I made one frame that did not and it bothers me every time I look at it.

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I rode a frame I made with out one quite a bit and had no issues (paragon sliders).

When I visited chumba they made mention that they have had some frames fail there.

Its inexpensive and not time intensive insurance to add one.

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I agree with everyone so far:

  • make sure you have room for the adjuster
  • some people have had failures there
    • although you never know the whole story:
      • tube diameter, wall thickness, weight of rider, brake rotor diameter
    • @Meriwether have you mentioned something about this before?
  • bonus points if you can make it look good with the rotor!

To add to this thread, a 3D-printed soft jaw really helps when using curved braces:

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I rode both Kona Unit and Soma Wolverine that had sliders and no brace, but given the opportunity to make things my own way I decided that it is a good idea after seeing it on the Chumba and couple other frames.

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@Daniel_Y I’m sure I’ve ranted about this before somewhere but don’t remember :joy:

I’ve never braced that spot when using Sliders but it can’t hurt!
“Institutional knowledge” says you don’t have to, that’s a benefit of using sliders but…there are some people out there that’ll break anything you build them (I have a couple of those customers).

I’d be interested to see where the failures were and the context if anyone’s willing to share.

I remember riding with someone testing a first gen disc aluminum frame built without a brace and the caliper on the seatstays. We were looking at the disc and wondering why they didn’t brace it. My buddy did some hard braking while popping the rear wheel sideways and BOOM…it snapped when his rear wheel landed while skidding. granted he was kinda trying to push it but still…
He had to walk home as I rode into work. :joy:

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