What is the max 27.5 clearance for non boost(12x100,12x142) bike if the rest of the geo is designed to fit it? Could 27.5x3.0 work, what about 3.5? Thinking is 1x11 unless 2x10 sword is possible.
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If you make the chainstays long enough you can probably fit anything in.
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What about the fork, pending a-c is high enough. I was thinking reasonable chainstay length of 440-445.
Depending on how extreme you’ll want to go, the chainline becomes the limiting factor. If you want to use 2x Microshift sword, the inner Chainring will sit at around 41mm off centerline. This limits the theoretical maximum tire size to around 3.2”. In reality this is a bit less, since your chain has a thickness, and your chainline moves when shifting up the cassette.
Despite this, If you are willing to adjust everything else (bend tubes, lengthen chainline and a-c) you can fit a tire as big as you can find.
Edit: Just did some quick drawing: with 445mm chainstays you will have very little chance to fit a tire that wide. Just grab a piece of paper, draw everything, and think about how you could thread the chainstay through the tire, chainring and crank area.
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An elevated chainstay design can help to maximize tire clearance by avoiding the chainring - chainstay - tire pinch point, although it comes with compromises (weight or strength/stiffness, take your pick). Either way (elevated or normal chainstay), the chainline is the real constraint on tire clearance. If you are willing to offset the rear hub to the driveside and push the chainring out to match (outer most position on an old triple crank, or just run a wider crank), you can fit a remarkably wide tire with a normal hub. If you are willing to offset the rear, I suggest looking at cranks and deciding on a chainline you are happy with, and designing from there.
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27.5x3.0 or 3.2 or 3.5? Really looking to see if I could get a frame with 27.5x3.5 front & 3.0 rear 1x and 2.8 2x, if possible, while staying non-boost. I was told boost makes things easier, would that be correct? Surly has a few bikes with cs in the 440-445mm range that could fit 27.5x3.0 rear.
How was Curve able to get 29x2.6 to work on non-boost, not that long of a cs of 440-443mm, and gravel standards? I just saw their Bigger Kev came out in a v2 with 29x2.6 clearance 1x.