Focus Izalco Max seat tube diameter?

[4ibanez]

Hope this isn't too off topic, but definitely curious what sort of tolerance do you guys think is acceptable between a seat tube and clamp? Should one only clamp right at the very top of the seat tube (mine had a lip caused by the paint before sanding - it was almost exactly 30.0mm as specced). But now it's possible to move the clamp lower where it has a slightly increased diameter. Wondering if I can get away with a Tune Skyliner in 30.8mm. No doubt Tune wouldn't recommend it officially, but looking for thoughts before I drop any coin. Would lower down the tube still be reinforced enough for clamping? I like the look of the Tune clamp and it's a couple of grams lighter than my Yuniper. It seems to be the closest full WW option - Carbonice could make a custom one for €73ish, but the great weight of their Eva (4.5g in 31.8 diameter) is skewed by the al bolt somewhat. Not sure that's a great idea!

[iamalex]

Moving the clamp further down the tube sounds risky. The relief slot cut into the top of the seat tube is going to allow the most movement there to best bite against the seat post. Might not be enough movement to bite further down. You’ll also just be squashing the tube.

I was under the impression that you might get away with a clamp +/-0.2mm different from the seat tube diameter - I think I saw it written on a clamp I had. More so and the clamp could bottom out against itself when trying to tighten enough. My 30.7mm KCNC sc9 is bottoming out against itself on the 30.4mm tube.

If the clamp doesn’t have a rotating nut I’m guessing the bolt could get overly stressed if used outside of spec. As tightened the surfaces of the two bolt holes through the clamp aren’t dead parallel.

I’m just thinking about the risks - not a mechanic or engineer. Going to look into Carbonice though for my issues though, thank you for the heads up

[iamalex]

You could also ask Tune if they have any seconds machined outside of spec, closer to the diameter you need. Seen some Tune bits on eBay with odd diameters.