Ok, so following from thinking that a 2.35 was a bit big in the back of my Soul (and before I do anything silly like buy new tyres…) I upended the bike and took a good look as it seemed the wheel was excessively close to the chainstay on the drive side. It is.
Out of interest I test fitted a few other wheels – with and without tyres – and established by this method that definitely one and possibly two of my rear wheels are incorrectly dished/possibly not dished and the hub is therefore shoving the rim noticably to one side such that the tyre edge almost contacts the chainstay on one side and has loads of space on the other. Decidedly off-centre. As some wheels are ok, I’m assuming I don’t have a knackered frame. Hanger is also not bent/passes the straight-edge test.
So, at some point very soon I’m going to have to look at these wheels, one of which (the one with the tyre tubelessed on… ) is a 20 spoke Mavic with the funny integral nipples.
I gather that unless spoke length is fundamentally wrong, the issue has to be that the drive side should be higher tension and shorter spokes than the non drive and I should be able to tweak this with spoke tension? I’ve replaced odd spokes but never quite got around to popping my wheel cherry so a bit nervous about this – getting head round wheelbuilding is something I’ve been meaning to do for ages now.
Also – while running the off-centre wheel, I’ve rubbed the chainstay to shiny metal in a tiny patch. Much less than fingertip. Frame is obviously steel – should I be touching it up or getting some converter or something on it? I’m not too precious about having a chip free bike (although I gather Revell 30 is a pretty good match) but it seems to me that bare metal on the inside of a chainstay is asking for it…