The bolt that clamps my Crud raceguard to the seatpost has seized.

Crudguard looks like this.

Can’t undo it, no matter what. It just spins. So the raceguard is loose and flops about like a bunny’s ears and my backside gets wet. Any clues on how I can get that bolt undone?

hacksaw blade

errr…should have said. still want to be able to use it, so don’t want to damage it.

Yeah, that’ll happen. GW’s spot on, cut along the slot with a hacksaw, the bolt’s aluminium so it’ll come apart. Then, email Crud and complain nicely, they know their design’s crap so they’ll send you the improved replacement bolt for free. If it’s an early one, they might give you replacement shims as well, that was another part of the problem.

Best solution I’ve found is to remove the thread and drill out the central hole, then fit an M6 bolt through the middle- use the old bolt as a spacer rather than a bolt, that way you can get a decent amount of torque on it. As standard the bolt just stripped in the plastic way before it was tight enough, it needs an awful lot of torque to hold it all. The standard bolt really needed an allen key or nut on the opposite end rather than relying on the friction.

Actually you could do the same with your cut bolt-might want to cut a bit out of the middle too, just to give better clearance. That’ll work.