I've got some Bonty tyres (XR) and its a battle to get them on the rim as they come up very tight...I've tried them on 717, 719 and 355 rims and its a complete pain. Mud-X are easier but still nothing like the ease of my Maxxis tyres which seem to slip on relatively easily.
So what tyre makes come up a bit looser and are easiest to fit on a rim?
(...awaits being told to MTFU
)

