If you are DIY-inclined, vice the drop-out to keep the upper and lower halves parallel (don't make the vice too tight, just enough to grip, ie. no play). Then gently hammer the lower half upwards until you get the right gap. Maybe you could use the tension-adjuster to set the gap if it's a close fit.
If you are DIY-inclined, vice the drop-out to keep the upper and lower halves parallel (don't make the vice too tight, just enough to grip, ie. no play). Then gently hammer the lower half upwards until you get the right gap. Maybe you could use the tension-adjuster to set the gap if it's a close fit.