New chainring is rubbing on chainstay
Needing some help understanding what is wrong here...
Bike, Kona Honzo AD/DL
BB, Shimano BB71-41
Crank, RaceFace Aeffect
Chainring, RaceFace 32t Narrow/Wide
So I've replaced an ageing and worn RaceFace 32T 104mm Direct Mount chainring. I've absolutely replaced like for like in terms of the chainring I am sure.
I have fitted the new chainring on the same crank, nothing else changed.
Now the new chainring with it's new unworn teeth are badly rubbing and sticking on the chainstay. Definitely got the right torque (54Nm) when tightening up the crank bolt.
I thought I had done something wrong, so I re-fitted the old worn chainring (same torque and everything) and re-checked. It turns smoothly on the crank and although very close to the chainstay (1mm) it spins without rubbing. I guess it was always this close.
Looking at the teeth on the old chainring, they are obviously worn with many years of riding, so they are not as pronounced and thick as the new chainring I'm trying to fit.
The original bottom bracket seems correctly fitted without any spacers (PF92 / Shimano SM-BB71-41), the bike's BB shell is 92mm (not 89.5mm), so according to Shimano you don't fit the BB71 with the 2.5mm spacer ring, so this seems all OK.
I don't understand what I have done wrong and how to solve this, I've just replaced the same RaceFace chainring, the new one obviously has predestine teeth, which the current seating of the crank/spindle etc. can't take - but surely this would have been a problem from new? When the original chainring wasn't worn? It is rubbing and sticking so badly, it obviously wasn't an issue when I got the bike, as you wouldn't have ridden it in this state.
Does anyone have any ideas or advice? I don't have much experience here to draw on and can't seem to find an answer despite days of searching online and have always relied on the shop sorting out my problems. I'm fairly practical so happy to work the solution myself. Everything seems setup right, 92mm shell, so BB71 without the spacer seems correct, and yet the new chainring catches the chainstay very badly. Is one solution to just add the 2.5mm BB71 spacer, even though the shell is 92 and so apparently not necessary.
Appreciate any suggestions.... thank you.