Aaaargh

I have replaced my own chainrings for years and always, always take care to fit them in the same orientation as the old ones, it kind of makes sense Shimano make them asymmetric for a reason – innit?

Anyway I have just replaced my middle XT ring and placed the old one in exactly the same configuration

Then for some stupid reason, and I wish I knew, I took the wrench to attach the inner ring whilst giving it a spin around aaaaargh, and I now have no memory of how the original came off

I guess the 2 main questions are:

1) Is the orientation critical?

2) If so how can I tell which way it needs to sit?

Ive tried Google images and theres a few pics online but none gives me the money shot

All help welcome please

Line up the numbers stamped on the inner faces, that gets the ramps correctly oriented. Although inner shouldn’t matter as no ramps on it.

Inner ring orientation? Doesn’t matter really.

Most if not all of mine have slight counter bores which the bolt head goes into.

Shouldn’t matter, but they often have an extra little ‘lobe’ on the inner circumference which lines up with the crank. Just after 12 O Clock on the pic here

Lump be inline with crank arm. Writing facing in.

Inner ring orientation? Doesn’t matter really.

If it’s in the wrong way it can cause chain suck, more if it’s worn than new though so you might get away with it. The shifting ramps are where they are for a reason, if it’s the right way round but the orientation is off it shouldn’t matter too much

If lobe is opposite crank (I.e. in line with non drive side one) will it affect things ?

Probably not as you shouldn’t be shifting the front under load anyway. They need to be lined up on all rings though for obvious reasons.

The lobe thing!!!!
Why have I never noticed hem before?

Many thanks