I’ve just fitted an FSA MegaExo Omega chainset to my road bike.

It seems that when I’m in the small ring (34T) and the small sprocket, the chain rubs on the shifting ‘lugs’ of the outer chainring?

Its almost as though the front derailleur is rubbing as it makes that jangling noise, but its not the front derailleur, its those pins in the outer rng that aid shifting to the big ring.

They seem to be designed for a 68mm shell width without the need for spacers as would be the case on an mtb chainset – so I don’t seem to be able to adjust the chain line.

Anyone any suggestions? Other than that I shouldn’t be pedalling small ring/small sprocket 34 x 11 ???

Dunno, but road chainsets are 68mm with no spacers. What BB are you using it in?

Don’t pedal in 34×11.

Yep, the BB came with the chainset, so good to confirm its meant to be 68mm with no variants!

Could the issue be that I’m running a 9spd chain on a 10spd chainset? It shifts fine but are 9spd chains marginally wider than 10spd?

Would swapping some chainrings from the old 9spd chainset help or is the spacing inherent in the crank arm design? I don’t want to go back to the 9 spd chainset, as it was an Isis and the bb has died.

As Simon Barnes says – don’t cross over small/small. Roadies don’t. MTBers do. Transmissions aren’t designed for it. Also whilst I’m on this subject – don’t ride big/big. Absolutely do ride big/small thought 😀

I thought that the chainline big-big or small-small were less extreme on a road double than on a triple?

I wouldn’t do it on my mtb triple, but I wouldn’t see it as that extreme on a road double?

I never ride in that combination, usually jumped onto the outer long before that.

Just breaking the habit of big/big though, was being a bit lazy about dropping onto the inner.

Just been looking at the actual chainlines on the bike, and it looks as though small chainring/big sprocket is actually a worse chainline than small chainring/small sprocket just cos of where the small chainring is. (I’d imagine about middle ring position on an mtb?)