Dura ace 9000 chainrings match

[EA120711]

So I was on the universal cycles website looking at switching my compact rings out for a sub compact set. I noticed that the site states that to get the best performance you should match the different chainrings up with the corresponding letters (ex 52 tooth MB with 36 tooth MB). Has any one heard of this or have any experience with using ones that do not match . Here's the description from the website:

Shimano FC-9000 Dura Ace Double Chainrings 11sp

•Exclusive for Dura-Ace 9000 cranksets
•11-speed SIS compatible
•Outer chainrings are hollow-forged and machined with integrated (blind) threads for optimized strength-to-weight
•For best shifting performance, match MA, MB, MC, MD-type chainrings
•Speed: 2x11sp
•BCD: 110mm

Thanks.

[11.4]

It depends to some extent on the particular combination, and you can have different issues. When they properly match, there's a tooth on a chainring aligned so it's sitting there ready to grab the chain when you shift off the other ring. Ramps and pins are all positioned likewise. When you mix and match rings, you get some slippery shifts. This means that if you knew how to shift before pins and ramps, you'll have no problem. If you grew up with shifting dependent on pins and ramps, you'll miss some shifts until you learn to be a little more aggressive in your shifting.

All that said, I've found a few obnoxious problems with certain combinations. Going from a 34/50 to a 42/50 has particular problems for me because the big ring on 9000 is hollow and tapers up towards the teeth. A 53 has a different cross-sectional taper to match the height of a 39, compared to a 50 matching the height of a 34. So what happens is that if you put together 42/50 (a nice combination for a crit and for a lot of not-hilly road racing), there is extra space between the rings at the point where the teeth of the 42 reside. If you shift up to the 50, the extra room makes it a little sloppy. But if you shift down to the 42, the chain wants to ride on the gap between the rings and not drop down onto the 42 tooth teeth. You can overcome most of this by readjusting the front shifter and by modulating your shifting a bit. Di2 seems to be good at solving the problem on its own. The pin and ramp shifting issues don't make the shifting worse than old (aka Nuovo Record) non-ramped rings, but this problem with the cross-sectional shape of the big ring can give you more problems. I could never get a 42/50 to be foolproof in racing, so I gave it up and went to flat Praxis rings inside and out and everything worked fine.

[EA120711]

It depends to some extent on the particular combination, and you can have different issues. When they properly match, there's a tooth on a chainring aligned so it's sitting there ready to grab the chain when you shift off the other ring. Ramps and pins are all positioned likewise. When you mix and match rings, you get some slippery shifts. This means that if you knew how to shift before pins and ramps, you'll have no problem. If you grew up with shifting dependent on pins and ramps, you'll miss some shifts until you learn to be a little more aggressive in your shifting.

All that said, I've found a few obnoxious problems with certain combinations. Going from a 34/50 to a 42/50 has particular problems for me because the big ring on 9000 is hollow and tapers up towards the teeth. A 53 has a different cross-sectional taper to match the height of a 39, compared to a 50 matching the height of a 34. So what happens is that if you put together 42/50 (a nice combination for a crit and for a lot of not-hilly road racing), there is extra space between the rings at the point where the teeth of the 42 reside. If you shift up to the 50, the extra room makes it a little sloppy. But if you shift down to the 42, the chain wants to ride on the gap between the rings and not drop down onto the 42 tooth teeth. You can overcome most of this by readjusting the front shifter and by modulating your shifting a bit. Di2 seems to be good at solving the problem on its own. The pin and ramp shifting issues don't make the shifting worse than old (aka Nuovo Record) non-ramped rings, but this problem with the cross-sectional shape of the big ring can give you more problems. I could never get a 42/50 to be foolproof in racing, so I gave it up and went to flat Praxis rings inside and out and everything worked fine.

Thanks for the info! This helps a lot especially since I wouldn't want to experience any type of faulty shifting after moving to 9000 from Campy. I think that I'm just going to stick with the stock combinations that Shimano provides , specifically the 52/36 since that seems to fit my needs .