Being blonde isn’t all it’s cracked up to be…
I just upgraded to D/A 10-speed. Guy puts on 39/52. I want my 42 back and am told it can’t be done – too big.
True or should I get help elsewhere?
Thanks for any help!!
You left out some important details:
Blonde Guy or Gal?
Do you need the 52? Or can you go bigger?
Guy or gal?
Nevermind, I just read your post in the Dirty Secrets thread.
Call Shimano about this one. They have specific rings designed to work together. Campy does the same thing. For example, they make a 53 for 39 ring and a 53 for 42 ring (Campy). I’m not sure about the Shimano’s. I believe they call theirs A-type and B-type. You have to use and A with an A or a B with a B. Their USA office number is 949-951-5003.
I’m sure that a 42/53 combo works, so I don’t see why a 42/52 combo would not also work. Is that what you’re looking for?
Also, there is a Shimano 53a and 53b chainring. One is made for a 39 tooth small chainring, the other for a 42 tooth small chainring. Not sure what the a/b difference is, but something to keep in mind.
GregK & Bru! Thanks for the great info!
Ze Gopha- After you figured out my gender, you didn’t respond to the question. Is it that you are as technically challenged as I am or do you find it difficult to chat up girls? That have classes for guys like you, ya know! 
Why would I want to bore a classy blonde such as yourself with technical mumbo jumbo?
Just tell the mechanic to make it work, and then flutter your eyelashes at him.
Because I asked nicely…
Have you not learned to give a gal what she wants?
The reason Shimano has A and B chain ring combos is because they have different shift ramps. The chain obviously sits in a diffent place on the small ring relative to the big ring depending on what size small ring you are running, hence the need for the shifting ramps to be different on the big ring depending on whether you are running a 39 or 42 inner. These shifting ramps are more crucial on the 10 speed drive trains as Shimano have eliminated the little “elbows” on the edge of the chain’s outter plate which helped assist the 9 speed chain in shifting. Eliminating these “elbows” is how they managed to narrow the chain enough to squeeze in a 10th cog on the cassette.
I do not believe that shimano makes a 10 speed 52A ring (the A designates that you are using it with a 42 inner ring) but I could be wrong. I believe on the old 9 speed set up that the triple cranks were 52/42/30 but on the 10 speed triple they have gone to 52/39/30, I think. In any case, set your bike up 52/42 with whatever rings you like and it will still shift just maybe not as cleanly and crisply as you would like. Hope that helps
See ZeGopha, no need to be afraid to get technical with a cute blonde!!!
Thanks for the explanation Badaxe! It makes a lot of sense.
Talked with Shimano and got the part #s for what I need.
Appreciate everyone’s help!
What she “wants?” Or what she “needs?”.
You’re Welcome Wave, any time. I am a repository of trivial bike information. Why can’t my brain retain important information, like stock prices or physics formulas or important dates? No, it has to be bike minutiae and obscure music trivia.
Mind you, watch out for Gopha, looks like he’s got his self alllll worked up now that the talk has turned, ahem, technical!!!