Bicycle Mechanics - Do Ultegra chainrings fit on 105 triples?
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07-23-04, 11:28 AM
Someday I might swap my 105 triple 30-42-52 (9 spd) for a 39-53 double. But before I do that I want to get used to the gearing and see if I should swap my 12-25 rear for a 12-27 (or even 11-23...NOT).
My question: Will the 39 and 53 Ultegra 9 spd chainrings I found at Performance fit on my 105 triple? Is the bolt pattern different? What about spacing? I just want to make sure before I blow another $50 + shipping. I am anticipating some minor front derailleur adjustments, though. Thanks.
The BCD is the same, cranks are interchangeable between the double and triple.
Spacing is determined by the crank, one ring goes on the outside, the other on
the inside of the crank arm. Spacing is same double or triple. Steve
07-23-04, 02:14 PM
Yes, the 39 and 53 Ultegra rings for double will fit on your 105 triple. However, the 39 will not have the ramps and pins for shifting up from the granny. It should still work though.
Why not just restrict the usage of your granny the equivalent low gear of a 39x53 combo? A 39/25 low gear is about the same as a 30/19 and a 39/27 is about the same as a 30/21. So if you need to use the 30/21, you should go with a 12-27. If you need to use 30/23 or 30/25, you should stick with the triple.
07-23-04, 06:41 PM
I have used my granny 3 times this season, the last time being in May near the end of a very fast group ride up a real leg breaker I wasn't familiar with. I want to change rings because I keep wondering how I would attack each hill with standard double gearing up front, yet a double conversion is out of my budget right now. If I get some new rings I will know for sure what rear end I'll need when I finally do make the switch.
But if a 39 double ring will render my granny unuseable, I might scrap the whole idea until I can afford the whole conversion. Yeah, screw it. I'll wait until I can make it a full season without using the granny then I'll do the conversion.
07-23-04, 09:00 PM
Save some bread. Get the 12-27. If it is not enough then get a 38t chain ring, this is the smallest that will fit a 130 bolt circle. It should be enough and will fit what you have. (No need to buy a crank set, BB, and der)
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