Change in design on Shimano Ultegra 6703 crankset?
I ordered a middle chainring for my Shimano Ultegra 6703 crankset from Amazon. The chainring I got came in Shimano Ultegra packaging, but it didn't fit my Ultegra crankset. I looked closer at the chainring and it was engraved 'Shimano 105'. The chainring, really a chainwheel, had an inner section made to mount the inner chainring from. But on my Ultegra crank, the middle and small chainrings both mount directly to the crank. And the picture on the Amazon page looks like the chainwheel they sent me, and on-line forums refer to this middle chainwheel with the mounting for the inner chainring.
So my question is, what happened? Did Shimano change the design of their 6703 crankset recently? Mine is only a few years old. Or are there two different versions of the Ultegra crankset out there? And, even if there are, why was the chainwheel I got engraved 'Shimano 105' while the packaging referred to 'Shimano Ultegra'?
whats the PN on this ring ?
105 is the group below Ultegra (it goes 2200, Sora, Tiagra, 105, Ultegra, DuraAce). Ultegra stuff is all 6xxx while 105 stuff is 5xxx.
here's the parts breakdown for the FC-6703 crankset, http://techdocs.shimano.com/media/te...9830753778.pdf and it sure looks like the granny gear bolts to the middle ring.
to add to the confusion, here's the FC-5703 '105' series equivalent crankset
Insane Bicycle Mechanic
The 6603 had separate bolt circles for the inner and middle/outer chainrings:
The 6703 mounted the inner chainring to the middle:
I would return the chainring to the vendor.
Ah, that makes sense. I have the 6603 crankset. I did return the chainwheel, no problem from Amazon, but I wondered what was going on. The engraving on the chainwheel was confusing. Thanks for clearing this up so quickly.
I'd guess the engraving on the chaing ring was really 10S so you know its a 10 speed ring not a 9sd ring. That got me the first time i saw it at work years ago on a dura ace spec'd bike i was thowing together.
Surprize. They changed the cranks so that they no longer have to make one for the triple. Don't you love how they take care of our interests and shove the 30t small ring down our throats?
Originally Posted by jonawebb
The adapter has been around for decades for people who decided that they needed lower gears.
Shimano started the single bolt circle with the granny on the middle ring with the previous generation (7800?) Dura Ace triple cranks. And yos, it allowed them to make one set of arms for both doubles and triples and the down side was that the larger granny bolt circle won't accept anything smaller than 30T.
Originally Posted by davidad
This design "improvement" made it's way to Ultegra in the 6700 series and, at this time, the 105 triple is the only model with two separate bolt circles on the crank arms and it retains the 74 mm size.
I'm sure mbbiker is correct that the ring was engraved 10S (10 Ess) not 105 to indicate its for 10-speed applications.