Subject: Re: Chain Rign Compatibililty Posted by: Jim on December 11, 2003 at 20:27:03: In Reply to: Re: Chain Rign Compatibililty posted by Al on December 11, 2003 at 12:58:09:

Message: >>>>Can an Ultegra triple chain ring set be used on a Dura-Ace triple crankset? There doesn't seem to be a 30-42-52 or 53 Dura-Ace chain ring set, and I don't like the 30-39-53 Dura-Ace standard. >>> >>>You can use the 42T and 52T as both Ultegra and Dura-ace are 130mm BCD for the two larger rings. But the 30T won't work. As Al pointed out, the inner ring on the Ultegra is 74mm BCD while the Dura-ace is 92mm BCD. >>.............actually, even tho the DA triple arms are 130 like the ultegras, aren't the arms specially machined to accept only the DA triple rings? A case of all 130 BCD rings not being the same? >The backside of the Dura Ace crank's arms do not have the superfluous lip which I guess is similar to what one often finds on a PISTA/track or BMX crank to save a few grams. >I have suggested to one person with whom I ride who has DA triple -- BUT, who has yet to utilize the granny -- that he should very seriously consider buying another middle ring BECAUSE, by my reckoning, a replacement for that "middle" Dura Ace chainring has got to be about $100+, retail [perhaps it is less expensive; but, doubtful]. OUCH! >He thinks it is too complicated to change the chainrings ... whatever!?! >At least one company used to make both 130BCD & 135BCD "middle" chainrings which accepted 74BCD rings; but, I don't recall who. > .......TA did and may still offer 130 and 135 tripilizer middle rins that would accept a bolt on 74bcd granny.