Bicycle Mechanics - Use DA 7700 Cranks for Triple

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.



PDA

View Full Version : Use DA 7700 Cranks for Triple

john hawrylak
10-04-09, 05:00 PM
Are there any problems with using a pair of 7700 Dura Ace cranks (double) with the DA or TA triplerizer gears i.e., DA 7703 D chainrings (53D, 39D, 30D) or with similiar TA Shimano compartible rings in a triplerizer format? I would use the 118.5 BB.

Recall, the DA triplerizer hangs the granny from the 39D rings, not from 5 supports on the cranks.

Got spare 7700 cranks and would like to them use as a triple, most likley with smaller TA rings (48/36/28)

TIA

John Hawrylak

joejack951
10-04-09, 07:40 PM
The only problem I can think of with respect to what you are attempting to do is that you won't be able to mount a 36T ring on a 130mm BCD crank. The smallest ring you can mount on that BCD is a 38T. Other than that, I see no reason why it wouldn't work.

How did you decide on the 118.5mm bottom bracket? The double and triple cranks obviously use different forgings so I would not assume that the double crank with the standard triple bottom bracket would yield the appropriate chainline. I would adjust the double's bottom bracket length by the amount of chainline difference between the triple and double crank (1.5mm on the drive side).