S
Sheldon Brown
Guest
Steve Palincsar wrote:
>>If you're into brifters you have to upgrade the left one. Beyond that, you need another crankset
>>and probably a bottom bracket, and a front derailleur capable of handling a triple. That could set
>>you back a bit, but you could do it for a whole lot less than $639 in parts if you don't insist on
>>a DuraAce triple. In fact, even with the extremely expensive DA triple crankset, it's kind of hard
>>to see where you could find a way to spend that much in parts.
A usually reliable source suggested:
> The DA triple crankset consists of a double crankset with a middle ring with extended ears to
> mount the granny to. You can keep the cranks, just change the smaller chainring and the axle. This
> solution is also offered by Stronglight and TA, but not at this pricelevel
That's what I thought the first time I saw the Dura-Ace triple. Unfortunately, it's not as
simple as that.
Although the special middle ring does mount on the standard "road" 130 mm bolt circle, the way the
chainring is constructed, it won't fit on a normal double crank.
Normal cranks feature "shelves" on the inside and outside of each spider arm that fit up against the
inner circumference of a standard chainring.
Conversion chainrings such as the TA and the $40 Willow unit are designed to clear this shelf, but
the Dura-Ace triple 39 has no such clearance. The special version of the Dura-Ace right crank
designed to work as a triple has no shelf on the inner faces of the spider arms.
It is possible to mount one of these rings on a standard crank, but only if you file away the
shelves on each of the 5 arms. Not many people will want to do heavy-duty filing on their
Dura-Ace cranks!
Another issue with the Dura-Ace triple is that, unlike the similar products from TA and Willow, it
does not use the standard 74 mm bolt circle for the small chainring. Instead, it uses a uniqe 92 mm
bolt circle, so there are no alternatives to the stock 30 tooth chainring!
I reiterate my recommendation of the Ultegra triple instead.
Sheldon "Most Expensive Isn't Always Best" Brown +-------------------------------------------+
| Genius may have its limitations, | but stupidity is not thus handicapped. | --Elbert Hubbard |
+-------------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone
617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com
>>If you're into brifters you have to upgrade the left one. Beyond that, you need another crankset
>>and probably a bottom bracket, and a front derailleur capable of handling a triple. That could set
>>you back a bit, but you could do it for a whole lot less than $639 in parts if you don't insist on
>>a DuraAce triple. In fact, even with the extremely expensive DA triple crankset, it's kind of hard
>>to see where you could find a way to spend that much in parts.
A usually reliable source suggested:
> The DA triple crankset consists of a double crankset with a middle ring with extended ears to
> mount the granny to. You can keep the cranks, just change the smaller chainring and the axle. This
> solution is also offered by Stronglight and TA, but not at this pricelevel
That's what I thought the first time I saw the Dura-Ace triple. Unfortunately, it's not as
simple as that.
Although the special middle ring does mount on the standard "road" 130 mm bolt circle, the way the
chainring is constructed, it won't fit on a normal double crank.
Normal cranks feature "shelves" on the inside and outside of each spider arm that fit up against the
inner circumference of a standard chainring.
Conversion chainrings such as the TA and the $40 Willow unit are designed to clear this shelf, but
the Dura-Ace triple 39 has no such clearance. The special version of the Dura-Ace right crank
designed to work as a triple has no shelf on the inner faces of the spider arms.
It is possible to mount one of these rings on a standard crank, but only if you file away the
shelves on each of the 5 arms. Not many people will want to do heavy-duty filing on their
Dura-Ace cranks!
Another issue with the Dura-Ace triple is that, unlike the similar products from TA and Willow, it
does not use the standard 74 mm bolt circle for the small chainring. Instead, it uses a uniqe 92 mm
bolt circle, so there are no alternatives to the stock 30 tooth chainring!
I reiterate my recommendation of the Ultegra triple instead.
Sheldon "Most Expensive Isn't Always Best" Brown +-------------------------------------------+
| Genius may have its limitations, | but stupidity is not thus handicapped. | --Elbert Hubbard |
+-------------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone
617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com
