mtseymour

By making the new Dura Ace disc brakes road-specific (in appearance and functionality), Shimano has reduced their universal appeal. For one thing, the brakes are intended for 140mm rotors (with an adapter for 160mm rotors).

By going for an aero fit, Shimano and Sram sacrificed backward compatibility. On the Sram website, someone asked if there was an adapter to use flat mount calipers with post mount frames and forks. Sram's reply was ""No. Flat mount calipers are only made to work with flat mount frames and forks."

A comparison of the 2 formats show why the new Dura Ace won't fit on current single and tandem frames. The Enve CX fork uses the common post mount, which sticks out far enough to accommodate larger rotors (160, 180 or 203 mm). By contrast, the new Dura Ace caliper sits flush to the fork with no protruding posts. So it's possible to use a post mount brake (eg. Shimano R785) on a flat-mount fork, but not the reverse. In other words, there is no adapter that can make the Dura Ace caliper get close enough to the hub because the post-mount will get in the way. We'll have to wait for after-market forks to adopt the new flat mount.

Unfortunately, the rear mount is also incompatible with tandem frames. The flat mount uses 2 bolts that are threaded in from the bottom of the chainstay. Tandem frames typically use the IS mount on the rear dropout to attach the rear disc.

mtseymour

Are you using the new BT-DN110 internal battery with Bluetooth capability?

I'm currently using the SM-BTR2 internal battery with the SC-M9050 display. If I upgrade to the DN110 battery, will I be able to get synchronized shifting with my Ultegra 6870 or Dura Ace 9070 components?

twocicle

The 140->160mm adapter for the front/fork appears to simply boost the mount position out by 20mm and it seems to attach in the same manner as our current post mount adapters. So for the front, it may still be possible to use a flat mount caliper if that can handle the larger curve of a 180 or 200mm rotor, ie: our Whisky fork is 160mm min + 20mm for the flat mount 160 adapter = 180mm. Similar idea for a 200/203mm rotor would involve an uglier config using a 20mm post mount adapter + the 160 flat mount adapter. Unfortunately, with the base fork size of 160mm that we have, it appears we will not be able to use the new Dura Ace 160mm rotor I was wanting... at least with our current fork. I'm still hoping we see more 1.5" tapered thru-axle 367mm forks (for our frame spec) be produced and with a lower base disc size.

Our current RS785 calipers are working fine functionally (now that I know the pistons need to be cleaned & lubed occassionally), but the front pads rattle badly (I hate rattles and squeeks) on rough roads and I have no solution for that yet.

DubT

I am also a Kickstarter supporter. I will be installing the Xshifter and the road remote on our Calffee to shift the 10 speed rear cassette. That will allow me to stay 10 speed with mechanical shifting on the triple. I was going to do the same with SRAM wireless but X****er allows me to keep my 10 speed setup. I have extra cassettes and extra derailleurs. This way I do not have to upgrade to 11 speed. I use a 12/30 rear cassette and am happy with the spacing. I have not found an 11 speed cassette, at a reasonable price that duplicates the ratios that I want.

Wayne

twocicle

I'm hoping these prices continue to lower. Performance Bike is not one of my prime online sources, but here they are showing a huge discount at $460/per kit. That comes to a more tasty $920 per set (incl calipers, hose, rotors - probably 140mm default, etc).

Fergp

I would like to convert my 2014 Cannondale T2 with FSA Gossamer crank from triple to double. Is there a compatible FSA Gossamer double "drive side" that will work with the tandem "timing sprocket side" so I don't have to replace the entire system?

radsmd

House of tandems makes a 34 tooth little ring that you can use with your existing big ring to make a double. You use your current "triple" crank.

Fergp

Thanks, I will look at this option!

twocicle

You can order a 34 tooth, 74bcd ring from xxcycles.com. I think TA Specialites makes one (I bought one a couple years ago from there but never used it. Yet another addition to my stash of bike parts).

This isn't really a Di2 topic, so perhaps start another thread for your conversion discussion.

colotandem

Funny, I was thinking the same thing. But this thread has been off the rails for a while. My eTap conversation included!

Fergp

Sorry to upset the apple cart! I am in the middle of a DI2 upgrade to my tandem and thought I could tap into the knowledge base. The DI2 discussion in this thread has been extremely helpful.

colotandem

No worries. This place is a wealth of information. Sometimes we get a little distracted - "squirrel!"

Where appropriate, it might make sense to start a new thread. That said, I derailed my on Di2 thread into the eTap topic, so I certainly can't judge.

I sort of gave up on this thread when we had the xshifter discussion.

FWIW, as long as we're off (Di2) topic, the Sram etap is AWESOME! I don't have a basis to compare to Di2, so don't ask. It is ridiculously simple to install and is very intuitive to shift and shifts swiftly and crisply every time (so far). There's snow on the ground now, so our rides on the road tandem have been limited to just a handful. I do notice when I get on our mtb tandems the mechanical shifting is not as crisp. But I don't think I'm prepared to upgrade the entire fleet. So mechanical will remain in my life for the foreseeable future.

Happy Holidays from Colorado!