Originally Posted by
TimothyH
Maybe its paranoia but I've been worried about how the front derailleur will mount.
Ultegra Di2 front derailleurs only come in braze-on models (that I know of) but the frame has no braze-on mounts. That means a clamp has to be used and its positioning relative to the low bottle cage mounts on the seat tube is a concern.
How can something as simple as bottle cages cause so much trouble?
The cage mounts are low enough that the clamp clearly has to go between either bolt and that means the clamp has to be thin enough to fit between the frame and the cage. Those Shimano clamps are so thick that they sometimes rub the tires on bikes with tight geometry. This clearly won't work and they are ugly anyway. The clamp also can't be too wide or sit too low or high or it will hit the one of the bolts.
One has a right to believe that the manufacturer of a bike with a nearly $9k list price would have figured this out and so I set about looking for pictures of how the derailleur clamps to the frame on the Five Star build.
[IMG]https://gzmyu4ma9b-flywheel.netdna-ssl.com/wp-content/uploads/2017/01/2017-Niner-RLT-RDO-carbon-gravel-road-race-bike08.jpg[/I MG]
There it is in its glorious ugliness, a garish silver clamp which looks to me to be too thick to allow a nice cage to be bolted close to the frame. I could be wrong.
The good news is that the build pictured uses an Ultegra crank with a 46 big ring. There appears to be plenty of room to move the derailleur clamp up and down on the tube without hitting a cage bolt.
My road bike uses the Parlee carbon braze-on adapter pictured below.
[IMG]https://www.dropbox.com/s/26080dq9qe1m6i5/parlee.braze.on.adapter.001.sm.jpg?dl=1[/IM G]
This thing is uber weight weenie but doesn't flex that I can tell. It is also thin as a whisper and might even fit between the cage and the seat tube on the Niner. Just to be prepared however...
[IMG]https://www.dropbox.com/s/dy34p6h91e4g9o6/cage.bolts.001.sm.jpg?dl=1[/IM G]
Two nylon washers were about 80 cents and who doesn't like looking through the fastener drawers at Lowes?
-Tim-
It is a design feature more than likely..
Usually you only see low-slung water bottle bosses on dedicated/serious CX bikes, in order to give more shouldering room through the front-triangle for your arm.
Take for example the Foundry Flyover, I was looking at this bike for a while, and spotted the same issue. Now I checked and your RDO is not listed as a CX bike but as a gravel bike.
Maybe they were thinking of allowing more clearance for bike-packing bags, which they love to show pictures of on their website....as bikepacking bags and standard water bottle bosses get into fights on medium and small frames.