I've been thinking about replacing the front fork on my Niner for a while now.
↑This one
It's not bad as-is,
but those three holes on the sides of the fork blades for bottle cage spacing are unnecessary for me, and
the front brake hose is partially exposed, with the hose routed through the fork blade interior starting from the left shoulder of the fork,
I can't use lights or other accessories mounted pointing downward from the handlebar.
The hose length on this Niner frame is extremely critical—if it's even slightly too long, it will constantly rub against the head tube. So there was a large transparent protective sticker on the head tube from the factory. I removed it right away, though.
Also, there was a chrome-plated plastic head badge attached with double-sided tape, but it wasn't applied cleanly and was slightly lifting, picking up grit, so while I didn't throw it away, I peeled it off early.
If I mount a light bracket pointing downward next to the stem,
it interferes heavily with the brake hose and brake outer.
On the other hand, if I mount it pointing upward,
it compromises the operability of the cycle computer at the center bracket.
I sourced a front fork. It's a Deda GERA EDGE model.
The RDO carbon fork that comes with the Niner frame has an axle-to-crown dimension of 400mm, whereas the GERA fork is 398mm. The RDO fork has an offset of 45mm while the GERA fork has 50mm offset, so a swap is possible.
The Niner RLT9 frame set has compatible tire widths of 25-50C. I understand the 50C upper limit due to frame and fork clearance issues, but I wonder about the point of specifying a minimum limit. For clinchers, the practical minimum size is 23C, and arguably 20C is the smallest that could work.
One possible explanation is that the manufacturer's intended trail figure assumes 25C as the minimum threshold.
In the diagram above, the blue line shows the ground contact for a 25C tire on the same front fork, while the red line shows it for a 50C tire—larger tire sizes result in greater trail.
I've always run this frame set with 25C front and rear, and recently switched to 28C front and rear when I got the Nomu Lab Wheel No. 9 with its wide 23.5mm internal rim width. But this frame set has steering that feels "the opposite of mushy"—it's very sharp and responsive whether on 25C or 28C tires.
I'm used to it now, but when I let first-time riders try it, they find the handlebar shaking side-to-side as they start out. This might also be related to the narrow handlebar width.
I suspect that if the bike could accommodate 38C or 42C tires instead of going all the way to 50C, this sharp-response tendency would improve or become more subdued. But honestly, the wider contact patch of larger tires probably contributes more to that than increased trail itself.
With this fork swap, the offset increases from 45mm to 50mm—meaning trail decreases and steering becomes even sharper—but when I rode it after the swap, there wasn't much difference. Maybe I'm just accustomed to it now.
The GERA fork's steerer tube has a D-shaped cross-section, allowing hoses and outers to be routed internally through the stem body. This requires a hole in the rear center of the handlebar as well.
↑This is a pretty old photo, but
I used to have the rear brake hose secured with zip ties to a slightly offset location on the underside of the down tube, but since it would pick up mud and grass,
getting fine scratches in the paint,
when using mechanical components with a front derailleur, I repurposed the hole in the upper down tube for full-outer shift cable routing and modified the down tube section to have the brake hose/outer routed internally. With the GERA fork swap, the brake hose/outer now routes through the head tube.
↑Exit point when using a front derailleur
Among Deda's gravel-oriented front forks, the GERA series has another model, the GERA CURVY. It has the same 398mm axle-to-crown dimension and 50mm offset, but the fork blade shape differs, and the CURVY, like the Niner fork, has three M5 holes on the blade sides.
The left blade has a disc brake mount and hose exit hole,
while the right blade and crown underside have hub dynamo holes. I sealed these later with tape.
There are also threaded holes for a fender on the outer side of the fork end and in front of the crown.
The Niner RDO fork also has a round hole for hub dynamo use,
which I keep sealed with a rubber cap,
and also has threaded holes for a fender.
↑Measured weight of the RDO front fork cut down to a length where only the stem can be mounted (without pressure anchor or through-axle, with lower race cup, fasteners still attached).
↑Measured weight with steerer tube uncut, without pressure anchor or through-axle, with fender fasteners, and lower race cup formed by the fork's own geometry. For reference, the GERA EDGE (↑this one) has a stated weight of 498g, while the CURVY is 545g.
The cut end of the fork steerer, leaving 15mm above the stem, weighed 45g, so post-cut the fork comes in around the stated weight.
After routing the hose/outer internally from the stem to handlebar and bleeding the front brake (hydraulic only),
I noticed when fitting the front wheel that the GERA fork, with reversed brake mounts, is compatible with... wait no, it's 180/160mm rotors, not 160/140mm. Argh argh argh argh argh argh argh
Since the hose length has zero redundancy, I can't pull the brake caliper down to make it work, so I'm definitely gonna have to swap the hose again and redo the bleeding. Argh argh argh argh argh
If the D-shaped steerer tube is hollow at the front, the clamping force of the stem fastener on the fork steerer drops significantly, but the pressure anchor included with the fork came with a wedge-shaped part to fill the hollow too.
↑When tapped in, it seats nicely.
The pressure anchor came with an off-center top cap for countersunk fasteners, but I wanted to keep using the YAWYD cap (→here).
I stacked the Deda cap and YAWYD cap together to check the hole offset.
I filed a slot just to the right point
to make it work.
↑Like this
The YAWYD cap has a stepped feature on its underside, so if it seats in the steerer hole or stem hole, it won't rotate or shift.
In all my life, I've never put a steerer spacer below the stem—I have this bad habit of just cutting the fork steerer flush above the stem. With the Niner fork, I did leave 15mm of steerer for a spacer above the stem, but I ended up cutting it flush later anyway. However, when decking out the handlebar area with various accessories, I felt constrained by the lack of adjustment flexibility, so this time I'm leaving 15mm worth of steerer height.
I installed the YAWYD cap modified with the off-center hole.
I replaced the front fork.
The handlebar area is now extremely clean.
But this has its downsides too. I already knew this from customers' aero-road bikes with integrated stem-bar setups, but...
When I lift the front wheel, the steering tends to pull left, and without restraint from hose/outer tension, the turned handlebar will accelerate and tap against the left side of the top tube.
This constant (on this bike) left-steering tendency and the effort needed to keep it straight despite the lack of hose/outer bracing—that's the annoying part about bikes with internally routed hoses/outers in the stem. I tested it and no-hands pedaling is possible. Also, the GERA fork doesn't have such low lateral stiffness that it flexes noticeably in descents, but its lateral rigidity is definitely inferior to the original RDO fork.