EB13: German:A Invents Teardrop Shaped Stanchions for Inverted Crown Suspension Forks

2014 German-A Revo inverted crown suspension forks

Inverted crown forks have long been the defacto design for motorcycles. They offer lower unsprung weight, which means better suspension action, and the larger diameter outer body is able to be held stronger at the crown, giving it better overall strength and stiffness to control the sliders. They can get away with this design because the weight penalty of a larger thru-axle doesn’t matter on something propelled by petrol instead of Powerbars.

The challenge with using the design on mountain bikes has been making the lower axle strong enough to resist the twisting forces of round stanchions inside the uppers without adding a ton of weight. It also had to keep the legs operating in parallel so they wouldn’t bind as one leg tried to move upward at a different speed (say, during hard cornering or an off camber hit).

German:A believes they’ve found the answer: Teardrop shaped stanchions…

2014 German-A Revo inverted crown suspension forks

The 2014 Revo forks will be offered in two versions, a shorter travel single crown and long travel dual crown. Both are, obviously, disc brake only. Complete specs (travel, damping, etc.) are yet to be revealed but it’s looking like they may offer only 1-1/8″ steerer tubes.

2014 German-A Revo inverted crown suspension forks

Like the new Cannondale Lefty’s, the exposed part of the slider is round, which makes it easier to seal off the internals from mud, dirt and dust. Once inside, though, they morph to a teardrop shape to prevent twisting (the Lefty uses a square shape).

2014 German-A Revo inverted crown suspension forks

German:A builds the bearing race directly into the fork’s crown, which they say improves force transfer into the frame to improve overall fork strength and durability. Most of their single crown forks have either a carbon or alloy steerer tube option, so we suspect the same will be offered here.

2014 German-A Kilo trapezoidal suspension fork

Their Kilo parallelogram fork carries over with slight changes to make it lighter. It comes in as light as 1098g with carbon legs on the CNC’d alloy linkage.

2014 German-A Kilo trapezoidal suspension fork

A few shock options are available, including one with a remote lockout. It’s available with a carbon steerer for 26″ wheels, and alloy steerer for 26/27.5/29er. Travel is 90mm, putting it in between travel and weight from something like the minimalist Lauf fork and a traditional 100mm fork.

German-A.de

Comments

Ryan - 09/11/13 - 10:00am

That open bend gives the appearance of an exhaust tube—which looks kind of neat.

Rohan - 09/11/13 - 10:21am

So how much travel do they have 160mm for the single crown would be nice plus compatible with 650B wheels.

Deets - 09/11/13 - 10:39am

What the hell is an “inverted crown fork?”

Jethro - 09/11/13 - 11:32am

Kind of like the old AMP forks.

MS - 09/11/13 - 12:11pm

Back in the 1990s, Mountain Cycles made an upside-down fork called Suspenders. Visionary, but unfortunately for them, disc brakes didn’t really exist and thru-axles weren’t on anybody’s radar. They had to do some goofy stuff to make cantilever brakes work with them: slots in the upper tubes being the most obvious.

wobbem - 09/11/13 - 12:21pm

Clever bastards them Germans. A Logical solution to the problem looks solved.

wobbem - 09/11/13 - 12:23pm

Now do the same with a dropper seat post

Maria - 09/11/13 - 12:57pm

MS,
You remember the Halston Inversion fork. Mountain Cycle had their own disc brakes at the time (1992).

Nice forks but they come with a weight limit.

matzman320 - 09/11/13 - 1:06pm

they only offer 1 1/8″ steerer tubes but the lower bearing is a 1 1/2″.

Tim - 09/11/13 - 1:07pm

MS- Mountain Cycles did make an inverted fork, but there were some primitive disc brakes available at the time, one of them being the Pro-Stop, offered by Mountain Cycles itself to solve the brake problem of an inverted fork. The Mountain Cycles Suspender fork had no thru-axle, unfortunately, but it did have large upper legs, and steel lower ones.
The company that made the inverted fork with slotted upper legs that you referred to was Halson Designs, their fork was called the Inversion, but it was rather clunky with a heavy brace and thick-walled aluminum construction. I owned one of those, and it did ride well for the time, mainly because it had a long elastomer stack and good elastomer springs that kept rebound speed to a minimum.

scentofreason - 09/11/13 - 1:50pm

Dear German:A,

The day you offer a 15mm through axle on the Kilo will be the day I buy one. Please please please make the 15mm available on the Kilo!!!!

Michael - 09/11/13 - 2:13pm

Clearance for my Krampus tires and a normal 15mm thru axle. That’s what I want. What esoteric international group of weirdos will provide it first?

Colin - 09/11/13 - 2:20pm

I’m surprised they didn’t give it a more aero teardrop shape. At the very least it would have been a good marketing campaign for them.

Tim - 09/11/13 - 3:06pm

Will the Kilo now be available with a tapered steerer?

Ham-planet - 09/11/13 - 3:37pm

Any word on what type of alloy the linkage is made out of?

@Michael
No one, hopefully. The consensus seems to be that a 20 mm TA is not stiff enough for an inverted fork, so no one’s going to try 15 mm.

josh - 09/11/13 - 4:27pm

Maverick’s DUC 32 and SC 32 are inverted fork designs that work quite well. They use a 24mm clamped axle.

WannaBeSTi - 09/11/13 - 5:18pm

German:A,

Please make the Kilo with a QR15, 160mm travel, 650b, tapered, customizable anodized colors, and fat bike compatible…

I WANT ALL THE OPTIONS!

Engineer - 09/11/13 - 7:41pm

@ Wobbem

Just curious why you think this would be good on a seatpost dropper?

carl - 09/11/13 - 8:19pm

I count 11 pivots on the KILO fork. That CAN’T be a good thing….

dontcoast - 09/11/13 - 10:48pm

wow! seems like a no brainer somehow

@engineer

ever had a dropper post? lateral play inevitably develops. this would prevent it, no?

Tim - 09/12/13 - 3:03am

About the teardrop slider/ stanchion arrangement for dropper posts- that would only work in frames with a large seatpost diameter, no?

Drew - 09/17/13 - 12:24pm

Whatever happened to the “normal” 20mm axle. Noticeably stiffer, minimal weight penalty. Disturbing to see it being ignored (attn: x-fusion goldmember)

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