2015 X-Fusion Inverted All Mountain Suspension Fork

2015 X-Fusion inverted long travel mountain bike suspension fork

No, that headline isn’t a typo, this is lining up to be a real, production 2015 product.

Their goal is to make a sub-4lb 160mm travel fork. From an engineering standpoint, they like the ability to fit various wheel sizes easier, gravity keeps the seals lubricated and binding is reduced on big hits, particularly with some head angles.

General manager Joel Smith says that’s why they went to an inverted design on motorcycles.

Inside, they’ve applied for a patent on the design to increase torsional stiffness inside the uppers. Without an arch, extra measures need to be taken to keep the stanchions from rotating in the uppers. A big thru axle solves some of that, but Joel say it wouldn’t be enough to keep the wheel straight in line with the fork under hard riding. According to Joel, you’d need a 38mm diameter axle to get the same benefit as their new system.

2015 X-Fusion inverted long travel mountain bike suspension fork

Currently, it’s weighing in a bit heavy, but they’re looking at taking the Uni-Crown design introduced with their 2013 forks and extending that to create a full one-piece steerer/crown/uppers.

2015 X-Fusion inverted long travel mountain bike suspension fork

Joel says its an immense engineering challenge because you’re trying to 3D forge something that needs to be exactly parallel on both sides and through the steerer.

2015 X-Fusion inverted long travel mountain bike suspension fork

And just for fun, here’s a cutaway of their shocks:

2015 X-Fusion inverted long travel mountain bike suspension fork

Comments

Juanito - 08/30/12 - 2:06pm

A lot of potential for one stop shopping- 26, 650B, 29, possibly fat bike compatible? If they get a handle some of the noodle-esque attributes that previous single crown USD forks had, they’ll have a real interesting product in their catalogue.

Steve M - 08/30/12 - 2:16pm

Never understood forks that grab the small diameter tube at the most highly loaded point (the crown). Inverted is the way to go. Trees figured this design out years ago…….

RoDe - 08/30/12 - 2:36pm

This is very promising like Steve M I never got the concept of loading the weak uppers.

let me splain - 08/30/12 - 3:30pm

The concept of a crown means that each fork leg is connected. Upside down and the fork legs (stanchions) are only connected at the axle with the tendency for them to move independently as well as twist. if you go big axle with big hardware like a motorcycle then there is no issue, if you make light weight then it becomes much harder to make it stiff as well.

Bob - 08/30/12 - 3:54pm

Meh,Maverick did this 8yrs ago.Still love my 160 mm sub 4 lb Duc!!Mav was WAY ahead of the times on suspension technology.

Steve M - 08/30/12 - 3:57pm

Let me splain right back…..

The tubes that are rooted at the crown are stanchions. The tubes that slide are well… sliders. Either way you want to hold the largest tube at the most highly loaded point- the crown. Then is is just a matter of running a thru axle to connect the dropouts. Having a bridge over the top of the tire is moot and now you have all kinds of mud clearance.

Oderus - 08/30/12 - 3:58pm

Current forks are the way they are because they work for the intended application. They are lighter and more importantly, the seals can handle a higher load/pressure when they are on top. Other companies have made inverted forks (Marzocchi, Maverick, Manitou) and they all had similar issues with oil leaks, wipers popping out, etc. All of those forks were buttery smooth out of the box, but a month later was a different story. Motorcycle forks don’t see the same internal pressures as a mountain bike fork because of their size so the seals and wipers take less stress from inside the fork. Hopefully X-Fusion gets it right and can put together an inverted package that can last.

Steve M - 08/30/12 - 4:47pm

Oderus

What? the seals have higher pressure because they are upside down?

Current forks are the way they are based on cantilever brake bosses. Look back to the Halson fork to see an attempt to go upside down and use canti bosses. The bridge over the tire is due to 9mm slotted dropouts having litttle to no moment carrying capability.

With disk brakes and thru axles inverted is the way to go. The downside is the sliders are closer to the ground and more prone to damage. A good lower slider guard is going to be a good idea.

Bob - 08/30/12 - 5:06pm

Oderus,
I have had no issue w/leaky seals(or any of the issues you claim) on my Maverick Duc,and have had it for 7 yrs now-and it is still super plush,yet progressive. And your comment about weight is just stupid.To this day no fork manufacturer has made a sub 4 lb 160 mm non inverted fork.

HWNSNBS - 08/30/12 - 6:29pm

@Bob–Meh, Maverick was WAY ahead in COPYING The Halson Inverted Suspension Fork–is what you should’ve written. Halson did this about 17 years ago…didn’t Mountain Cycle do an inverted fork too! Nothing new here.

Ricky Bob - 08/30/12 - 6:52pm

What problem does this solve besides less weight (so they say) and more wheel diameter options? It has obviously been tried before with little to no adoption in the community. This seems like a marketing led decision to me.

vectorbug - 08/30/12 - 7:57pm

If its stiff, strong, reliable and light, then I’ll be interested in it over traditional mtb forks. As a Maverick fork owner I have been disappointed with its seal reliability and now parts availability despite the great times we have on the trail.

DeeEight - 08/30/12 - 8:15pm

Mountain Cycles Suspenders forks had only two inches of travel (give or take a quarter inch depending on model year) and Halson Inversions had 1.9 or 2.5 inches (depending on version). The suspenders used massive stanchion tubes that were forged WITH the crown as one-piece. The top caps you unscrewed to get access to the elastomers inside were nearly two inches in diameter. They also had a thru-axle hub, 12mm bolt-on or QR (depending on version) at a time period when there wasn’t even anything in suspension hubs yet from any other brand. The Halsons used slotted stanchion tubes and a brace that was bolted to the sliders (and ran along inside the slots) to hold the cantilever/v-brake studs.

Brendan - 08/30/12 - 9:12pm

Cannondale seems to make one that works pretty well and is kind of light too.

Bogwolf - 08/31/12 - 8:59am

One other advantage of upside down forks is unsprung weight. In theory you should have less mass bouncing up and down, making for a better ride.

As for the comments about motorbike forks and pressures, that’s rubbish, off road bikes may have slightly larger forks that an mtb, but as they are dealing with approx twice the weight (total bike and rider) and often handle significantly bigger hits.

Pete - 09/18/12 - 11:53pm

I got one of the original Maverick DUC forks. Love the way it rides – it has saved my ass many times over the years. Recently (finally) had a mechanical that requires parts, so have been looking at other options. I was happy to just find out about xFusion (seemingly quality at a reasonable price), and even happier to learn that Paul Turner – one of the founders of RockShox before starting Maverick – is a key member of their development team. Hopefully, he can help them fine tune their product line so I/we can get our hands on a product that feels like an evolution (improvement?) of the awesome Maverick forks.

Mr. Bojangles - 12/17/12 - 9:40am

2015 release date means I have a couple of years to save for another new fork(or two depending on it’s ability to fit a fatbike wheel)

Mazza - 09/13/13 - 9:04am

I happen to agree with Brendan.. This will be released at the same time as the lefty supermax for 26/650B.. That will be lighter, plusher and stiffer? The downside is cannon dale ofc. XD

tjdog800 - 11/15/13 - 9:26am

Why wait until 2015? Carver has their TransFat fork out now. I’ve been riding it for 2 months already!
http://forums.mtbr.com/fat-bikes/carver-bikes-trans-fat-suspension-fat-fork-ready-go-870885.html

Freeride Forever - 04/10/14 - 1:31pm

Steve M pretty much nailed it here. The failure of inverts to be adopted is similar to the failure of derailleurs to meet their very well deserved death in favor of gearboxes. The powers at be want to keep selling us sh*t that needs to be replaced with more sh*t. They feed the public with false info that the sheeple gobble up to justify all the things they’re selling that don’t make any sense.

My old 66VF lost its arch (it broke off in a light accident) a long, long time ago & at 6-7″ travel, one crown & no arch it works as good as it did when it was new. All you need is a large axle & solid clamps, which don’t add any meaningful weight, & you’re fine. To think that some little cast mag arch is going to do anything for the rigidity of the fork is ridiculous. Those arches only ever existed like Steve said, for the sake of rim brakes. They’re unnecessary & obsolete now.

Some of the things written here like MX seals being subjected to less stress because of their size is incredibly a** hatted. LMFAO!!!! Really? Someone actually thinks a 250 lb MX bike pushed by 50+ HP places less stress on any part of its fork than a human/gravity powered MTB? Hilarious!!!!

Last thins is, I think “let me splain” not only has the difference between stanchions & sliders confused, but arches & crowns as well.

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