Inverted X-Fusion

[honns]

X-Fusion Prototype Inverted Fork - Eurobike 2012 - Pinkbike

Benefits are what, exactly?

[Bike Whisperer]

X-Fusion Prototype Inverted Fork - Eurobike 2012 - Pinkbike

Benefits are what, exactly?

Read the article

It boils down to less unsprung weight (mass not supported by the suspension) that allows the suspension to react quicker to impacts, with another plus being that the fork's lubrication oil is likely to spend more time around the seals and bushings, thereby keeping the fork running smooth.

[CharacterZero]

X-Fusion Prototype Inverted Fork - Eurobike 2012 - Pinkbike

Benefits are what, exactly?

If you had read the article you'd have already found the answer.

edit: whisperer beat me to it!

[honns]

Missed the important paragraph, it would seem.

[mullen119]

If it becomes available, I will be the first in line to buy it. I want to upgrade my Lyrik to a Vengeance anyway, and I have always been a huge USD fork fan. At 155lbs, its a match made in heaven.

[Renegade]

" Why would X-Fusion, among others, pursue an inverted design, especially when it presents such a design challenge? It boils down to less unsprung weight (mass not supported by the suspension) that allows the suspension to react quicker to impacts, with another plus being that the fork's lubrication oil is likely to spend more time around the seals and bushings, thereby keeping the fork running smooth. "


there you go

[Salespunk]

So sick! Hopefully they build it and it works.

[Kiwiplague]

Plus they look amazing! If they do nail the stiffness issues, they could be onto a winner with that fork.

[ryguy135]

Can anyone explain to me why all motocross bikes use inverted forks but mtb uses standard? I'm a mechanical engineer but this has me stumped. My buddy that rides both says Honda came out with a standard MX fork once but then everyone complained it was too flexy!?!?

[honns]

Yea, I see the benefits now. I'm with ryguy, why did the motorcycle world move to inverted? Seems like if it works better for the motorcycle world, it would also work better for MTB.

[steadite]

Can anyone explain to me why all motocross bikes use inverted forks but mtb uses standard? I'm a mechanical engineer but this has me stumped. My buddy that rides both says Honda came out with a standard MX fork once but then everyone complained it was too flexy!?!?

Just guessing...maybe cause MTb has only recently had thru axle type connections. Couldn't do inverted with old style 9mm bicycle dropouts.

[ryguy135]

Just guessing...maybe cause MTb has only recently had thru axle type connections. Couldn't do inverted with old style 9mm bicycle dropouts.

Good guess, but this can't be it. Fox had a prototype inverted DH fork that Aaron Gwin had been spotted doing practice runs on at World Cup races. Here maybe 6 months ago though they made an official announcement saying they were abandoning development citing excessive flex as the reason.

[mullen119]

The larger diameter stanchions on motocross bikes allow for extra stiffness. There have been many attempts at inverted mtb forks, but larger riders still complain of flex. If someone makes a stiff USD fork, it would take over.

[beanbag]

I have enough scratches on my fork lowers that I wouldn't want my delicate stanchions to be in that area.

This fork is stiffer than a standard fork in certain ways (front-back motion, for example), but seems much less stiff against the wheel tilting from side to side due to independent leg compressions.

[mullen119]

Assuming this fork ever makes it to production, I would be very surprised if it doesnt come with stanchion guards similar to what comes on the Manitou Dorado or White Brothers Groove. I would think they just kept them out of the picture to give a better look at the fork.

Its long been said that to make a bicycle USD fork stiff enough(twisting wise), for larger riders and extremely aggressive riders, a larger diameter axle would be required. Manitous 20mm Hex axle is suppose to be the best thing at 20mm, but still suffers from some flex. At this point, nobody wants to make a 25mm axled fork that comes with a hub. They dont feel the market is big enough to have the inconvenience.

[Fix the Spade]

Benefits are what, exactly?

It looks badass.

[Fix the Spade]

Just guessing...maybe cause MTb has only recently had thru axle type connections. Couldn't do inverted with old style 9mm bicycle dropouts.

Marzocchi were doing 20mm inverted Shivers in 2002, they were great forks relative to what else was available (like Psylos...) but did suffer from left-right twisting. Mine didn't, but I was 14 and weighed bugger all, big guys could get visible flap out of them.

My guess is X Fusion have taken the keyed stanchions from the HiLo post and applied them to the inverted fork. If one little stanchion can resist twisting at the saddle, then two bigger ones bolted together should have no problems at the front wheel. As long as they stay in the uppers and avoid the wiper seals that should solve any twist issues.

Regardless, I definately want one!

[David C]

Another issue so far with USD forks being stiffer is the weight. They are already heavier than most big forks on the market and to get a stiffer fork, you will need to either find a killer design or use stronger, but heavier materials and structure. And I'm pretty sure an inverted motocross fork weights a lot more than any MTB fork already. But I'm pretty sure they're gonna come up with something good one day, as carbon fiber, titanium, magnesium and other superior materials are being used in better ways and designs.

[mullen119]

I dont know, 4.3lbs for a 160mm fork is pretty damn light. Dorado's are pretty light at 6.6 lbs as well. There used to be a carbon legged Dorado but at 2400msrp, it didn't last very long.

[bad mechanic]

There's a reason every USB single crown fork has failed in the bicycle market. Without a second crown the fork cannot be made stiff enough without making it weigh a ton. Aside from that you're still dealing with more easily damaged stanchions and less wear/damage tolerant seals. Then at the end of the day the benefits from going USD on a bicycle are questionable.

On a motorcycle weight doesn't matter nearly as much and USD forks can be beefed up to be stiff enough. You can also run tighter and better seals since the weight of the motorcycle makes it more tolerant of stiction.

I really like X-Fusion, but it makes me sad they're wasting their resources on a evolutionary dead end.

[gabe0807]

There's a reason every USB single crown fork has failed in the bicycle market. Without a second crown the fork cannot be made stiff enough without making it weigh a ton. Aside from that you're still dealing with more easily damaged stanchions and less wear/damage tolerant seals. Then at the end of the day the benefits from going USD on a bicycle are questionable.

On a motorcycle weight doesn't matter nearly as much and USD forks can be beefed up to be stiff enough. You can also run tighter and better seals since the weight of the motorcycle makes it more tolerant of stiction.

I really like X-Fusion, but it makes me sad they're wasting their resources on a evolutionary dead end.

But they look so coooooooool

I've become a fan of X-Fusion stuff, but I am also a bit concerned about heading down this path. They already make good stuff that is way cheaper than the competition. Why not just go head-on into the DH scene with a traditional fork. There are no shortage of poor downhillers who will appreciate the value.

I'll try to withhold judgement though. I hope its totally badass.

[OffCamber]

Just for fun. 2002 Marzocchi Shiver SC. My wife's retro Klunker.

[Fix the Spade]

Interesting note.

There is an interview with the DVO suspension guys in this month's Dirt. There are no pictures but apparently DVO's new downhill fork will be inverted as well.

Inverted revival time?

[mullen119]

You can't say they have all failed since a couple companies still make USD mtb forks. You can't say weight for motorcycles doesn't matter either. People spend hundreds of dollars on TI bolts for motocross bikes just to save a pound. The flex issue is real though, and its caused by the stanchions being able to twist inside the uppers. If x fusion had found a way to solve this, and they sound confident that they did, it could be a great step forward. Anyone who has ridden on a USD fork loves the feel they give, other then the twisting of course.

[Jon Richard]

Isn't Paul Turner of Maverick Bikes now in league with X-Fusion? I love my DUC32 forks for trail duty.