ed 

I was just thinking...top shelf Moto's are running inverted suspension forks. I know there have been several in MTB's, but why haven't bicycle suspension forks gone inverted as a standard?

How come the 40 has better potential than the Shiver?

-_RebelRidin'_-

???

ed 

Shiver


Dorado


Dorado SC


Maverick DUC


Mav SC

ed 

Verses what's available currently:

ed 

I'm assuming it's a lateral rigidity-to-weight ratio issue?

Dannihilator

There's alot of flex in an inverted design.

-_RebelRidin'_-

I see know.

I do better with pitures and diagrams lol!

Pocko

Speak for yourself... my Pocket mtb runs inverted forks!






But seriously though, for full scale long travel bikes... there is a flex issue when these forks are constructed way lighter than the motorbike versions.

The "arch" in the traditional fork sliders is what makes the conventional forks stiffer. I think Maveric has solved this problem with an oversized thru-axle (40mm if I remember correctly). But that's hard to get into the "mainstream" because of the non-standard 40mm front hubs.

I'd like to see them make a come back though... when the time is right...

.

scrublover

Nope. 24mm. And they are still more flexy. Crap damping and leak prone as well.

WannaGetGood

Doesnt it make it kinda akward to ride? All the weight is now in your hands.

ed 

So...what I'm getting at is one of these:

1. MTB is infant and will one day be inverted
2. Moto will one day realize that they can drops some more weight by mimicking the MTB forks
3. The factors are way to great. That is a line that probably can't be crossed with the two sports.


I'm kinda leaning toward #3 in that the weight savings will be negligible to change Moto, and it's TOO IMPORTANT to neglect for MTB's, therefore "it is what it is" and it's gonna stay that way.

Lebowski

seems like the inverted fork would get more dirt and debris on the seals. thats probably not a problem with the technology these days, man has conquered small debris particles.

a buddy of mine who is a motocross rider said that inverted forks are much stronger than conventional designs.

i however do not think we are in the infancy of suspension. its all relative though.

https://www.mombat.org/Suspension_Museum.htm check out these dinosaurs.

:edit:
https://mombat.org/Suspension.htm

dminor 

I've had four inverted forks (well, all the same make, just different model years) and I never experienced flex in them. Maybe I am not the most subtle detector; but at the time I was running them, I was still working on my jumping skills. I had a lot of off-kilter, blown or near-blown landings, off-balance nose-downs and such and the 8" just absorbed and sucked it up and forgave my mistakes more times than I care to remember. I also don't think I ever had the sliders twist in the triple clamps in a crash.

I do know, though, that Shivers had a widespread reputation for being flexy.

But inverted technology is the preferred method for off-road motorcycles now; it's so far along that there is no reason for an inverted bicycle design to be flexy if done correctly. The larger diameter structural members are the longer ones, so should impart better rigidity. The 'right-side-up' design is as quaint and long in the tooth as the venerable Cerrianis on my old flat track frame.

UnsafeAlpine

I'm skeptical that inverted cannot become stiff enough. MX bikes are concerned about weight, so if that were an apparent road block to making a stiff fork, we'd still see regular forks. There's something I'm just not seeing here... I'll need to think about this more...

jcook1989

The new Dorados have a hexagonal axle so they are stiffer they also use carbon in the uppers to make them a lot stiffer and keep weight down. The one big downside though is that they are like $1000 more the a Boxxer WC.

dminor 

An axle that threads firmly into one side with a 'locknut' should secure the lower end every bit as good as the hexagonal axle, though. I spot the carbon uppers for sure; but most any inverted should inherently be more torsionally rigid by its nature because of the large diameter uppers and the potential for nearly double the bushing overlap. What am I missing?

Pocko

I had ridden and mech'd on the old Manitou Dorados (with hex axles)... and besides leakage problems we also noticed some flex. If you jammed the front tire against a wall corner and steered the handlebars, the flex on the Dorados were considerably more than the trad Boxxers. I'm still not sure whether this flex mattered or not, as in the field the riders weren't put off by it although they noted that it was noticeable.

When Honda came to New Zealand for the DH World Champs, I kept and eagle eye on the RN01. Every body was fascinated with the top-secret gear box, but I was more interested about the inverted SHOWAs that were on the bike. I was aware of the problems that plagued the inverted "offerings" from the MTB industry, but I recon if anybody knows how to build upside-down forks correctly, it would be Honda. Needless to say, they performed flawlessly and I've never seen a Honda mechanic go anywhere near those forks for any reason whatsoever.

Now that the RN01 program is over, we may never know what the Showa fork is like - as it may never be available to the public! Time will tell if Honda will release that Showa fork commercially...

Couldn't find my pics, but I found this one. Love that Showa!

Pocko

Ooops, sorry I was mistaken... it wasn't Maveric.

It was the X-Fusion Delta 8 fork and it's a 35mm thru axle not a 40mm.


Here's the hub:




And the fork:

Pocko

Found my Honda pics... why does it's always have to be in the last CD from the pile!!

Here's a pic from the Nov2006 MTB World Championships. The Showas on the bikes Honda brought over were the carbon version of presumably the same fork (I like the bare metal ones better). Not much to look at but they would have all the proven inverted fork knowledge Honda have accumulated through years and years of moto-x racing... but they're not telling, nor selling.

ed 

Yeah, I agree that there are some inverted forks out there but it's not a standard like in Moto.

-_RebelRidin'_-

So what are the advantages of having "your suspension upside down?"
Does it ride better or take up the bumps better?

Sorry I have never ridden a Dirt Bike so I am 100% unaware of how the "upside downers" work.
I ride ATV's lol.
no forks.

ed 

So if MTB's further evolve...inverted may become std...b/c inverted is stiffer in moto. TA size maybe?


Not buying that one, man. Guards have been on Moto's for years w/o those issues. They ride in crappier deep mud with debris mixed in than we can possibly pedal in...not to mention that following the leader closely trying to pass results in a rooster tail smack in the face and fork.

-_RebelRidin'_-

Motocrosses seals and guards are going to be a lot more durable and heavy duty than found on an MTB. I don't think MTB bike will be able to get the same results as Moto due to that size/durability factor.

dminor 

Fixed . . . a bit (not trying to pick at you ).

I agree. It's funny, when Minnaar, Honda and Co. were here at the Schweitzer, ID Nationals with the then-very-new RN01, it was all very hush-hush. They had everything in a big walled tent and the tech hovered over everything and kept it out of sight. Besides the Honda techs, there were two Showa techs going over and through everything between runs.

I find it interesting, too, that there have been some shots from the Japan national races with RN01s sporting Kayabas (KYB) insteas of Showas. Here is Ida Isao's RN01. Ida won the 50+ at the '06 Masters Worlds (and completely smoked me ). Note the KYB:

scrublover

Keep this in mind:

The two most well known inverted single crowns out there? Shiver SC and the Maverik SC fork? Flexy, flexy, flexy. The DC forks out there? Either long travel, heavy, expensive, too flexy, leaky, crap damping or some combination of those wonderful traits.

If someone could build a 5-6" SC inverted fork with good damping, not leak prone, not any heavier/flexier/spendier than my Lyrik Solo Air or Pike Dual Air and they'll have something. Otherwise (IMO) inverted forks are a solution to a problem that doesn't exist - at least in the MTB world for the non big DH fork crowd.

Sure, big upside down forks are "it" in the moto world...heavy enough to accomodate the travel/prevent unwanted flex but also where you have a much larger engine than the human body to move the thing forward.