[FireFly]

Got a question...Whats the advantage to having upside down forks compared to the standard forks? ( 600RR forks compared to 600F4i forks) What is it that makes them better?? Thanks

[s a x m a n]

they are more rigid (sp?) and don't flex as much

[SVRACER01]

one is upside down and the other is right side up.... but i dont know which is which

[Hardcore]

Originally posted by FireFly
Got a question...Whats the advantage to having upside down forks compared to the standard forks?

when you crash + the bike lands upside down on top of you, the fork oil won't all run out on you !

[hessogood]

03-04 600RR are standard
05-06 are inverted

the advantage is...when you're inverted in a 4g negative dive with a MiG 28, you can flip 'em the bird.

[Hardcore]

Originally posted by hessogood
03-04 600RR are standard
05-06 are inverted

the advantage is...when you're inverted in a 4g negative dive with a MiG 28, you can flip 'em the bird.

Thanks "MAVERICK"!

[Punjistick]

Uh, that's classified.

[Joker]

Also theres no underhang past the axle. On dirtbikes that is good for clearence with ruts.

[bump909]

Originally posted by hessogood
03-04 600RR are standard
05-06 are inverted

the advantage is...when you're inverted in a 4g negative dive with a MiG 28, you can flip 'em the bird.

Communicating.. keeping up foreign relations. You know... giving him the bird.

[Currently]

Either way, the forces will have to go somewheres ...

Typical forks will bend the fork tubes.

USD forks are stiffer and the forces are transferred to the
triple and frame stem.

[deezyellownutz]

The only physical difference I know of is that inverted forks have a less chance of having the chrome part knicked by road debris and reduces the chance of a busted or leaking seal due to imporper sealing about the tube. The chrome part if the top 1/2 and a normal fork will have the chrome part on the bottom 1/2 and you can usually tell by looking become the front fender and it usually wraps around the forks to protect it. Just my 2 cents.

[Honclfibr]

USD forks result in less unsprung mass.

[benVFR]

Originally posted by Honclfibr
USD forks result in less unsprung mass.

Yay we have a winner... that's gotta be the #1 most important reason as flex isn't always the worst thing in the world.

[gmdboston]

Originally posted by Honclfibr
USD forks result in less unsprung mass.

Not really, the USD forks often weigh more than the convetional. Stiffness is the main reason. It's easier to control the spring coefficient of the fork flex by varying the wall thickness, and tube diameter. This also helps with stiction tremendously. we run stiffer valving and spring rates on USD forks than on conventional forks on the same bike. Also you have more options with travel and ride heights as well.

[Honclfibr]

Originally posted by gmdboston
Not really, the USD forks often weigh more than the convetional.

Right, but the heavy parts, the fork tubes, are sprung in a USD fork, yes?

[gmdboston]

They weigh about the same, you've been listening to the marketing bull shit.....

[benVFR]

So they vary the outside diameter of the female/upper portion of the forks to tune the flex?

I can see that... you can't really do that with conventional forks.

[gmdboston]

Originally posted by benVFR
So they vary the outside diameter of the female/upper portion of the forks to tune the flex?

I can see that... you can't really do that with conventional forks.

And the inner tubes as well, it all about the harmonics

[benVFR]

So they vary the outer diameter of the outer tube and the inner diameter of the slider?

The two surfaces that mate have to remain constant diameter to keep a seal right?

Sorry for bugging you but it's pretty interesting.

[gmdboston]

Inner tubes are 41, 43, 48, and 50mm OD. The tube wall thickness is varied as well as the outer tube OD and wall thickness. the bushings and seals are common DU bushings and NOK/ARS Seals.

[Rye]

Interesting post. Reinforces my thoughts on converting a conventional setup to usd's. Something I would never do. Big debate on another forum as to whether to convert an XR650 setup to a CRF setup. One of the members contacted Honda, and a rep. got back strongly advising against doing it. Definitely something to worry about given the construction of rigid aluminum frames.

[gmdboston]

I've seen perfectly good handling motorcycles completly botched by mounting USD fork. OTOH early model SV's respond very well to GSXR front ends. Generaly the stiffer the frames can tolerate a stiffer fork, and a more flexible frame needs a more flexible fork. The early SV's have one of the stiffer frames I've worked with.

As for OEM advise, they have to be careful of liability, you will never get an OEM rep to recomend any thing that does not come from the parts fiche. Lawyers and accountants have more say in M/C desing than the engineering dept.

[benVFR]

There is so much of that ricky racer engineering going on with the VFR...

People are constantly swapping RC51 front ends on... swapping 954 shocks on, putting bizzare shims in, etc..

And half these people don't even go to the track which makes me really question the whole thing.

[KB]

Don't belive half of that bs Ben. Just idiots with too much time and money on their hands.


I say just run it.

KB

[Honclfibr]

Originally posted by gmdboston
They weigh about the same, you've been listening to the marketing bull shit.....

Guess so. Cool thread