USD forks? Why?

Questions and comments about converting to beefier forks..
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Slick_Nick
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Post by Slick_Nick »

I would be able to get all the measurements myself, I have background in that kinda thing, I'd basically take in a schematic or CAD drawing of ecactly what I needed and see if they can machine it for me.
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Post by canyncarvr »

It might've saved some blabbing if you had mentioned that earlier....

Didn't you know the answer to the question before you asked, then?

:hmm:

It's not nice to fool Mother Nature......... :neutral:

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Post by jgas »

I think part of why I like the stock KDX forks is due to my terrain. When I ride a DX it's only in the nasty stuff. Rocks, roots, steep climbs, etc. I admit, I have to slow down on some G outs and drop offs, but I'm old, I do that anyway. I think I like the fork flex. The DX forks have a little too much flex, but I like a little flex. With only stiffer springs and heavier fork oil in stock DX forks, I'm happy. They aren't perfect, but pretty good, and better than many USDs I have tried. I hate, hate, HATE the early WP USDs on any KTM before about 07, but love the old 97-98 RSUs WPs on older KTMs. Again, especially in rocks and roots with very technicak Singletrack. Pretty much all I ride these days.

As I said before, I finally rode a bike with a set of USDs that I loved, an 07 CRF 250 X. Pretty sure they have Showa forks? Those forks soaked up everything, were butter smooth, and had perfect damping for me.

I am old, sit down most of the time, and on a good day only have B class speed, so I probably just don't need what many do.

Now, the underhang thing sucks! No arguing about that, it just sucks. Sometimes I can ride all day and never hang a fork. Maybe even several outings. Just when I forget about the underhang, BANG! Then I am nervous for an hour before I forget again.
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Post by Mr. Wibbens »

RSU's work for me too

I recently went from using ATF in my forks to 10w fork oil

Man what a difference! Took away a lot of the "bounce" I was getting from my .46's

I can ride across ruts like never before.

Bike seems to just float over stuff now

The underhang sucks but I usually have the pegs stuck long before the forks get hung up
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Post by river »

>|<>QBB<
jgas wrote:
I have had USDs on many bikes, always hate em in rocks and roots. They just don't ever seem to be supple or reactive enough to not deflect on the small-medium stuff.

The only USD fork I have ever used that I liked is the Showas on the 07-08 Honda CRF-X. It is the only USD fork I've ever tried that actually soaks up the small medium chop without deflection and will still take medium-large jumps without undue deflection or bottoming.
Finally a description that might help me understand this whole right side up vs upside down debate. Oh, I hope so much that somebody really answers this post's last question:

Can you (or anybody) explain what you mean by "deflection?"

What you're saying is with the USD forks the bike bounces off stuff the regular KDX forks absorb unnoticed, right?

Isn't that what you'd expect from a suspension that provides more precise control because it's stiffer?

SO WHY NOT JUST SOFTEN the springs/damping of the USD forks to get that absorption? They are more adjustable than the KDX forks.

Thanks.
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Post by Julien D »

SO WHY NOT JUST SOFTEN the springs/damping of the USD forks to get that absorption? They are more adjustable than the KDX forks.
This is KEY. Any fork you just throw on it quite likely gonna suck for YOUR riding style and YOUR terrain. Suspension setup is arguably the single most important part of setting up your bike. It has to be tuned, just like anything else.
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Post by river »

Thanks, but then the question is, why do people say that USD forks do not have this or that quality of the conventional KDX forks, when they could just adjust the USD forks to have those qualities? Or can they?

Logically, moving to USD should lose nothing, just adjust.
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Post by Indawoods »

Who says that? :cool:
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Post by river »

I see lots of posts to the effect that the conventional forks are better, usually because they are more flexible, plusher, absorb stuff better, and frequently the word "rocks" and "roots" occur in those posts. Even to the point that people put the conventionals on bikes that came with USD. I got my XR650R before my KDX, so a lot of that is from BRP forums, but I see the same kind of posts and comments WRT KDXs. Reread this thread for example, and elsewhere too.
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Post by Indawoods »

Conventional and stock KDX forks should not be used in the same sentence IMO. Stock KDX forks are under sprung spagetti.

A true set of conventionals are a different story. However... they are hard to find and expensive. Otherwise everyone would have went that route.

There is quite a history to wanting to convert to something that works better on the KDX. The KX USD setup was a compromise and works fairly well.
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Post by river »

Thanks. Suppose I was riding here in the desert sandy whoops, gullied out roads, and mountin trails, what would I notice that is caused by being spaghetti (aside from thinking about garlic)?
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Post by bcdonyo »

>|<>QBB<
river wrote:Thanks. Suppose I was riding here in the desert sandy whoops, gullied out roads, and mountin trails, what would I notice that is caused by being spaghetti (aside from thinking about garlic)?
Yesterday I took my KDX out in the desert for a couple hours. The conventional forks are vague feeling and flex too much to me. In my opinion these deficiencies are more pronounced the harder you ride, and the heavier you or the bike is. The forks don't seem as bad as the conventionals on heavier bikes like XRs I've ridden.

The front end feels more planted and precise on my USD equipped bikes. I haven't put the USD forks on my KDX yet, and it does okay, considering the suspension is bone stock and I weigh a lot. I know I'll like it better with the KX forks dialed in.

I've never liked any conventional forks I've tried. I admittedly haven't ridden a bike with "good" modern conventionals. In the mid to late 90's, conventionals seemed set to make a come back. When the Euros started using the Marzocci conventionals, they got good press reviews, even though the seals leaked. Then KTM/Husaberg started running large diameter WPs that were supposed to be pretty good. The Showas that Suzuki used on the '97 RM were said to be awesome, but since Jeremy chose to run USDs on his bike that year Suzuki went back to USD (IMO).

For most riders, large diameter cartrige conventionals should be the great for trailriding and off road. Not all of us ride supercross at Jeremy's level. A set of DRZ forks would probably be cool on a KDX, but the KX swap seems to be the easiest. Just my opinion.
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Post by Julien D »

those mid-late 90's suzuki conventionals were rumored to be da bomb. Never had my hands on any, personally. My buddy has a KTM with the zook's, and I think they suck.
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Post by Slick_Nick »

I found me some KX500 USD's! Still can't find out though, does the KDX wheel / axle work with the KX500 USD's or do I need that too? I know the KX500's are the most "bolt on" forks you can get.
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Post by scheckaet »

I think you need fork, triple clamp, axle and wheel. (probably the brake line too)
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Indawoods
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Post by Indawoods »

We always suggest getting the entire front end to avoid fitment issues. The second someone says... yes... you can do this and it fits, that's when someone else will say it did not work for me.
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Post by Slick_Nick »

Ya the KX500 forks I found need new head bearings but they include the triple clamps.
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