Kx-KDX front end help!

Questions and comments about converting to beefier forks..
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F1
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Kx-KDX front end help!

Post by F1 »

I will have my lower triples back from RB today with the stem swap done.

I am short - 5'6" and prior to starting the swap I was going back and forth with the Kouba 2 link in the rear between rides. The bike fits me much better with the link. I have read many differing opinions about using the link - and the guys who say just ride it at stock height are just incorrect (and probably tall) Unless you want to spend half your day falling over because your feet dont touch the ground, I reccommend the link. MX riding is dfferent - in the woods there are simply too many gnarly issues to deal with to not be able to put a foot down if need be.

I maintained the geometry of the bike with the link by lowering the front stock forks about 1/2 inch. With the rear sag at 3 inches the 1/2 inch in the front was about right.

Since I was close with my old setup - I need to set the new 1" longer KX forks at the positional equivalent of the old forks which were 1/2 inch up in the clamps. Am I correct if I mount the forks 1.5 inches above the KX upper triple? (doesnt seem right to me) Or is there some difference in the position of the top of the KX upper triple in relation to where the KDX top triple was? (If that makes any sense!) The KX triple is taller than the KDX one. So should I be measuring from the center of old KDX triple to the top edge plus the 1/2 inch and whatever that distance is I should measure from the center of the new KX triple and add an inch? I have bar risers to provide me extra clearance if necessary.

Thanks for any assistance!
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turtle
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Post by turtle »

Can you just measure a reference point with your current setup (could be anything but say for example the distance from the front axle centerline to a point on the frame) to maintain the same geometry without getting too complicated? Just a thought.
Bill
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Tedh98
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Post by Tedh98 »

Sounds like you could be sliding the forks up quite a bit. Once you determine the final height, I'd check to make sure the forks bottom internally without the tire making contact with the fender or the bolts holding the fender in place.

Probably not a fun time if the tire can make contact with the fender bolts.
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Post by F1 »

>|<>QBB<
Tedh98 wrote:Sounds like you could be sliding the forks up quite a bit. Once you determine the final height, I'd check to make sure the forks bottom internally without the tire making contact with the fender or the bolts holding the fender in place.

Probably not a fun time if the tire can make contact with the fender bolts.
I agree. If they will bottom I will have to drop them just until the wheel clears and then deal with the rear end if I have to. What I cant figure is if the rake of the new triples is different, or any other differences in the triples that would require me to add or subtract from the 1" longer KX forks plus the 1/2" I was already moving them up.

Turtle- I cant do it now bc the front end is off!
F1
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Post by F1 »

>|<>QBB<
Tedh98 wrote:Sounds like you could be sliding the forks up quite a bit. Once you determine the final height, I'd check to make sure the forks bottom internally without the tire making contact with the fender or the bolts holding the fender in place.

Probably not a fun time if the tire can make contact with the fender bolts.
I agree. If they will bottom I will have to drop them just until the wheel clears and then deal with the rear end if I have to. What I cant figure is if the rake of the new triples is different, or any other differences in the triples that would require me to add or subtract from the 1" longer KX forks plus the 1/2" I was already moving them up.

Turtle- I cant do it now bc the front end is off!
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rbates9
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Post by rbates9 »

Depending on the year of the forks you may not be able to go up much more than an inch and still have the clamps land on the raised portion of the fork tube.
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Post by Julien D »

>|<>QBB<
rbates9 wrote:Depending on the year of the forks you may not be able to go up much more than an inch and still have the clamps land on the raised portion of the fork tube.
This.

You can only go as high as the "clamping sections" on the fork tubes will allow. With my YZ front, it wasn't much. The difference between triples was different on the YZ, so I ran out of room on the lower clamping area while I still could have gone a good bit farther on the top. It hits the bars, anyway. In your situation I guess the best solution would be to lower the forks internally via the use of spacers if you can not drop the triples down far enough.
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marrk_us
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Post by marrk_us »

+1 on the spacers.

I've known and helped a few "wee people" with their kdx's in the past. The kdx's can be made to fit shorter people easily. First- "To Kouba link or not Kouba link, that is the question". Make a decision and stick with it. The link will change the height AND the ratio of the rear suspension linkage. That's not a problem, the shock can be revalved/resprung by a competent suspension shop to compensate. Once the rear is properly set up with the link, switching the link back to the stock link will throw everything off.

There's also an easy solution to the front end height problem. Ask the previously mentioned "competent suspension shop" to install spacers internally in the forks. The spacers keep the forks from expanding to full length. If the height needs to be an inch shorter to match the lowered rear they can do it. At the same time they can revalve/respring to compensate for the reduced suspension travel on the front. Yes you'll have less travel in the front but no less travel then the stock kdx forks have, and better to have the travel limited by the installed spacers then by slamming the front tire into the underside of your fender/triple clamps.

If you ever sell your bike to a giant, they can switch back to the stock kdx rear link and have the spacers removed from the forks when they have the suspension revalved/resprung for their weight.
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