Geometry/wheelbase (old CV on 19' sxf)

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4/12/2020 2:11 PM
Edited Date/Time: 4/12/2020 2:12 PM

Hi guys!

I'm trying to setup my suspension well, but i have a little difficulty with that...
I have a 2019' sxf350.
My front fork is Wp cone valve from 2014, the rear shock is a Trax without trax mechanism...
I heart the fork is shorter, than Black CVs with 6mm, and 12mm from AER.
I trying to compensate with put down in the clamps, 1.5 preload on the springs(left: 4.6nm, right :4.4nm - 76kg) and a WPTuner put a 3mm washer to the top of the springs. The rear sag is 106mm.
On the tripleclamp picture you can see how i use on loose condition track. It means 1mm from the top of the fork.
If i go up the forks with 2mm, it will unstable front.

Im thinking about, to raise the wheelbase and i can go upper whit the forks. What do you think about this?
Im not sure the trail will change that much, what is enught to put the forks higher in the clamps. If you see the picture from the rear axel it could go back with 10-12 mm... (final gear ratio 14:51)
Could this changes good, or stay on my a$$, and ride with this experienced setup?

Other question, how the wheelbase affect the trail?
Thanks!

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4/12/2020 6:10 PM

I have the same set also built in ‘14 on my ‘18 and I have them at the second line. Trax also turned off and a ride engineering performance link at 103mm sag. I have zero stability issues and it handles great.

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2018 KTM 250sx
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4/12/2020 7:16 PM

Everyone has a different feel. Flush forks and 106 sag should be about neural to OEM. You might be feeling unstable because the short wheelbase. I run 14/52 on my 350 with the rear pretty far back.

Maybe you need to adjust your clickers for a more even ride, it’s not just fork height and sag that give you balence.

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4/12/2020 11:15 PM

CarlinoJoeVideo wrote:

Everyone has a different feel. Flush forks and 106 sag should be about neural to OEM. You might be feeling unstable because the short wheelbase. I run 14/52 on my 350 with the rear pretty far back.

Maybe you need to adjust your clickers for a more even ride, it’s not just fork height and sag that give you balence.

Finaly i have been thought about the same...

I measured different ratios at the rear axle to get now how can i calculate the wheelbase. So i run with 14:51 with 116 chainlink for 3 years, this is what i prefer, not longer. I tried first to put 1 more link, but i couldnt extend the chain, cuz i reach the backside of the swingarm.
Second idea was i should run with 13:47, which is almost the same ratio, but i have to get out 1 link... If i change with 1 teeth less at the rear, it means +5mm on the wheelbase. Picture: 13:48 redline in the middle. (13:48 with 114link). So if i use 13:47 i get + 7-8mm wheelbase. But if i use 14:52 i think, i reach almost the longest wheelbase in the swingarm...

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4/12/2020 11:21 PM

Some people say they have used a half link but no idea where to buy them. If you find out I’d be stoked to try one.

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4/13/2020 7:53 AM

Over thinking it.... set sag between 105-108...I like 105....start with forks on first line... adjust as needed... tight track, raise forks to 2nd line, long fast, rough, sand track flush with caps or first line on forks...

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4/13/2020 8:14 AM

sandman768 wrote:

Over thinking it.... set sag between 105-108...I like 105....start with forks on first line... adjust as needed... tight track, raise forks to 2nd line, long fast, rough, sand track flush with caps or first line on forks...

Pretty much this ^

Everyone is different. They have different riding styles, are different heights and weights, different skill level, etc., so there's no one clear answer. OLn top of that, the tracks and riding types are all different.

It's why I always laugh at a 1mm longer "performance link" being the answer for everyone. Have you ever seen a link sold that's shorter than stock? They're always 1mm or 1.5mm longer. You'd think the OEMs would figure out that they've been making them just a bit too short for years! laughing

Get the bike to a reasonable baseline (sag set around 108, forks a couple lines up, correct spring rates and valving) and ride it. Get comfortable enough to understand what feels off (at least a couple laps) and adjust accordingly. Adjust one thing at a time so you have a good understanding of what does what. Repeat over the course of a day and you should end up at a pretty good setting, or at least get 90% of the way there and be able to change it up for different track conditions.

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Billy Wight
Luxon MX
@LuxonMX
https://luxonmx.com
Motocross Components Engineered for Performance

4/13/2020 9:55 AM

I would double check the fork length but if it’s actually 12 mm shorter than the aer I would leave them flush with the clamps always, and run 108-110 mm of sag

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4/13/2020 10:07 AM

I have the same forks on my 2018 Rockstar Husky and run them flush. They are 5mm shorter than the black CV forks and 10mm or so shorter than the AER fork. I have the Luxon (N2D) link and valving setup with 105mm sag.

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Take it to the limit, one more time!

4/13/2020 10:49 AM

sandman768 wrote:

Over thinking it.... set sag between 105-108...I like 105....start with forks on first line... adjust as needed... tight track, raise forks to 2nd line, long fast, rough, sand track flush with caps or first line on forks...

Luxon MX wrote:

Pretty much this ^

Everyone is different. They have different riding styles, are different heights and weights, different skill level, etc., so there's no one clear answer. OLn top of that, the tracks and riding types are all different.

It's why I always laugh at a 1mm longer "performance link" being the answer for everyone. Have you ever seen a link sold that's shorter than stock? They're always 1mm or 1.5mm longer. You'd think the OEMs would figure out that they've been making them just a bit too short for years! laughing

Get the bike to a reasonable baseline (sag set around 108, forks a couple lines up, correct spring rates and valving) and ride it. Get comfortable enough to understand what feels off (at least a couple laps) and adjust accordingly. Adjust one thing at a time so you have a good understanding of what does what. Repeat over the course of a day and you should end up at a pretty good setting, or at least get 90% of the way there and be able to change it up for different track conditions.

Thanks your detailed answer, I will follow this scenario!
Could you tell me what cause the 1mm longer link?

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4/13/2020 11:16 AM

Dani#279 wrote:

Thanks your detailed answer, I will follow this scenario!
Could you tell me what cause the 1mm longer link?

The +1mm link was more of an off topic rant than anything else. You'd only have one on your bike if you bought one for it.

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Billy Wight
Luxon MX
@LuxonMX
https://luxonmx.com
Motocross Components Engineered for Performance