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Discussion Starter #1
One of the things I like to daydream about is M/C suspension.

Here is a great article that describes three basic damping curves:

http://www.shimrestackor.com/Code/Sample_Applications/Damping_Profile/damping-profile.htm

My question for the room: to ride McNutt the fastest, would you want progressive, linear, or digressive setup?

I think either a linear or a digressive setup, and have good arguments for either.

For those who have not ridden there, McNutt is lots of first and second gear climbing with rock splats followed by faster tight and rough singletrack.

So big hits and tight rough single track.

Of course, this is bench suspension tuning. I am not yet at the pace where I am thinking of revalving my KTM.
 

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definitely not digressive, it wont be compliant enough for the rough stuff, and will create traction issues on the technical climb stuff.
 

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Discussion Starter #3
remember you are only going 5 kph on the technical climbs... and the rear tire is a 6 PSI.
 

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Think trials suspension... light spring, lot's of preload, Linear setup and adjust with clickers... change it all if you want to go fast in different terrain... haha, (my best guess)
 

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Discussion Starter #6
Think trials suspension... light spring, lot's of preload, Linear setup and adjust with clickers... change it all if you want to go fast in different terrain... haha, (my best guess)
Why lots of preload? Shouldn't it be standard, as in around 15% of free spring length?
 

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To provide some force to the extension at the top of the stroke, get the suspension extended fast for the next obstacle, soft spring so the compliance is easy, damp the movement with the valving (clickers)...

15% of spring length is alot of preload... correct rate of spring and about 15mm preload for a 4 stroke (because of the engine braking), less for a 2smoke... variable according to what works for you...
 

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Discussion Starter #8
To provide some force to the extension at the top of the stroke, get the suspension extended fast for the next obstacle, soft spring so the compliance is easy, damp the movement with the valving (clickers)...

15% of spring length is alot of preload... correct rate of spring and about 15mm preload for a 4 stroke (because of the engine braking), less for a 2smoke... variable according to what works for you...
Hmm. I am thinking of a weighted street bike, not an off road M/C. Your comments on preload make a lot of sense.
 

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I think a street bike is more like heavy spring, lot's of preload, so the suspension returns to extension quickly, ... to keep the bike oriented correctly on the pavement (mantain it's geometry)...
 

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Discussion Starter #10
So yesterday I rode my KTM 300 XC-W and my KLX450r back to back at Mcnutt. Both setup with little preload, 1 click of compression on everything, and moderate rebound. Wow, what a difference. The 300 is a couch, twice as fast easily. Even going down flat trails over roots and ruts the 450 beats you up twice as much. Not sure I am going to revalve the 450, it is not the ideal Mcnutt bike, but I do like the tractability. I think a 300XCF would be ultimate. Staying with my 300 two stroke for now though, feels dialed with trials tires. Dialed for Mcnutt, anyway.
 

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Agreed..... 300 XCW is the ultimate McNutt bike. Touch to much power but adding the map switch to the bars is an inexpensive mod that allows you to dial it back and still have that extra bag on the open sections. Hence a little to much whiskey throttle from the picture, on a positive note it gave me the chance to inspect the skid plate.

View attachment 134418
 
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