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I've always been curious about what actual spring rates riders run for SX. You hear about how uber stiff it is but to actually know how man spring rates above they go would be interesting.
At least a 60 i bet
just to keep in mind. ktm spring rates are vastly different than the japanese bikes. If you run a 5.2 on a kx that's not a 5.2 on a ktm.
Fork is same. Only CV thats runs a spring rate lower. 5.6nm is 5.6.
Rear is 10nm difference of you run stock linkage on MX-line.
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What rider should a 5.6 work for in a KYB?
A 5.6 kg/mm spring would approximately equal a 55 n/mm spring. That’s still a pretty damn stiff fork spring. He’s obviously going a lot faster than we do!
A spring rate like that for 170-180lb along with a shim stack like this is insane
It’s all in the shims
I recall seeing Tomac get off his bike and I was amazed by how little the rear moved. Looked like a pretty stiff setup!
Its not kg, its nm. All mx springs is measured in newtonmeter. Not sure why some in US refer to it as kg, when they are not even using metric system for anything else. Just confuses people 😄
55nm x2 in the fork wouldnt move even if he cased a triple 😂
I run 5.1 for 200lbs.
Around 260-270 maybe for 5.6 i guess
i’m 215 vet B and Mark at REP has me at 5.2 front springs in my CV forks… Keefer has a video up where his mechanic jade dungey talks him through the set up and he states that chase runs a more normal spring rate… so maybe that’s 5.6?
Maybe because for many years it was common for the springs to be rated and listed in kg/mm (especially aftermarket) and a lot of people are still used to this scale. Here are some snips from Kawasaki and Yamaha manuals showing both scales of measurement -
iirc Eli was running a 6.4 rear for SX
You are clearly a retarded foreigner lol
In late 2014 like two weeks before A1 Eli pulled up to Cahuilla bc all the SX tracks were flooded. Anyways, I remember he said he was riding on SX suspension and he showed us how stiff it was, he was putting a good amount of effort to get it to compress and the forks budged like an inch. Also the track was SOO gnarly, like 8 inch deep ruts from one edge of the track to the other and from out the corner all the way up the jump faces. By the end of the day no one was even jumping anything anymore, but he was out there HAMMERING. So gnarly.
side note: I can't even imagine how stiff JS7's set up was
Yes, agreed. Manufacturers published their springs in kg/mm for a long time in the USA, so most of the industry here used that as the standard.
I almost always give people numbers in both units to avoid confusion.
@quadzrulebro, the numbers you gave would be ten times that of a very stiff fork spring.
The fork spring rates will be in the order of 5.6N/mm ≈ 0.57kg/mm
With that in mind, the rate listed on Chase's sticker is N/mm, not kg/mm.
Just for example a stock KTM shock spring rate on a 450F is 45N/mm ≈ 4.6kg/mm.
Unfortunately knowing Chase's shock spring rate would be less meaningful because he probably has a factory linkage.
Pit Row
His mechanic is named Ryan Dungey?
How many kg/mm in a nm?
Nobody knows…
solid reference 😂
I'd imagine stiff AF since he loads the bike a lot.
The spring is not what is making the suspension stiff. Its the compression damping that makes it stiff. If the spring was that stiff they would never be able to set the proper sag.
I would think these guys sx setups don’t go by standard sag/free sag numbers. I bet their shocks have little preload and free sag. If any at all
1 kilogram-force millimeter = 9.80665 N*mm
That is why they are running low sag numbers like 95-98. Spring is for sure part of the stiffer setup since comp go hand in hand with increase or decrease of spring rates in bigger swings that we talk about here. Rebound goes same way.
whoops sorry for the mix up, my brain wasn’t keeping up with my typing evidently!
No, 5.6n/mm is about .55kg/mm
You have the conversion factor numerically correct, but the units wrong. They are a ratio, not a product.
1 kgf/mm ≈ 9.81 N/mm
Spring rates are force over displacement.
Usually, spring rate is expressed as k, force as F, displacement as x or d.
This comes from Hooke's law F = k*x which can be solved for k.
k = F/x which works out to [N/mm], [lbf/in], [kgf/mm]
Get out. Out of the boat, now
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