Spring rates for 2012 XCs

[ggalex]

With thanks to Clay for the following very useful info for baselining the suspension on the new 2012 XCs...

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Originally Posted by Clay

...I think you might be surprised how good these forks work with the odd set up I'm using. First get the springs correct. This is critical. Then back the clickers out all of the way and turn the pfp valve in one turn. I'm sure that Marzocchi did not intend to for the fork to be used this way but it really is working good for me and Zach, my son. I can not remember my front wheel running down a root in the last two national enduros. I think you guys should give this a try before you spend re-valve money.
Here is an approximate guide that I worked up on springs:
140 pounds stock front stock rear
160 pounds .44 5.4
180 pounds .46 5.6
200 pounds .48 5.8
220 pounds .50 6.0
240 pounds .52 6.2
260 pounds .54 6.4
The first number is the fork spring, second the shock spring.
Clay

[twowheels]

Originally Posted by ggalex

With thanks to Clay for the following very useful info for baselining the suspension on the new 2012 XCs...

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Looks about one to two rates too high, but that might just be me.

[Jakobi]

I thought the same thing..

I'm 175 nude and the stock .42 and 5.2 weren't far off. Its just the riding gear and sack of tools that push me over.

[STM Suspension]

I've been having this conversation with Jake...

The spring is an interesting thing and it has lots of roles; it has to hold the bike up in the right position- too high and the bike never compresses and the wheel has no ability to follow the hollows in the ground, too low and you're always in the progressive part of the air spring; it has to hold the bike up during weight transfer from acceleration and deceleration- when you brake hard and the front goes down too far and the gets nervous (our new AA Pro Enduro test rider had this comment about his new '12 300 with the 48 Zoc's, and he's 165 lbs) this is typically because of too soft fork spring- remember, damping is a velocity term- that means that it's only effecting stuff while the suspension is moving- if you're braking long enough that the front goes down and settles, it's spring, not clickers. And much more.

But also the spring pushes the wheel down on the ground. If the spring is too light, then when you hit something (like a rock), the wheel 'jumps' up out of the way. Or tries to. Then you have high suspension speeds. Damping is a velocity term, so you get a ton of high speed damping when you least need it. Sometimes, if you use a little more spring, ie a stiffer rate, (to a point), the suspension actually feels more plush- because now the spring is helping to do it's part- it's holding the wheel down a little more, giving the damping circuits a little time to catch up.

I'll be honest, this is seriously important. There's a lot, if not more, to valving and getting that right so it all compliments each other- everything has to do its part otherwise we're just trying to band-aid stuff- adding preload or adding compression damping trying to make up for a too light spring is just going to make the bike ride like crap. Really.

This is just scratching the surface of what really needs to be going on when you talk to your suspension person- they really need to be understanding all of this. A lot of people I talk to comment on how complicated suspension tuning is. I whole-heartedly agree- that's why after I started doing suspension work I went back to university and got a bachelor of science degree in mechanical engineering with an emphasis in vehicle dynamics. I think I have an ok grasp of what's going on but I learn new things every day, every day. So if you're having a hard time wrapping your head around it, that's ok, it really is that complicated.

[STM Suspension]

Oh, and those spring rates posted above are almost assuredly directly from Ohlins.

[Simmo737]

I reckon they are ohlins, 4.8 to 5.0 for 200lb rider weight no gear.
They are the same as Race tech for 200 lb for a bike the same weight enduro/desert including gear.

Can't agree more with stm. You use a spring that requires more than 5mm preload front or around 10 rear to get good sag setting and it will be harsher than the heavier spring with correct preload and correct sag. I proving in to myself again and again. Don't think for a moment that soft springs mean soft ride. You ask nine out of ten pro or fast amateur riders and they will like light valving( by their standard)/ heavy springs.

[mikemoto]

I know this is getting off the subject but, I'm having issues with Ohlins TTX forks. They sent me 48 with the kite and it felt harsh, so I went back to 44's now the bike wont turn (ride's like it's on ice) and the fork is harsh on everything but big hits( whoops, big log) Yesterday I mounted my video camera on my forks and went out for a test ride, and what feels like the fork not moving looked more like the fork got into the middle of the stroke most of the time. Now I talked to Ohlins yesterday and they told me that there was an upgrade to the 2011 valving to remove some compression dampening, But now I'm thinking the heavier spring's will make it ride higher, hence in the softer part of the stroke. Anyway my point is Ohlins sent me 48 for my 190 lb. weight

[GMP]

Thats way stiff. You shouldn't have to go off the map with springs to get it to work. It needs to be revalved for you, even if it did cost $1K. It can't work great everywhere for everyone no matter how much it cost. Ask any tuner they will tell you the same.

[Jakobi]

Glenn, This is what I've been discussing with Dave at STM after reading what you have said on the matter in the past. I'm going to let him send me what he feels will be best to run.

I don't think anyone is arguing that they may need a revalve as well.

The more I think about it the more I realise there's more than one way to skin a cat. You can go light on the springs and then valve firmer, or you can go heavier on the springs and lighter on the valving.

Daves theory makes perfect sense though. If the spring is firmer it will do more of the work, allowing the valving to do what it has to without blowing through its stroke too easily. The only issue is if the springs are so firm that you can't compress them.

Alternatively, the lighter springs will feel plusher initially, however are more prone to blow through the stroke and then the firmer valving in the mid/top will be harsher than expected (unless valved perfectly).

1+3=4 / 3+1=4 ..Same but different.

[ggalex]

All the above well-stated, is it then reasonable to say in brief that if you have to change the springs, you will most likely need to change the valving to match?

Case in point: For my Berg FE450 (I know, this is not husaberg.org, but all bikes have forks), for my 190#s+ I was recommended .48 fork springs to replace the stock .44s-- this felt too harsh/stiff for me, but frankly I did not try adjusting far away from the stock clicker settings for the .44s. So I elected to go down to .46s and that felt a lot better. But they blow through the stroke on big landings. The feel is too much LS comp dampening and not enough HS comp dampening.
Sounds like I need to go up to those .48s and just break down and get the valving done right?