[sanjosedre]

I'm dialing in my CCDB on an Orange Alpine & using a 450 lbs spring with zero preload to acheive 33% sag. Now my question is how a lighter spring with added preload (to get the same sag) would change things?

Thx,
Dre

 

[Squash]

A lighter spring with more preload would reduce small bump sensitivity. I know it seems counter intuitive, but the more preload you add to a spring the more force it takes to start the spring to compress. Also increased compression damping can have an effect on the small bump compliance as well. With the dual high/low speed compression adjustments of the CCDB you might get away without increasing low speed compression. But you'd still be loosing sensitivity due to the heavier preload. And you would have to increase your damper settings to compensate for the lower spring rate in mid stroke and to prevent heavy bottom out.

Generally if you need 30 to 33% sag and are getting it with a 450lb spring and 0 preload, you've got what most would consider an ideal set up. From what you describe I can't think of a reason to go with a lighter spring.

Good Dirt

 

[PMK]

I would disagree with Squash.

Given the choice of no preload or too much preload, for off road none would normally be better.

That's not your situation. The bike would respond and have better small bump compliance with one rate less on the spring and a bit of preload. This will set the spring on it's true rate without any end conditioning effect. The amount of damping change should be very slight if any.

Additionally, no preload settings are not tunable, and often it is found that depending on conditions a quarter turn either way from what you have found to be optimum sag, not what the book gives as a base line, will give you a better handling bike capable to run hard without getting sketchy.

Your call since it is ridable as is. I'd borrow a spring and test.

PK

 

[Uncle Six Pack]

I know it seems counter intuitive, but the more preload you add to a spring the more force it takes to start the spring to compress.

Only when the tire leaves the ground-as long as the suspension is loaded, spring rate is spring rate... when the tire is completely unloaded-THAT is when preload will have some small effect on perceived rate as the preload must be overcome before the spring will compress. Within reason, this shouldn't be too big of a concern for 1-2 turns on the preload collar.

hmmmmm.... math, math, math....

2 turns is like what... 1/8 inch... maybe 3/16 (my shock isn't here right now or else I would measure)? So on a 400 spring (one rate lower then his current), that is 50-75 lbs, but then you have to figure leverage ratio, so that knocks 50-75 down to like 20-30 lbs (for a 2.5 leverage factor, which is pretty conservative for lots of frames-that orange may be closer to 3?). When you compare that to the force being applied to the frame when you are landing from a jump or drop, it sounds fairly insignificant.

Where I could see it being significant is a situation is where the suspension is unloaded, but the bike is not off the ground (flowing through a rock garden or pumping rough terrain).

To the OP: if you like the way you frame rides with 33% and no preload, then I would stick with what you have.... then if you ever need to jack up the rear slightly to avoid pedal strikes, you can always add a turn or two. If you run a lighter spring with 2 turns at 33% and want to adjust slightly (to 25-30 range), then you are going past 2 turns which is generally not recommended for lots of reasons.

Also, a lighter spring with more preload will generally bottom-out easier (I forget the difference, but I figured it for my bikes and the small amount of preload is not enough to make the lighter spring "act" like a heavier spring much past that static sag point)... so you would need to compensate to some extent with compression. Ideally, compression settings will vary by riders and terrain. I like my compression more active and open, but you may like more damping-depends...

You should ride your current set-up and get to know it, then decide if there is something you would like to change (like you aren't using your travel even though compression is wide open)... otherwise the effect of lighter spring/more preload has no context.

HTH. Have fun.

 

[mullen119]

I agree with squash. A spring that gives you proper sag with no preload is going to perform better then a lighter spring that is preloaded. If your are preloading a spring, you are doing so because the spring is not the correct spring for your weight. Preloading should be used if you are in between springs, not as a tuning technique.

 

[derby]

A lighter spring with more preload and no change in damping is more small and large bump compliant. But with a softer spring more compression damping may be needed to reduce mid-travel blow-through when pumping corners and g-outs and avoid bottoming bigger hits, and that added damping will reduce small bump compliance compared to a firmer spring with less compression damping.

I generally like a coil requiring 2 turns preload for my desired sag, so I can adjust preload and damping softer or firmer for changing conditions without swapping coils. And I swap coils 50# in rate firmer for very different environments (and also swap the fork coil one step with the shock coil change), generally for riding unknown or bigger hit areas. I feel it's better to be too firm than too soft where I'm not familiar with the flow of the ride.

You won't really know what spring weight is best until trying for yourself.

 

[PMK]

I agree with squash. A spring that gives you proper sag with no preload is going to perform better then a lighter spring that is preloaded. If your are preloading a spring, you are doing so because the spring is not the correct spring for your weight. Preloading should be used if you are in between springs, not as a tuning technique.

Interesting, what happens if you can not get full travel, but you have correct sag and no preload?

Like any vehicle, it must have a proper rate spring to perform well. Sag and preload are two of many parameters to dial in a vehicle. These guidelines for preload were not carried down the mountain on slabs of stone, not my suggesting some is needed or yours saying none is ideal.

So back to my first statement, the two of you say the best setup is a book derived sag and zero preload. The OP rides his bike and it hops around under braking and never lets the sealhead touch the cushion on big hits. Now what.

On the flip side, same spring, same good sag numbers but the suspension drops to deep into the stroke, now what, add preload or up the spring rate.

What if the suspension design is based on a falling rate, what if the design is rising rate.

Far to many parameters to just say zero preload and perfect sag...you need to swing a leg over her and see how she feels. As for preload being a tuning aid, yes, it can give the subtle changes to alter frame angles or place linkages or whatever moving components into a better sweet spot, tuned for each rider.

Also as the OP asked, what about making a clicker change, yes altering the control of the damper will have an effect, but would you take out a lot of damping to get full travel but let the bike hop around, or would you make it harsh and deflect to prevent bottoming.

Sorry but I won't be sailing on your ship, the seawater moving across the decks may have dampened them, and we would need to clean them with a damp mop. Couldn't help it, I had to, love your little siggy.

PK