[life_in_sepia]

Hello. Does anyone know or have reference to the correct stock spring rates for the Showas? We set the sag at the shop when I bought the bike. It rides pretty stiff to me, though our roads are pretty rough and I haven't yet started messing with the clickers. At this point, I'm just trying to get knowledgeable on my new-to-me ride.

The on-line Race Tech spring rate guide provides info for 04 (no distinction between mono and bi), and indicates stock fork springs are 1.000 kg/mm. Their chart says my fat ass (213 w/o gear) for street riding should be .961 kg/mm -- fairly close!

The Ducati Up North site has a chart that indicates that the 999 mono (does differentiate from bi) has a stock rate of 7.15 newton meters, or nm. The chart also indicates that I should have a spring rate of 10 nm -- not close at all!

I've also seen reference in the 999 Cathcart book that the bi spring rate is stiffer than the mono, adding some credibility to the DUN chart.

Given the differences in these authorities, I'm confused. And I haven't found any other resources. Any assistance is appreciated toward my effort to get proper springs for my weight in my new baby.

Regrets if this is posted elsewhere -- I didn't find it.

Ed

 

[life_in_sepia]

Anybody got the 411 here?

 

[BrianG]

As you know, spring rate determines your sag values and for the most part, damping determines suspension compliance.

For the street I preferred 15-20mm free/30-35 mm loaded sag at the fork, and 15mm free/25-30mm loaded at the shock. This seems to give good range of motion for the street riding environment.

For street riding comfort I back off the compression damping, set the rebound damping to allow on totally free cycle, and then add only small amounts of compression damping "as necessary" to stabilize the bike in cornering bumps, based on road feel. I generally end up with little compression damping.

Do not get this confused with a track set-up. It's not!

 

[life_in_sepia]

Thanks Brian. As I understand it, my weight determines the ideal spring rate I should have for forks and shocks, and then tinkering with compression/rebound provides adjustments for varying road and riding conditions. And I understand it is important to good suspension settings to have a spring that comes close to the ideal -- otherwise the extreme preload settings negatively affect the suspension travel. But, as of today, I don't know what the stock spring rate is, and one authority says it is close to ideal and another says it is far from ideal. So, I'm wondering if someone has any info on this -- the stock spring rates for a 999 mono-- as it would seem a pretty common issue to address among a group such as this, especially given that it is a 4 year-old model. But maybe it isn't or hasn't been. In any event, thanks again for your reply! Ed

 

[corvus]

My forks have 1.0 springs in them and I weigh 220 and they work fine for me , bike is used for the track only . rear shock has a 9.5 kg spring , but that is a Ohlins shock , hope this helps

 

[life_in_sepia]

very helpful -- thanks!

 

[BrianG]

My '05 999 monoposto is also an "S", so Ohlins equiped, but I don't think that the damper manufacture could affect the spring values.

Anyway the OEM fork springs are .95 kg, and the rear spring was 70Nm, which I swapped out for a 90Nm unit. These springs give me ~20mm free/~35 mm loaded sag at the fork, and ~15mm free/~30mm loaded at the back. This suits me (at 220 lb) fine for spirited road work.

My research reveals that the common thought is that the 999's came with an overly soft rear spring but pretty close fork springs, for a 200lb +/- rider. Some sources recommend a small change of the rear spring (to 80 Nm), some recommend as much as 110 or more for a 200+ lb rider.

I disagree with the "hard is best" chassis tuning perspective of the old days. I'm more congruent with the "chassis compliance means better tire contact" theory, so you may find my numbers a bit soft for the track.

 

[life_in_sepia]

thanks Brian!