Fork spring advice?

[memper]

I'm going to replace the springs in my forks when I change my oil in the hopes that they will help the nose dive effect of my shitty Marzocchi forks. I know I should get better suspension but my boss should pay me more. Until then its the bandaid method.

My questions are these:
1) I weigh roughly 185lbs in regular clothes. I'm looking at getting Racetech springs. Do I get the 85kg or the 90kg?

2) should I replace the fork oil with stock weight or go heavier?

[stopintime]

I'm not you and I'm not an expert, but anyway...

IMO the biggest problem is lack of rebound damping.
If you choose a stiffer spring, it will only make that particular issue worse.
Unless heavier oil improves the rebound (I'd be surprised if it does)

So, a relatively soft LINEAR spring and heavier oil is my first thought.

[memper]

Im no expert either. Heavier oil will help with the rebound in my imagination.  But I too could be way off.
What concerns me most is the dive on hard stops. Wouldnt a stiffer spring help in that regard and not a softer one?
I plan to call Racetech on monday to sort it out but I figure my fellow Ducatisti would have some input. Thanks Stop.

[bdfinally]

Just call racetech, they're super friendly and helpful.

[brad black]

are they showa or marzocchi?

[stopintime]

Brad: Marzocchi.

My impression is that the rebound valving is so poor that the gain you get from heavier oil won't be very noticeable. Not because heavier oil doesn't help, but because the starting point is so far off.

If the new springs return with relatively more force than the new rebound damping can absorb - you end up with faster rebound.

If the new springs are 'soft', the poor rebound damping won't be as problematic. Going linear will help against the quick dive - even if the spring is relatively 'soft'.

The challenge is to get all the factors in harmony.

[brad black]

40 or 43mm?

[stopintime]

40 or 43mm?

http://www.ducatimonsterforum.org/index.php?topic=62211.msg1167623#msg1167623

I can't tell from this picture, but you can.

[brad black]

oh, those 40mm marzocchi.

they're crap.  they have no compression damping function until about 2/3 compressed, which means the only way you can remove dive under braking is springs and preload.

at 85kg i'd be fitting a 0.8 - 0.85 spring I guess.

[memper]

oh, those 40mm marzocchi.

they're crap.  they have no compression damping function until about 2/3 compressed, which means the only way you can remove dive under braking is springs and preload.

at 85kg i'd be fitting a 0.8 - 0.85 spring I guess.

Linear or progressive IYO?

[brad black]

linear.

[xsephirot]

Can someone please explain why everyone recommends linear springs? I thought this depends on whether you plan on doing more for street or track. Cause a nice progressive spring for 95% street and 5% track would still be a much better option than a linear spring.

[Speeddog]

Can someone please explain why everyone recommends linear springs? I thought this depends on whether you plan on doing more for street or track. Cause a nice progressive spring for 95% street and 5% track would still be a much better option than a linear spring.

You don't necessarily need a different spring for track vs. street.

The forks actually end up with a progressive spring rate due to the air volume trapped in them.
Easier to tune that progression with oil height if you feel a need to.

Rear suspension on all Monsters other than 696/796/1100 have a progressive spring rate due to the linkage.

[xsephirot]

You don't necessarily need a different spring for track vs. street.

The forks actually end up with a progressive spring rate due to the air volume trapped in them.
Easier to tune that progression with oil height if you feel a need to.

Rear suspension on all Monsters other than 696/796/1100 have a progressive spring rate due to the linkage.

Thanks speeddog! Interesting, I never knew a fork with linear springs ends up a progressive rate.

[memper]

So I spoke with a tech at Racetech. He advised .85 linear spring with either 20 wt oil or slightly more. Haynes says to use 7.5 SAE