Shock oil weights

[richardmid1]

What weight shock oil is best for bumpy tracks? Roughly?

[Chrislong]

This question has not definitive answer as it depends on the piston, the car, the shock positions and springs.

BUT, any setup you find for 8th Rallycross is likely to suit bumpy, as bumpy is the nature of the class - smooth tracks are boring.

[rocketrob]

Originally Posted by Chrislong

This question has not definitive answer as it depends on the piston, the car, the shock positions and springs.

precisely

Originally Posted by richardmid1

What weight shock oil is best for bumpy tracks? Roughly?

there really is no good or "best" answer - only general rule of thumb is that the bumpier/rougher the track surface the lighter the oil, the smoother the track and larger the jumps the heavier the oil (comparatively speaking).

[Chaz]

Then it depends on how hot or to cold

[gnr racer]

Originally Posted by richardmid1

What weight shock oil is best for bumpy tracks? Roughly?

What vehicle are you running?
As has been said lighter oils are more suited to bumpy tracks & larger hole pistons, but then if you are running with BIG jumps v.light oils & large hole pistons may well make your car bottom out on landing

[richardmid1]

Thanks guys. I thought as much. Im running 50 weight at the moment which im guessing is quite heavy? Its a Caster ZX-1 with standard shocks. Ill try some 40. I was on a really bumpy track the other day and although I had lots of saggy suspension the car was bouncing about like the suspension couldn't move fast enough to absorb the bumps.

[Chrislong]

Originally Posted by richardmid1

Thanks guys. I thought as much. Im running 50 weight at the moment which im guessing is quite heavy? Its a Caster ZX-1 with standard shocks. Ill try some 40. I was on a really bumpy track the other day and although I had lots of saggy suspension the car was bouncing about like the suspension couldn't move fast enough to absorb the bumps.

That could be:
too thick oil
too small/few holes in piston
too light spring
or a combination of the 3.

Ideally, find somebody else running the Caster on similar tracks and see what they use in there shocks (Piston, Oil, Spring, Position) and copy that as a starting point.

[richardmid1]

Are stiffer springs generally shorter? If I add spacers to stiffen the springs it increases ride height which I dont want to do.

[Chris Doughty]

pre-load to adjust ride height is different to running a stiffer spring.

you choose the spring rate you want to get the right stiffness and then adjust the pre-load to get the correct ride-height, which on most cars a base setting is so that the driveshafts are paralell to the ground, maybe a little bit lower than that if its high grip

[Chrislong]

Originally Posted by richardmid1

Are stiffer springs generally shorter? If I add spacers to stiffen the springs it increases ride height which I dont want to do.

See the bold in your post I have quoted here, this is Preload. Spring rate is totally different.

You will have to replace the springs to the rate required. This is why they are colour coded. As I said - find somebody else who's been running one and checkout there setup.