Springs & Oils

[pjay]

Not been racing for long, so relative newby but ive got to the point where id like to try some shock tuning (currently on kit springs & oil ,B5M, running at York)
Cant really find any info on matching oil weight to spring rate, as in ball park figures of which weight is suitable for which spring rate.
Is this mainly trail & error stuff?

[jcb]

I'm not sure there is a set way of matching oil and springs, it's more a case of setting things to suit a bumpy track or a smooth track, or high grip or low grip.

I'd ask some of the quicker guys at your local club or check out some setup sheets from the manufacturer website. That will give you a good starting point and may save you buying oil and springs you might only ever use once.

I'm not familiar with the B5 range of cars, but traditionally with 2wd off road cars your looking at running oil between 30wt and 40wt in the front and 25wt and 35wt in the rear. Usually 5wt thinner in the rear.

Thinner oil for bumpy tracks and thicker oil for smoother tracks or when there is lots of grip.



Remember you can also change the pack of the shock by using different pistons, A smaller piston hole increases pack and a bigger hole reduces pack, with small holes being good on smooth tracks or ones with bugs jumps, while bigger holes help on bumpy tracks. Just to throw another variable in there!

[Roscopeco]

I run my b5m at york with 32.5 oil in the front and 27.5 in the rear with white springs alround and for me it's drives nice

[Allan1875]

This isn't a hard and fast rule but more of a guidance.

It tends to be linear so the harder the spring, the thicker the oil but as above, there is no set rule.

If the track was low grip and bumpy you would be thin oil, soft springs.

If a track was a high grip and flat you would be thicker oil and harder springs.

However in off road you get a mix of both, especially on astroturf where you have bumps but also high grip. You need a happy medium. Refer to setup sheets on petit rc to give yourself an idea of what people are using.

[pjay]

Thanks all, gives me a good starting point to have a play around.