Shock Valving question.....single digit valving rating vs three digit lbs/in rating.

[Henesian]

What's the difference between a shock that's rated in a single digit valving system like 6/6, 3/5, 5/3, 7/4, 7/7, vs a shock that's like 600/65 lbs/in, or 120/700 lbs/in?

[alocker]

You have to ask the manufacturer or the shop building the shock. For example, Ohlins uses single or double digit numbers to identify a certain valving or shim stacks. These numbers may or may not correlate to a specific dyno curve or it may be specific to the shock itself.

[Ron Sutton]

The numbering system you're referring to is decades old, created for oval track racing initially.

Shock valving numbers can be complex, due to a gazillion possible curve shapes ... and because even knowledgeable racers have different opinions about which piston speed numbers mean what ... and different ideas of what they want. So to simply things for racers (customers) ... so they would buy more shocks ... shock companies came up with a 1-10 scale for valving. For the most part, these numbers correlate to a range of pounds of force resistance at a specific shock piston speed of X inches per second.

These were often expressed with just 2 numbers, the first number being compression and the second being rebound. If you had a straight 5 ... it was considered a 5 on compression & a 5 on rebound. If you had a 5/6 ... it was 5 on compression and a 6 on rebound. So if you had a 5/6 on a corner and put on a 4/7, you knew the compression would be softer & the rebound stiffer than the previous shock.

Of course this method is too simplistic for advanced tuners who want to know resistance force at different & specific shock piston speeds. But it made things simpler for the average racer/tuner, so even if you weren't a shock guru, you could still tune the car with shock valving.

I have seen a few charts with the 1-10 scale and their corresponding range of resistance force in the typical pounds per inch, but the charts varied not only from manufacturer to manufacturer ... but even with different lines of shocks from the same manufacturer. So it's not accurate to compare a 4/7 shock from QA1 to 4/7 shock from AFCO. The charts were made to help racers tune within the brand & model of shocks they were running.

Another interesting point is the scale of 1-10 initially was created with 10 being the stiffest force they could imagine at the time. Since then, with modern high travel suspensions running a lot more rebound, today's stiffer rebound valving exceeds the original range, so the numbers grew past 10. I have some shocks the manufacturer considers to be 4/15 with a lot of low speed rebound stiffness for that shock. But if I applied that 1-10 system to some of extremely mean shocks we run in upper tiers of pro racing, those shocks would need to be called a "45" on the rebound side. :rolleyes:

Of course we don't use that 1-10 system in upper levels of racing because it simply doesn't tell us the whole picture, nor it is as finely accurate as we need. It's not uncommon as we fine tune the shocks on a race car to have the valving stay within a range, so the 1-10 number wouldn't change, because we're making small changes and sometimes just tweaking different areas of the curve. But the 1-10 system is still used to help less trainer racers effectively tune their race cars.

I attached an AFCO example for their Twin Tube shocks, just for reference.


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