Jim wrote in article ...
I modify stock-mount/application automotive shock absorbers for the lower oval-track racing divisions where racing shocks are not allowed to be used, and "stock" shocks are mandated. I generally use the "price-conscious" line
- the "$9.95" shock - from either Gabriel or Monroe as a platform for my modifications.
I have several Gabriels and a Monroes (in addition to others) apart on my shock bench, and I would defy you to tell me which is which based on the piston and valve designs. They are, virtually, identical internally.
As a matter of fact, cut open any number of old, junk passenger car shocks, and you will be likely find that the internals are more similar than different as you move from manufacturer to manufacturer.
There are some slight, measureable spring pressure differences on the foot valve (compression) and main piston (rebound) that can be seen on a spring tester such as the Rimac valve spring tester, but otherwise quite similar.
On the shock dyno, there is often as much difference between two same-brand and same-part-number shocks sitting side-by-side on the shelf as there is between the two different brands for the same application...usually 50-100 p.s.i. @ five inches per second shaft velocity.
If the choice is for the most economical shocks between the two biggest shock manufacturers in the country (Gabriel and Monroe), they are pretty much the same.....Go for the best price.
As you move up in quality, both are now using disc valving in some of their upper-level shocks, which is what current racing shocks use, but the engineers have developed too many stages - incorporating concepts such as "V-groove technology" which serves as a low-speed, mid-shock-travel bleed - to make these shocks any good for racing purposes. Their compression/rebound dyno pattern is a lot "softer" overall than the cheapest shocks which often only have two or three stages - which is why I use the "$9.95 shock."
The "luxo-shocks" - with their multi-stage valving and pressure bleeds - do offer a great boulevard ride, however.
You really have no way of knowing which particular part number uses disc valves and which still uses coils - unless you take it apart. When I spoke with a Monroe engineer, he said he would have to call up the build specs for each individual part number in order to tell me which do and which do not use disc valving.
And, Gabriel has recently introduced a mono-tube shock for trucks based on current auto racing technology - similar in design to the Penskes and Ohlins, but that is a cat of a much different color. I haven't been able to buy one from any Gabriel dealer yet.
Bob Paulin - R.A.C.E. Chassis Analysis Services