I've stated before that I run older vintage style buggies. I do have a newer car but it's more of a project. All of my cars are 2wd. I recently got my JRX-Pro SE tuned quite well. On the outdoor dirt track (which is what the car was originally designed around) here it'll hang with anything else. Not so much on the hard packed blue groove clay track here though but that's more of a durability issue as it just can't take a wrong landing as well as the tougher new cars. The tuning I've done to this car is consistent with my other buggies though and relevant to new vehicles as well.

I run an equal amount of droop front to rear. My total suspension travel is always equal at each end. Since the front shocks are mounted further inwards than the rear, the front shocks have less travel which is why they are shorter. If I was running the same shock pistons front to rear, the shock pack would not be equal front to rear since the piston speed per amount of wheel travel up front is slower than the rear. This means that the front shocks will have less pack per wheel travel even though the pistons are the same. The speed of the shock oil through the front pistons is always going to be slower.

Since I run an equal amount of suspension travel front to rear, it's easy to see how much shock travel I have at each end. I took the total shock travel at the front and divided it by the total travel at the rear. I'm talking about shock travel only measured at the shock shaft. Not wheel travel. I ended up with about 75% of the total travel in front as the rear. Since I didn't want to end up trying to calculate piston speeds I took a different approach and said that whatever the total area of the piston holes I had in the rear, I wanted something close to 75% of the total hole area in the front shocks. I have always liked #55 orange pistons in Losi rear shocks. I originally started running them in 1992 when Losi drivers used them. Back then I copied driver's setup sheets too.

Losi offers pistons with hole sizes ranging from a #53 hole size up to a #60. It's easy to look up a drill size chart to see what diameter each hole is. All of those standard bore Losi pistons have 3 holes in them too so using this information I made a simple chart showing the total hole area of each piston.
Since I decided to start with a #55 piston in the rear and wanted roughly 75% of that total area up front, all I needed to do was look at the chart. A 3 hole #55 piston has a total hole area of .006368 sq in. Since all of them are .00 something, I drop those 2 digits on the chart so I use 6368. A #56 piston is 5092, a #57 is 4354, and so forth and so on. When I divide 5092 (#56 piston) by 6368 (#55 piston) we can see that it (#56) is 79.9% of the total piston hole area of a #55 piston. I started there and installed a #56 piston in the front shocks. I also needed to run lighter oil up front. I ended up running 30W in the rear and 20W up front to balance. The car now passes the level drop test with oil installed.

How does it drive? Fantastic. On our off road track it is very forgiving. It's funny to see kids wonder how a car that is much older than they are can handle so well compared to theirs. Mine is tuned. Theirs isn't. It's that simple. Total potential of each vehicle is another matter altogether. If I need more or less pack anywhere, I'll change pistons at both ends. Losi was kind enough to offer many piston choices and the new big bore shocks out there also have many options. If I decide to go up to a #56 piston in back, I'll also go to a #58 up front and change oils accordingly.

Associated standard bore shocks are another thing altogether. They offer 3 piston choices. All 3 of them are 2 hole. A #1 is a #54 hole, a #2 piston is a #55 hole, and a #3 piston is a #56 hole. They also offer a blank piston so you can drill your own and in my opinion this is a must have. Using their 3 available sizes I run a #1 in the rear and a #3 up front. It works quite well but I need to play with my own sizes to improve on them or just go to big bores.

Anyways, play around with this as a guideline and see how you like it. I'm still tweaking the technique a little bit but this is a fantastic starting point to build off of. It is working quite well for me. I'm still playing though to account for weight difference at each end and not only shock travel so I may yet revise this.