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Upgrading Radflo Bypass Shocks - Bypasses for Beginners

Posted in How To on January 1, 2010
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I've been looking around the shock industry for some time, thinking about external bypass shocks. Working for the mag, I feel like I should have tried a set of bypass shocks by now, and I've read/written/seen enough about them to be comfortable to tune them on my own once I had a set. But I've never actually watched a bypass shock be put together in front of me, nor have I ever had firsthand personal experience with them. Part of my lack of bypasses is probably due to the fact that all my trucks are usually broken (you don't need special shocks on something that doesn't move), but the other part that kept me from getting some was the fact that I didn't really think I had any trucks that I could justify putting external bypass shocks on in place of a well-valved standard remote reservoir shock.

The standard external bypass shock is a triple-bypass. It has two compresson bypass tubes and one rebound bypass tube. Radflo does all their work in-house at their facility in Fountain Valley, California, The tubes are bent, then cut, and machined to the correct height.

One day recently, while I reasoned out in my head why I didn't yet have bypass shocks on something, I realized that the justification of why I didn't have them was the very reason I needed them-I am no whiz at setting up my own shock valving or knowing exactly what valve stack I need. I know if shocks need to be softer or firmer, or if the rebound or compression is too fast or too slow, but I would never try to assemble my own shock valve stack. The absolute beauty of external bypass shocks is that you start with a general valve stack in the shock that is good for your vehicle (actually one that's on the stiff side since the fluid bypass tubes bleed off resistance), and you fine tune everything from a few simple allen wrench-adjustable tubes on the body of the shock. If anything, shock novices almost have more reason to run external bypass shocks than shock experts do (let those experts run the internal bypass shocks!) since it's hard to know what's best until you actually go out and use them.

And if you're already at the intermediate shock user's level-using a high-end remote reservoir shock, but not yet up to externally adjustable bypass-then you're halfway there. Since I had already had some smooth-body Radflo shocks (sorry, coilovers will mean you need to run a second shock for bypasses) on a multi-purpose Blazer, I took them back to Radflo to have them modified and upgraded to external bypass units. The cost is around $420 per shock for a three tube bypass (two compression tubes, one rebound tube) setup, and though it basically doubled the price of my 14-inch stroke 2.5 smooth-body shocks (around $400 each), it was much cheaper than going out and buying completely new external bypass shocks (around $780 each). Of course, if the shock needs a rebuild or other parts, the price will go up.

The bypass adjuster housing is found on the end of the bypass tube. It has an adjustable set screw (an allen screw) that puts more (tightened) or less (loosened) resistance on the bypass popper valve. The looser the bypass tube is, the more fluid it will allow to bypass going through the shock's valve stack.

I took some time and drove down to Radflo in Fountain Valley, California, to watch my old smooth-bodies have some bypass tubes added to them. When finished, I grabbed my shocks and headed north to my favorite sand dunes to start tuning them. It was intimidating at first, but as I got more used to tuning them, the truck rode better and better through rough stuff and whoops.

14-inch stroke 2.5 smooth-body shock $400 per shock
14-inch stroke 2.5 External triple-bypass shock $780 per shock
External bypass tube upgrade to standard 2.5 shock $420 per shock

Each bypass tube is built on a jig that makes sure everything is aligned straight. Ryan Evelo is shown here TIG welding the bypass tube together to make sure everything will line up perfectly.
PhotosView Slideshow
PhotosView Slideshow


Radflo Shocks
Fountain Valley, CA 92708

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