Handling the Handling (Shock Adjustment)

In my post about the drive to and from 4Peaks in August (See 4Peaks 2021 - Road Report), I mentioned the impact of the wind on the handling of the bus. Today's post covers my initial attempt to address it. I say "initial" because I have not 100% confirmed this is the end-all solution to the issue.

Identify Causes

It makes sense to start with what the possible causes could be for the wind to have such a dramatic, and newly so dramatic, impact. I have thought about this quite a bit, mostly while driving Hapy, and I have come to the conclusion that the root cause is one of 2 things.

My first thought is around a change I made to the bus. Back in Spring, I added a tow hitch. No big deal there, with regards to wind, but I think it looks really good (See Bus Tow Hitch). Starting with the trip to Leisureland I added one of those carrier platform things from Harbor Freight that go into the square trailer hitch thing. I also got the zippered bag that fits it and refer to the pair as "the Boot". I don't put much in the Boot, but it creates lots of room inside the bus... and it creates this little .6m (2 foot) high by .5m deep waggy-tail sticking out the back. I thought, with the loaf-of-bread broadside, that this addition would not have an impact. I could be wrong. If that is the cause, I would still like to keep using it so I need to improve the handling to compensate.

My next thought is around the adjustable Koni oil-filled shocks I installed years ago. I was part of the first group purchase that triggered Koni to start manufacturing them again. I didn't write that for kudos, rather to illustrate how long I have had them. That purchase was, like, 15 years ago. I didn't do anything with them other than pull them out of the box and install them. Now, so many years later, I realize that out-of-the-box they are set at their softest setting (face-palm). That setting might be great for an unloaded bus tooling around town, and when the shocks were new, maybe they even had a little stiffness in them as they broke in. Well, it's been many years and while I haven't driven Hapy around much (less than 20k miles total since I bought Hapy almost 20 years ago), the last few years would have definitely gotten them past the break-in period if he wasn't past it already. With all the camping gear, plus the Boot, I am asking much more of those shocks than when I used an empty Hapy to get to/from work back when I first installed them.

So, I figured I can start with stiffening the shocks.

Adjust Shocks

Koni 80-series shock

The 80-series Koni shocks were designed to be easily adjusted. Of course, I neglected to do anything with them after install. After doing some reading, I have found others with a similar vintage bus and similar need: better handling when loaded for camping. The consensus is to stiffen the ride. The lack of consensus is by how much. Because of the extra tail created by the Boot, I did a full turn in the rear and a 1/2 turn in the front. I expect, that with the heavy duty 7/8" anti-roll (sway) bar in the front, even the 1/2 turn is more than I need, but I would rather feel the bumps a little more and have the bus hold steady than the alternative. Shout out to RAtwell for his page on these shocks. It's an older page, and hasn't been updated in a while, but there is some great, still relevant, information in there.

Adjustment is relatively simple. The videos from Koni show the shocks uninstalled, and some of the verbiage seems to say opposing things. I don't want to remove the shock entirely from the bus to adjust them anyway, and I don't think anyone else does either. So, I did it like this:

Rear's first. With the bus on the ground, just crack both the top and bottom bolts enough to remove any torque (19mm). It may be too difficult to get to the top one, and it may not be 100% necessary. I didn't loosen the top bolt on the driver side, and it wasn't an issue. Regardless, completely remove the bolt from the bottom. Notice that there is a nut on the other side (wheel side) that requires a 17mm wrench while you work the ratchet from the inside. With both hands, push the lower end of the shock (you have them installed with the thicker section on top like the picture above/right, right?) up into the upper section. When you are just about bottomed out, start rotating the end of the shock you're holding a little bit. You are looking for a click to tell you that the adjuster has engaged. When you feel that click, you are ready to adjust ad you can completely bottom out the shock (but do it gently). I did not feel the click on all 4 shocks, but once fully compressed, I could only rotate the shock 2 full turns, so some (older) models may not have that satisfying click.

original image
from RAtwell.com

From below, rotating it clockwise will stiffen the rebound of the shock. Rotating it anti-clockwise will soften the rebound. That is the only adjustment you can make on these red 80-series oil-filled adjustable Koni shocks. You should be able to get 2 full turns from most soft to most stiff. Consider that you do not have to adjust in 1/2 turn increments. So, you can really dial in your rebound, if you have the time. Once you have the setting where you want it, let the shock out a little bit to release the adjuster. Now, you can orient the bolt hole with the lower mounting hole. Slide the bolt through, finger-on the nut and torque it down.  Re-torque the top bolt, if you loosened it. Repeat on the other side to the same degree of rebound (same degree of turn from most-soft or most-firm). The rears should match each other and the fronts should match each other, but the fronts and rears do not need to be the same. Still, I would encourage you to keep them within the same ballpark. I mean, 100% soft fronts and 100% stiff rears could make for some unpredictable handling performance.

 

The front shocks mount a little differently. The lower mount is a stud that is part of the wheel assembly. So, I loosened the nut to release any pressure, and then removed the upper bolt instead. Unlike my rear's, the nut behind the upper mount point is 19mm. Otherwise, the process is the same (free one end, compress, adjust, de-compress, align, re-bolt).

Once I made the adjustment, I had a new challenge of finding a way to test whether it helped. I live a few miles from the nearest freeway, and if I'm not loaded for camping the test isn't really valid anyway. So, I delayed the loaded-for-camping, freeway test. I did execute the mostly-empty around-town test, though. Around town, the ride is definitely stiffer. I can feel more bumps, but the steering feels about the same. The true test, however, is loading the bus for a weekend of camping and hitting a freeway.

Hapy Birthday

pic from Bend: note
the Boot in the back

My first opportunity to perform a freeway loaded-for-camping test was for the celebration of Hapy's 50th birthday, the weekend of 3-September. I will post on that later, but suffice to say, we had fun. The drive to and from our destination was a perfect test. We hosted multiple camp sites at LL Stub Stewart State Park, which is about 40 minutes west of the greater Portland metro area, between Manning and Vernonia. Access is from Oregon state route 47, by way of US-26. US-26 pre-dates the interstate system, but it is a multi-lane highway that passes through the open farm country between the western suburbs and the coast mountain range. A perfect test. There was definitely a wind, and I could see the greenery bending to it and feel it pushing on Hapy, but he held the road. I needed both hands on the wheel, but it was not the white-knuckle experience I had on I-5 nor US-26 east of Mount Hood on the 4Peaks return. I could not tell what angle the wind was coming from, but it was partially head-on, pushing Hapy's temperature up. Still, the handling was much better. Boo drove a chase car and reported that Hapy did not appear from behind to be all over the road. The return drive was even easier (tailwind on-angle), so I think, at least for now, the suspension can handle the road. I hope for another run down to Eugene or Liesureland before the very end of the decent weather, for one more test, on the road that started it all (I-5) to prove the suspension before winter.

That's it for today. Thanks, as always, for following along-