Addressing truck/wind push in a Sprinter based Class C

With or without the cab over bunk?
Either way, if you're running the unit loaded for travel at close to the GVWR 11,030lbs, on soft tires, there's not much you can do.
Others have tried everything from air bags, to sway bars (Helwig?), to stiffer shocks, to whatever.
I have noticed some handling improvement from adding Sumo Springs constant contact bump stops, front SSF-106-47, and rear SSR-338-54.
That's as far as I chose to go. I also run my tires at 75+psi all around to reduce the mushiness of the ride, but leave a little room for temperature expansion/contraction.
You may find that you'll get used to the crosswind and truck bow wash wander over time.
I hardly notice it now, unless it's really bad, and then we just find a place to stop, and wait it out.

MDKMDK wrote:
With or without the cab over bunk?
Either way, if you're running the unit loaded for travel at close to the GVWR 11,030lbs, on soft tires, there's not much you can do.
Others have tried everything from air bags, to sway bars (Helwig?), to stiffer shocks, to whatever.
I have noticed some handling improvement from adding Sumo Springs constant contact bump stops, front SSF-106-47, and rear SSR-338-54.
That's as far as I chose to go. I also run my tires at 75+psi all around to reduce the mushiness of the ride, but leave a little room for temperature expansion/contraction.
You may find that you'll get used to the crosswind and truck bow wash wander over time.
I hardly notice it now, unless it's really bad, and then we just find a place to stop, and wait it out.

Thanks for the response.
Ours has the cab over bunk which I imagine exacerbates the issue. It's not horrible and I question throwing money at it at all. I get used to it. In a recent trip there was a lot of crosswind and I was introduced to Mercedes' "Crosswind assist feature". I had no idea what it even meant, but apparently it automatically adjusts a few things to maintain lane.

Sumo springs seems to be what a lot of folks recommend and that's a pretty cheap and easy thing to try.

Does the 75 PSI give you a lot of unwanted road feedback, like expansion joints? I think max on those tires is 80.

I installed a rear track bar on my Ford Sunseeker and it helped with bow waves of overtaking trucks as well as trucks traveling in the opposite direction on 2 lane roads.

As It was explained to me , Its suppose to eliminate the slight side to side movement of the rear axle . The track bar attaches the rv frame and axle shaft making it a solid connection.
Without a track bar that movement gets transferred to the front axle affecting steering. It helped with bow waves but didn't eliminate them completely.
Imo, out of all my aftermarket mods, the track bar gave me the most bang for the buck. I would imagine that it would have the same benefit on the Sprinter chassis.

When an 18-wheeler overtakes your RV, it's bow-wave of air hits the left rear of the RV first, and that pushes the rear toward the shoulder. When the body rear moves right slightly before the rear axle does, it amplifies the push to the left that you feel in the front causing you to correct steering

As the 18-wheeler bow wave moves toward the front , it pushes the front of the RV to the right, it amplifies the steering correction you have already done causing you to have to correct to the left.

This whole thing, if you are not used to the feelings, can be quite scary. One way to overcome that is to install Vortex Generators like Air Tabs They cut down on the dead air and drag on the rear of RV and greatly reduce the bow wave of passing trucks.

I have AIRTABS on my Class C.

They really help on a cross wind situation,no more sudden buffeting. It has also stopped the sideways push when being passed or passing a large truck.

They are a vortex generator that produce a counter rotating air trail several feet behind the vehicle, This airflow alteration improves vehicle stability. As far a mileage it may helped some but the stability they provided is amazing.

might check on the tire for proper tire inflation 65 sounds low to me I have a older sprinter michilin tires, tire inflat says 80psi,I run 75. yep get some push but not real bad.

I have a 2019 23' C and the label recommends 60 or 65 psi, but I run 80 all around. Sometimes I tow sometimes not. Just my experience it seems to work great. Good luck.

Hi,

I did not have much of a problem with being pushed around in my E-450 class C. It did get better when I added air tabs. Rear tires are at 80 psi; front at 65 psi.

The air tabs also lowered the noisy level in the RV.

I think I'll try bumping up the PSI. My main concern was ride harshness with more air. It rides nice at 60 psi otherwise, temps stay good and I usually don't see any more than an 8 psi increase when they warm up. But if you guys mitigate some wind push without sacrificing ride, I may give that a shot. Certainly the easiest thing to try.

Thanks!

way2roll wrote:

MDKMDK wrote:
With or without the cab over bunk?
Either way, if you're running the unit loaded for travel at close to the GVWR 11,030lbs, on soft tires, there's not much you can do.
Others have tried everything from air bags, to sway bars (Helwig?), to stiffer shocks, to whatever.
I have noticed some handling improvement from adding Sumo Springs constant contact bump stops, front SSF-106-47, and rear SSR-338-54.
That's as far as I chose to go. I also run my tires at 75+psi all around to reduce the mushiness of the ride, but leave a little room for temperature expansion/contraction.
You may find that you'll get used to the crosswind and truck bow wash wander over time.
I hardly notice it now, unless it's really bad, and then we just find a place to stop, and wait it out.

Thanks for the response.
Ours has the cab over bunk which I imagine exacerbates the issue. It's not horrible and I question throwing money at it at all. I get used to it. In a recent trip there was a lot of crosswind and I was introduced to Mercedes' "Crosswind assist feature". I had no idea what it even meant, but apparently it automatically adjusts a few things to maintain lane.

Sumo springs seems to be what a lot of folks recommend and that's a pretty cheap and easy thing to try.

Does the 75 PSI give you a lot of unwanted road feedback, like expansion joints? I think max on those tires is 80.

I think it might make the ride a little rougher, both the higher PSI and the constant contact (Sumo Springs) bump stops, but I don't think there's a perfect answer for this issue.
I traded the softer ride for the slightly better stability. I'm on the NCV3 chassis, and don't have the Crosswind Assist option, because WGO cheaped out on it, and didn't get all the MB bells and whistles. I have the older ESP (electronic stability package) on mine, and it does react to hard crosswind push/sudden aggressive steering changes with a dash light, although that only happened in the early days of getting used to the vehicle's idiosyncrasies.
Yes, Sumo Springs are an inexpensive "might help" option.
Try it, keep your OEM bump stops, JIC you want to go back to stock.