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18 wheelers pass close
Just read an article in the recent issue of FMCA discussing suspension systems and related issues. They discuss how the air from a passing 18 wheeler will push you (which steering to the right is needed to compensate) then release you after passing (which in turn results in over steering to the left due to pervious steering compensation). I have definitely experienced this in past RVs.
The Prevost seems to hold solid in its lane (with little to no steering compensating) while the passing 18 wheeler appears to get pushed slightly to the left while passing then the trailer drops back to the right (getting close to my drivers mirror) as the 18 wheeler is about 90% of the way past.
My guess is the weight, lower profile and suspension of a Prevost allows it to remain stable in its lane while the increasing air pressure between the two passing vehicles pushes the 18 wheeler away (to the left) until it most of the way forward, which then drops out the air pressure that was between the two vehicles letting the 18 wheel trailer drop back towards my mirror (sometimes almost hitting it).
So is this something I am trying to convince myself of or is it Reality?Chuck
2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL -
4 Replies
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I have had the same observation. Almost like the very back of the trailer is in a suction.
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Yep
Described very well in just a few words.
Chuck
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18 wheelers, big trucks, busses, etc don’t bother me. We all share the road and just want to get to our destination without drama.
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I have about 72,000 miles driving our 1999 Liberty XL45. I don’t think I get pushed around very much.
I also deliver finished box trucks for Marion Body Works. They range from 16′ boxes on gasoline powered Isuzu cab over chassis to 28′ and 30′ boxes on tandem axle Peterbilts and Kenworths … and everything in between. The trucks are empty; just the chassis, drive train, and empty box.
These trucks tend to get pushed around by semi’s and even enclosed car trailers pulled by one ton duallies.
I think it comes down to a number of factors:
1. Weight of what we’re driving. 49,000 pounds for an XL45 on a 45′ coach and corresponding wheel base. The weight per tire on the pavement is relatively high.
2. Weight distribution. Low center of gravity on our coaches. I think that ads significantly to our stability.
3. Geometry. The long wheelbase of the coach adds to the stability. More leverage to keep it stable. I’ve noticed the shorter wheelbase box trucks can get really pushed around, longer the wheelbase not so much.
Think about the stability of our buses in high cross winds. I think the same forces are at work.
So our high relative weight, low CG, and long wheelbase results in a very stable vehicle.
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