Trailer Shocks Truck on Highway

[wkpoor]

I really like the new trailer but have an issue that really raised its ugly head on my recent trip to Indy. On highways where expansion joints are under the pavement the trailer picks them up and sends nasty shocks waves at high frequency through the truck. So bad that after only a few miles it becomes un barrable. I assume the truck/trailer wheel base is close to 20' therefore just as one bump occurrs another comes right after therefore acting like a sign wave through the truck frame at a good rate. Enough to make your inerds feel like they are coming loose. Any thoughts on a remedy or what I'm doing wrong. Oh tried lowering tire pressure, doesn't really help but don't want that as a solution cuase when I get where I'm going and put a load on the trailer I'll have air back up. Its already been suggested slipper springs can do this.
OBTW....does the area around Indy have some of the worst roads in the midwest???

 

[SPYDERLK]

is your truck a dodge?

 

[wkpoor]

is your truck a dodge?

Hehehehehe no its Chev. However my guess is this problem wouldn't matter whats its attached to.
I went the same way back in May with a different trailer and didn't experience this problem at all.

 

[SPYDERLK]

our dodge exhibits that sort of problem whereas our chevy didnt. But the Dodge has a Cummins which makes it all worth it.

 

[jayste]

I really like the new trailer but have an issue that really raised its ugly head on my recent trip to Indy. On highways where expansion joints are under the pavement the trailer picks them up and sends nasty shocks waves at high frequency through the truck. So bad that after only a few miles it becomes un barrable. I assume the truck/trailer wheel base is close to 20' therefore just as one bump occurrs another comes right after therefore acting like a sign wave through the truck frame at a good rate. Enough to make your inerds feel like they are coming loose. Any thoughts on a remedy or what I'm doing wrong. Oh tried lowering tire pressure, doesn't really help but don't want that as a solution cuase when I get where I'm going and put a load on the trailer I'll have air back up. Its already been suggested slipper springs can do this.
OBTW....does the area around Indy have some of the worst roads in the midwest???

Where you loaded?....I mean the trailer...was it loaded?

 

[smitty9266]

use one of the cushioned draw bars they do make a big difference. They absorb some of the shock loads transmitted to the tow vehicle.
Cushioned Ballmount Trailer hitch bike rack and trailer hitches - etrailer.com

Jeff

 

[MikeD74T]

Another cushion hitch source: Crysteel Truck Equipment

etrailer also has shock absorbing spring equalizers that may help. MikeD74T

 

[BeezFun]

I think what's happening is the road is driving a natural frequency of the vehicle and trailer as they oscillate around the hitch. It's a bit expensive, but I think a weight distributing hitch would solve the problem. You need to change the spring constant of the combined vehicle and trailer around the hitch, that should move the natural frequency away from the frequency that the road is driving. The weight distributing hitch significantly changes that spring constant, which is essentially zero right now. It has the added benefit of improving handling a bit and allowing a slightly higher tongue load.

Normally you could also change the mass of the system to get the same effect, but since you can only significantly change the mass of the trailer, and the trailer is mostly independent of the vehicle, that might not solve the problem.

 

[Erik_in_Hoyt]

did you try speeding up or slowing down 5 mph?

 

[Diamondpilot]

WKPOOR

I have experienced the same thing many times. I am guessing the stretch of highway you are talking about started 40 miles or so east of Indy on I-70. I can tell you I drive this road weekly, sometimes 3-4 times a week and its the trailer. I had the same thing happen with my buddies 14K dump behind my F-350. It seems to be worse with trailers that have the wheels aprox 60% of the way back from the tongue. Boat trailers, which I tow 90% of the time do not do it nearly as much. It think it has to do with the teeter/tooter effect. I towed a travel trailer down that road that weighed about 8K with my F-150 and it did the same thing. Made my innards feel like they were in a blender.

Chris