RGN trailer front too low if loaded

[Mother Deuce]

We made up these blocks to better height match our new to us lowboy trailer to the tractor that we had. I think they were 3" thick if I remember correctly. Took a while to drill through the 3" blocks though!

That is what I have done historically as well. Used to own and operate a heavy haul outfit. Your block arrangement worked very well on all of our equipment even with 6' slides to load the nose. Also added rigidity over the drivers. Worked with TK 70s through 13 axle combinations. A winning modification for us as well.

 

[old-iron-habit]

I always used both when I had to shim a mechanical neck trailer. The single biggest change will be at the heel of the neck but sometimes that little extra at the pin helps.

I have a buddy in Southern California with a Cozad. He also does both when he hauls his DW-21 or anything real heavy. I am glad you brought it up. I always wondered if I should cover my eyes when he shimmed it.

 

[Birken Vogt]

I heard some stark warnings that ride height on tractors should NEVER be adjusted and that there is only one correct ride height. I would rather not mess with that and address the neck issue.

I've had lots of them where the valves slowly go bad and change ride height to something it shouldn't be, start having a really wide dead band, or otherwise behaving strangely. I have heard it is near impossible to get correct ride height out of the mfrs either, though I never bothered. The only way to know for sure would be to measure it when you get the truck at some known point and then periodically check it. But ride height valves were one of the most common items I changed, and when you put a new one on, how are you supposed to know where to adjust it if the last one was broken?

 

[Shimmy1]

I've had lots of them where the valves slowly go bad and change ride height to something it shouldn't be, start having a really wide dead band, or otherwise behaving strangely. I have heard it is near impossible to get correct ride height out of the mfrs either, though I never bothered. The only way to know for sure would be to measure it when you get the truck at some known point and then periodically check it. But ride height valves were one of the most common items I changed, and when you put a new one on, how are you supposed to know where to adjust it if the last one was broken?

Set it to spec? Only problem is you have to know where to measure at, on each truck, but there is a spec for every suspension.

 

[pushbroom]

Ride height matters more on some suspensions then others. Pete low air leaf, for example, really angles the diffs when aired up too high or too low. They are super picky for ride height and will growl/vibrate back through the trans if the height is out. Some of the kenworth suspensions are alot more of a parallel lift where it doesnt angle the diffs as much. There is alot bigger window of error on them. There is a posted ride height for each type of suspension but the cats ass is to run a digital protractor on the diff housings and run it through Eaton's Driveline Analyzer. It spits out the amount of rads/sec the current diff angles will give.

 

[ichudov]

Guys, just a little update. I had to have a small trip with my RGN yesterday and we added shims made of angle iron. I put them in the back of the goose neck.

It very visibly adjusted the ride height near the neck and the front looked very nice and level with the back, about 6 inches off the ground. I am VERY happy. Thanks to ALL for your great ideas!

The load was 30,000 lbs (a forklift) and everything looked very well.

I may go to plastic shims (HDPE, like kitchen cutting boards) though just to avoid denting these shimmed surfaces.

 

[crane operator]

Glad you got a height you liked. On the HDPE thing, I think when the trailer bounces around a little, it would shatter the plastic. I'd stick with steel shims that fit well.