Towing Bump Stop Contact (1 Viewer)

[MHLC08]

All,
Had my 08 LC in the shop this week and they noted the bump stops were making contact. I mentioned I tow a boat and they commented it must be huge. The boat is a Yamaha AR240 that weighs around 4,000 pounds and (i think) a 300lb tongue weight. The backend definitely sinks a lot when I lower the boat onto the hitch. Is this common when towing? Any recommendations?
Thanks

 

[Sandroad]

Definitely not common when towing. I suspect the tongue weight is a lot more than you think, or the LC springs/shocks are shot. I’d start with a weigh at a CAT scale to find out what you’re dealing with rather than guessing. Then consider adding air bags to the rear springs and new shocks all around. Lots of good posts on airbags on here. I use the Firestone brand.

 

[Cincodemustache]

There are a bunch of pics of trucks hauling 500 and 600ish pound tongue weights on Mud with only a hair of rear sag. If it's an 08 I'd venture at least the rear suspension is tired. Maybe there are some take off rear springs and shocks on Mud from guys lifting/upgrading?

 

[MHLC08]

Good feedback. I'm not super mechanical. The struts were leaking and replaced about 40K miles ago (145K on the truck). Could it be springs causing the sag? How often do those get replaced? Thanks!

 

[GordJ]

Boat trailers tend to have a pretty low hitch height, on level ground does your trailer appear to be level? Of my four trailers the boat is the lowest and riding high in the front causes a lot of wear on the rear axles. I’m assuming that your trailer has surge brakes? I think it is problematic to use a weight distributing hitch on surge braked trailers but I don’t know for sure. Having said that, I decided to put airbags on my ‘08 LC to be able to tow more than one trailer. There are other options but that was the route I took.

 

[Sandroad]

Good feedback. I'm not super mechanical. The struts were leaking and replaced about 40K miles ago (145K on the truck). Could it be springs causing the sag? How often do those get replaced? Thanks!

If you mean the front struts were replaced and the rear shocks and springs were not, probably be a good place to start. Spring and shock replacement are routine on the 200 and any place that does suspension work can do it. Might be good to buy the OEM springs and shocks new and take them to the shop. When springs go in is an easy time to add airbags because they go inside the rear springs.

But, I would still weigh your set up to see what your dealing with. It’s likely fine, but if for some reason it’s way over what you think, you might want to consider alternative suspension options. In the end, hitting the bump stops while towing is hard on everything and that should be a very rare event. From the looks of those on your truck, it is not rare.

 

[Sandroad]

Just out of curiosity, I looked up some weight data on that boat. From a variety of forum sources, it seems there is a possibility that boat/trailer/fuel/battery/anchor/equipment going down the road is well over 5k lbs. I wonder if the tongue weight is over 500 lbs? Plus, what are you carrying in the LC that loads the suspension? All that may be stressing 14 year old springs and shocks with 140k miles on them.

 

[MHLC08]

Thanks for the feedback. I will double check weight. Correction: The back shocks were replaced at around 100k miles but not the springs. Likely replacing springs and adding bags will help?

 

[TeCKis300]

Do you have a picture of the setup? Possibly a picture of the hitch setup? Are you having any ride and handling concerns?

Hitting but bump stops in and of itself is not a problem. There's conditions that this can and will happen even without towing. If you feel like the rig is sagging greatly, and riding on the bump stops, which from your description may be true, then yes it's a problem worth addressing.

I ask for a picture of the hitch as the setup there can matter. Do you have the ball relatively close to the bumper or is it projected pretty far out? Like a seesaw, the same weight farther out from the bumper does two things: 1) give additional leverage to tongue weight 2) transfers load from the front axle to the rear axle further exascerbating the issue. Which is why it's pretty important to keep the ball close and tight to the bumper.

If that's all well and fine, 500lbs seemingly shouldn't create that much of an issue. Still, airbags are great for such mixed loads. With the ability to have spring rates factory soft when unladen for a great ride, but also great articulation off-road. Then with 10-20PSI of air, stiffen the rear end to minimize sag, but also better support and control when laden.

 

[MHLC08]

Will post pics soon. Thanks all!

 

[bloc]

Do you off-road much? The bump stops you post pictures of are kind of the last resort on our trucks, and partially intended to limit how much we can stuff a wheel into the wheel well on rear axle articulation.

The bulk of the load handling and much, much more progressive “bump stop” action is done by the jounce stops within the springs. It doesn’t take much weight in the back to start to get contact on these, but they are designed specifically to hit early, and softly, and progressively get stiffer and stiffer assisting the spring rate as the suspension compresses further.

The frame stops should provide a significantly more harsh and sudden feeling when you hit them.

Do you remember specifically jarring rear suspension events while towing?