Back end of truck bouncing up and down while towing

scubieman · 12-09-2010, 07:55 PM

I have a 30 foot travel trailer. I have stablizer bars and sway bars. Anyways when I hit certain areas of road my back end goes up and down real fast like the road is real ruff. Unsure if this could be because overweighted. Will it help to stiff suspension in or put more or less weight on rear end?

M109Rrider · 12-09-2010, 08:15 PM

Sounds like you need to adjust your WD. I'd try putting a little more weight on the rear wheels.

scubieman · 12-09-2010, 08:17 PM

I will give it a try. Thank you. I'm trying to avoid spending more money on things besides camping things.

Dave_Monica · 12-09-2010, 08:28 PM

May be worthwhile to take your set-up and weigh it at a CAT scales. You should get the front and rear axles weights of your TV and axles weight of the camper while hooked up, then re-weigh the TV front and rear axle weights. That will give you all the info you need...hitch weight, total camper weight, amount of weight transferred to the front axle of the TV.

You should be looking for 10 - 12% hitch weight of the total camper weight.

Dave

MtnGuy · 12-10-2010, 08:54 AM

Quote:

Originally Posted by Dave_Monica

May be worthwhile to take your set-up and weigh it at a CAT scales. You should get the front and rear axles weights of your TV and axles weight of the camper while hooked up, then re-weigh the TV front and rear axle weights. That will give you all the info you need...hitch weight, total camper weight, amount of weight transferred to the front axle of the TV.

You should be looking for 10 - 12% hitch weight of the total camper weight.

Dave

This weigh-ins should determine if your WDH is setup correctly. I have mine set up to add about 40 lbs. to the front axle. That gets some added weight on the front axle, but still lets the rear axle carry most of the weight.

What is the tongue weight, and what is the rating of your spring bars ?? Too stiff or too light of bars can cause problems.

acadianbob · 12-10-2010, 10:34 AM

Quote:

Originally Posted by M109Rrider

Sounds like you need to adjust your WD. I'd try putting a little more weight on the rear wheels.

I would reach the opposite conclusion. Perhaps there is too much weight on the rear axle. I transferred a little more weight to my front axle to reduce bouncing at the rear.

M109Rrider · 12-10-2010, 10:51 AM

When I first got my 6800lb Keystone TT I had this problem. The rear suspension on my 1500 dodge was too light so I adjusted the hitch for a lot of WD. The porposing was caused by too much rebound in the spring bars. Once I put more weight on the rear wheels it almost completely stopped.

08flagvlite · 12-10-2010, 12:48 PM

What year and/or mileage is on your tow vehicle? The factory shocks are not exactly the best choice for towing, and they last about as long as the factory warranty does, at least on my vehicles. I put a set of Bilstein gas shocks on my Ram, and it stopped the bouncing very well. I had 60k on it at that time, incidentally. Really helps the ride when not towing, too! Randy

scubieman · 12-10-2010, 01:46 PM

I have a 2005 gmc sierra with about 95,000 miles. I do remember leaving the dealership on some ice and my tires spun fairly easy ( by my opinion). I figured with about a extra 500 -1000 pounds sitting on my truck the task would of been harder

side note: only certain sections of road would do it not all the way home. I do have sometimes without towing with my truck or others vehicles sometimes they hope a bit if road is not done the best. But i will try to add more weight to rear end.

it was first tow so may need some adjusting to find my sweet spot.

MtnGuy · 12-10-2010, 01:57 PM

Quote:

Originally Posted by scubieman

side note: only certain sections of road would do it not all the way home. I do have sometimes without towing with my truck or others vehicles sometimes they hope a bit if road is not done the best. But i will try to add more weight to rear end.

I hope you realize that with the statement of adding more weight to the rear end of your GMC, the poster meant by your adjusting your WDH. And I am not sure if you need more or less back there....that is where the weigh-in at a CAT scale or the local rock quarry can give you the important figures.

scubieman · 12-10-2010, 01:59 PM

Okay, I will have to remember that. Right now it's well December and I live where we get snow so camping is not in my near furture

Thanks for the responses

08flagvlite · 12-10-2010, 02:04 PM

My 06 Dodge Ram 1500 pulling my 30 footer trailer bounced like crazy coming down a long bridge here in Fl. After replacing the shocks, it's not a problem anymore. That was at 60,000 miles. Shortbed, Quad cab Hemi. Randy

scubieman · 12-10-2010, 02:06 PM

How much are shocks? I guess I haven't really needed them?Well till now

kz08h5 · 12-10-2010, 02:47 PM

Check Bilstiens out on the WEB. They are probably $100 to $150 for your truck.. I have a set on my Jeep Commander and they do make a difference. They are well worth the money.

scubieman · 12-10-2010, 02:50 PM

Would it be possible springs are too weak? I know shocks should do something with the bouncing. But when I stand on the back of my truck it goes down a few inches.

**bikendan** · 12-10-2010, 05:42 PM

scubieman, you still haven't stated what engine and rear end ratio you have. this is important info that's needed to help you.

all you've said is that it's a 2005 gmc sierra. not whether it's a 6cyl., regular cab, short bed, and so forth. even cab style and bed length are important factors.

scubieman · 12-10-2010, 05:46 PM

Quote:

Originally Posted by bikendan

scubieman, you still haven't stated what engine and rear end ratio you have. this is important info that's needed to help you.

all you've said is that it's a 2005 gmc sierra. not whether it's a 6cyl., regular cab, short bed, and so forth. even cab style and bed length are important factors.

sorry Crew cab 5.3 liter v8. The gears I am uncertain. But just assuming are way to tell. I get about 17 to 19 MPG being nice to truck down road. I have dealership checking into prices for replacing gears to get me more power. After all I don't use 4th gear towing. I know some had said this is for OD. But if i go into tow/haul mode it will use 4th gear still.

Hope this answers must of what you need bikendan

**bikendan** · 12-11-2010, 03:01 AM

personally, i think a 30' TT is 3/4 ton land.

i have a '07 Avalanche with the 5.3 and a 3.73 rear end.
i tow a 23' HTT that weighs around 5000lbs. loaded and i wouldn't want to tow anything much bigger.

even a ultra lightweight 30' TT will weigh a lot.

scubieman · 12-11-2010, 02:59 PM

Right now Im at 5500 dry. If I go short distance I am fine. If I go long distance I would be looking into a new truck. Maybe with tax season that will be my gift.

**bikendan** · 12-11-2010, 03:50 PM

Quote:

Originally Posted by scubieman

Right now Im at 5500 dry. If I go short distance I am fine. If I go long distance I would be looking into a new truck. Maybe with tax season that will be my gift.

by "dry", do you mean the fictional brochure "dry" weight or the UVW from the factory "dry" weight?

by the way, what year and model trailer is it?

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