towing ride

[emillsboro]

What causes a "bucking bronco" ride which is very hard to stop? Is it a throttle issue or a suspension issue or something else? This condition seems to start with bumpy roads and often at slower speeds.

[BenK]

GREAT handling vs 'ride quality' is almost an oxymoron...

Loved Edelbrock IAS shocks on pavement, but hated them off roading. You might
like them. Busted one when a Land Rover jumped a stop sign...nailed him, and
it took out my passenger side front suspension. The shop informed me that two
others were leaking...but after ~60K miles, can't complain about that.

I paid north of $80/each back then

Summitracing.com Edelbrock IAS shocks on sale


Reason hated them off road...heck even in parking lots with speed bumps...because
they are valved for street handling...so they were 'stiff' or 'rigid' going
slowly over speed bumps

So, slow movements would have them almost lock up...that made it painful for
me off roading and on speed bumps...unless I took those speed bumps FAST...or
off roading 'FAST', but I don't drive like that off roading...slow is my speed

They did well for me on highway tar or transition strips. Hit them at speed and
the valving would open up to allow the suspension to compress...then lock up
when they extended 'past' null (Z height)

I'd get them again if I turn my Sub into a pavement only truck...again
for those who weigh 'ride quality' high...do NOT get these

[rhagfo]

BenK, I tend to agree with your thoughts on ride quality! To me towing handling and performance is far more important than empty ride! My TV is also my DD, but that little roughness is paid back in far better towing handling!
Those that max out a 150/1500 because they like that smooth ride empty, then start posting why do I have sway issues, or mushy ride fully loaded.

I wanted a TV that could pull a docent sized 5er, that is what I have, it doesn't ride like a Caddy, but I don't expect it to.

[emillsboro]

I am driving a 2005 Chevy Crew Cab, 2500HD 4wd Duramax. I haven't seen any sign of leaking shocks but had to have complete brake line and calipers replaced and complete fuel lines replaced and it wouldn't surprise me if the shocks need replacing too. I know about smart valve shocks so that might be what I will try next. Hope I get to a point where porpoising doesn't happen too often. I know enough to slow down when it happens but nearly stopping on 4 lane interstate not what I want!!

[BenK]

Adding air bags is just changing the spring rate with a second
set of springs. That changes the natural harmonic of the suspension


HD or higher PERFORMANCE level shocks with smart valving


For those who need to 'see' how harmonics works...go to a soft sprung TV, like
any 7K GVWR range with 'P' class tires

At a dealer, one out on the street (ya might get yelled at), or someone who
has one...

Push sideways on the rear bumper.

Notice how it springs back...and...then some...and oscillate a bit
side to side...to then settle down

Then do it again and again and again...matching the frequency it comes back
towards you...push when it just stops coming towards you and add to its travel
away from you

If you find and match it's harmonic...you can get it to jump over either way
off the pavement...or showroom floor...

That is its natural harmonic and the amount of force you have to exert is not
all that much...given you match its natural frequency

'Smart Valving' costs more and are there to provide 'ride quality' on normal
driving

'Smart valving' will have it sense 'the rate of change', or how fast the shock
piston moves

If it is moving FAST, it will open up to allow it to move fast...but once it
slows down...it closes that valve to reduce the movement speed (dampens it more)

That will null the proposing, but only so much it can do...you have to either
speed up or slow down to get the input bumps (tar strips, seam differences, etc)
to not be encountered in a frequency that matches your setups natural harmonic

Just know that going HD and/or Performance, will have the potential of reducing
your ride quality. If 'ride quality' is high on your have to have, then adjust
your speed as the main management metric

Ride quality is not on my have to have list and is at the bottom of my nice to
have list....most folks do NOT like how my trucks ride...but I love it that way

Have smart valving on my shocks and noodling adding a second set
(double shocks) to make it corner and handle better

Do know that I'm an old guy with a bad back too...

[enblethen]

I have had good service out of this series Monroe shocks.
Monroe
I would not use the air bags until other methods are tested.
What do you have a 2500 or 3500/ Two wheel of four?

[emillsboro]

So name a "higher rate shock" or give me some more clues about such a shock. My mechanic suggested air bag suspension system. Any thoughts about that?

[BenK]

Can happen to ANY sized TV & size/type of trailer

Has to do with the natural harmonics of the whole setup

Softer sprung has lower harmonics and higher sprung has higher harmonics (frequency)

Many components and sub-systems come into play and they ALL need to be reviewed
and addressed

As springs get compressed carrying/holding weight (no matter coil, leaf, etc)
they change in their natural harmonic in a static mode...but...during dynamic
movements through their spring rates...they get back into their soft spring rate
to then compress into their higher spring rate

What that does is to 'launch' their load when compressed to their higher spring
rate. Further into their higher spring rate area during regular road conditions
where it finds the harmonic to further compress those springs...to then be
'launched' again and again....AKA porpoising

Shocks job is to 'dampen' those oscillations....and...become an oxymoron with
'ride quality' shocks. Why 'smart' valving is the norm on higher priced shocks

Another component/sub-system that comes into play are the WD Hitch system and
their springs

When they all sync due to the road conditions (joints, tar strips, etc...at a
certain speed)...they have the whole vibrate at teh harmonics to make each
'launch' more efficient (higher tossed) to grow ever more

Slow down, or speed up to get out of the harmonics of the road conditions and/or
change to higher rate shocks and if ride quality high on your have to have list,
pay for smart valved shocks

Another is to change the spring rates, but that is tougher and more expensive

[emillsboro]

Bigger tires on 5er? Axle spacing may not allow bigger tires. Now have ST235/80/16R. Could do the water tank thing to increase pin wt. Will check truck and 5er tire pressures for sure. Might be getting new TV shocks. That can't hurt anything but the wallet.

[rhagfo]

emillsboro wrote:
5th wheel porpoising.
Kingpin load wt 1920 which is 18%
5vr wt 10700
TV rear axle wt is 5140

This doesn't change much for the cure.

Check the Fresh Water tank if it is over or forward of the 5er axles Fill it to increase pin weight.

Very Good SHOCKS for the TV Bilstein's 5100's or 4600's your choice!

Get the 5er Level, or slightly nose down. Bigger wheels/tires, flip the axles from above the springs to below the springs.

SHOCKS on the 5er,if you question, watch it in the mirror on a rough road.

Tire pressure, not the 80 psi on the side wall. 245's carry 3,042# ea. at 80 psi 6,084 total 5140/6084= 85% so about 65 to 70 psi in the rears.

[emillsboro]

5th wheel porpoising.
Kingpin load wt 1920 which is 18%
5vr wt 10700
TV rear axle wt is 5140

[campigloo]

this question is most often geared toward travel trailers. Maybe you would get better responses in the 5th wheel category.

[Old-Biscuit]

emillsboro wrote:
Saw a lot of good info to my concerns. Thanks. However, I just recently got into a new 5 wheel. Although the "porpoising" occurred with my previous travel trailer at times, it seems as though this 5 wheel is more prone to the condition. I will check my suspension components. I have a dealer installed Pull Rite auto slide hitch on 05 Chevy 2500 HD Duramax crew cab. Went on CAT scales and all weights are within range. But now pulling about 3000 more pounds then before. Many bad roads out there for sure. I-71 NB in downtown Cincinnati all ate up! Still seeking replies to 5 wheel "porpoising" condition.

5th wheel proposing:

Towing nose high
Light pin weight
Truck suspension --- springs flattened, worn shocks, type of tires, overloaded

You scaled it.....what is rear axle weight?
How much pin weight are you carrying?
Does 5vr tow level?
How much does 5vr weigh?

[CWSWine]

We had that problem with a Cougar and found the more fresh water we had the tank the worse it got. The fresh water tanks were behind the wheels and affected the pin weight. Even with the tank empty we had still had some porpoising so we installed a Mor-Ride pin which seem to help but we never did get the porpoising to zero.

[emillsboro]

Saw a lot of good info to my concerns. Thanks. However, I just recently got into a new 5 wheel. Although the "porpoising" occurred with my previous travel trailer at times, it seems as though this 5 wheel is more prone to the condition. I will check my suspension components. I have a dealer installed Pull Rite auto slide hitch on 05 Chevy 2500 HD Duramax crew cab. Went on CAT scales and all weights are within range. But now pulling about 3000 more pounds then before. Many bad roads out there for sure. I-71 NB in downtown Cincinnati all ate up! Still seeking replies to 5 wheel "porpoising" condition.