Freeway hop?

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On I-5 between Olypia WA and Seattle WA yesterday I traveled on a couple stretches going north and south where my 2500 4x4 regular cab pickup was really taking a beating.

Had the same thing happen on Hwy 99 in CA last month. (with the stock tires on)

To me it seems that my wheelbase must be the exact length that if the road has a slight wave to it that matches (?) my wheelbase that my pickup really takes a beating.

The strange thing is I can look at other vehicles traveling the same section of road and they don't appear to be having any problem.

I've got a set of Rancho 9000 shocks that I haven't installed yet and hope that maybe they'll tame the ride a bit.

It's about time to rotate my tires, so I'll have the dealer recheck the balance on the tires and see if I've got some out of balance tires. Although I'd think if the tires were out of balance that I'd notice this shaking problem more often.



[This message has been edited by Irontrader (edited 07-20-2000). ]

 

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We must of crossed paths somewhere along the way. I just returned from the Sierra's outside of Fresno, CA. I-99 does have some rough spots(besides the locals). The worst stretch of road for hopping is I5 northbound just south of Olympia.


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01 Ram 2500 QC LWB ETC
Dark Garnet/Driftwood
All options except heated leather seats added Smittybilt SS Side Bars and EGR Bug Guard,ARMA Coating Bedliner
And I Love it!

 

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Rumor is that it is caused when they poured concrete sections instead of the newer continuos pours. With each section you end up at different a different height than the previous section and the center could be higher or lower than the ends depending on how it was floated out.

BTW - Our car does the same thing in certain areas but the Ram's wheel base seems to setup a porpoise or seesaw pattern/bounce.

[This message has been edited by BV (edited 07-20-2000). ]

 

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I made a similar posting at the end of May after I just got my truck and went driving on some of the cement highways in Los Angeles. I thought we were going to break-up. The rear end bounced so hard it was ridiculous.

Several recommendations were made. New shocks, velvet ride spring shakles (I think), and lowering the air pressure in the rear tires. I tried the air pressure thing and it helped to a small extent. There are still some sections of freeway that are cookie tossers. I may look into the new shocks and velvet ride set up as well. Let us know if your Ranchos do the trick!

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'01 2500 SLT+, QC, LWB, 4X4, 3. 54s, AT, SPA guages, Alpha Liner, Stolen Silencer ring, every option but running lights! To come: DD Stage II's PE or DD Boost Module, Exhaust brake, 4" turbo to tail, etc...

'98 DUCATI ST2 "Bombed" 944CC with Ducati Performance Carbon Fiber Exhaust, F. I. M. Chip, K&N and "modified" air box.

 

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Another annoying place is headed westbound over Snoqualmie Pass, the left 2 lanes. Our trucks have heavy springs, lots of unsprung weight and relatively light rearends that all conspire to create this problem.

Back a couple issues Sam Memmolo had something done to the rear springs on his "Midnite" ('97 3500 4x4 QC) that helped the ride out considerably on the highway (rearched or something). He gave a name and address, read through the article, it's in there somewhere.

On my '98 putting RS9000s on the rear helped noticeably but it still bucked a lot. The worst stretch I've driven over is between Spokane and Couer d' Alene.

 

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2nd that on Snoqualmie pass,I did it with ice on the road last winter,thought I was going to lose it a couple of times.

 

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Rancho 9000's, all 4 set on softest settings, Rancho double shock (5000's) steering stabilizer, 55-60 lbs. front, 45 lbs. rear tires (no load), that's about as good as it gets.

Same problem here in NM. Even the new continuous pour concrete section of I-40 east of ABQ is rough, but the setup above settled my truck down to a point where it's more bearable.

I think more weight would help alot to stop the rear end porpoising. Spray-on bedliner, which I don't have adds about 150 (?)lbs, camper top, bricks, whatever. Was thinking about Velvetride shackles also but decided against after reading posts on some other threads awhile back.

Like the man said, "hey, it's a truck, whaddya want?" #ad


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Tom
96 2500 Ext-Cab, 4x4, 5sp/3. 54, NRA sticker, Pep Boys Li'l Skunk airfreshener, etc.

 

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When I lived in LA I had the same problem.

New Blisteins didn't help. Neither did the firestone air bags.

What did help was about 500 lbs. of sand bags from Home Depot placed at the rear of the bed toward the tailgate.

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'98 B5. 9 5spd 4x4 Quad Cab 3500, 3. 54, Banks PowerPack, PacBrake, 60-gallon Aero fuel tank, Bilstein shocks, Firestone air bags, Reese 20K fifth-wheel hitch, Icom 2m ham radio

 

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I've got a quad cab 4x4 and the same thing happens to me on some roads. I think it has something to do with bump frequency and the resonance (?) from the frame flex. Like when some buildings/bridges make through an earth quake and others are reduced to rubble. On mine it seems like it's the whole truck, not just the rear or front. It's a real kidney buster -- can't even carry on a conversation!

 

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Irontrader. . Put those damn Ranchos on boy... hehe they will do the trick. . fronts on setting 3 rears on 2 or 1 as you like they will give you some love. . #ad
#ad
note signature

I had same thing severe. . [I travel that road 5/6 times year... also 580 by Livermore will give ya hemroids]

Gary

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OL' # 1 [now deceased] 98 24v 5sp Qcab 4x4 3500 4. 10, SLT em. grn. , alum. rims235/85/16's. .
Scotty system. . DDIII's & 4 wire box,McLeod Dual Disk,pacbrake,Isspro ga. soon 4"exhust,HX40cm2...
NRA

 

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Yea, try the 710 coming out of the port of Long Beach. Now you know why I haul a camper around. It's right at the gvw limit and still rides like a tank. Just slight overkill on the rear springs.

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2000, 13k miles,4x,qc,6sp,3. 54,285/75r16 bfg/at's, VA, popup cmpr, 9000 lbs,14. 5-16. 5 mpg, WB6BFD for ID.

 

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Irontrader, The 9000's should help. I run them on 2 of vehicles and they really smooth out the ride. Plus you acn adjust to load you are carrying or towing.

 

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I think any Californian traveling concrete freeways can verify the severity of what we call Freeway Hop.

All of the above suggestions sound like a good approach. My brother had pretty good success with velvet ride shackles.

Hop is worst when the natural frequency of the suspension matches the wave frequency in the road. It seems that most long bed trucks have a resonance near the concrete road bed at a speed of about 70 MPH.

Since I don't travel often unloaded, I try to vary my speed until the hop is down to kidney withstanding level. Since I don't like to slow down below 65, I sometimes push the upper limit of comfort as the traffic will allow.

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John S. '99 QC 1T 4. 11 A/T Leather Driftwood, 50 Gal aux tank/tool box, gearvendors, BD brake/autolok, BD ISB comp, guages.

Just a Little BOMBed and liking it a lot.

 

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Yea, the wheelbase is just perfect for the cement freeways. Sometimes it actually feels like the transmission is going to rip right out if you dont vary the speed. With a load its not bad.

 

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Hey RT66DOC,

As a point of interest, I just had a bedliner sprayed in last weekend and I asked how much weight it added... . he said probably only about 40 lbs. or so. I was kinda hoping for more to calm that ride down!

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'01 2500 SLT+, QC, LWB, 4X4, 3. 54s, AT, SPA guages, Alpha Liner, Stolen Silencer ring, every option but running lights! To come: DD Stage II's PE or DD Boost Module, Exhaust brake, 4" turbo to tail, etc...

'98 DUCATI ST2 "Bombed" 944CC with Ducati Performance Carbon Fiber Exhaust, F. I. M. Chip, K&N and "modified" air box.

 

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Got the Velvet Ride shakles and it made a difference #ad
. Now the co-pilot no longer has to use a sports bra when she rides in the big dually. The Monroe shocks are next.

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2001 Driftwood 3500 Quad Cab 4x4, Long Bed, 5. 9L HO Cummins Diesel (ETH), 6-Speed HD Manual (DEE) Loven the shift thing (Arrrrrh), 3:54, SLT+, 3. 54 Anti-Spin Axle, Camper Special Group, Trailer Tow Group, 18,000 LB 5th Wheel Hitch, Leather, Sliding Rear Window,
BDs E-Brake, Rhino Liner (gray), Velvet ride shackles, cup smoothy, Power Edge box w/elbo, SPA Gauges, Jardine Exhaust. Love the smell of diesel in the morning.

 

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You haven't traveled a rough road until you travel on I40 in Arkansas. Most of the road between Conway and Oklahoma was built in 1969-1970 and I'd swear they haven't done much to it at all.

If BC builds his prez library in Little Rock, all the people from NW Arkansas will be flocking down that rough I40 to LR to view his books and other 'significant' works etc. Of course, we do have all the 'good' magazines already available to us at the local 7-11.

I'd like to drag the governor and state highway commissioner behind my Dodge the full length of I40 to see if they enjoy it as much as the rest of us.

When LBJ was prez, Texas received all kind of benies and guv'ment projects. BC being prez hasn't helped Arkansas one bit. He must be spending all our taxpayer $$ in NY trying to get Hilarious elected. They've got to stay on the public payroll somehow.

I reduced air pressure in the tires for the last trip and it helped some. I'm going to add weight before the next trip.

Will be looking for some shocks soon. Interested in the results of the Ranchos vs. Monroe Sensatracs, Bilsteins, etc.

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"Red Rage" - 2001 2500 SLT 4x4 QC Lowered Rear End 2. 5" 5spd, 4. 10 K&N Stock Replacement - 9,000 miles and counting! 30' 5th Wheel

[This message has been edited by bennettj (edited 07-21-2000). ]

 

[Archive]

bennettj,

You got that right! I visit kin in Yell Co. once in a while. The first time I went from Fort Smith to Russellville I thought I was going to have to see a dentist to get my fillings put back in. WOW!! I take SR10 now to Ola. Slower but I'll live longer I think.

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Joe George
Eureka, CA

'95 2500 CC auto 4X4,Combo EGT/boost guage,custom switch panel,PacBrake,TST #5,BD valve body,Automatic motorhome steps on both sides,Foldacover hard bed cover,Cummins chrome kit,Black steel grill guard,Front hitch receiver

 

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Hey Scooby, that's interesting about the 40 lbs. I forget exactly where I read that about the weight of the spray-in liner. Might have been an article about Rhinoliners in 4-Wheeler. Also stop and think about the Herculiner, can't weigh more than the whole can does before you paint it on.

BTW, does your new liner make the truck quieter?



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Tom
96 2500 Ext-Cab, 4x4, 5sp/3. 54, NRA sticker, Pep Boys Li'l Skunk airfreshener, etc.

 

[Archive]

It is a resonance set up because of the relationship of the length of the wheel base and the expansion joints in the concrete. I have noticed the same on phords as well. It is always concrete, always the same sections of road. I have yet to find ashpalt that causes the same resonance of the body.