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-   -   Why Jeeps Ride Rough !! (http://www.wranglerforum.com/f274/why-jeeps-ride-rough-311689.html)

Mystic Explorer 09-25-2013 04:40 PM

Why Jeeps Ride Rough !!
 
I wrote in a separate post my wife wants a new Wrangler Sport but the ones we drove rode so rough it hurt her neck from a previous auto accident. I spent 25 years doing high end motorhome designing so I know a bit about tire pressure.

Tires are designed to carry a given weight under a given pressure. When you over inflate you cause a pogo-stick ride. So I talked with the Goodyear tire engineering department today.

On the P225/75/16 Jeep wants you to run 35 psi this pressure will carry 1984 pounds per tire, almost half the weight of the Jeep. At 26 psi it will carry 1698 pounds per tire.

1698 X 4 = 6792 pounds almost 2500 pounds more than the jeep weighs and 1500 pounds more than the maximum weight of the Jeep with a full load.

With the 17 SR-A tire at 26 psi it will carry 2294 pounds which is a total of over 9,000 pounds...at the recommended 35 psi it is 10,200 ...over twice the weight of the Wrangler 2 door.

Tires have a minimum pressure for a variety of reasons but even at the minimum 26 psi these tires can carry much more than any Wrangler....so why?

Comments welcome !!!

Up Hill Bill 09-25-2013 04:55 PM

I think (just from experience, not specific 'learnin') that there is a lot more to tire pressure than the 'safe' load capacity at pressure. Pressure greatly affects tire shape, ground contact patch, flexibility, etc. I look for a balance between ride comfort, road contact, and wear. For the stock 255/75/17s on the Rubi, I've settled on 35 psi (the sticker recommended and TPMS setting is 37.)

It seems many, including mine, come from the factory (and thus are test-driven) way over pressure. Mine was at 45 when delivered. Talk abouut a rough ride on our bad roads!!!

gorillahydrographics 09-25-2013 04:58 PM

You can run any PSI you wish...just lower them. Its a broad brush when it comes to PSI to cover a braod range of vehicles. Its a starting point that manufactures recommend without putting themselves in line for a lawsuit.

Then you have sidewall stiffness...want stronger sidewall for off road - well your going to sacrafice some ride quality on the street.

Want 35's? Sacrafice some ride quality.

Lift the jeep... sacrafice some ride quality depending on how tall you go.

My 2013 2 door rode like a car IMO off the lot.

Added 35" and a 3.5" lift....not so much like a car anymore. But pretty good.

You could always trade the tires from a stock jeep for a car tire....but why?

detajr 09-25-2013 05:06 PM

I am new to the Wrangler world but I like this thread. I learn more ever time I log on to these forums. I thought that jeeps were notorious for having a bad ride. I had a pick up and when speaking of "the ride" I would get the response "its a truck not a car." Can the same be said for the Wrangler? I love my WU with it's good an bad. If someone told me how to make it ride better, I wouldn't NOT listen!!
I will be following this thread!!!

JTPhoto JK 09-25-2013 05:32 PM

Upgrading the Sport's shocks will greatly improve the ride. Running a C or D rated tire will also enhance the ride. Currently I run 27psi in 35x12.50x17 E rated Pitbull Rockers with upgraded shocks I am quite impressed with the ride. 25-27psi in these tires produces an even wear across tread face.

kjeeper10 09-25-2013 05:33 PM

A good set of shocks will make all the difference in the world. Even the rubi/Sahara shocks on a sport will make a huge difference.

Mystic Explorer 09-25-2013 05:40 PM

I just spoke with an engineer at Goodyear that works with Jeep - OFF the record he said he would run 25 to 27 psi on the road and down to 12 to 15 off road.

He did a test at 60 psi and then at 22 psi on for 2,000 miles each and he detected no extra tread wear or gas mileage reductions.

He did get three flats at 60 and none at 22.

kjeeper10 09-25-2013 05:53 PM

You will need a procal to lower psi for tPMS.

Optimal psi can be determined by doing the chalk test. For a factory 32 I'm thinking 30-32 ish but you will lose MPG's

I'm running my 35's at 24-25

Phaedrus 09-25-2013 06:41 PM

Quote:

Originally Posted by kjeeper10 (Post 4857105)
A good set of shocks will make all the difference in the world. Even the rubi/Sahara shocks on a sport will make a huge difference.

I think that a lot of people know that stock factory shocks are the very cheapest, off the shelf, compromise on many vehicles. I believe that is true for all of the Wrangler models. One of the least expensive and most impressive upgrades you can make will be quality aftermarket shocks. I would suggest Rancho 9000 adjustable shocks. Do that first, worry about tire pressure after. I don't want to minimize the importance of tire pressure, but with the correct shocks on board, lowering tire pressure rightly becomes an important traction consideration off road, and not a ride quality consideration. Put on premium shocks and your wife will think that the Jeep rides like a dream, and you will think that it handles great! Adjustable shocks will let you dial in the combination that suits you and your wife best. I have had three sets of shocks on my Wrangler: Factory Stock/Bilstein 5100/Rancho 9000 adjustable. The difference between them is amazing.

Plasticpirogue 09-25-2013 06:42 PM

I have settled at 30 psi for my stock GS/As (255/75/17); gives me a soft enough ride but still responsive enough for a general purpose road warrior.

Bamafever19 09-25-2013 06:44 PM

Did you expect buying a jeep was going to be like riding in a Cadillac? Ha!

5JKs 09-25-2013 06:51 PM

If you come down a ledge on a trail, or hit the brakes real hard on the street - you'll put a lot of weight and stress on two tires. Hence, some of the extra load rating on tires.

Plasticpirogue 09-25-2013 06:51 PM

Quote:

Originally Posted by Phaedrus (Post 4858857)
One of the least expensive and most impressive upgrades you can make will be quality aftermarket shocks. I would suggest Rancho 9000 adjustable shocks. Adjustable shocks will let you dial in the combination that suits you and your wife best. I have had three sets of shocks on my Wrangler: Factory Stock/Bilstein 5100/Rancho 9000 adjustable. The difference between them is amazing.

You are probably right, but your definition of "least expensive" and mine are apparently different. I don't consider $400 for a set of shocks inexpensive. I guess I am just cheap (or poor) or both. When my stock tires and shocks wear out, I will upgrade, but not to Rancho. 25 years ago I put a set of highly acclaimed RS5000s on a 4wd Toyota trk and they were JUNK. Not going that route again.

kjeeper10 09-25-2013 06:54 PM

Quote:

Originally Posted by Phaedrus (Post 4858857)
I think that a lot of people know that stock factory shocks are the very cheapest, off the shelf, compromise on many vehicles. I believe that is true for all of the Wrangler models. One of the least expensive and most impressive upgrades you can make will be quality aftermarket shocks. I would suggest Rancho 9000 adjustable shocks. Do that first, worry about tire pressure after. I don't want to minimize the importance of tire pressure, but with the correct shocks on board, lowering tire pressure rightly becomes an important traction consideration off road, and not a ride quality consideration. Put on premium shocks and your wife will think that the Jeep rides like a dream, and you will think that it handles great! Adjustable shocks will let you dial in the combination that suits you and your wife best. I have had three sets of shocks on my Wrangler: Factory Stock/Bilstein 5100/Rancho 9000 adjustable. The difference between them is amazing.

Although I agree with the upgrade the factory rubi shocks are decent. Talking to the owner of TNT off road. He said the factory Rubi's are made by Bilstein or the company that makes them. True ? Not sure but not the first time I heard this.

With that being said ...... Rancho's 9000's :thumb:

DIXIEDOG 09-25-2013 07:02 PM

Quote:

Originally Posted by Plasticpirogue (Post 4859161)
You are probably right, but your definition of "least expensive" and mine are apparently different. I don't consider $400 for a set of shocks inexpensive. I guess I am just cheap (or poor) or both. When my stock tires and shocks wear out, I will upgrade, but not to Rancho. 25 years ago I put a set of highly acclaimed RS5000s on a 4wd Toyota trk and they were JUNK. Not going that route again.


Don't hold much of a grudge do you? :lmao:

kjeeper10 09-25-2013 07:22 PM

Quote:

Originally Posted by DIXIEDOG (Post 4859545)
Don't hold much of a grudge do you? :lmao:

X2

Wow ... Junk ??

Try to find a negative review on the 9000's. A lot of folks on here run them and have 0 complaints.
I'm running their newer 7000's and can't say enough good things about them.

Things change over 25 years ... Jus sayin :)

Phaedrus 09-25-2013 07:29 PM

Quote:

Originally Posted by Plasticpirogue (Post 4859161)
You are probably right, but your definition of "least expensive" and mine are apparently different. I don't consider $400 for a set of shocks inexpensive. I guess I am just cheap (or poor) or both. When my stock tires and shocks wear out, I will upgrade, but not to Rancho. 25 years ago I put a set of highly acclaimed RS5000s on a 4wd Toyota trk and they were JUNK. Not going that route again.

Perhaps you misread my post. Are Jeep factory stock shocks worth $400? If they are, that is not what Jeep paid for them at the factory. I have more than $10K invested in modifications to my Wrangler, so premium shocks are a minor expense compared to that. By the way there is a rebate on Rancho shocks available now. I am not associated with Rancho in any way, but I replaced the factory shocks on my new GMC Suburban in 1989 with Rancho 5000's. I still own the Suburban today with 189,000 miles on the clock and the Rancho shocks are still going strong. They were a great improvement then and now. I never sell a vehicle...I just drive them until they fade away...I suspect the same will be with my Wrangler, only I may be the one to fade away first :happyyes:

legitposter 09-25-2013 09:49 PM

Quote:

Originally Posted by JTPhoto JK (Post 4857097)
Upgrading the Sport's shocks will greatly improve the ride. Running a C or D rated tire will also enhance the ride. Currently I run 27psi in 35x12.50x17 E rated Pitbull Rockers with upgraded shocks I am quite impressed with the ride. 25-27psi in these tires produces an even wear across tread face.

Thanks for chiming in. I recently switched to E tires and am dieing from the terrible ride. This is combined with bilstein HD's. Hearing you running down at 27psi gives me hope. I will try lowering PSI.

JTPhoto JK 09-25-2013 09:59 PM

Quote:

Originally Posted by legitposter (Post 4864761)
Thanks for chiming in. I recently switched to E tires and am dieing from the terrible ride. This is combined with bilstein HD's. Hearing you running down at 27psi gives me hope. I will try lowering PSI.

The Bilstien HD shocks may also be a bit too stiff for a Wrangler. I installed Rancho RS9000XL adjustable shocks so I can tune the ride as needed. Hope the lower pressure works for you.

JTPhoto JK 09-25-2013 10:17 PM

Rancho 9000 adjustable is what I put on as well. Much better then stock ride when you dial them down a bit. The Sahara shocks were good as they are also a premium shock however they have a few miles on them and they are a bit stiff with E rated tires.

MarkinOhio 09-25-2013 10:37 PM

Sorry kjeeper10 (Ken) but here is your first negative review on the Rancho 9000 XL's.

I put mine on last February. They did work fine for the first 16 months, and they really, really do give the Jeep a nice ride, on and off road.

Then my problems started. I tore the boots off after many folks said they just collect water and mud. They were absolutely correct. These shocks look terrible, after just over a year. Rancho's website says they are coated to prevent this, well, call me unimpressed.

Then, when I went wheeling in July, 3 of the 4 shocks won't adjust over 6. Not good when you are going wheeling and normally run 7 or 8 depending on where you are going.

Now, this is just unacceptable for shocks that cost $400. I have tried PB Blasting them after Rancho (Matt here on the forum) suggested it. Didn't help a bit.

Now, my recourse is to contact Rancho support, find out what to do, where I can take them, and then get an exact replacement. Guess I am going to do that, then try to sell them and get others, maybe 7000's this time. Not really happy with Rancho (the brand) right now.

Wish I had a pic of them, they really look bad. Will post one soon.

tab22092 09-25-2013 11:04 PM

They don't come with a lifetime warranty? I may be wrong but i could've swore my 7000's came with some sort of lifetime warranty....

kjeeper10 09-26-2013 04:36 AM

Quote:

Originally Posted by MarkinOhio (Post 4866001)
Sorry kjeeper10 (Ken) but here is your first negative review on the Rancho 9000 XL's. I put mine on last February. They did work fine for the first 16 months, and they really, really do give the Jeep a nice ride, on and off road. Then my problems started. I tore the boots off after many folks said they just collect water and mud. They were absolutely correct. These shocks look terrible, after just over a year. Rancho's website says they are coated to prevent this, well, call me unimpressed. Then, when I went wheeling in July, 3 of the 4 shocks won't adjust over 6. Not good when you are going wheeling and normally run 7 or 8 depending on where you are going. Now, this is just unacceptable for shocks that cost $400. I have tried PB Blasting them after Rancho (Matt here on the forum) suggested it. Didn't help a bit. Now, my recourse is to contact Rancho support, find out what to do, where I can take them, and then get an exact replacement. Guess I am going to do that, then try to sell them and get others, maybe 7000's this time. Not really happy with Rancho (the brand) right now. Wish I had a pic of them, they really look bad. Will post one soon.

Ken :thumb:
Sorry to hear. Location will affect the shock. Here in the NE the salt/sand reeks havoc my shocks. I only had one season on my 9000's and the adjusters were ok. Body was getting pitted and started to rust in those areas.
As far as the adjuster ... Iirc they are removed to run the Myride system. My guess easily replaced ?

MarkinOhio 09-26-2013 04:46 AM

Yeah, they have a lifetime warranty. Shouldn't have to mess with them after such a short time period, is what I'm saying.

I don't have the Myride, so not sure how to replace the adjusters. Matt didn't mention it.

dav5942 09-26-2013 06:46 AM

After driving my '98 XJ and our '04 TJ for ten plus years, the '13 JKUR rides better than a Cadillac! Had it up to 98 the other day and it was as solid as a rock!!! Did lower tire pressure to 32.

tab22092 09-26-2013 06:53 AM

Quote:

Originally Posted by kjeeper10 (Post 4869249)
Ken :thumb: Sorry to hear. Location will affect the shock. Here in the NE the salt/sand reeks havoc my shocks. I only had one season on my 9000's and the adjusters were ok. Body was getting pitted and started to rust in those areas. As far as the adjuster ... Iirc they are removed to run the Myride system. My guess easily replaced ?

Wonder how our 7000's are gonna do. New york likes to salt the roads till the point they turn into jerky

jj77 09-26-2013 07:21 AM

im happy with the stock ride of the sport unlimited. I have been looking into the Rancho 9000's. I had the 5000's on my dodge ram 1500 with a minor lift and nitto tera grapplers and that truck rode awesome. My only complaint is that the finish rusted almost instantly. I emailed Rancho several times and never got a response. Makes me want to look elsewhere on another brand due to customer service sucking.

MTNJeep 09-26-2013 08:56 AM

When I drove my Rubicon home from the dealer, the ride was awful. I kind of thought to myself what did I get myself into. Checked the tire pressure... the dealer had it 45 lbs. :eek:
Dropped them to 35 and went for a spin. Ahhh, like buttah

hair2831 09-26-2013 09:14 AM

I'll never understand why dealers and tire shops insist on putting so much air in these tires. It's ridiculous! When I got my 35's mounted and balanced my teeth about chattered out on the ride home. I checked my pressure, and they had me set at 37psi. WTF! I chalk tested them the next day and now drive at 26 psi. Could not be happier and my treadwear after 17k miles is even and excellent.

legitposter 09-26-2013 09:30 AM

Quote:

Originally Posted by hair2831 (Post 4873345)
I'll never understand why dealers and tire shops insist on putting so much air in these tires. It's ridiculous! When I got my 35's mounted and balanced my teeth about chattered out on the ride home. I checked my pressure, and they had me set at 37psi. WTF! I chalk tested them the next day and now drive at 26 psi. Could not be happier and my treadwear after 17k miles is even and excellent.

I don't get it either. My guess is its a legal issue. They don't want to be liable for possibly putting in the wrong psi, so they go by what's printed as the max on the side of the tire.

I almost cried after driving home with E rated tires from Discounttire that were inflated to 45psi.


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