# T/v Rear-Bounce, Tire Issue?



## Todd&Regan (Jul 1, 2010)

I have a 2012 F-150 with stock P-metric Goodyear tires, and experience some rear-end bounce when towing on not so smooth highways. I've checked and re-checked my w/d hitch, and have added helper springs to stiffen the rear suspension. The rear-end bounce is still there. That leaves me with the tires. I know LT tires are recommended for towing heavy trailers, but I don't want to spend $800+ for new LT tires when my truck/tires have only 5000 miles on them. Ford's recommended tire pressure is 35 PSI. I've thought about adding 9 PSI to the rear tires which will put them at the tire's max recommended pressure of 44 PSI (when towing only). Any thoughts/suggestions?


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## Dave-Gray (Jul 9, 2012)

I think you've diagnosed your problem. The P-metric tire are passenger tires and are not made for loads such as towing. To my knowledge, you're left with two choices.

1. Keep the tires and increase the PSI to the max allowed by the tire and no more than that. But there could be another problem that may be a bigger issue and that is overloading. Have you weighed your rig? Do you know how much weight you have on the rear axle? Even at max PSI, you could be overloading the tires and that is not good at all. To lean more about weighing your rig, visit Fifth Wheel St.

2. The best thing to do is bite the bullet and purchase that correct size LT tire to meet your towing requirement. You'll know that when you weigh and complete the Weight Safety Report at Fifth Wheel St.

Here is another possible problem: I'm not certain, but your trailer may be too heavy for your truck, depending on what the axle ratio and wheelbase is. (i.e. Exceeding the tow rating and overloading the rear axle.) Visit the website mentioned to learn more.

I wish I had better information for you. I'm sure others will provide some personal experience for you.


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## CamperAndy (Aug 26, 2004)

Added air pressure can help but I think you may want to just break down and buy the LT tires.

Porpoising is an issue that can be caused by many things and tires are just one of them.

Having said you checked and rechecked the weight distribution hitch is good but what were some of the criteria you used when setting it? Was the truck and trailer loaded for camping when you set it or was the truck empty? Try adding 500-600 pounds to the bed of the truck and recheck the the WDH and reset if needed to get the correct rear end lift. See if that changes the porpoising. If it does then you most likely need heavier weight bars.

Did you have any water in the tanks? Half full tanks can slosh and contribute to the issue.

One issue that you can do nothing about is the natural harmonic of the truck and trailer combination on some segmented roads. The spacing of the joints when they are close to the wheel base of the truck and the trailer can just set things in motion and you can not do anything about it.


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## Bob in Virginia (Jul 15, 2010)

I think you may have a couple of things working against you. You may be close to your max weight for a 1/2 ton PU. I looked on Trailer Life for the tow capacity for the 2010 F150 and there are lots of variances to the capacity of the various F-150s, anywhere from 5300 - 11,000 lbs towing capacity. The 270BH dry weight is 5944 with a cargo weight of 1856 giving you a gross of 7800. Those 1856 get eaten up pretty quickly with propane, bedding, clothes, food, and any water in the tanks. Adding a couple of pounds of air isn't going to make the P tire sidewalls stiffer like my 10 ply LT tires with 75-80 psi when I tow.

As Dave and Andy said, the best (safest) thing to do would be to upgrade to the LT tires.


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## willingtonpaul (Apr 16, 2010)

consider shocks also. i know your OEM shocks are new (do you have an FX4 package with the ugraded "rancho" shocks ? they are not full ranchos) but they are not great shocks.

i went to rancho 9000XL's all around and adjust them up to 9 when towing and down to 5 in the back and 3 up front when empty. makes a world of difference loaded and unloaded. not sure if rancho makes a shock for your 150 that is adjustable, but check. look at summit racing, they have excellent prices and service, i have purchased from them many times. bilstiens are also great shocks, i know others here and elsewhere have them for their 1/2 ton trucks.

so do tires and shocks.....


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## Todd&Regan (Jul 1, 2010)

willingtonpaul said:


> consider shocks also. i know your OEM shocks are new (do you have an FX4 package with the ugraded "rancho" shocks ? they are not full ranchos) but they are not great shocks.
> 
> i went to rancho 9000XL's all around and adjust them up to 9 when towing and down to 5 in the back and 3 up front when empty. makes a world of difference loaded and unloaded. not sure if rancho makes a shock for your 150 that is adjustable, but check. look at summit racing, they have excellent prices and service, i have purchased from them many times. bilstiens are also great shocks, i know others here and elsewhere have them for their 1/2 ton trucks.
> 
> so do tires and shocks.....


I've thought about shocks too, I've had Bilsteins on a couple of my past F-150's. My truck is an XLT with the "Off Road" package. When I had my extended cab 2009 F-150, I did not have this porpoising issue. On that truck suspension was stock, but I did have LT tires. I agree with everyone that going with LT tires will pretty much resolve this issue. Just didn't want to spend the $$ to replace tires with lots of life left, but the bounce is very annoying and I don't want to shake my Outback to pieces on those bumpy roads. Thanks to all for your input.


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## Leedek (Nov 28, 2010)

double d said:


> I've thought about shocks too, I've had Bilsteins on a couple of my past F-150's. My truck is an XLT with the "Off Road" package. When I had my extended cab 2009 F-150, I did not have this porpoising issue. On that truck suspension was stock, but I did have LT tires. I agree with everyone that going with LT tires will pretty much resolve this issue. Just didn't want to spend the $ to replace tires with lots of life left, but the bounce is very annoying and I don't want to shake my Outback to pieces on those bumpy roads. Thanks to all for your input.


Just a quick suggestion. If advertised correctly, explaining your need to upgrade your tires, it's possible you could re-coup some of your LT tire cost buy selling your "old used" tires on Craigslist.







There are a lot of people out there looking to save money and tires with 5000 miles on them could go quickly.

I will add that my truck performs better in the suspension department after I added a Firestone Air-Rite Spring System. It stiffened the back end and is somewhat adjustable when weight changes due to trip loading. Firestone Suspension Products


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## W5CI (Apr 21, 2009)

I installed the NAPA High Performance shocks on my chev and it solved the problem.


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