RV Tires - affect on ride

[TomKat08]

Own a 2002 Fleetwood Fiesta 31'. Ford F53 chassis. Prior owner had just replaced the tires. The tires are: TOYO M143 225/70R19.5. The tag on the driver side door says inflate to 80 PSI. The sidewall on the tire says 110 PSI. I'm driving them at 90 PSI. Wondering if the tires are part of the rough ride I'm experiencing and whether the PSI is making it worse and how low on the PSI can I go and be safe and how much softer would the ride be.. or are their better softer, smoother tires available.

Since I acquired it, I've added Bilstein Shocks, a Davis tru-trac Stabilizer, stronger control arms, and a Safe T Plus Steering Stabilizer. I'm happy with the stability and tracking but the ride is rough. (especially on these ill maintained CA. highways)

As always thanks in advance for your continued advise.

[doxiemom11]

We have Toyo tires on a 36', 20,500 ford chassis. Our 19.5 tires are load range H and are inflated to 95#. Your coach should be lighter than ours, so check out the load rating chart for Toyo, you may be running too much pressure for your weight causing the rougher ride. The truck facility that put ours on started with 105# and that was way more than we needed and it was an awful ride.

[tropical36]

johnhicks wrote:
Weigh your rig and set pressures to Toyo's chart plus a few psi _or_ set it to stated max psi of the tire or rim. There is no other answer and just randomly lowering pressure for a better ride is idiocy. Underinflated tires blow out. Remember the Ford Explorer blowouts and rollovers?

I use Toyo 8R19.5 tires and weigh 20,000lbs. By Toyo's (and others) chart I need to run 105 psi on the front and 110 psi on the rear. Oddly, stickers on the rig indicate 95 psi, which is underinflated for the stated max weight of the rig. It's not a smooth ride but it's a safe ride.

The next time you replace the tires, you might want to look into the 225/70R-19.5, as a modern alternative.
Definitely for the front and there should be enough room between the rear duals without the need for spacers.

[crasster]

I've had best results with Hankook or Michelin. They DO affect the overall ride smoothness. Toyo I have not had the best results with.

[Effy]

timmac wrote:

Effy wrote:


This is bad advice and please don't heed this "guesswork". Weigh your coach and adjust the PSI properly per the manufacturers chart. Timmac, please stop telling people to adjust their PSI to a random number. It's dangerous advice and frankly irresponsible.

I am not saying a random number OK, his Federal factory air specs says 80 PSI, I also have owned 2 Fleetwood's with the same size of tires and same length/weight and 80 psi is all you need, any more and it rides rough, and a few less pounds in front tires are OK and rides better as long as it never goes below 75 psi but buy most 19.5 tire specs you can go as low as 70 psi at a certain weight and 31 foot Fleetwood Flair is light in the front as was my Flair and my current Bounder, after 7 combined years riding on these tires with 76 psi in front I have never had a isuue..

And 80 psi should be the lowest setting in the rear, NO BAD ADVICE HERE AS YOU SAY :M

The point is you can't offer advice on the specs of your MH and expect it to be accurate to someone else's. Each person's MH and what they carry and how it's loaded and where they travel and the temps they travel in and the brand and type of tire are different. Therefore you can't offer up a specific PSI because you don't know their parameters. You only know yours. The sticker that came with the MH is a moot point because the tires have changed. The only way to get the proper PSi is for the owner of their MH to weigh it and set it. 76 in that case could very well be dangerously low if you find that it actually requires 85 - as an example. Throwing a number out there because that's what you do is a bit like telling me to turn up the thermostat in my house because your house is cold and they are close to the same size. It's not related and there are a ton of other factors at play. The correct answer to this question is always "weigh it and set it to manufacturers specs for cold psi". Period. The answer should never be "do what I do" or some number that you think will work.

[timmac]

Effy wrote:


This is bad advice and please don't heed this "guesswork". Weigh your coach and adjust the PSI properly per the manufacturers chart. Timmac, please stop telling people to adjust their PSI to a random number. It's dangerous advice and frankly irresponsible.

I am not saying a random number OK, his Federal factory air specs says 80 PSI, I also have owned 2 Fleetwood's with the same size of tires and same length/weight and 80 psi is all you need, any more and it rides rough, and a few less pounds in front tires are OK and rides better as long as it never goes below 75 psi but buy most 19.5 tire specs you can go as low as 70 psi at a certain weight and 31 foot Fleetwood Flair is light in the front as was my Flair and my current Bounder, after 7 combined years riding on these tires with 76 psi in front I have never had a isuue..

And 80 psi should be the lowest setting in the rear, NO BAD ADVICE HERE AS YOU SAY :M

[Effy]

mlslcan wrote:
Effy,

You are incorrect in your statements. You state that the tire placard is a "guideline" and that it is based on the dry weight of the RV. Federal law actually requires that number to be based on the Gross Axle Weight Rating so if the placard shows 80lbs as the recommended weight as long as the OP RV is not overloaded that is a good starting point. I am not sure where the 76 number comes from and that would be a bad assumption to think that the RV is under loaded and the tire pressure could be reduced without weighing the RV. I agree that weighing and adjusting the pressure to the amount for the actual weight is the best practice but in lieu of weighing using the pressure from the tire placard is the next best.

Mike

The assumption is based on the fact that it has the same tires as it did when it left the factory. It doesn't so the sticker is moot.

[TomKat08]

To all responders:

I'm going to have my axles weighed. I've already downloaded the TOYO inflation charts and am doing my due diligence on different tire options.

As always .. THANKS.. the members here looking out for each other is what makes the RV community stand out..

[mlslcan]

Effy,

You are incorrect in your statements. You state that the tire placard is a "guideline" and that it is based on the dry weight of the RV. Federal law actually requires that number to be based on the Gross Axle Weight Rating so if the placard shows 80lbs as the recommended weight as long as the OP RV is not overloaded that is a good starting point. I am not sure where the 76 number comes from and that would be a bad assumption to think that the RV is under loaded and the tire pressure could be reduced without weighing the RV. I agree that weighing and adjusting the pressure to the amount for the actual weight is the best practice but in lieu of weighing using the pressure from the tire placard is the next best.

Mike

[Effy]

timmac wrote:

TomKat08 wrote:
Own a 2002 Fleetwood Fiesta 31'. Ford F53 chassis. Prior owner had just replaced the tires. The tires are: TOYO M143 225/70R19.5. The tag on the driver side door says inflate to 80 PSI. The sidewall on the tire says 110 PSI. I'm driving them at 90 PSI.
As always thanks in advance for your continued advise.

Yes 90 psi will make it ride hard, at the size and weight of your RV 80 psi is all you need, you could even run 76 lbs in the front for a softer ride and tires will not run hot.

Just don't run any of those tires in the low 70's range.

This is bad advice and please don't heed this "guesswork". Weigh your coach and adjust the PSI properly per the manufacturers chart. Timmac, please stop telling people to adjust their PSI to a random number. It's dangerous advice and frankly irresponsible.

[timmac]

TomKat08 wrote:
Own a 2002 Fleetwood Fiesta 31'. Ford F53 chassis. Prior owner had just replaced the tires. The tires are: TOYO M143 225/70R19.5. The tag on the driver side door says inflate to 80 PSI. The sidewall on the tire says 110 PSI. I'm driving them at 90 PSI.
As always thanks in advance for your continued advise.

Yes 90 psi will make it ride hard, at the size and weight of your RV 80 psi is all you need, you could even run 76 lbs in the front for a softer ride and tires will not run hot.

Just don't run any of those tires in the low 70's range.

[sdianel_-acct_c]

We had Toyo tires on our '04 Country Coach Allure. They were "ok" but did ride stiff. We now have Michelins and the ride is noticeably softer. You have to weigh the cheaper Toyos against the better ride of Michelins which are much more expensive.

[Jim_Norman]

If no one else has said it...

Weigh the rig, all four corners separately. Weigh the rig in total as well.

Look up the tires you have on the rig on the manufacturer;s website. Get the EXACT tire, do not assume that yours is like the one listed above or below where you think yours should be, If they aren't listed, get the manufacturer's tech people on the phone. inflate the tire to the suggested PSI for the load you are placing on the tire. If the tire is rated for less than what you have weighed in at, you need to STOP and REPLACE your tires, DO NOT PASS GO! You are looking for a major hurt to your rig and potentially your physical well being.

[10forty2]

One other quick clarification to what Effy said... set the tires to the recommended pressure according to your coach's weight when the tires are COLD. That means after it has not moved overnight and BEFORE you drive anywhere. If the tire pressure is properly set while the tire is at ambient temperature, then it will proportionally increase for the temps that you incur once you pull out and you will not exceed the maximum pressure that the tire's engineers designed. Cold pressure doesn't mean a certain temperature, but simply means the ambient temperature and when the tire hasn't been driven on. As a general rule, you never want to increase or decrease the tire psi when the tires are hot from driving on them.

That tidbit always trips folks up.....

[johnhicks]

Weigh your rig and set pressures to Toyo's chart plus a few psi _or_ set it to stated max psi of the tire or rim. There is no other answer and just randomly lowering pressure for a better ride is idiocy. Underinflated tires blow out. Remember the Ford Explorer blowouts and rollovers?

I use Toyo 8R19.5 tires and weigh 20,000lbs. By Toyo's (and others) chart I need to run 105 psi on the front and 110 psi on the rear. Oddly, stickers on the rig indicate 95 psi, which is underinflated for the stated max weight of the rig. It's not a smooth ride but it's a safe ride.