Tire Pressure 225/70/19.5 ?

skloon · August 06, 2020, 01:20 PM

I have looked all over for a sticker but cant find one I swapped the 8R tires for 225/70/19.5 and wonder what pressure I should run them at

Eyez Open · August 06, 2020, 03:41 PM

A link to generalized pressures, your tire mfg should have the actual pressure for your tires. And it is up there generally from 80/100 lbs. Rocks on wheels comes to mind.

http://www.rvtirepressure.com/assets/images/extrapages/Michelin_Rv_Load_Inflation.pdf

ClydesdaleKevin · August 07, 2020, 07:49 AM

Quote from: skloon on August 06, 2020, 01:20 PM
I have looked all over for a sticker but cant find one I swapped the 8R tires for 225/70/19.5 and wonder what pressure I should run them at

Somewhere on the tires you will find the recommended air pressure from the tire manufacturer. Every tire made in modern times has the recommended PSI somewhere on the tire. For stock 19.5 8r tires, the pressure should be between 80 and 110 psi.

Kev

Rickf1985 · August 07, 2020, 10:00 AM

What is molded into the tire is the maximum tire pressure. Do not go above that. The recommended tire pressure depends on the weight on the axle and the tire manufacturers recommendations. Unfortunately Samson does not have a recommended pressure chart for those of us running Samson tires.

skloon · August 07, 2020, 03:39 PM

I am running Conitinental HSRs

Ericb760 · August 09, 2020, 12:51 AM

Quote from: ClydesdaleKevin on August 07, 2020, 07:49 AM
Somewhere on the tires you will find the recommended air pressure from the tire manufacturer. Every tire made in modern times has the recommended PSI somewhere on the tire. For stock 19.5 8r tires, the pressure should be between 80 and 110 psi.

Kev

That's a 30 psi range. You've been out and about. What psi works best for you?

ClydesdaleKevin · August 09, 2020, 08:12 AM

Quote from: Ericb760 on August 09, 2020, 12:51 AM

That's a 30 psi range. You've been out and about. What psi works best for you?

30 psi is WAY too low for any motorhome. I always ran mine around 95-100 psi.

Kev

Elandan2 · August 09, 2020, 05:09 PM

Hey Kev, I think he meant the 30 psi range between 80 and 110 psi.

Eyez Open · August 10, 2020, 08:57 PM

Quote from: skloon on August 07, 2020, 03:39 PM
I am running Conitinental HSRs

110 psi max pressure @ 3970 max load...i just happen to have those tires. A note here however...my tires are 225 75 19.5...they carry about 400lbs more total capacity..

mytoolman · August 11, 2020, 08:35 AM

Quote from: Eyez Open on August 10, 2020, 08:57 PM

110 psi max pressure @ 3970 max load...i just happen to have those tires. A note here however...my tires are 225 75 19.5...they carry about 400lbs more total capacity..

My rig currently has 8r19.5 on 6 inch wide rims running the impossible 5 lug with 8 inch spacing budd wheel. I would love to have more tread surface to the ground and to improve the look a wider tire will add.....Please if you will...what is the difference in PROFILE of the 75 series vs the 70? Do you know if a 6 inch wheel is too skinny? Can I presume the 75 series profile will be taller and if so how much taller than 70 series. Likewise is it likely thethread to the ground will be narrower for the 75 series in comparison to the 70? You are using Continentals correct? My fast Google search did not show that Conti 75 size....I will also call them... TRANSEAGLE, Another brand listed this 225/75R19.5 size but stated they in this size and configuration was for TRAILERS ONLY NOT FOR TRUCKS maybe THEIR configuration was ONLY for use with TRAILERS and not for use on a Truck and Conti can be...the other descriptions TRANSEAGLE had sounded like they would be wonderful on an RV also...I dont know why they would disallow use on a truck...maybe they dont flex for cornering? but that would only be a concern on the front of a truck....I guess I need to call them please DISREGARD ALL OF THIS CONCERNING TRANSEAGLE FIRST OF ALL THEIR CUSTOMER SERVICE IS AWFUL> SECONDLY IM AN IDIOT I PURSUED THEM ANYWAY(about 3 hours on hold all together in the three attempts/ a frustrating online chat where the question what is the minimum with of rim this tire fits on couldnt be answered) ONLY TO FINALLY FIND OUT THAT MY GOOGLE SEARCH GAVE ME THEM AND THEIR TIRE IS NOT A 19.5 it is a 15 inch which is why it is for a trailer only....who would put a load range G tire on anything 15 inch other than a trailer? lol....Google is your friend?

https://www.prioritytire.com/transeagle-all-steel-st-radial-st-225-75r15-124-121l-g-14-ply-trailer-tire/?utm_source=google&utm_medium=cpc&adpos=&scid=scplpN1012476-99&sc_intid=N1012476-99&gclid=Cj0KCQjwg8n5BRCdARIsALxKb95VEkh3Ve3RzAkOateyL4NXrLHr1QrnI999gV7sQgdDMUjuLTpF4bAaAhcNEALw_wcB

Elandan2 · August 11, 2020, 08:57 AM

Here is a copy of the load/inflation table from Toyo. https://www.toyotires.com/media/1475/rv_inflation_tables.pdf

Rickf1985 · August 11, 2020, 10:18 AM

The profile is is a percentage of height to width. 70 series is 70-% as high as it is wide. So going from as 75 to a 70 means that both height and width change. It will be shorter and wider.

penskepartyof4 · August 11, 2020, 03:08 PM

Could I ask here? Has anyone switched from 8r19.5 to 225/70/19.5 and seen anything good about doing it?

Is there a benefit with AH11 vs AH35? Other than paying more?

I am considering something by Cooper. We have good luck with them on heavy cars.

I need to order tires. I have super old ah35 hankook 8r19.5 on now. They seem to be good brand and durable. I dont know the difference since this is my first RV.

We are planning a boondocking trip in a few weeks and need new tires. I need to order now to make sure I am a week early on the install with no issues.

Eyez Open · August 11, 2020, 03:41 PM

Ive made a error in my comments to tire size, i stated 275 tire when in fact it is actually a 270. The weights and inflation numbers are accurate. I to have been all over market looking for a wide track tire in a attempt to smooth out a p30 suspension. Some things just have to be addressed with fundamental thinking, in my case rim size is the limiting factor. One just cannot get around a 6 or 7" rim by using a only tires. The only solution i have found for tires is 22" rims and supported by larger 22" tires. Larger width rims larger width tires manufactures are well aware of this. I dont believe there is a wide track 19.5 tire made.

On a car it is one thing to place a wide track tire on a smaller rim, on a heavy...top heavy RV it would be a disatour is my opinion. Side wall flex due to small rims and wide tires creates a lot of heat and blowouts.

Eyez Open · August 11, 2020, 08:39 PM

Quote from: penskepartyof4 on August 11, 2020, 03:08 PM
Could I ask here? Has anyone switched from 8r19.5 to 225/70/19.5 and seen anything good about doing it?

Is there a benefit with AH11 vs AH35? Other than paying more?

I am considering something by Cooper. We have good luck with them on heavy cars.

I need to order tires. I have super old ah35 hankook 8r19.5 on now. They seem to be good brand and durable. I dont know the difference since this is my first RV.

We are planning a boondocking trip in a few weeks and need new tires. I need to order now to make sure I am a week early on the install with no issues.

Some issues that can come up would be the inner tire clearance on the duallys..It can happen where the inside of the tires meet each other and rub, a very bad thing. Again this goes to the width of the rims...On my HR rambler there is a inch of room when the rig is just sitting, going down the road and the tires flexing enough to rub each other is not something i have yet to experience...I do monitor this closely however.

Sasquatch · October 22, 2020, 11:19 PM

I converted my M500 chassis on 19.5 rims from 8R19.5 to the 225/70r19.5 years ago. I am on my second set of tires in that size now. The upside: More stable, less wiggle on the road. Less roll in the corners. More precise handling. The downside: Slightly less tall meaning your speedo will be off a bit and the engine will rev a bit higher at any given speed. But you will have better acceleration. I would never go back to 8R's.

Blksmk80 · March 15, 2021, 03:27 AM

I'm running 225/70R/19.5 bdw-r tires, noticed a great traveling, mileage and traction improvement.

Yes I realize the topics old.

89 chieftain 33ft 454 with 128000 kms

Oz · March 15, 2021, 06:18 AM

The topic may be old, but our RVs aren't getting any younger. Lol!
Thanks for the feedback.

penskepartyof4 · April 13, 2021, 08:19 PM

Quote from: Blksmk80 on March 15, 2021, 03:27 AM
I'm running 225/70R/19.5 bdw-r tires, noticed a great traveling, mileage and traction improvement.

Yes I realize the topics old.

89 chieftain 33ft 454 with 128000 kms

I assume the rims do not have to be changed out just replace tires from 8r19.5 to 225/70r19.5 correct?

I have to pull mine out of pole barn storage soon. Scared to see how it made it through the winter.

Sasquatch · February 01, 2023, 11:58 AM

Quote from: penskepartyof4 on April 13, 2021, 08:19 PM
Quote from: Blksmk80 on March 15, 2021, 03:27 AMI'm running 225/70R/19.5 bdw-r tires, noticed a great traveling, mileage and traction improvement.

Yes I realize the topics old.

89 chieftain 33ft 454 with 128000 kms

Wheels will work fine. I have been on that setup for 15 years now with my 1976 Executive on a Dodge M500 chassis (2nd set of tires). Like I stated in my earlier post the tires are a bit shorter which will make the engine rev a bit higher at cruise speeds. If you have an overdrive it is not an issue. Before I installed an OD transmission in mine it would run at 3100 rpm at 65 mph and cruise all day. I would never go back to 8R tires. The 225s handle so much better. They are also available anywhere, which is good because I do not carry a spare. I know I am gambling there, but after owning this coach for almost 30 years I have never needed one so I chance it.

I assume the rims do not have to be changed out just replace tires from 8r19.5 to 225/70r19.5 correct?

I have to pull mine out of pole barn storage soon. Scared to see how it made it through the winter.