tire sizes for rear of 1998 U320.

Topic: tire sizes for rear of 1998 U320. (Read 793 times) previous topic - next topic

tire sizes for rear of 1998 U320.

July 17, 2024, 01:23:22 am

I put 295/75R 22.5 tires on the front of my coach.
I did have to "file" some of the air bag mounts aways to have them fit properly without rubbing.
I am considering installing the same size tires on the rear.
Has anyone done this and does it make a difference with the size?
Peter

Re: tire sizes for rear of 1998 U320.

Reply #1 – July 17, 2024, 07:43:25 am

You can run 295 or 275 on your coach. Just don't mix on same axle. We run 295 on all 8, they replaced 275's that were factory.

Re: tire sizes for rear of 1998 U320.

Reply #2 – July 17, 2024, 09:09:18 am

We have 275/80-22.5 all around on our 1998 U320 36-foot.

Re: tire sizes for rear of 1998 U320.

Reply #3 – July 17, 2024, 09:27:50 am

There's a lot of talk about changing tire size on these coaches. I have a Jeep Rubicon and I definitely put much larger tires on that from what it came with from the factory and I know the pros and cons of doing that. For the life of me I can't think of a good reason to change tire size on my coach from what it was engineered for. Maybe if availability was an issue but I think the 275/80's are still pretty common.

Re: tire sizes for rear of 1998 U320.

Reply #4 – July 17, 2024, 09:35:20 am

275/80-R22.5 vs 295/75-R22.5 Tire Comparison - Tire Size Calculator | Tacoma...

Re: tire sizes for rear of 1998 U320.

Reply #5 – July 17, 2024, 10:05:13 am

Quote from: Doug W. – July 17, 2024, 09:35:20 am

275/80-R22.5 vs 295/75-R22.5 Tire Comparison - Tire Size Calculator | Tacoma...

Best answer-- they are VERY close. Verify any change you make is rated for the same max load.

One size on front, another on the rear is fine. Do NOT mix sizes on an axle.

Re: tire sizes for rear of 1998 U320.

Reply #6 – July 17, 2024, 01:28:35 pm

I would verify that 295/75's are ok on YOUR coaches exact dual rear rims.. Versus too close to each other?

Re: tire sizes for rear of 1998 U320.

Reply #7 – July 17, 2024, 06:23:38 pm

Quote from: Doug W. – July 17, 2024, 09:35:20 am

275/80-R22.5 vs 295/75-R22.5 Tire Comparison - Tire Size Calculator | Tacoma...

I get that the two sizes are essentially the same diameter but the width of the 295 is 20mm wider. Still looking for a reason why this would be an advantage. Especially when you will likely run into interference issues with the suspension/steering at maximum extensions. The 275's are specified by the manufacturer, they carry the maximum load of the axles and they fit. Just wonder what are the reasons that some opt to change size.

Re: tire sizes for rear of 1998 U320.

Reply #8 – July 17, 2024, 06:37:41 pm

I was changing sizes because of availability. The 275 tires are near impossible to get in Canada in a Michelin and I do not know why

Re: tire sizes for rear of 1998 U320.

Reply #9 – July 17, 2024, 07:25:26 pm

Quote from: Peter – July 17, 2024, 06:37:41 pm

I was changing sizes because of availability. The 275 tires are near impossible to get in Canada in a Michelin and I do not know why

This is the best reason, especially for the rear axle. Much better selection and availability and also cheaper.

Re: tire sizes for rear of 1998 U320.

Reply #10 – July 17, 2024, 07:30:00 pm

Quote from: Geodmann – July 17, 2024, 06:23:38 pm

I get that the two sizes are essentially the same diameter but the width of the 295 is 20mm wider. Still looking for a reason why this would be an advantage. Especially when you will likely run into interference issues with the suspension/steering at maximum extensions. The 275's are specified by the manufacturer, they carry the maximum load of the axles and they fit. Just wonder what are the reasons that some opt to change size.

One of the big reasons I went with 295's is it is a common size for class 8 trucks. Trying to find a 275 in small town USA on Sunday can be a challenge. Also a lot more choices in the 295 size.

Re: tire sizes for rear of 1998 U320.

Reply #11 – July 17, 2024, 09:30:32 pm

My coach came with the 295's and if it hadn't I would have change to them as they are easier to
get.

Re: tire sizes for rear of 1998 U320.

Reply #12 – July 18, 2024, 03:50:56 am

I would be very careful to verify that 295/75 series radial tires have enough distance mounted and under load to not induce heating and rock jamming issues. You may well be the tester as no one seems to have tried 295/75's

James Triana at FOT would know for sure. Tell him bob hulka sent you. He will laugh. I was the ca stores sales manager long ago and was at the unihome intro in oct 87 in NAC.

Re: tire sizes for rear of 1998 U320.

Reply #13 – July 18, 2024, 07:03:15 am

Quote from: Caflashbob – July 18, 2024, 03:50:56 am

. You may well be the tester as no one seems to have tried 295/75's

No Bob I see a lot of coaches that come through my place with 295s so he will just be another one.

Mike

Re: tire sizes for rear of 1998 U320.

Reply #14 – July 18, 2024, 09:26:52 am

Quote from: Pamela & Mike – July 18, 2024, 07:03:15 am

No Bob I see a lot of coaches that come through my place with 295s so he will just be another one.

Mike

Mike is 100% correct. A search of the forum shows years of topics where folks are running 295/75s.

ETA - Toyo seem to be the most commonly-discussed brand. TOYO Tire differences

Re: tire sizes for rear of 1998 U320.

Reply #15 – July 18, 2024, 09:46:20 am

Our U295 has 275/80R22.5's on the front and 295/75R22.5's on the rear. The 295's have been on for over 30,000 miles. I used a 3' length of 2x6 and tapped it in between the rear duals with just my hand. Definitely snug, but fit. I also have an OTR truck that has 275 Michelins on the front drive axle and 295 Firestones on the rear. Same result with the 2x6 on the Firestones and fit easily between the Michelins. The gap between the 2x6 and tire was maybe 1/4" (about 6mm) on one side and closer to an 1/8" (about 3mm) on the other. Nowhere near the 3/4"+ (20mm) that the size would suggest. Hope this clears it up for some.

Re: tire sizes for rear of 1998 U320.

Reply #16 – July 18, 2024, 10:06:05 am

Just to add some info, our coach had 295/75's when I purchased it and I have been replacing with the same. However I plan to move the 295's I bought at Quartzsite to the rear at the Q next year and put 275/80's on the front. This last trip the broken concrete lanes beat us to death and I am hoping to be able to use less pressure with the 275/80's and take some of the jarring out. I have been putting 120 psi. cold in the fronts and they reached 135 psi on hot days which is ok as far as safety but maybe too hard for comfort.

Re: tire sizes for rear of 1998 U320.

Reply #17 – July 18, 2024, 10:29:16 am

So the answer to my question of why choose 295's seems boil down to availability. No other advantage has been presented and there are several possible complications regarding interference between the tires and frame and reduced clearance between duals. I will stick with oem sizes while they remain available. I do appreciate the discussion though.

Re: tire sizes for rear of 1998 U320.

Reply #18 – July 18, 2024, 10:47:09 am

Quote from: craneman – July 18, 2024, 10:06:05 am

Just to add some info, our coach had 295/75's when I purchased it and I have been replacing with the same. However I plan to move the 295's I bought at Quartzsite to the rear at the Q next year and put 275/80's on the front. This last trip the broken concrete lanes beat us to death and I am hoping to be able to use less pressure with the 275/80's and take some of the jarring out. I have been putting 120 psi. cold in the fronts and they reached 135 psi on hot days which is ok as far as safety but maybe too hard for comfort.

I fear I am drifting off subject but it does relate. The 20mm wider tires would have a larger contact area and as I understand will require less air to support the same weight. So as the 295 are truck tires loaded to near capacity. These are all reasons I chose the 295s in the first place. My 295 just polish the airbag mounts during turns. I have no issue with this happening. Yes the do have stiffer sidewalls and I do agree the ride is firm to say the least. I have no experience with the factory size tire. Next year my new tires will be 5 years old and I will replace with the same and sell the old ones for half of the replacement cost.
The cost of a blowout justifies changing them out to me.
Running the bigger tire makes sense to me
Having tougher tires for the way we operate also seems better. I'm always worried of sidewall damage
Yes they ride rough but ignorance is bliss???
Chuck I'm looking forward to your results if you do end up changing .
Side note I had a tire high temp warning on my loaded truck last week. I have the warning set to 145 degrees. To resolve one must allow more time for tire cooling. SLOW down, increase air pressure (less tire flex) decrease load.
195 degrees is considered the point were tire life is reduced and and 225 was the death imminent temperature. Coach last week was under 125. So I'm kinda conservative on temps . Slowed down and drove home. 80 degree cold temperature pressure was at 76 psi. Was hauling steel on the side of my diesel truck. It was hot. Should of aired up before I left.

Re: tire sizes for rear of 1998 U320.

Reply #19 – July 18, 2024, 10:57:02 am

Quote from: craneman – July 18, 2024, 10:06:05 am

Just to add some info, our coach had 295/75's when I purchased it and I have been replacing with the same. However I plan to move the 295's I bought at Quartzsite to the rear at the Q next year and put 275/80's on the front. This last trip the broken concrete lanes beat us to death and I am hoping to be able to use less pressure with the 275/80's and take some of the jarring out. I have been putting 120 psi. cold in the fronts and they reached 135 psi on hot days which is ok as far as safety but maybe too hard for comfort.

Are you changing to a higher load rating or am I missing something? My LRG Toyo 295's need the same psi as the LRG Michelin 275's. I plan to replace the fronts with LRH 295's when the time comes so I can run them a little lower. Not at all trying to argue, just curious.

Re: tire sizes for rear of 1998 U320.

Reply #20 – July 18, 2024, 11:11:29 am

I am going on my brothers research for his 2005 Monaco which came with 275/80 r22.5 from the factory. He had a blowout and replaced the fronts with 295/75 r22.5 on his vacation. When he inflated the tires to match his front axle weight he said the ride got much rougher. He then sold me the new 295/75 r22.5 he put on and replaced with the original size and it took some of the roughness out. I did not research the load charts of the 2 different sizes with load range H which after Scott's comments I need to do.

Re: tire sizes for rear of 1998 U320.

Reply #21 – July 18, 2024, 11:46:20 am

The inflation tables are the same for both tire sizes in the same load range. The sidewall height is virtually the same at 1 mm. A softer ride would seem to have more to do with differences in tire construction.

Re: tire sizes for rear of 1998 U320.

Reply #22 – July 18, 2024, 06:27:52 pm

Quote from: Dave Larsen – July 18, 2024, 11:46:20 am

The inflation tables are the same for both tire sizes in the same load range. The sidewall height is virtually the same at 1 mm. A softer ride would seem to have more to do with differences in tire construction.

I absolutely agree tire construction plays a huge part of this. I'm confident Foretravel engineers gave consideration to the tires with the documentation to support. I'm also confident they were seeking a better experience in general. Running H rated tires in the rear isn't necessary but yet so do. 4000 miles on interstate 40 this month had me also thinking it could be a better ride. Con to the smaller tires is I can't sell the half live tires as easily. Looking forward to see the differences.

Re: tire sizes for rear of 1998 U320.

Reply #23 – July 18, 2024, 07:11:56 pm

Much ado about tire sizes. I'd be willing to bet if you had 2 identical coaches with the 2 tire sizes and one didn't know they couldn't tell the difference. The same goes with tire inflation 10 psi one way or the other in the ride or handling. Especially on the interstates in the NE.

Re: tire sizes for rear of 1998 U320.

Reply #24 – July 18, 2024, 09:00:22 pm

Well I am out of luck, my brother's Monaco calls for 295/80 R22.5 and the load chart on it is 7,850 lbs. @120 psi which he can lower the pressure from the 295/75 R22.5 he sold me. So ignore my thoughts on getting 275/80 R22.5's to replace my front tires.

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